JOM Archives – Volume 19, Number 4, 2004
There is an ongoing controversy over the use of vitamin C in conjunction with chemotherapy. This writer has reviewed 44 scientific and other articles on the effectiveness of vitamin C alone, or with other vitamins, with chemotherapy. The purpose of this bibliography is to summarize these findings–international in scope–in chronological order. This paper presents 24 positive studies, 12 positive reviews, one neutral study, one negative study, two negative reviews and four responses to the latter. It then discusses these findings. It is necessary to point out that, although the first two studies reviewed involve terminal cancer patients not undergoing chemotherapy, they appear here because they were the first, or among the first, major clinical trials conducted with high-dose vitamin C.
Positive Studies (Table 1)
Study 1. 1976
Cameron E, Pauling, L: Supplemental Ascorbate in the Supportive Treatment of Cancer: Prolongation of Survival Times in Terminal Human Cancer. Proceedings of the National Academy of Sciences, USA, Oct 1976; 73/10: 3685-3689.
Cameron and Pauling wrote: “There is increasing awareness that the progress of human cancer is determined to some extent by the natural resistance of the patient in his disease. Consequently there is growing recognition that improvement in the management of these patients could come from the development of practical supportive measures specifically designed to enhance host resistance to malignant invasive growth.” Since the authors believed “the free availability of ascorbic acid” to be an “important factor in host resistance”, they conducted a clinical trial at the Vale of Leven District General Hospital in Scotland to test this theory. In the study, 100 terminal cancer patients, many of whom had been treated with chemotherapy, were given supplemental ascorbate as part of their routine management.
It was found that their survival times were much greater than a controlled group of 1,000 similar patients who had not received the supplemental ascorbate. The method of treatment was through daily high-dose (about 10g) intravenous administration for about 10 days and then continued orally. This treatment was applied after it had been considered by independent clinicians that continued conventional treatment “would offer no further benefit” to the patients involved. There was no indication in the study that supplemental ascorbate did any harm to patients. On the contrary, life was both prolonged and enhanced by the administration of ascorbate which would have a positive effect on “the natural mechanisms of resistance.” The treated group lived an average of more than 210 days compared with 50 days for the control group. Cameron and Pauling concluded “ that there is strong evidence that treatment of patients in Scotland with terminal (untreatable) cancer with about 10 g of ascorbate (ascorbic acid, vitamin C) per day increases the survival time by the factor of about 3 for most of them and by at least 20 for a few (about 10%).”
Study 2. 1978
Cameron E, Pauling L: Supplemental Ascorbate in the Supportive Treatment of Cancer: Reevaluation of Prolongation of Survival Times in Terminal Human Cancer. Proceedings of the National Academy of Sciences, USA, Sept 1978; 75/9: 4538-4542.
In this study, Cameron and Pauling confirmed the results of their previous clinical trial (1976) after “several experienced investigators in [the] field” had raised questions about the selection of the control and treatment groups. Using a new control group, not only were the previous results reconfirmed, but this study showed that “the increase in life expectancy of ascorbate-treated patients … [was] found to be somewhat larger.” Indeed, eight of the terminal cancer patients who were treated in 1976 were still living at the time of this study. Cameron and Pauling concluded “again that there is strong evidence that treatment 1⁄4 with about 10g of ascorbate per day increases [the patients’] survival significantly (by an average of about 300+ days).” Likewise, the quality of life was enhanced, and there was no indication of any harm done to the patients.
Study 3. 1982
Murata A, Morishige F, Yamaguchi H: Prolongation of Survival Times of Terminal Cancer Patients by Administration of Large Doses of Ascorbate. International Journal for Vitamin and Nutrition Research Supplement, 1982, Vol. 23, pp. 101-113.
This study by Murata et al. supports the conclusions of Cameron and Pauling (1976 and 1978) that high-dose ascorbic acid increases the life expectancy of terminal cancer patients and to a certain extent enhances their quality of life. The clinical trial at the first (large) hospital was conducted between January 1973 and December 1977. It was involved of 99 patients–48 male and 51 female in two groups (high-dose and low-dose ascorbate) and without a control group. The high-dose group contained 55 patients who were provided with “5 g per day or more” and the low-dose group involved 44 patients who were given “4 g per day or less” of ascorbate. Other criteria were age–the average age being 60.5 years–and different types of cancer classed as nine primary and other, with stomach, lung and bronchus and uterus being the main tumors. With regard to average survival time, the results “to April 1, 1980, for those still alive” were as follows: “None of the low-ascorbate patients survived more than 174 days, whereas 18 (33%) of the high-ascorbate patients” had an average of 620 days. “Three (6%) of the high-ascorbate patients were still alive: …with cancer of the uterus… breast and thymus …. These 3 patients were clinically well, but with no significant progression or regression in tumor; that is, the patients survived in symbiotic existence with their tumors.” These results were compared with an earlier period (1967-1972) when the patients either received no ascorbate or the administration of ascorbate was low, and the average survival time was also low. For high-ascorbate patients who received between 5 and 29 g per day, the average survival time was 246 days–“5.6 times as long as the patients [who received] small doses of ascorbate.” This group’s average survival time was 43 days. “Three of the high-ascorbate patients were still alive, their average survival time being 1550 days on April 1, 1980. Murata et al. concluded: “Ascorbate is especially effective for cancer of the uterus, whereas it gives smaller increase in survival times for cancer of the stomach and lung than for other kinds of cancer.” The authors added: “In many cancer patients, the administration of ascorbate seemed to improve the state of well-being, as measured by improved appetite, increased mental alertness, decreased requirement for pain-controlling drugs, and other clinical criteria.” A second smaller clinical trial was conducted between January 1975 and December 1979. It was comprised of 31 patients, with an average age of 66.8 years. The commonest cancer was that of the stomach. Fifteen male and 16 female were divided into two groups (high-dose and low-dose). There was also a control group. Both of the treated groups had six participants, while the controls numbered 19. The high-dose group was administered “5 to 30 g per day” of ascorbate and the low dose group was given “0.5 to 3 g per day.” Other criteria were the same as those at the trial at the large hospital.
Again Murata and coworkers noted ascorbate improved survival times. “None of the control patients survived more than 98 days, whereas 3 (50%) of the high ascorbate patients (receiving 5 g per day or more) survived longer than 98 days, their average being 158 days. One of the high-ascorbate patients was still alive, with a survival of 215 days.” The tumor (bladder) in this patient had decreased. Average survival time for the controls was 48 days, while for the high-ascorbate patients it was 115 days – “2.4 times that of the controls.” No comparison was made of the average survival time for high-ascorbate and low-ascorbate patients and for low-ascorbate patients and controls, since the authors believed that “the value obtained would have little statistical significance because of [the] small numbers of the subjects.” In reference to ascorbate and pain control, the authors noted that pain control drugs were given mainly to the control and low-ascorbate groups as opposed to the high-ascorbate group.
Murata et al. concluded: “The results of the clinical trials conducted at the [two hospitals showed] that large doses of ascorbate [offered] some degree of benefit to advanced cancer patients, even though there were some defects in the methods.” The authors ended by explaining the reasons for their not conducting “a double-blind trial”. They mentioned the impossibility of finding “matched pairs for comparison within” their small practice and cited “the effectiveness” of Cameron and Pauling’s studies (1976 and 1978). “Moreover,” they stated that as their “clinical experience increased, [they] felt it to be ethically wrong to withhold ascorbate in otherwise hopeless situations, merely for the sake of obtaining observations of dubious significance for statistical comparison.” Beyond this, “no harmful long-term side effect was observed among the patients who received large doses of ascorbate.”
Study 4. 1987
Taper HS, De Gerlache J, Lans M, Roberfroid M: Non-Toxic Potentiation of Cancer Chemotherapy by Combined C and K3 Vitamin Pre-Treatment. International Journal of Cancer, 1987; 40: 575-579.
Taper et al. investigated: “The influence on the survival of ascitic liver tumor (TLT)- bearing mice of combined vitamin C and K3 administered before or after a single i.p. dose of 6 different cytotoxic drugs, all commonly used in human cancer therapy.”
The results of the study showed that (1) the vitamin treatment “produced a distinct chemotherapy-potentiating effect for all drugs examined, especially when injected before chemotherapy”, and (2) the “treatment did not increase the general and organ toxicity that accompanies cancer chemotherapy.”
“The main object of the potentiation of cancer therapy [as stated by Taper et al. was] to increase the cell-destructive action of cytotoxic drugs or radiation, if possible in a most selective, irreversible and non- toxic way. Such a potentiation might considerably increase the survival of cancer patients.”
The authors continued: “Based on our previous observations, we hypothesized that DNase-reactivating compounds could act as potentiators of cancer therapy…. Among the different compounds examined, vitamin C (ascorbic acid or sodium ascorbate) exclusively activates acid DNase in a transplantable hepatoma whereas K3 (menadione sodium bisulfite) selectively and distinctly influences alkaline DNase.”
This acid-alkaline observation was seen in an earlier study by Taper; still earlier, other investigators had made the same observation.
The test was conducted with 10 or 12 ascitic transplantable mouse liver tumor (TLT)-bearing mice, six cytotoxic drugs of varying dosage, vitamin C (1g/kg), vitamin K3 (10 mg/kg) and controls, The vitamins were administered i.p. before and after the chemotherapy. “Since the optimum time of therapeutic efficiency was not known, both vitamins were administered twice, 24 and 3 h[ours] before or after a single dose of chemotherapy.” The observations re: mortality etc. were made on mice “considered as long-term survivors (LTS)–these were: “The mice which [had] survived 45 to 59 days after tumor transplantation and exhibited no external signs of tumor [and] were killed and autopsied.”
The results were as follows: For CK3 alone, the increase in life span was (% ILS 45.79) as compared to the controls.
For CK3 and three drugs (cyclophosphamide, procarbazine hydrochloride and asparaginase), the administration of the vitamins before the chemotherapy in- creased “the therapeutic effect of [the] drugs alone, thus indicating a synergistic effect.” It was further noted that both mean survival time (MST) and ILS were in- creased, with LTS only increasing for the first two mentioned drugs. Also, when CK3 was administered after the first drug, the “treatment appeared less efficient”.
For CK3 and two drugs (vinblastine and adriamycin), the administration of the vitamins before the chemotherapy produced a higher effect than after the chemotherapy which was “consistently lower.” In the case of the first drug, when the vitamins were administered after the chemotherapy, there was “no significant effect in any parameter, except a slight increase in LTS (+16%).” In the case of the second drug, when the vitamins were ad- ministered after the chemotherapy, three of the parameters were “significantly increased”. The increases were: “MST (30.3), ILS (+70.2%) and LTS (40%).” On the other hand, when the vitamins were administered before both of the drugs, the “treatment was highly potentiating, since the ILS [for the first drug was] +87% [and for the second drug] +88.8% …, and 50% of mice were LTS after both drugs.”
For CK3 and 5-Fluorouracil, the administration of the vitamins was most effective both before and after the chemotherapy. When the drug was used alone, it “had an insignificant effect (slight increase of all parameters)”. When CK3 was administered after the drug, the effect was “considerably increased.” The parameters were: “ILS +73.1% [and] LTS + 20%”. CK3 treatment before the drug “produced the greatest potentiating effect” which was plus or minus 143% ILS [and] plus or minus 60% LTS.”
Another experiment was conducted to confirm the result that CK3 administered be- fore the chemotherapy produced a better effect. Taper et al. wrote: “It appeared important to evaluate whether combined administration of both vitamins was required to produce the potentiation of tumor chemotherapy” as described.
The authors continued: “In order to investigate the effect of CK3 on the toxicity of the antineoplastic drugs, 2 more experiments were performed with cyclophosphamide.” These experiments showed that “administration of CK3 before a single dose of 80 mg/kg of the drug did not increase loss of total body weight as compared to treatment with the cytotoxic drug alone. Other experiments, using higher doses of cyclophosphamide alone or together with CK3, gave similar results.”
To conclude, Taper et al. stated: “Several hypothetical mechanisms may be involved in the action of vitamin C”, among them the generation of H2O2 as reported by other investigators. Vitamin K3 may also generate H2O2 as reported by an investigator.
The authors continued: “The possible generation of peroxides followed by membrane lipid alteration, DNase activation and DNA destruction by combined vitamin C and K3 in catalase-deficient cancer cells might be involved in the mechanisms of this selective potentiation.”
Finally, Taper et al. stated again: “The potentiating action of CK3 does not increase the general toxicity of cancer chemotherapy” and they saw no need for objection in the use of vitamin C and vitamin K3 with chemo- therapy, although further research was needed.
Study 5. 1990
Hoffer A, Pauling L: Hardin Jones Biostatistical Analysis of Mortality Data for Cohorts of Cancer Patients with a Large Fraction Surviving at the Termination of the Study and a Comparison of Survival Times of Cancer Patients Receiving Large Regular Oral Doses of Vitamin C and Other Nutrients with Similar Patients not Receiving Those Doses. Journal of Orthomolecular Medicine, 1990; 5(3) 143-154.
Hoffer and Pauling used “the biostatistical analysis of mortality data for cohorts of cancer patients based on the Hardin Jones principle” as developed by Dr. Pauling in their clinical test of 134 patients. These patients were from Dr. Hoffer’s practice and most of them had received chemotherapy.
The 134 patients were divided into three groups. Two of the groups were ad- ministered 3 to 40 g but “mostly” 12 g daily of vitamin C and other nutrients. The third group did not follow the regimen. The average age of the patients was 53.1. The authors stated: “An important reason for carrying out such a test is the determination of the mean survival times of the homogeneous subcohorts that compose the cohort being tested.”
Hoffer and Pauling concluded from the results that “80% of the patients who followed the regimen [had] a probable survival time 21 times that of the controls … or 13 times that of the controls …, or, for all 81 patients, 16 times that of the 31 controls.” (Originally there were 33; Moss (1999) said that one died and one was very ill.)
In response to questions raised about “the validity of the results presented in [the] paper”, Hoffer and Pauling stated that although “the Hardin Jones principle has been discussed briefly in several books and papers during the last thirty years” only two writers addressed “any significant discussion of its general validity for homogeneous cohorts of cancer patients.” Moreover, other methods suggested for use have been said by the authors to be “less powerful than the method that [they had] used”. They believed that this method is an acceptable one as evidenced by the number of studies using it because of its “accuracy and reliability”.
In addition, the authors noted that the results obtained in this study compare favourably with those associated with the use of high-dose ascorbic acid for terminal cancer patients by Cameron and Pauling (1976 and 1978). Once again there was no indication of harm caused by the administration of ascorbic acid.
Hoffer and Pauling concluded that their trial “will have value in calling to the attention of both physicians and patients the possibility that this regimen, as an adjunct to appropriate conventional therapy, may have great value.”
Study 6. 1991
Meadows GG, Pierson HF, Abdallah R: Ascorbate in the Treatment of Experimental Transplanted Melanoma. American Journal of Clinical Nutrition, 1991; 54: 1284S-1291S.
In this study Meadows et al. showed: “Sodium ascorbate supplementation in drinking water inhibited subcutaneous tumor growth, enhanced levodopa methyl- ester (LDME) chemotherapy, and increased survival of B16 melanoma-bearing mice.”
This study compared basal and restricted diets either with sodium ascorbate or LDME alone, or in combination. These groups were matched to a control group. In mice on the basal diet:
(1) “Ascorbate had variable effects on tumor volume. Some tumors were sensitive whereas some were resistant to inhibition by ascorbate.”
(2) “LDME treatment inhibited tumor growth during the treatment period and for 8 days after treatment was stopped. The tumor then began to grow, but the mean tumor volume never reached the level of the untreated group.”
(3) “The greatest suppression of tumor growth was observed in the LDME plus ascorbate group, where ascorbate supplementation enhanced the growth-inhibitory effect of LDME.”
Results were better for mice on the restricted diet. To quote the authors directly: “The most pronounced growth-inhibitory activity on B16 melanoma was obtained in mice fed the restricted diet. This diet alone greatly inhibited tumor growth. Ascorbate alone and in combination with LDME was more effective than LDME alone at retarding tumor growth, even though the differences were slight.” In addition the authors noted that:
“Tumors generally were more invasive in untreated mice fed the basal diet than in mice fed the restricted diet.” Beyond this: “The primary tumor masses from both dietary groups receiving ascorbate were smaller, more well defined and less invasive. Secondary tumor masses were encapsulated and the size of the tumors in mice fed the restricted diet was smaller.”
Meadows and coworkers concluded:
“The combination of LDME and ascorbate reduced the size and distribution of secondary tumors with the greatest effect observed in mice fed the restricted diet.”
In reference to survival time, the results for the basal diet group showed that survival time was similar with LDME, ascorbate and LDME plus ascorbate treatments. This increase in survival was “significantly different” from the controls. In contrast, the results for the restricted diet group showed that survival time was similar and greater with LDME and ascorbate treatment alone, but greatest for LDME and ascorbate treatment. These increases in survival time were also “significantly different” from the controls.
With regard to the mechanism that was involved in the activity of ascorbate, the authors stated: “Although the mechanism underlying this enhancement is un- known, it may be related in part to the almost threefold greater accumulation of ascorbate in tumors from mice fed the restricted diet compared with mice fed the basal diet.”
Meadows and colleagues pointed out: “An important effect of ascorbate in all studies was the potentiation of the growth-inhibitory effects of LDME chemotherapy in mice fed either basal or restricted diets and bearing primary or experimental metastatic tumors. This modulating role is not without precedent and may be the most important role for ascorbate in treatment of metastatic disease.”
The authors cautioned however: “Ascorbate should not be used indiscriminately as an adjunct to chemotherapy because it may abrogate the effect of some drugs” as reported by other investigators.
Meadows and coworkers concluded: “In summary, ascorbate alone has some inherent antitumor activity against primary B16 melanoma in vivo; however, it exhibited anti-metastatic activity only in the presence of tryosine and phenylalanine restriction and/or LDME treatment. This adjuvant activity may also be important to the therapy of other cancers, and more studies are needed to evaluate this role for ascorbate.”
Study 7. 1991
Skimpo K, Nagatsu T, Yamada K, Sato T, Niimi H, Shamoto M, Takeuchi T, Umezawa H, Fujita K: Ascorbic Acid and Adriamycin Toxicity, American Journal of Clinical Nutrition, 1991; 54: 1298S-1301S.
Skimpo et al. wrote: “Adriamycin (ADR) is effective against a wide range of human neoplasms. However, its clinical use is compromised by serious cardiac toxicity, possibly through induction of peroxidation in cardiac lipids.”
In their study, the authors tested the effectiveness of ascorbic acid and two derivatives “in reducing ADR toxicity in mice and guinea pigs.” At the same time, they observed the survival time of the animals citing an interest in the clinical trial of Cameron and Pauling (1976 and 1978). The results of the tests showed that the ascorbic acid and its derivatives can play a role in increased survival and in preventing cardiac toxicity in mice with leukemia and carcinoma. The tests were as follows:
(1) Five leukemia-bearing mice were administered ADR 5 mg/kg and ascorbate 2 g/kg for  days i.p. The test showed that the treatment “prolonged the life of [the] mice”, and toxicity of ADR was reduced.
(2) Five carcinoma-bearing mice were tested in three parts: (1) ADR 0.5 mg/kg and ascorbate 2 g/kg for 12 days i.p., (2) ADR as above and the derivative (CV-3611) 50 mg/kg for the same time, and (3) the other derivative (ascorbyl palmitate) with the same dose and time as above. The tests showed that the treatment with both the derivatives also “prolonged the life of … [the] mice”. The toxicity of ADR was also reduced. In addition, only “ascorbyl palmitate had a tendency to potentiate the anti-tumor effect of ADR.”
(3) Ten leukemia-bearing mice were administered two sets of ADR – “1 mg/kg” and 5 mg/kg and the same dose of ascorbate as above through the same method. The test showed an increase in survival – the effect was most marked at the higher dose of ADR (5 mg/kg), and toxicity of ADR was reduced
(4) Eleven carcinoma-bearing mice were tested in two parts: (1) ADR 15 mg/ kg and CV-3611 430 mg/kg and (2) ADR as above and ascorbyl palmitate 1240 mg/kg. These doses were administered subcutaneously for seven days with the derivatives given before ADR and for 14 days after. For CV-3611, the survival time increased “significantly” while for ascorbyl palmitate, survival time increased “only slightly”. Reduction in toxicity of ADR was observed for both.
(5) Another test was conducted on ten “normal guinea pigs, which, like humans, cannot synthesize ascorbic acid”. In this test with ADR 0.5 mg/kg and ascorbate 143 mg/kg, survival time increased “significantly”, and there was also a reduction in toxicity of ADR.
(6) With reference to lipid peroxide levels in mouse heart ADR toxicity, ascorbate or ascorbyl palmitate was used. “Ascorbate (2 g/kg) or ascorbyl palmitate (50 mg/kg) was administered intraperitoneally for 5 days before a single subcutaneous ADR (15 mg/kg) administration, and ascorbate or ascorbyl was continued for 5 days.” The test showed that ADR plus ascorbate “decreased the elevated lipid peroxide levels by ADR, significantly in the heart.” ADR plus ascorbyl palmitate showed “similar results”.
(7) The effects of ascorbate in cardiomyopathy in guinea pigs were measured by electron microscopy. This permitted the authors to learn that: “The earliest alterations of dilation of sarcoplasmic recticulum and tranverse tubular system and the appearance of a large number of cytoplasmic fat droplets, which were seen in cardiac tissue from guinea pigs receiving ADR, were apparently reduced in animals that were treated with ascorbate.”
Skimpo and colleagues concluded: “Our results suggest that ascorbate and the derivatives may delay general toxicity of ADR and also prevent cardiac toxicity, possibly due to its activity as an antioxidant. Moreover, the ascorbate derivatives alone are likely to prolong the life of tumor-bearing animals.”
Study 8. 1993
Hoffer A, Pauling L: Hardin Jones Biostatistical Analysis of Mortality Data for a Second Set of Cohorts of Cancer Patients with a Large Fraction Surviving at the Termination of the Study and a Comparison of Survival Times of Cancer Patients Receiving Large Regular Oral Doses of Vitamin C and Other Nutrients with Similar Patients not Receiving These Doses. Journal of Orthomolecular Medicine, 1993, Vol. 8, No. 3, pp. 157-167.
The purpose of this study was two-fold. Firstly, it was an extension of the study by Hoffer and Pauling (1990) but with a large number of cancer patients. Secondly, it was designed to allow comparisons with the studies of Cameron and Pauling (1976 and 1978) on the produced effectiveness of vitamin C alone or in combination with other nutrients in the treatment of cancer.
This latter study involving 170 cancer patients produced similar results to the first study with 134 cancer patients. The participation rate in this second project was higher with 155 patients following the regimen and 15 choosing not to do so. The results showed that for the controlled group of 15, the mean survival time was 135 days – the same for the 1990 study. The treated-group of 155 in the designated sub-group, that of four specific types of cancers and other cancers, were analysed as being excellent and good responders.
The mean survival time of about 50% of the first sub-group was “greater than 5 years”, and for the other 50% it was 630 days. The mean survival time for about 33% of the second sub-group was also “greater than 5 years” while for the remaining 67% it was 540 days.
According to the authors: “The main difference between the results of the Hoffer studies and the Cameron studies is that the fraction of excellent responders is about 4 times as great for the Hoffer regimen (50%…, 33%…) as for the Cameron regimen (10%). The good responders (about 60% for Hoffer, 90% for Cameron) seem to be benefitted by about the same amount (mean survival time 4 or 5 times the values for the controls).” They continued: “These differences suggest that an additional 30% of patients with advanced cancer may be “cured”, (with survival times of five years, or more, after reaching an advanced stage of the disease) by following the more ex- tensive orthomolecular regimen prescribed by Hoffer rather than only the vitamin C regimen prescribed by Cameron.”
Hoffer and Pauling concluded that both “regimens have some value, often great value, for all cancer patients as an adjunct to appropriate conventional therapy.” They recommended “that all cancer patients begin the orthomolecular regimen as early in the course of the disease as possible. The Hoffer regimen (varying somewhat from patient to patient), in addition to including fruits and vegetables in the diet, includes” the vitamins and minerals described in the 1990 study.
Study 9. 1993
De Loecker W, Janssens J, Bonte J, Taper HS: Effects of Sodium Ascorbate (Vitamin C) and 2-Methyl-1,4-naphthoquinone (Vitamin K3) Treatment on Human Tumor Cell Growth in Vitro. Synergism with Combined Chemotherapy Action. Anticancer Research, 1993; 13: 103-106.
De Loecker et al. reported that when vitamins C and K3 were combined with certain chemotherapeutic agents, “in well defined conditions” and dosage, the application resulted “in a synergistic effect on growth inhibition.” It was further noted that when the vitamins reached “their own synergistic cytotoxicity levels [they] frequently [obscured] the additional synergistic levels attributable to the chemotherapeutic agents.” However, it is believed that “less defined secondary mechanisms” than free radicals both of the vitamins and the chemotherapy may be “responsible for the observed stimulated cytotoxicity.”
The authors cited previous work on the increased effectiveness of combined vitamins and chemotherapy application on hepatoma-bearing mice. In their own study the authors examined the “effects of a combined application of both vitamins together with chemotherapy on a human endometrium adenocarcinoma cell line.”
This study consisted of a treated series and a controlled series both of which met certain criteria but with the application process differing. For example, when the test material reached what was termed “50% confluence stage” for the treated series, “the cells were exposed for 3 hours” to certain chemo-therapeutic agents and then to a combination of the two vitamins. For the controlled series, after a certain confluence stage was reached, these cells “were only treated for 4 hours” with the chemo-therapeutic agents “and for 1 hr.” with the vitamins but not with a combination of the vitamins and chemotherapy.
The results showed that the effectiveness of the chemotherapy together with the vitamins was considerably greater than that of the chemotherapy alone.
De Loecker et al. concluded: “Although the specific characteristics of the different cytostatic drugs used have not been further explored or analyzed, it appears that to visualise any synergistic effects between chemotherapy and combined Vit C and K3 treatment in vitro, the therapeutic dose levels have to be adequately proportioned and adjusted in function of actual cell density to avoid either an insufficient effect or an undesired predominance of one kind of treatment pattern.”
Study 10. 1993
Sarna S, Bhola RK: Chemo-Immuno-therapeutical Studies on Dalton’s Lymphoma in Mice Using Cisplatin and Ascorbic Acid: Synergistic Antitumor Effect in Vivo and in Vitro. Archivum Immunologiae et Therapiae Experimentalis, 1993; 41: 327-333.
Sarna et al. noted “the serious side effects” of high dose cisplatin treatment as reported in a review of the drug. The objective of the study then was “to find out the effects of ascorbic acid on enhancement of tumor growth inhibition induced by [a] low dose of cisplatin.”
The method used was “direct treatment of tumor cells in vivo and in vitro.” The test using Dalton’s lymphoma mice treated with different doses of either cisplatin and ascorbic acid alone or in combination was conducted in two parts; namely, chemo-therapeutical studies and chemo-immuno-therapeutical studies. A controlled group of mice was used for comparison.
The results obtained from the chemo-therapeutical studies were as follows:
For ascorbic acid alone: “When tumor bearing mice were treated with ascorbic acid (20 or 40 mg/kg x 4) a slight increase in their mean survival time compared to control mice was observed. Animals treated with [a] high dose of ascorbic acid (60 mg/kg x 4) failed to show significant increase in their life span; however, 20-25% [of the] animals appeared as tumor free survivors.”
For cisplatin alone: A “dose of cisplatin (3 mg/kg) was able to prolong the survival time of the … mice (life span increased to 166%)”-35 days without tumor free survivors.
For ascorbic acid and cisplatin: “Mice treated with cisplatin [as above] along with ascorbic acid 20 or 40 mg/kg x 4) showed increased mean survival time from 13 days in control to 50 days in treated animals.” “Both [of] the concentrations of ascorbic acid in combination with cisplatin resulted in 40% tumor free survivors. Animals receiving 60 mg/kg of ascorbic acid with cisplatin survived beyond 60 days, 50% appeared as tumor free survivors without any sign of tumor and its reappearance, the rest of them died at a later stage prolonging their life span by 400%.” The life span with 20 mg/kg and 40 mg/kg was pro- longed by 287% and 275% respectively.
The results obtained from the chemo-immuno-therapeutical studies were as follows: For ascorbic acid alone: “Dalton’s lymphoma cells …, when incubated with different concentrations of ascorbic acid and injected into normal mice, developed tumor in all the animals similarly as in control mice. Mice receiving tumor cells, incubated with 25 μg/ml ascorbic acid showed 10-15 day increase in their life span; however, innoculation of tumor cells incubated with 50 μg/ml of ascorbic acid resulted in mean survival time of mice similar to the control.” The mean survival time was: 20 days for the controls, 34.6 days for ascorbic acid 25 μg/ml and 21.6 days for ascorbic acid 50 μg/ml. “No tumor free as well as 60/more than 60 day survivors were observed with either concentration.”
For cisplatin alone: “Mice injected with cisplatin (5 or 10 μg/ml) incubated tumor cells showed significant increase in their survival time compared to the control.” The latter concentration was more effective that the former resulting “in 70% 60-70 day survivors with 204% increase in their life span.” The increase for the first concentration was 110%. “Both [concentrations] of cisplatin significantly enhanced the mean survival time of mice to 43 and 62 days respectively. No tumor free survivors were observed … with either dose.”
For ascorbic acid and cisplatin: “Tumor growth was significantly affected after injecting tumor cells incubated with cisplatin (5 μg/ml) along with 25 or 50 μg/ ml of ascorbic acid. Up to 30% mice failed to develop tumor…. Even those mice which developed tumor exhibited significant increase in their mean survival time.”
The tests were as follows: “Tumors cells incubated with cisplatin [as above] along with 50 μg/ml of ascorbic acid, when injected in mice resulted in 30%, 60/more than 60 day survivors apart from tumor free survivors.”
“Mice injected … with 10 μg/ml of cisplatin along with 25 μg/ml of ascorbic acid resulted in 20% tumor free survivors, the rest of them developed tumor with an increase in their mean survival time up to 48 days including 20% of 60 day survivors.”
“Tumors cells incubated with cisplatin (10 μg/ml) along with ascorbic acid (50 μg/ ml) when injected … showed maximum survival time of mice up to 70 days without any tumor free survivors…. The mean survival time in this [latter] group of mice was 58 days which increased significantly compared to the control mice.” As seen above, the control mice survived for 20 days. The result for cisplatin 5 μg/ml and ascorbic acid 25 μg/ml was not recorded, but the increase in mean survival time was 42.2 days.
In summary, Sarna et al. observed that in chemotherapeutical studies the most effective dose [of usage] of ascorbic acid in combination with cisplatin was found to be 60 mg/kg which has given almost 100% tumor free survivors up to 65 days. About 50% mice further survived indefinitely like normal animals. Even low doses of ascorbic acid (20 or 40 mg/kg) were found to be effective in regressing tumor when combined with the subtherapeutical dose of cisplatin. This finding shows that ascorbic acid somehow increases the therapeutical potential of the low dose of cisplatin resulting in complete regression of tumor in most of the animals. The sub-therapeutical dose of cisplatin alone resulted in an increase in the mean survival time of tumor bearing mice without any tumor free survivors.” In chemo-immuno-therapeutical studies:
“The tumor growth inhibition [by cisplatin alone] was further enhanced when vitamin C was combined with the low dose of cisplatin in vitro.” The authors continued: “One of the causes of the enhancement of cisplatin induced tumor inhibition by vitamin C … might be an increased uptake of cisplatin into the tumor cells” as reported “for vitamin E….”
In conclusion, Sarna et al. wrote that their present “studies suggest that cisplatin and ascorbic acid should be given together for combination therapy of Dalton’s lymphoma in mice. Treatment with ascorbic acid under certain conditions enhances the tumor growth inhibition induced by cisplatin. Possible causes of the enhancement … are: (i) modulation of permeability of tumor cell membrane by ascorbic acid which elevates the intratumor contents of ascorbic acid, (ii) increased uptake of cisplatin into tumor cells, (iii) increase of the efficiency of adduct formation in genomic DNA making less efficient the DNA repair of cell, thus rendering the cisplatin more effective as an antitumor agent.” The authors ended by stating:
“In view of [their] studies the potential usefulness of ascorbic acid in the prevention and treatment of cancer should not be ignored.”
Study 11. 1994
Prasad KN, Hernandez C, Edwards- Prasad J, Nelson J, Borus T, Robinson WA: Modification of the Effect of Tamoxifen, cisPlatin, DTIC, and Interferon-α2b on Human Melanoma Cells in Culture by a Mixture of Vitamins. Nutrition and Cancer, 1994; 22/3: 233-245.
In this study vitamin C was one of the antioxidants used either alone or in combination to test its effectiveness both on the reduction of growth and the enhancement of the growth-inhibition of certain chemotherapeutic agents for human melanoma cancer.
The results showed that vitamin C (sodium ascorbate), when used alone “inhibited growth of melanoma cells … without affecting the morphology” while in combination the growth inhibition was either more or significant.
With regard to the enhancement by vitamin C in conjunction with a chemotherapeutic agent, the results were as follows:
Vitamin Treatment with Tamoxifen: Vitamin C 100 μg/ml alone and vitamin C 50 μg/ml with three vitamins “increased the growth-inhibitory effect of tamoxifen,” while vitamin C 100 μg/ml with three vitamins showed no significant change.
Vitamin Treatment with cis-platin: Vitamin C 100 μg/ml alone “increased the growth-inhibitory effect of cis-platin”, vitamin C 100 μg/ml with three vitamins “enhanced the cis-platin effect” while vitamin C 50 μg/ml with three vitamins “also in- creased the cis-platin effect.”
Vitamin Treatment with DTIC: Vitamin C 100 μg/ml alone “enhanced the growth- inhibitory effect of DTIC,” vitamin C 100 μg/ ml with three vitamins “did not result in further suppression of growth” while vitamin C 50 μg/ml with three vitamins “markedly enhanced the DTIC effect.”
Vitamin Treatment with Interferon α2b Vitamin C 100 μg/ml alone “enhanced the growth-inhibitory effect of interferon,” vitamin C 100 μg/ml with three vitamins “enhanced the interferon effect” while vita- min C 50 μg/ml with three vitamins “significantly increased the interferon effect.”
In summary, vitamin C 100 μg/ml with three vitamins and the four anti-cancer agents “reduced growth of melanoma cells by about 85%. This vitamin mixture in combination with cis-platin and interferon further reduced growth…, but in combination with DTIC or tamoxifen, no better effect was noted.” Vitamin C 50 μg/ml with the same number of vitamins “markedly enhanced the growth-inhibitory effect of all chemotherapeutic agents.”
The authors believed: “These results suggest that the addition of vitamin C, [and the other vitamins] at nontoxic doses of each vitamin may enhance the growth-inhibitory effect of currently used therapeutic agents on human melanoma cells in culture.”
Prasad et al. suggested: “Another scientific rationale for using vitamins in combination with chemotherapeutic agents involves the reduction of toxicity of [these] agents on normal cells by vitamins. This rationale cannot be tested in tissue culture systems. However, several studies using individual vitamins showed that they can reduce tumor therapeutic agent-induced toxicity in animal models …. Vitamin C … has been shown to reduce the adverse effects of some chemotherapeutic agents on normal cells in animals” as reported by other investigators.
The authors ended by stating: “The mechanism of action of vitamins in tumor therapy is not totally clear”; they then explained the mechanisms of action that may be involved in the effectiveness of vitamin C and other vitamins in cancer therapeutic agents’ activity.
Study 12. 1994
Chiang CD, Song E, Yang VC, Chao CC: Ascorbic Acid increases Drug Accumulation and reverses Vincristine Resistance of Human Non-Small-Cell Lung-Cancer Cells. Biochemical Journal, 1994; 301: 759-764.
Chiang et al. “established a [vincristine] VCR-resistant subline from human lung- cancer PC-9 cells which displays a reduced drug accumulation”. This resistant subline (PC-9/VCR) treated with cytotoxicity from a MTT dye assay showed a higher “increase in resistance to VCR” as opposed to the increases of other anti-cancer agents; for example, adriamycin and cisplatin. The addition of ascorbic acid enhanced the treatment of PC-9/VCR.
The authors wrote: “A reduced accumulation of VCR was demonstrated. Interestingly, the VCR resistance of the PC- 9/VCR cell line was partially reversed by ascorbic acid, and the drug uptake was enhanced.”
The results were as follows: “The effect of ascorbic acid on cellular response to VCR was measured by the MTT-dye as- say. To eliminate complications from the modulating agent itself, a non-toxic or low cytotoxic concentration of ascorbic acid was used.” While low concentrations of ascorbic acid “had no profound effect” on resistant cells, a high concentration did. “At 25 μg/ml, ascorbic acid slightly inhibited cell growth.” In addition, a treatment with “25 μg/ml” ascorbic acid significantly lowered the resistant-cell proliferation. Lower concentrations of ascorbic acid were also effective in sensitizing VCR toxicity.”
Chiang et al. concluded that “ascorbic acid effectively inhibited the resistance of PC-9/VCR cells to VCR” noting: “Although the exact mechanism whereby ascorbic acid sensitizes PC-9/VCR cells to VCR is not clear, it is possible that the drug-accumulation-associated membrane activity detected in this study is modulated by ascorbic acid through an oxidation mechanism.”
The authors, after explaining the particular mechanism, suggested: “This novel mechanism of drug resistance may be an additional resistance pathway encountered in clinical cancer therapy.”
Study 13. 1996
Hoffer A: One Patient’s Recovery from Lymphoma. Townsend Letter for Doctors & Patients, 1996; Nov: 50-51.
Hoffer reported on the use of “megavitamin therapy of which ascorbic acid was the main and most important compound.”
In this case of a man who had become very depressed as the result of “extreme hardship, torture, and malnutrition” as well as personal problems, and who developed a rare form of cancer, Hoffer administered a high dose of vitamin treatment.
The patient had undergone surgery, and chemotherapy had been started. At the same time Hoffer “increased his ascorbic acid to 12 grams daily”, along with another vitamin and two minerals. Over the course of time the dosage of ascorbic acid was increased to 24 g daily” as radiation had also been applied. This vitamin treatment was effective in helping the regression of the “severe lymphoma”. Throughout the whole period, the patient’s personal problems had remained and he had continued to be depressed.
This patient survived “14 years after he first saw [Dr. Hoffer], 13 years after he was diagnosed.” Hoffer noted that since this first case: He had “seen 19 patients with lymphoma … who were treated by the same cancer clinic, and by [him], using the orthomolecular program.”
The author continued: “Out of 13 male patients, six were alive after five years and two more will probably make it. An 80% five-year cure rate is pretty good. One patient did not start the program. He lived 1.5 years. The six female lymphoma cases did not do nearly as well. Only one lived for one year. The starting time was always from the date they first saw me. This is a small series and indicates a trend. I have not been able to find any factor which distinguishes the two sexes. They received similar orthodox treatment and the same orthomolecular treatment.”
Hoffer ended by noting:
“In an earlier report with Linus Pauling [1990 – described elsewhere in this presentation], we showed that in general every group of cancer patients given megavitamin treatment lived much longer than did their comparison group who were not given the benefit of these vitamins.”
Study 14. 1996
Kurbacher CM, Wagner U, Kolster B, Andreotti PE, Krebs D, Bruckner HW: Ascorbic Acid (Vitamin C) improves the Antineoplastic Activity of Doxorubicin, Cisplatin, and Paclitaxel in Human Breast Carcinoma Cells in Vitro. Cancer Letters, 1996; 103:183-189.
Kurbacher et al. used vitamin C (ascorbic acid) and three antineoplastic agents in a study of their effectiveness on “human breast carcinoma cell lines”. The vitamin and each agent were tested alone and in combination. Vitamin C at certain levels “improved the cytotoxicity” of the three antineoplastic agents “significantly”.
In the test with doxorubicin (DOX), it was found that vitamin C “both at non- toxic and at cytotoxic concentrations [produced] a consistently synergistic antineoplastic activity”. The authors noted that “this effect might be related to the generation of free radicals which have been shown to have an impact on DOX-induced cell kill” in one of the cells tested as reported by other investigators.
It was found that the test with cisplatin (DDP) “produced synergistic cytotoxicity solely when the [vitamin] was added at cytotoxic concentrations, [which] might indicate that mechanisms other than those mediated by oxyradicals are more important for DDP-activity compared to DOX, at least in some breast tumors.”
The last test, that with paclitaxel (Tx), showed “a significant potentiation of Tx activity induced by Vit C.”
Kurbacher et al. ended by stating: “In conclusion, we were able to demonstrate that ascorbic acid is likely to potentiate three of the most active drugs for the treatment of [breast cancer]. Combination effects mostly were synergistic or at least additive. The mechanism by which Vit C is able to improve the cytostatics studied is not known at present and should be elucidated in further investigations. Due to the low toxicity of Vit C even at very high concentrations, combinations of ascorbic acid with cisplatin, doxorubicin, or paclitaxel seem to be attractive for the future treatment of breast cancer.”
Study 15. 1997
Chen Y, Li C, LiuY: [Effect of Ascorbate on the Permeation and Photosensitizing Activity of Hematoporphyrin Derivative (HPD) in Tumor]. Zhonghua Zhong Liu Za Zhi, Sept, 1997; 19/5: 350-352.
The summary is extracted from an abstract as the article was written in Chinese. Chen et al. tested “the depth of permeation and concentration” of the anti-cancer agent (HPD) alone or in combination with ascorbic acid in their examination of “photosensitizing effect.” The test with mice tumor of a certain size was conducted in three groups as follows: In group I, HPD (PsD-007) 1 mg/ml was administered to the mice. In group II, HPD (PsD-007) 1 mg/ml and ascorbic acid 20 mg/ml for 1 hour was administered to the mice.
Group III was used for comparison with HPD (PsD-007) 10 mg/ml alone, and the treatment “was injected intravenously to mice bearing tumor of similar size”. The tumor was removed 24 hours later.
The examination through the photo-sensitizing of the three tumors showed that for groups I and II, “red fluorescence was mainly at the periphery of tumors that had been immersed in HPD whereas the fluorescence was weaker and more evenly distributed in tumors that had received HPD i.v.” A further comparison with HPD and other mixture and groups I and II of frozen material showed similar features. For example, the concentration of the new mixture – malondialdehyde (nmol/L) – “was higher in tumors that had been immersed in [HPD] plus ascorbate than in tumors immersed in [HDP] alone. Tumors of mice that had received PsD-007 i.v. had the lowest concentration of both PsD-007 and malondialdehyde.”
Chen et al. concluded: “Ascorbate facilitates permeation of HPD into tumor and enhances the photodynamic effect of HPD.”
Study 16. 1998
Roomi MW, House D, Eckert-Maksic M, Maksic ZB, Tsao CS: Growth Suppres- sion of Malignant Leukemia Cell Line In Vitro by Ascorbic Acid (Vitamin C) and Its Derivatives. Cancer Letters, 1998; Jan; 122/ 1-2: 93-99.
Roomi et al. wrote: “Despite the various reports on [ascorbic acid] toxicity, no work has been reported underlying the critical chemical structural features for its activity. The present study addresses this question.” The authors described two “moieties” of ascorbic acid (AA), and these compounds were tested on a murine leukemia cell line.
In addition to investigating the mechanism which was involved in the cytotoxicity of ascorbic acid, Roomi et al. looked at the “effect of modifying the structure to yield the maximum cytotoxic effect of tumor cell growth.”
An observation of one of the tests suggested “that the cytotoxic effect of ascorbate was apparently not related to the metabolic or vitamin activities of ascorbate at the cellular level. Furthermore, studies on the viability of the treated cells indicated that the observed effect on cell growth was not cytostatic in nature but was the result of a direct cell killing action of ascorbate.” The results of the study demonstrated “that the critical underlying feature for AA cytotoxicity [was] the dihydroxy γ- crotonolactone ring [moiety].” The other moiety – ethylene glycol – was “not an important feature for its toxicity.” Roomi et al. concluded that the above compounds in addition to two others “could be potential candidates for human trials.”
Study 17. 2000
Nakagawa K: Effect of Chemotherapy on Ascorbate and Ascorbyl Radical in Cerebrospinal Fluid and Serum of Acute Lymphoblastic Leukemia. Cellular and Molecular Biology, 2000; 46/8: 1375-1381.
The purpose of this study on ascorbate (ASA) and ascorbyl (ASR) was two-fold. One section involved patients with “various human malaises” not having chemotherapy, and the other involved patients with acute lymphoblastic leukemia (ALL) treated with chemotherapy. This presentation reports on the latter part.
Nakagawa described an action of vitamin C by stating that ascorbate “reacts with short-lived free radicals such as OH radical and forms ascorbyl radical (ASR).” He continued: “The propagation of chain reactions initiated by the short-lived free radical can be minimized due to the relative stability of ASR. Steady state concentration of ASR in serum can be related to diseases and the treatments. Electron paramagnetic resonance (EPR) spectroscopy is a reliable technique to investigate free radicals.” The author pointed out that studies had been done on “ASA or ASR” and “ASA in cerebrospinal fluid (CSF)”. However, he stated: “details of ASR along with ASA in CSF and serum such as the effect of medical treatment and dynamic aspects concerning ASA and ASR are not yet known.”
In this study “to examine the effect of chemotherapy” on ASA and ASR in CSF and serum, the test comprised two groups of 73 acute lymphoblastic leukemia (ALL) patients. Group 1 with 57 ALL patients – 36 male and 21 female – were undergoing chemotherapy. Group 2 with 16 ALL patients – 12 male and 4 female – had followed chemotherapy. (This latter group was a type of control.) The average age of the groups was 9.7 years and 8.7 years respectively.
The results for group 1 (undergoing chemotherapy) showed: “ASA concentration in CSF was approximately two times higher than that in serum. ASR concentration in CSF was also higher than that in serum.” Statistical analyses showed:
“The statistical values [were] consistent with that of ASA, which is in blood at first and becomes ASR. It [was] noted that ASR in CSF does not correlate with ASA in CSF. This correlation implies that oxidation of ASA in CSF may not interrelate with the subjects studied. However, ASR in serum has reasonable correlation with ASA in serum. This implies that oxidation of ASA in serum may be induced by the treatment.”
The results for group 2 (following chemotherapy) showed: “Weak correlation … [was] obtained for ASR in CSF and serum. No strong correlation for ASR and ASA in serum nor for ASA in CSF and serum was obtained.” The author continued: “These results were different from those for patients undergoing the treatment and may be attributed to remission.”
In conclusion, Nakagawa stated: “The analyses showed that ASR and ASA in CSF and serum had good correlation for patients undergoing chemotherapy but not for pa- tients after the therapy. The correlation for ASR and ASA suggests that ascorbate may play an important role during chemo- therapy.”
Study 18. 2001
Reddy VG, Khanna N, Singh N: Vitamin C augments Chemotherapeutic Response of Cervical Carcinoma HeLa Cells by stabilizing P53. Biochemical and Biophysical Research Communications, 2001; 282: 409-415.
Reddy et al. wrote: “Human Papilloma Virus (HPV) is associated in most instances with cervical cancer. The HPV oncoproteins target P53 protein [a tumour suppressor gene] for degradation, leading to deregulation of cell cycle.”
The authors found that vitamin C through a down-regulating action was shown to decrease one of the functions of HPV, and as a result stabilized P53. They also observed: “Accumulation of P53 and its target gene bax then sensitized HeLa cells to cell-cycle arrest, cell death/apoptosis induced by cisplatin, and etoposide.”
For the down-regulating activity, low dose vitamin C (1 μM) was administered for various time periods (6 – 36 hrs) to the cell culture of human cervical carcinoma cell line (HeLa). This treatment was found to be non-toxic.
The test using vitamin C with the two anti-cancer agents showed that “cisplatin treatment (2-10 μM) for 48 h[ours] in Hela cells primed with vitamin C (1 μM) for 24 to 36 h[ours] resulted in increased cell death…. Flow cytometric analysis showed that the percentage apoptosis increased from 13.7% with cisplatin alone, to 18.9, 32.6, and 49.23% after vitamin C priming for 12, 24, and 36 h[ours], respectively….” Similar results were observed with vitamin C (1 μM) and etoposide (2 μM) for 36 hours.
In summary, Reddy et al. stated: “The cause for poor responsiveness to chemotherapy lies in the etiopathogenesis of cervical cancer i.e., HPV infection and loss of tumor suppressor gene function due to inactivation of P53 [and another].
The restoration of P53 levels could be a potential strategy to increase chemo- responsiveness. However, there are conflicting reports regarding the role of P53 and chemosensitivity” as reported by other investigators. The authors continued: “Different authors have adopted different strategies… [to] stabilize P53 levels. We selected vitamin C based on the fact that it prevents the development of CIN to cervical cancer and decreases methylcholanthrene (MCA) induced cervical cancer in mice” as reported by other investigators. Reddy et al. continued: “Vitamin C at low doses was seen to… increase in p53 protein… but was not sufficient to induce apoptosis”- thus its augmenting capability.
With regard to cisplatin, Reddy et al. stated: “Cisplatin, the single most active drug against cervical cancer, was found to produce maximum addictive affect in vitro on vitamin C pretreatment.” The authors also stated: “Another important finding of our study was that the combination of high doses of vitamin C and cisplatin could decrease the effect of chemotherapy.” They added: “Our findings suggest that priming with low dose of vitamin C can have a significant additive effect particularly with low dose of in vivo achievable chemotherapeutic drugs, as shown by increased apoptosis.”
In conclusion, Reddy et al. stated: “Increasing drug sensitivity of cervical carcinoma cells by stabilizing P53 using vitamin C is a novel approach and has potential clinical relevance.”
Study 19. 2002
Blasiak J, Gloc E, Wozniak K, Mlynarski W, Stolarska M, Skorski T, Majsterek I: Genotoxicity of Idarubicin and its Modulation by Vitamins C and E and Amifostine. Chemico-Biological Interactions, 2002; 140: 1- 18.
Blasiak et al. stated in this mini-review of treatment with antioxidants and chemo- therapy: “Genotoxicity of anticancer drugs in non-tumor cells is of special significance due to the possibility of inducing secondary tumors. It is therefore important to determine genotoxic potential of a drug, which is to be used in chemotherapy.” They cited other investigators in considering DNA damage “as essential markers of genotoxicity.”
The authors noted: “Idarubicin is an anthracycline anticancer drug used in haematological malignancies. The main side effect of idarubicin is free-radicals based cardiotoxicity.”
Blasiak et al. stated: “Because diet of patients receiving chemotherapy can be easily supplemented with vitamins, it is reasonable to check whether these vitamins, …, can suppress the adverse effects of anticancer drugs.” The authors cited studies which “indicated profitable activity of vitamins against side effects of cisplatin, DOX and other anti-cancer drugs.”
For example, it was reported that (1) “vitamin C can promote the removal of oxidative DNA damage from the DNA and/or nucleotide pool, through the upregulation of repair enzymes,” and (2) it “can cause strand breaks and base modifications in DNA via the production of hydroxyl radicals or lipid alkoxyl radicals by reaction of the reduced metal ions with hydrogen peroxide or lipid hydroxy-peroxides.”
Blasiak et al. stated that in their study, they “investigated DNA-damaging potential of idarubicin in normal human peripheral blood lymphocytes using the alkaline single cell gel electrophoresis (comet assay).” A further study sought to discover “mechanisms underlying genotoxicity of idarubicin”, and to this end a test was conducted to check “the ability of vitamins C and E and amifostine to modulate DNA-damaging effect exerted by the drug.”
The tests were conducted with normal human lymphocytes and murine transformed (cancer) cells.
With regard to normal human lymphocytes, which were treated with the drug in the presence and absence of the vitamins, the result showed that vitamin C (sodium ascorbate) 10 μM “significantly decreased the mean % tail DNA of the cells exposed to idarubicin at all tested concentrations of the drug” – thus being effective with normal cells. On the other hand, the same dose of sodium ascorbate “had no influence on [the] murine … transformed cells” – thus not being effective with cancer cells. The authors had noted that the latter cells “can be treated as model cells of human acute myelogenous leukemia.” To conclude, Blasiak et al. stated:
(1) “Our experimental data [indicated] that idarubicin can generate damage to DNA in intact normal human peripheral blood lymphocytes. It is likely, that the damage is caused by oxygen radicals generated by idarubicin; DNA methylation by the drug can also contribute to the damage.”
(2) “Our results [indicated] that not only cardiotoxicity but also genotoxicity and in consequence induction of secondary malignancies should be taken into account as diverse side effects of idarubicin.”
(3) “Genotoxicity of idarubicin may be considered as the origin of its anticancer activity, but the genotoxic effect exerted by the drug on normal cells should not surpass the effect on cancer cells.”
(4) “Vitamin C can be considered as protective agents against DNA damage in normal cells in persons receiving idarubicin-based chemotherapy, but the use of vitamin E cannot be recommended and at least needs further research.”
Study 20. 2002
Catani MV, Costanzo A, Savini I, Levrero M, De Laurenzi V, Wang JYJ, Melino G, Avigliano L: Ascorbate Up-Regulates MLH1 (Mut L Homologue-1) and P73: Implications for the Cellular Response to DNA Damage. Biochemical Journal, 2002; 364: 441-447.
Catani et al. stated as reported by other investigators: “The cellular response to DNA damage requires activation of MLH1,
which can co-operate with the tumour-suppressor p53 gene to promote cell cycle arrest and cell death.”
In this study using cell culture, the authors “investigated the ascorbate-mediated up-regulation of the MLH1 gene, as an involvement of ascorbate in the regulation of DNA repair enzymes [as] has been postulated.”
Their results showed “for the first time, that this antioxidant vitamin positively regulates the apoptotic cascade primed by MLH1 in response to DNA damage” as re- ported by other investigators. MLH1 was shown to modulate “the effectiveness” of cisplatin when used in conjunction with ascorbate. “Ascorbate, by increasing the cellular content of MLH1, improves the cellular response to DNA damage. Indeed, induction of increased MLH1 gene expression by DNA damage allows faster c-Abl [pathway] activation; thereafter, increased p73 activation (which is also regulated by ascorbate) could be achieved.”
In conclusion, Catani et al. stated that “biochemical mechanisms accounting for this activity are not fully understood.” However, the authors suggested that “both the anti-carcinogenic and anti-cancer activities of ascorbate might be explained by modulation of MLH1 gene expression. The chemopreventive activity may be attributed to the ability of ascorbate to act as a radical scavenger and also to prime, through induction of MLH1 and p73 gene expression, the apoptotic programme in DNA-damaged cells, which otherwise would proceed towards tumorigenic progression. By modulating MLH1 gene expression, ascorbate can also enhance the anti-neoplastic activity of several drugs: in our experimental model, ascorbate, used in combination with cisplatin, increased the apoptosis of tumour cells.” Catani et al. noted that their results compared with the results of other investigators; namely, Sarna and Bhola (1993) as seen elsewhere in this annotated bibliography.
Finally the authors stated that “combined therapy with ascorbate and DNA-damaging drugs (such as cisplatin) may allow the same pharmacological effectiveness to be attained with lower doses of the chemotherapeutic agent, with a consequent reduction in collateral effects.”
Study 21. 2002
Calderon PB, Cadrobbi J, Marques C, Hong-Ngoc N, Jamison JM, Gilloteaux J, Summers JL, Taper HS: Potential Therapeutic Application of the Association of Vitamins C and K3 in Cancer Treatment. Current Medicinal Chemistry, 2002; 9/24: 2271-2285.
Calderon et al. stated: “Oxidative stress can stimulate growth, trigger apoptosis, or cause necrosis depending upon the dose and the exposure time of the oxidizing agent.”
The authors continued: “A large body of evidence supports the idea that oxidative stress induced by redox cycling of vitamins C and K3 in association surpasses cancer cellular defense systems and results in cell death, The molecular mechanisms underlying such a process are, however, still unknown. Indeed, several types of cell death may be produced, namely autoschizis, apoptosis and necrosis.”
The method which Calderon et al. studied in the treatment of cancer cell death was the use of combined C-K3 treatment with chemotherapy. Some abbreviations are ILS–increase in life span and MST-mean survival time.
The authors stated that “the oxidative stress induced by redox cycling of these vitamins make cancer cells – which are deficient in antioxidants enzymes [as reported by other investigators] more sensitive to the anti-tumoral compound.” They continued: “Indeed, it has been reported that the loss of redox homeostasis either by vitamin C or by vitamin K3, results in cell death by apoptosis. Due to the close relationship between apoptosis and oxidative stress, the increase in the intracellular levels of hydrogen peroxide (H2O2) was thought to be the explanation for the cytotoxicity of the combined vitamins”; vitamin K3 can also “produce reactive oxygen species.”
One of the following tests was similar to that described in Taper et al. (1987)– Taper, as indicated, is one of the authors here. The results of the in vivo tests are as follows:
(1) C and K3 alone and C plus K3: Twelve ascitic TLT-bearing mine were administered i.p. with C 1 g/kg and K3 10 mg/kg alone or in combination. A control group was used for comparison. The test showed that the combined treatment of CK3 resulted in a mean survival time of “23.1 days as compared to 15.8 days” for the control group. The vitamins alone did not “have any significant effect on the life span” of the mice.
(2) Cyclophosphamide alone and CK3 plus Cyclophosphamide: The number of mice and the dose of the vitamins were the same as above, and the drug treatment was i.p. 80 mg/kg. The result for cyclophosphamide alone was similar to CK3 alone, whereas that for CK3 plus cyclophosphamide showed a much higher increase in life span over the controls. “The cyclophosphamide alone increased the MST from 16.8 days in untreated mice to 20.6 days (ILS=23%). The effect of CK3 on cyclophosphamide treatment resulted in an increased MST and ILS of 26.8 days and 59.5% respectively.”
(3) Vincristine (Oncovin®) alone and CK3 plus Vincristine (Oncovin®): In this test, the number of mice was ten and the dose of the vitamins was the same as above. The drug treatment was i.p. 0.3 mg/kg or 1.0 mg/kg. The result showed that the first dose of oncovin had a “MST of 19.0 days and CK3 alone a MST of 22.5 days (as compared to 18.5 days in untreated animals)”. In contrast “CK3 before injection of oncovin [increased] the MST to 36.5 days, that is an ILS of 97.3%.”
In summary, “CK3-treatment selectively potentiated tumor chemotherapy, [and] produced sensitization of tumors resistant to some drugs,” among other effects not particular to this work.
With regard to the mechanism involved in CK3 activity, Calderon et al. noted: “One of the main questions raised by the selective activity of CK3 against cancer cells concerns the mechanisms conditioning the cell death.” Among the mechanisms for this activity may be the generation of H2O2 by both vitamins as noted in Taper et al. (1987). Here, Calderon et al. stated that they “have formulated the hypothesis that H2O2 is the major reactive oxygen species involved in the cell death by combined vitamins C and K3. The experimental evidence supporting such hypothesis” was then explained.
To conclude, Calderon et al. proposed “the association of vitamins C and K3 as an adjuvant cancer therapy which may be introduced into human cancer therapy without any change in the classical anticancer protocols, and without any supplementary risk for patients.” The authors added: “Such adjuvant cancer therapy…, will not produce any supplementary risk … but, on the contrary it will lead to beneficial effects of clinical cancer treatment.”
Study 22. 2003
Mantovani G, Maccio A, Madeddu C, Mura L, Massa E, Gramignano G, Lusso MR, Murgia V, Camboni P, Ferreli L: Reactive Oxygen Species, Antioxidant Mechanisms, and Serum Cytokine Levels in Cancer Patients: Impact of an Antioxidant Treatment. Journal of Environmental Pathology, Toxicology and Oncology, 2003; 22/ 1:17-28.
“The main goal” of this study by Mantovani et al. “was to verify if the administration of different antioxidant agents, given either orally or i.v. to cancer patients, is feasible and effective – that is, if it reduces the blood levels of ROS [reac- tive oxygen species] and increases antioxidant enzymes.”
“ROS play both positive and negative roles in vivo.” The negative role is associated among others with the production of oxidative stress (OS), which in its turn is associated with certain degenerative dis- eases such as cancer.
The measuring tool used in this study was “the most important clinical index of disease progression – namely, the Eastern Cooperative Oncology Group (ECOG) Performance Status (PS).” The study of 28 patients was conducted in five groups with a selection of antioxidants administered individually for 10 days with limited chemotherapy involvement. The results for the group which was administered a vitamin A-E-C mixture showed that this mixture was “effective in reducing reactive oxygen species levels,” as well as having “the additional effect of increasing glutathione peroxidase activity” (GPx – anti- oxidant enzyme).
The test comprised of 28 advanced- stage cancer patients, 10 male and 18 female, who had eight different tumors and who met certain characteristics of age, height and weight. Two of the patients had been on a chemotherapy regimen at least two weeks prior to the study. A controlled group comprised 20 healthy individuals with similar physical characteristics. The measuring tool was the “WHO – approved ECOG-PS scale.” A number of tests using different parameters including the single antioxidants and the combined vitamin mixture in the five groups was conducted. The controlled group was not tested with the individual antioxidants. Of the five groups, the vitamin A-E-C group was termed Arm 5. This arm was comprised of four females only and were designated by the number 1 of the ECOG PS, classified as stage III (1) and IV (3) patients and had breast (1), lung (1), melanoma (1) and myeloma (1) cancers. The treatment administered orally per day for 10 days was vitamin A 30,000 IU, vitamin E 70 mg and vitamin C 500 mg.
The results of the test at baseline and after for Arm 5 (A-E-C treatment) showed that the “blood levels of ROS decreased significantly” with the treatment. (Three of the other arms also showed this decrease.) With regard to GPx (antioxidant enzyme) activity, Arm 5 showed the lowest increase of the arms.
With regard to safety (in the different tests), Mantovani et al. stated: “The ad- ministration of antioxidant agents has been proven safe: no adverse events were recorded except in one patient who, after amifostine administration, had a short episode of orthostatic hypotension, which cleared up spontaneously in a few minutes. The compliance to the antioxidant treatment was very high, and no patient was withdrawn from or refused to continue treatment.”
In reference to Arm 5 (A-E-C treatment), Mantovani et al. stated that these antioxidants “have … been shown to be effective at [their] institution and in several of the articles cited.” They noted that a further study on the impact of antioxidants on reactive oxygen species among others has been “accepted for publication.” (A note pertaining to that study follows this summary.)
The authors continued that antioxidants “have different mechanisms of action”, and that “numerous recent data [have] demonstrated that antioxidant agents are effective in reducing the OS [oxidative stress], and they even have an impact on cancer progression.” They referred to a study with vitamin C alone or in combination where the effect on oxidative stress had been shown.
In their conclusion however, Mantovani et al., based on the results of this study did not suggest the vitamin combination as a “best treatment” as they did for three of the antioxidants. They had stated in the same paragraph that a number of factors was required to reach a “best antioxidant treatment”. Finally, the authors stated that their “results warrant further investigation with an adequately large clinical trial to test the hypothesis that the supplementation of antioxidant agents may mitigate oxidative stress in cancer patients, occurring either spontaneously or enhanced by treatment with cisplatin or other oxidative damage-inducing drugs” as reported by other investigators.
The anticipated follow-up on further study of the A+C+E treatment was not forthcoming as that treatment was not among the combined antioxidant treatments of the phase II study below. A phase III study mentioned in the earlier article “is soon to be activated at [the authors’] institution.”
Mantovani G, Maccio A, Madeddu C, Mura L, Gramignano G, Lusso MR, Murgia V, Camboni P, Ferreli L, Mocci M, Massa E: The Impact of Different Antioxidant Agents Alone or in Combination on Reactive Oxygen Species, Antioxidant Enzymes and Cytokines in a Series of Advanced Cancer Patients at Different Sites: Correlation with Disease Progression. Free Radical Research, 2003; 37/2: 213-223.
Study 23. 2003
Drisko JA, Chapman J, Hunter VJ: The Use of Antioxidants with First-Line Chemotherapy in Two Cases of Ovarian Cancer. Journal of the American College of Nutrition, 2003; 22/2: 118-123.
Drisko et al. stated: “Because of poor overall survival in advanced ovarian malignancies, patients often turn to alternative therapies despite controversy surrounding their use. Currently, the majority of cancer patients combine some form of complementary and alternative medicine with conventional therapies. Of these therapies, antioxidants, added to chemotherapy, are a frequent choice.” Vitamin C is among the antioxidants used.
In this study, the authors reported on “two cases of advanced ovarian cancer where antioxidants were added adjunctively to chemotherapy without adversely effecting outcome or survival.” The study was observed as Case 1 and Case 2 because as will be seen, the patients’ procedures were not the same in all respects.
Case 1: This patient was 55 years old who had undergone surgery and was found to have what is called Stage IIIC papillary serous adenocarcinoma of the ovary. After the surgery, the patient began a combined oral antioxidant treatment. This treatment “included vitamin E (1,200 IU), coenzyme Q10 (300 mg), vitamin C (9,000 mg), beta-carotene (mixed carotenoids, 25 mg), and vitamin A (10,000 IU).” Then the patient received the first cycle of chemotherapy. This application consisted of “standard carboplatin (AUC 6) and pacilitaxel (175 mg/m2) chemotherapy for a total of six cycles”. The next procedure was a treatment of intravenous vitamin C. This application of ascorbic acid began with “15 grams and increased to 60 grams per infusion given twice weekly.”
Drisko et al. continued: “The 60-gram ascorbic acid infusions were given two times per week during the six cycles of consolidation chemotherapy, after which the patient continued the 60-gram ascorbic acid infusion once per week. This dose and schedule was continued for one year, after which the patient chose to reduce the frequency of the infusion to every 10 to 14 days.” They continued: “The patient is currently over 40 months from initial diagnosis and remains on ascorbic acid infusions. She has had several CT scans, as well as a PET scan, all of which remain negative for disease. Her CA-125 remains normal at a value of 8.8.”
Case 2: This patient was 60 years old who also had undergone surgery and was found to have what is called Stage IIIC mixed papillary serous and seromucinous adenocarcinoma of the ovary. Three months after surgery, because of a problem involving a respiratory condition, this patient also began a combined oral antioxidant treatment. This treatment consisted of “ascorbic acid (3,000 mg/day), vitamin E (1,200 IU/day) and beta-carotene (25 mg/day) and vitamin A (5,000 IU/ day)” but no coenzyme Q10. Then the patient also received the first cycle of chemotherapy. This application consisted of “carboplatin (AUC 6) and paclitaxel (135 mg/m2) for six cycles”. The next procedure for this patient differed from that of the other patient because:
“After the completion of her first course of chemotherapy, the patient was found to have disease in the pelvis…. The patient declined consolidation chemotherapy, instead opting for continuation of oral antioxidants and initiation of parenteral ascorbic acid infusions.” The intravenous ascorbic acid application was the same as for patient 1 – “15 grams and increasing to 60 grams per infusion.”
Drisko et al. continued: “The patient [then] had daily 60-gram ascorbic acid infusions for one week and then began twice weekly infusions, which continues to date 36 months post-diagnosis. Although further diagnostic imaging was declined, physical examination has remained normal. Her most recent CA-125 is 5, and she is over three years out from diagnosis.”
With regard to side effects of chemotherapy, Drisko et al. observed from the results:
(1) “Both patients were monitored for toxicity, and neither patient had grade three or four toxicity that limited completion of six cycles of front-line chemotherapy.”
(2) “Both patients had mild, self-limited nausea.”
(3) “Patient 1 noted the onset of numbness and tingling of both hands and feet during the first course of chemotherapy, but prior to the institution of parenteral ascorbic acid.”
(4) “Patient 1 also complained of the onset of fatigue, increased shortness of breath and peripheral edema during the first course of chemotherapy, but prior to the introduction of intravenous ascorbic acid.”
(5) “Neither patient demonstrated hematologic toxicity, including neutropenia or thrombocytopenia” or “required colony-stimulating factors. There was no evidence for febrile neutropenia or infection.”
(6) Neither patient “demonstrated elevated renal or liver enzymes.”
The only concern was the cardiac problem which was resolved with other treatment. Finally, Drisko et al. stated, after reviewing a number of studies on the use of antioxidants with chemotherapy: “Despite the fact that chemotherapy- induced formation of free radicals is well demonstrated, chemotherapy-induced cytotoxicity in general does not seem to depend on formation of reactive oxygen species; thus, the concept that antioxidants are contraindicated during most chemotherapy regimens is no longer valid. In fact, as demonstrated with the reported cases, antioxidants when added adjunctively to chemotherapy may improve the efficacy of chemotherapy and may prove to be safe.” The authors noted that a further study based on “the positive results” of this studyis underway at their institution.
Study 24. 2003
Abdel Rehim WM, Sharaf IA, Hishmat M, El-Toukhy MA, Abo Rawash N, Fouad HN: Antioxidant Capacity in Fasciola hepatica Patients Before and After Treatment with Triclabendazole Alone or in Combination with Ascorbic Acid (Vitamin C) and Tocofersolan (Vitamin E). Arzneim.-Forsch./ Drug Res., 2003; 53/3: 214-220.
Abdel Rehim et al. noted: “In Egypt, an increasing prevalence of human fascioliasis was observed in the last 20 years”, and according to other investigators a new drug, triclabendazole, “has recently been registered in Egypt for the treatment of human fascioliasis.”
The authors stated: “The aim of the present study was to investigate the effect of triclabendazole (…) therapy alone or in combination with ascorbic acid (vitamin C, …) and tocofersolan (vitamin E, …), in Fasciola hepatica patients, on Lipoperoxidation (LPO) and blood antioxidant capacity.”
The clinical test was conducted with 32 Fasciola hepatica patients both male and female who had an average age of 28 years old. They were grouped as 16 acute and 16 chronic patients. These two groups in turn were grouped in two subgroups of eight patients each. It was in these subgroups that the clinical test was observed along with a controlled group of ten healthy subjects both male and female of the same average age.
“One subgroup was given two consecutive oral doses each of 10 mg/kg body weight of trilabendazole suspension and the other received vitamin C (1000 mg/day) and vitamin E (600 mg/day) for two months, together with the same dose of triclabendazole given to the first subgroup.”
Five biochemical parameters were used for the test: (1) serum lipid peroxide, (2) erythrocyte lipid peroxide, (3) reduced glutathione (GSH), (4) glutathione peroxidase (GPx) and (5) superoxide dismutase (SOD).
The results showed that the combined treatment with the drug and vitamins was more effective than the drug alone. The test also showed that a statistical correlation between the biochemical parameters was either positive or negative.
Abdel Rehim et al. observed the following:
For Lipid Peroxides-“The results obtained in the present study revealed a significant increase in the levels of lipid peroxides expressed as MDA [malonyl dialdehyde] of both serum and erythrocyte in chronic and acute Fasciola patients before and after triclabendazole treatment alone or in combination with vitamins as compared to the corresponding control levels.” The authors also observed: “In the group of chronic Fasciola patients …, the levels of MDA were significantly decreased as compared to the corresponding values after triclabendazole treatment”. They continued, as reported by other investigators, that “this may be due to the reduction in oxidative stress induced by the free radical scavenging effect of vitamins C and E with a consequent improvement of patient’s antioxidant capacity.”
For Reduced Glutathione-“In the present study, there was a significant decrease in the level of glutathione content in chronic and acute Fasciola patients before and after triclabendazole alone or in combination with vitamins as compared to the corresponding control level.” With regard to both groups of patients, the authors observed, as reported by an investigator:
“The significant decrease in blood glutathione peroxidase enzymatic activity in all Fasciola patients compared to controls could be partly due to the reduction of glutathione itself where glutathione peroxidase (GPx) functions together with glutathione to exert its effect.”
For Glutathione Peroxidase and Superoxide Dismutase-“The activities of GPx and SOD were significantly higher in all Fasciola patients treated with triclabendazole and vitamins when compared with those of patients treated with triclabendazole alone.” The authors continued: “This could be explained on the basis of increased antioxidant capacity of these patients exerted by vitamins C and E supplementation.”
Lastly, in reference to the statistical correlation, Abdel Rehim et al. stated: “A highly positive correlation was observed between GSH and SOD, and between GSH, GPx and SOD and between serum and erythrocyte lipid peroxides …, while a significant negative correlation was found between lipid peroxides and GSH, GPx and SOD….”
Finally, Abdel Rehim concluded: “The significant improvement of SOD and GPx activities and in lipid peroxide levels after vitamins supplementation as compared to their corresponding values after treatment with triclabendazole alone could be explained on the basis of the potent action of these vitamins in protection against oxidative damage.”
This summary brings to an end the section on positive studies.
Please see ‘The Use of Vitamin C with Chemotherapy in Cancer Treatment: An Annotated Bibliography (Part 2)’