Vitamin C : A Case History of an Alternative Cancer Therapy

Any consideration of high-dose vitamin C in cancer therapy must include a careful analysis of its use, some 30 years ago, by the Scottish oncologic surgeon, Ewan Cameron, in the treatment of patients with advanced untreatable cancer in the Vale of Leven Hospital, Loch Lomondside, Scotland. Cameron’s treatment program, which typically involved about 10 grams of ascorbic acid given first by intravenous injection, followed by oral administration, was carried out in collaboration with the renowned American chemist, Linus Pauling. It became clear early in this clinical experience that while vitamin C had no important effect on the disease course of most of the patients, important and sometimes astounding benefits occurred for a substantial minority of them. Patients experienced an increase in subjective well-being that was accompanied by such objective clinical evidence of retardation of tumor progression, reduced pain from bone metastases, reduced rate of accumulation of malignant effusions, reduced obstructive jaundice, or improved respiratory function. There were a few cases of clinical remissions, and others in which there was objective evidence of acute tumor hemorr-hage and necrosis. This last dramatic effect did not benefit patients, of course, for it hastened their demise. But these dramatic events, bolstered in many cases by the results of autopsy examinations, represent potent evidence of an important biologic effect of high-dose ascorbic acid in some situations. Cameron and Pauling also noted that, on average, vitamin C treated patients lived substantially longer than other patients not admitted under Cameron’s service, and hence not given ascorbic acid, but otherwise similar with regard to sex, age, tumor diagnosis, and clinical stage, and treated by the same physicians in the same hospital using the same norms of clinical care. The clinical results of treatment of the first 50 patients appeared in 1974 in Chemico-Biological Interactions. One case control study was published in the Proceedings of the National Academy of Sciences (PNAS) in 1976. A second study, using different case control matching criteria, and with the same conclusion, was published in the same journal in 1978. In 1979 Cameron and Pauling published their book, Cancer and Vitamin C, which describes the results of their clinical experience in detail. Subsequently two randomized doubleblind controlled trials comparing the effects of oral vitamin C and placebo were carried out at the Mayo Clinic, in Rochester, Minnesota, under the direction of C.G. Moertel, an expert in cytotoxic chemotherapy trials. Moertel concluded that vitamin C is of no benefit whatsoever in cancer therapy. In the light of current understanding of the mode of action of biologic response modifiers, as well as other considerations pointed out at the time of the studies, these Mayo Clinic studies seem naive in conception and seriously flawed in their design and execution. The question as to the value of ascorbic acid therapy in cancer therapy thus remains unresolved nearly 30 years after the initial Vale of Leven experience. This review provides a historical overview and interpretive analysis of the Cameron-Pauling experience and a critique of the Mayo Clinic Trials. In it I endeavor to frame the issues that drove the controversy, and to draw attention to the lessons that may be learned from it in a modern consideration of vitamin C as a cancer Vitamin C: A Case History of an Alternative Cancer Therapy