Vancouver — Breast cancer patients who take megadoses of vitamins and minerals during conventional treatment have a higher chance of relapsing and dying compared to women who don't use such alternative therapies, a new study suggests. The five-year survival rate for patients who were prescribed vitamin C, beta-carotene, niacin B3, zinc, selenium and coenzyme Q10 was 72 per cent compared to 81 per cent for those receiving standard treatment alone, the observational study concluded. Over a 10-year period, those who took megadoses of vitamins and minerals were 10 per cent more likely to die, said Dr. Ivo Olivotto, co-author of the study and leader of the radiation and oncology program at the B.C. Cancer Agency's Vancouver Island Cancer Centre. The study, which was published recently in the international journal Breast Cancer Research and Treatment, is the first of its kind to compare outcomes of women who use alternative therapies with a control group, Dr. Olivotto said. "Women with breast cancer who are being pressured to take a lot of extra pills and potions and remedies like this because it'll help cure their cancer, I think I could be reasonably confident that it's not likely to be helpful," he said. The study involved 90 women who were given varying amounts of minerals and vitamins, including a daily dose of up to 24 grams of vitamin C. That's 320 times the recommended amount for a healthy woman. The women were patients of Dr. Abram Hoffer, a co-author of the study, who prescribed the megavitamin treatment within six months of diagnosis. Dr. Hoffer's patients were matched to two women each in the control group of women with similar prognostic factors including age, tumour size and stage of the breast cancer. The 180 women had received only standard treatment including hormones, chemotherapy and radiation. All the women were diagnosed between 1989 and 1999 with cancer in one breast that didn't spread to other organs. Information about their treatment and outcomes was obtained from a database at the B.C. Cancer Agency. Dr. Hoffer, who is not affiliated with the B.C. Cancer Agency, is an orthomolecular physician who aims to prevent and treat disease by administering nutritional supplements. He has treated over 900 cancer patients with large doses of vitamins and minerals, including 271 breast cancer patients. He didn't wish to comment on the study unless his entire 2½-page written statement was included. Some proponents of megavitamin and mineral treatments believe the supplements will increase the efficacy of radiation and chemotherapy while decreasing the toxicity of the conventional treatment, the study says. Although the sample size for the study was small, investigators were surprised with the results because they had hypothesized that the vitamin-mineral prescribed patients would have a 25 to 30 per cent increase in survival rates compared to the control group. But it's not known why megadoses of vitamins and minerals would have adverse effects on breast cancer patients undergoing treatment. "Some oncologists believe that antioxidants could interfere with the actions of some chemotherapy agents," the study says. "However, the scientific debate on this subject is still ongoing. "In the meantime, the study suggests caution in the use of megadoses of vitamins and minerals in patients with operable breast cancer who are being treated with curative intent." Dr. Olivotto said the results will help him talk to patients who are considering taking vitamins and minerals to fight breast cancer. "People are spending billions of dollars on [alternative therapies] in North America but if it's being promoted and sold as a remedy for cancer recurrence it's probably false." Mary Lesperance, a co-author of the study and a statistician at the University of Victoria's department of mathematics and statistics, said the results of the study are thought-provoking. "If I were diagnosed with ... breast cancer personally, I would think hard before I decide to do any megadose vitamins." Last year, the National Cancer Institute in the U.S. began recruiting healthy men aged 55 and over for the largest-ever study on the effectiveness of vitamin E and selenium. The 12-year study of 32,400 men is being conducted in the United States, Canada and Puerto Rico to determine if the supplements can protect against prostate cancer, the most common form of cancer, after skin cancer, in men. |
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