Cancer prevention trial comes to a halt
Editor in Chief Marc B. Garnick, M.D., puts the latest findings on selenium and vitamin E into perspective
For men everywhere, the news was disappointing. At the end of October 2008, the National Cancer Institute (NCI) announced that a study designed to test whether selenium and vitamin E, taken alone or in combination, could lower the risk of prostate cancer was ending early; researchers had grown concerned that taking the supplements might do more harm than good. It wasn't the conclusion we were expecting.
Based on earlier data, researchers had had high hopes for selenium and vitamin E as cancer fighters. Though a study of selenium and skin cancer first reported in 1996 found that the supplement offered no protection against skin cancer, researchers discovered that the incidence of prostate cancer was 63% lower among men who had taken selenium for about six-and-a-half years than among men who had taken a placebo. A 2002 follow-up report showed that among men who took selenium for more than seven-and-a-half years, the incidence was 52% lower.