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Supplements Don't Hold the Answers

Conquest - Spring 2009

Results from the Selenium and Vitamin E Cancer Prevention Trial (SELECT) have shown that neither of these supplements taken alone or in combination for an average of 5 1/2 years prevents prostate cancer. Begun in August 2001, the study set out to determine whether selenium, vitamin E or both could prevent prostate cancer and other diseases in relatively healthy men.

Funded by the National Cancer Institute, with additional contributions from the National Center for Complementary and Alternative Medicine, the Phase III trial followed 35,533 participants from 427 sites in the United States, Canada and Puerto Rico. The randomized, placebo-controlled and double-blind trial divided the participants into four intervention groups: selenium, vitamin E, both selenium and vitamin E, and placebos.

While the study found no evidence of benefit in any of these categories, the data showed two statistically non-significant findings of concern: slightly increased risk of prostate cancer in the vitamin E group and type 2 diabetes mellitus in the selenium group. Both trends may be due to chance and were not observed in the group taking the two supplements together.

“SELECT presented a unique opportunity to improve the lives of men from every social and ethnic background through chemoprevention,” says Scott Lippman, M.D., professor and chair of M. D. Anderson’s Department of Thoracic/Head and Neck Medical Oncology, who led the Southwest Oncology Group study along with Eric Klein, M.D., of the Cleveland Clinic Lerner College of Medicine.

“Although supplementation has been discontinued, we will continue to follow these men and monitor their health for approximately three more years, conducting regular prostate screening tests and questioning them about diabetes and other health issues,” Lippman says. “Doing so is critical not only to determine any possible long-term effects of the selenium and vitamin E, but also to gain a better understanding of prostate and other cancers and age-related disease.”

Reported in the Dec. 9, 2008, issue of the Journal of the American Medical Association.

© 2015 The University of Texas MD Anderson Cancer Center