Ian Thompson, M.D., discusses the results of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) at a press conference held at the Cancer Therapy & Research Center of the UT Health Science Center. Dr. Thompson, one of the study’s authors, is director of the CTRC and an internationally known cancer researcher and physician.
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Contact: Elizabeth Allen,
210-450-2020

SAN ANTONIO (October 11, 2011) — New results from a study of more than 35,000 men reveal that taking vitamin E supplements increases the risk of prostate cancer among healthy men by 17 percent.

The results were published online Oct. 11 in the Journal of the American Medical Association. Top researchers from the study held a press conference the following day in San Antonio at the Cancer Therapy & Research Center of the UT Health Science Center San Antonio.

“The impact of this study is profound,” said CTRC Director Ian M. Thompson Jr., M.D., one of the study’s authors. “The concept that 50 percent of adults over the age of 60 are taking vitamin E, and that 23 percent are taking at least the dosage that was used for the study, suggests that many men are impacted by this study. Over 200,000 men per year are diagnosed with prostate cancer. The fact that vitamin E increases this risk by almost 20 percent means there is a potential for a substantial reduction in the number of men diagnosed with prostate cancer — simply by a change in supplements.”

SWOG leadership present
Dr. Thompson was joined at the press conference by Laurence Baker, D.O., study co-author and chairman of SWOG, an international network of research institutions that carried out the Selenium and Vitamin E Cancer Prevention Trial (SELECT).

“We have evidence that vitamin A supplementation does not prevent lung cancer but rather increases the risk. Now, we have evidence that vitamin E doesn’t prevent prostate cancer but rather can increase the risk,” Dr. Baker said. “Understanding why this happens is important, especially with the increased use of vitamin D supplementation, as vitamins A, D and E are our common fat-soluble vitamins.”

Shown at the SELECT news conference are (left to right) Howard Parnes, M.D., chief of the Prostate and Urologic Cancer Research Group in the National Cancer Institute’s (NCI) Division of Cancer Prevention (DCP); Mark E. Watson Jr., member of the CTRC Foundation Board and CTRC Board of Governors; and Lesley Ford, M.D., acting deputy director and associate director for clinical research in the DCP.

The SELECT study
SELECT is a randomized, double-blind, placebo-controlled study of 35,533 men assigned to four treatment groups. SELECT was funded by the National Cancer Institute (NCI) and other institutes that comprise the National Institutes of Health. SWOG carried out SELECT at more than 400 clinical sites in the United States, Puerto Rico and Canada.

The men in SELECT either received selenium, vitamin E, both, or a placebo. SELECT was halted in 2008, its seventh year, after data showed no benefit from taking either supplement. Follow-up has revealed that in fact there is a statistically significant increase in prostate cancer risk.

Further study
SELECT researchers are now examining the levels of micronutrients in participants’ blood at the beginning of the trial, before they began taking SELECT supplements, to see how those levels may have affected risk for prostate cancer and how adding the supplements may have changed that risk. The participant samples come from the study biorepository of blood and toenail clippings which is a resource for further study. Other researchers are looking at how genetic makeup could affect a man’s risk of developing prostate cancer while taking vitamin E.

“SWOG is soliciting proposals from researchers nationwide to use the SELECT biorepository to help answer the biological question of why vitamin E increased risk instead of decreasing it,” Dr. Baker said. “There are many more questions raised by these study results than we have answers for, and thus the need for further investigation.”

Dr. Thompson added, “We’ve often thought that the best source of vitamins is in the form of a pill. Unfortunately, when you do that you receive a limited number of the broad range of potentially beneficial substances found in nature. Most likely, the best supplements are not manufactured and packaged by people, but are found in the produce section of your local grocery store.”

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The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio is one of the elite academic cancer centers in the country to be named a National Cancer Institute (NCI)-designated Cancer Center, and is one of only four in Texas. A leader in developing new drugs to treat cancer, the CTRC Institute for Drug Development (IDD) conducts one of the largest oncology Phase I clinical drug programs in the world, and participates in development of cancer drugs approved by the U.S. Food & Drug Administration. For more information, visit www.ctrc.net.