The study, the 'SELECT' trial, conducted by the National Cancer Institute (NCI), has been stopped by government health experts after an early review of the data showed neither supplement, taken alone or together, prevents prostate cancer.

The NCI says that more of a concern, was that slightly more users of vitamin E alone were getting prostate cancer and slightly more selenium-only users were getting diabetes.

The study involved more than 35,000 men age 50 and older who have been taking one or both supplements or dummy pills; earlier research had suggested that the nutrients might help, but they have instead failed.

The NCI says the trial did not prove there is a risk from the supplements, as neither statistic was statistically significant, and could be merely a coincidence.

Meanwhile the researchers will continue to track the men's health for another three years, including previously scheduled blood tests.

As with most studies, the participants were unaware which nutrients they had been assigned to take, or if they were in the placebo group - doctors are now obliged to tell them if they ask.

Dr. Eric Klein of the Cleveland Clinic in Ohio, who worked on the study, says the study's results will be more accurate if most of the men wait to find that out when the follow-up health tracking is complete - the study's active phase had been scheduled to run through to 2011, so the latest-enrolling participants could take the supplements for seven years - average use now is five years.

Prostate cancer is the most common cancer amongst American men and more than 186,000 cases are expected to be diagnosed this year - prostate cancer will claim as many as 28,660 lives.

Other research has shown that a drug already used for an enlarged prostate, finasteride, can help prevent prostate cancer as well, but side effects limit its use.

Except for skin cancer, prostate cancer is the most common type of cancer in men in the United States. In 2008, there will be an estimated 186,320 new cases of prostate cancer and 28,660 deaths from this disease in the United States. "Finding methods to prevent and treat prostate cancer remains a priority for the NCI, and with the aid of new molecular diagnostic tools and applications, we hope to continue to make headway in reducing deaths and new cases of this disease," said NCI director John E. Niederhuber, M.D. "The science of cancer prevention is also leading toward individualized, molecular prevention, in which we will calculate risk and design preventive steps based on an individual's genome."

SELECT has been funded by NCI for $114 million, with additional monies from the National Center for Complementary and Alternative Medicine, and with substudies funded and conducted by the National Heart, Lung and Blood Institute, the National Institute of Aging and the National Eye Institute at NIH. The substudies were evaluating the effects of selenium and vitamin E on chronic obstructive pulmonary disease, the development of Alzheimer's disease, and the development of macular degeneration and cataracts, and will continue without participants taking study supplements. An NCI-funded substudy is looking at the effects of the supplements on men who developed colon polyps.

"The SELECT trial owes a tremendous debt to our volunteers, the thousands of men who offered their time and enthusiastic participation, all in the interest of a future when prostate cancer can be prevented," said Laurence H. Baker, D.O., chairman of the Southwest Oncology Group. SELECT investigators are analyzing the data and will submit the analysis for publication in a peer-reviewed medical journal.

For a Q&A on SELECT, please go to cancer/newscenter/pressreleases/SELECTQandA.

The Southwest Oncology Group (www.swog) is one of the largest cancer clinical trials cooperative groups in the United States. Funded by research grants from the National Cancer Institute, part of the National Institutes of Health, the group conducts clinical trials to prevent and treat cancer in adults, and to improve the quality of life for cancer survivors. The group's network of more than 5,000 physician-researchers practice at nearly 550 institutions, including 18 NCI-designated cancer centers. Headquartered in Ann Arbor, Mich. (734-998-7130), the group has an operations office in San Antonio, Tex., and a statistical center in Seattle, Wash.

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