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The Gerald P. Murphy Cancer Foundation Contributes to Pace-Setting Recruitment Effort In Largest Ever Prostate Cancer Prevention Study

The Gerald P. Murphy Cancer Foundation has helped to set a new pace for recruitment to clinical trials. In less than three years, the Murphy Foundation and 428 other sites enrolled 32,400 men for the largest-ever prostate cancer prevention trial.

SELECT (the Selenium and Vitamin E Cancer Prevention Trial), sponsored by the National Cancer Institute and conducted by a network of researchers coordinated by the Southwest Oncology Group (SWOG), began enrolling participants on August 22, 2001. It was expected that recruitment of all the men needed for the study would take five years.

“Reaching this huge recruitment goal so quickly is remarkable,” said Charles A. Coltman, Jr., M.D., chairman of SWOG. “This accomplishment is a tribute to the men who have volunteered to participate in SELECT and all the people involved in the study at each site.”

Previous research into the effects of vitamin E and selenium — in studies focused on other kinds of cancer — suggested that these nutrients might help prevent prostate cancer.

“SELECT is focused on prostate cancer and, when the study is finished, we will know for sure whether these supplements can prevent the disease,” said Dr. David Waters, Executive Director of the Murphy Foundation.“ We are pleased that many men have come to the Murphy Foundation to participate in this historic trial.”

SELECT is the first study designed to look specifically at the effects of vitamin E and selenium, both separately and together, in preventing prostate cancer. Selenium and vitamin E are naturally occurring antioxidants. They are capable of neutralizing molecules known as “free radicals” that might otherwise damage the genetic material of cells and possibly lead to cancer. These nutrients were chosen for study because of the results of two other large cancer prevention trials. While the earlier studies indicated these antioxidants may be beneficial, it is necessary to look at them directly to get accurate data.

In a study of selenium to prevent nonmelanoma skin cancer in more than 1,000 men and women reported in 1996, investigators found that while the supplement did not reduce skin cancer, it did decrease the incidence of prostate cancer in men by more than 60 percent. Another trial, published in 1998, in which beta carotene and vitamin E were tested to prevent lung cancer in 29,000 Finnish men who smoked, those who took vitamin E had 32 percent less prostate cancer. Neither beta carotene nor vitamin E prevented lung cancer.

“SELECT is far from over,” said Leslie Ford, M.D., associate director for clinical research in NCI's Division of Cancer Prevention. “We appreciate the dedication of the men participating who will continue in the study for several more years in order for us to get the true answers about the benefits and risks of selenium and vitamin E.”

Although no more men will be recruited for SELECT after May 26, 2004, those already involved in the study will continue to visit a study center once every six months, for a total of at least seven years. Upon enrollment, each man was assigned by chance to one of four groups. One group is taking 200 micrograms of selenium daily plus an inactive capsule, or placebo, that looks like vitamin E. Another group is taking 400 milligrams of vitamin E daily along with a placebo that looks like selenium. A third group is taking both selenium and vitamin E. And a final group is taking two placebos.

“The 32,400 men participating in this study for the next few years will help contribute to learning ways to prevent prostate cancer in future generations,” said Dr. Waters.

In 2004, prostate cancer is estimated to affect 230,110 new men and about 29,900 will die of the disease. It is the most common form of cancer, after skin cancer, in men.

Additional Reading

Clark L.C., Combs GF Jr, Turnbull B.W., et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. JAMA 276:1957-1963, 1996.

Heinonen OP, Albanes D, Huttunen JK, et al. Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial. J Natl Cancer Inst 90:440-6, 1998.