Over 30,000 to participate in prostate study
The largest-ever prostate cancer prevention study will test selenium and vitamin E to determine whether the two dietary supplements can – individually or together – protect men against prostate cancer.
Vanderbilt-Ingram Cancer Center is the only facility in Middle Tennessee to participate in the trial, which will enroll 32,400 men in the United States, Puerto Rico and Canada and will take 12 years to complete.
The study, known as the Selenium and Vitamin E Cancer Prevention Trial (SELECT) was launched Tuesday, July 24, by the National Cancer Institute and a network of research sites known as the Southwest Oncology Group (SWOG).
“Previous research involving vitamin E and selenium suggested that these nutrients might prevent prostate cancer, but SELECT is the first study designed to look directly at that potential,” said Dr. Michael S. Cookson, assistant professor of Urologic Surgery. He is principal investigator of Vanderbilt-Ingram’s arm of the trial, which is being conducted through the Department of Urologic Surgery.
During this year alone, prostate cancer will be diagnosed in more than 198,000 Americans and more than 31,500 are expected to die of the disease. In Tennessee, prostate cancer affects nearly 4,000 men each year and is responsible for 600 deaths.
Men are at higher risk for developing the disease after age 55, if they are African-American, or if their father or brother has had the disease.
Selenium and vitamin E, both naturally occurring nutrients, are antioxidants. They are capable of neutralizing toxins known as “free radicals,” which might otherwise damage the genetic material of cells and possibly lead to cancer.
SELECT follows up indirect leads from two other prevention trials to test these nutrients as potential prevention agents in other cancers. In the first, reported in 1996, selenium was tested in 1,000 men and women and was found ineffective at preventing a type of non-melanoma skin cancer; however, in the men who took the nutrient, the incidence of prostate cancer was decreased by 60 percent. In the second, reported in 1998, beta carotene and vitamin E were tested in 29,000 Finnish men who smoked to see if it could prevent lung cancer. It did not – in fact the smokers who took beta carotene were more apt to develop lung cancer and die than were those who did not. But again a reduction in prostate cancer was observed – a 32 percent reduction among those who took vitamin E.
“SELECT is the critical next step for pursuing the promising leads we saw for the prevention of prostate cancer,” said Dr. Leslie Ford, associate director for clinical research in NCI’s division of Cancer Prevention. “The only way to determine the real value of these supplements for prostate cancer is to do a large clinical trial focused specifically on this disease.”
Men may be able to participate in SELECT if they:
•are age 55 or older (age 50 or older for African-American men)
“African-American men have the highest incidence of prostate cancer in the world. We especially encourage them to consider joining this trial,” Ford said.
•have never had prostate cancer
•have had no other cancer, except non-melanoma skin cancer
•are generally in good health
Participants will be assigned by chance to one of four groups. One will take 200 micrograms of selenium daily plus an inactive capsule, or placebo, that looks like vitamin E. Another will take 400 milligrams of vitamin E daily along with a placebo that looks like selenium. Another will take both, and the last will get two placebos.
Men who join SELECT will not need to change their diet in any way, but they must stop taking any supplements they buy themselves that contain selenium or vitamin E. If participants wish to take a multivitamin, SWOG will provide, without charge, a specially formulated one that does not contain selenium or vitamin E.
Study investigators hope to recruit all the study participants during the first five years of the trial, so that each man can be followed for at least seven years.
Men interested in joining the study can call Vanderbilt-Ingram at (615) 322-7300.
For more information about the study or about prostate cancer:
The NCI Cancer Information Service at 1-800-4-CANCER. The number for callers with TTY equipment is 1-800-322-8615.
The Vanderbilt-Ingram Cancer Information Program at 1-800-811-8480.
Four pharmaceutical companies are providing selenium and vitamin E capsules and multivitamins for the study: Roche Vitamins Inc., Parsipanny, N.J.; Sabinsa Corporation, Piscataway, N.J.; Nutricia Manufacturing USA Inc., Greenville, S.C.; and BioAdvantex Pharma Inc., Mississauga, Ontario, Canada.