BETHESDA, MarylandResearchers have begun accruing 32,400 men for a
long-term prostate cancer study that will test whether selenium and/or vitamin
E can prevent the disease. The Southwest Oncology Group (SWOG) will coordinate
the Selenium and Vitamin E Cancer Trial (SELECT) at more than 400 sites in the
United States, Canada, and Puerto Rico. Participants will be followed for up to
"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," the National Cancer Institute (NCI) said in announcing the trial’s
Selenium and vitamin E are antioxidants. The postulated mechanism for any
protective benefit is the ability of antioxidants to neutralize free radicals
and thus prevent genetic damage to cells that could lead to cancer.
Evidence that supplements of the two nutrients might help protect men
against prostate cancer emerged from two prevention studies reported in the
mid- and late 1990s. A study of selenium supplementation in 1,000 men and women
found that it did not reduce nonmelanoma skin cancer. However, male
participants had a reduction in incidence of prostate cancer of more than 60%.
Similarly, a Finnish study of 29,000 male smokers found that neither vitamin
E nor beta-carotene reduced their risk of lung cancer, and, in fact, those
taking beta-carotene were more apt to develop and die of the disease. However,
the men who got vitamin E had a reduction in prostate cancer incidence of 32%.
"Because these trials were not designed with prostate cancer as their
primary endpoint, the SELECT trial has been designed to answer the question
definitively," said Charles Coltman, Jr., MD, director of the San Antonio
Cancer Institute and chairman of SWOG.
Prostate cancer will strike some 198,100 American men during 2001 and cause
31,500 deaths. "These statistics give us a glimpse of the important impact
prostate cancer prevention could have on the lives of men of all ages, but most
critically black men, who are at the highest risk," Dr. Coltman said.