Norris Cotton Cancer Center Enrolling Men in Largest-Ever Prostate Cancer Prevention Trial: Vitamin E and Selenium to be Tested as Prevention Agents

Lebanon, NH, -- Healthy men age 55 and older are needed for the largest-ever prostate cancer prevention study, launched by the National Cancer Institute (NCI) and the Norris Cotton Cancer Center at the Dartmouth-Hitchcock Medical Center, which is part of a network of research sites known as the Southwest Oncology Group (SWOG). The Selenium and Vitamin E Cancer Prevention Trial, or SELECT, seeks to learn if these two dietary supplements can protect against prostate cancer, the most common form of cancer, after skin cancer, in men.

More than 400 sites in the United States, Puerto Rico, and Canada are recruiting participants for SELECT, which will take up to 12 years to complete. The study will include a total of 32,400 men.

"SELECT is the first study designed to look directly at the effects of vitamin E and selenium, both separately and together, in preventing prostate cancer," said John Heaney, MD, professor of surgery at Dartmouth Medical School, who is principal investigator for SELECT at DHMC. "Previous research involving vitamin E and selenium suggested that these nutrients might prevent prostate cancer, but we don't know for sure. When SELECT is finished we will know whether these supplements can prevent prostate cancer."

During this year alone, prostate cancer will be diagnosed in about 198,100 Americans and more than 31,500 men are expected to die of the disease. In New Hampshire, 800 men will get prostate cancer and 100 men will die of it; in Vermont 300 men will get prostate cancer and 100 men will die of it. Risk factors for the disease include being over age 55, being black, or having a father or brother with prostate cancer. 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.

Selenium and vitamin E, both naturally occurring nutrients, are antioxidants. They are capable of neutralizing toxins 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.

In a study of selenium to prevent one type of nonmelanoma skin cancer in 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. In fact, the men who smoked and took beta carotene were more apt to get lung cancer and die from it than men who didn't take this supplement.

"It is crucial that men of all races and ethnic backgrounds participate in SELECT," said Leslie Ford, M.D., associate director for clinical research in NCI's Division of Cancer Prevention. "And since African-American men have the highest incidence of prostate cancer in the world, we especially encourage them to consider joining this trial." The disease also strikes black men at a younger age, so they will be eligible to enroll in the study at age 50, vs. age 55 for other racial and ethnic groups. There is no upper age limit for participation.

"SELECT is the critical next step for pursuing the promising leads we saw for the prevention of prostate cancer," said Ford, who is responsible for all aspects of NCI's involvement in SELECT. "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 in the study from New Hampshire and Vermont will visit Dartmouth-Hitchcock Medical Center once every six months. Upon enrollment, they will be assigned by chance to one of four groups. One group will take 200 micrograms of selenium daily plus an inactive capsule, or placebo, that looks like vitamin E. Another group will take 400 milligrams of vitamin E daily along with a placebo that looks like selenium. A third group will take both selenium and vitamin E. And a final group will be given 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.

Men may be able to participate in SELECT if they:

• are age 55 or older; age 50 or older for black men
• have never had prostate cancer and have not had any other cancer, except nonmelanoma skin cancer, in the last five years
• are generally in good health

For more information about the study or prostate cancer:

• in the United States (including Puerto Rico), call the National Cancer Institute's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237) for information in English or Spanish. The number for callers with TTY equipment is 1-800-332-8615.
• In Canada, call the Canadian Cancer Society's Cancer Information Service at 1-888-939-3333 for information in English or French.
• Visit NCI's Web site at http://www.cancer.gov/select/ or visit SWOG's Web site at http://swog.org and choose SELECT.

* 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. Nutritional Prevention of Cancer Study Group. 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.

Steve Snyder

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