NCI launches massive prostate
cancer prevention study
SEATTLE -- July 24,
2001 (Cancer Digest) -- The National Cancer Institute today launched
a 12-year, $180 million study to determine whether two dietary
nutrients can prevent prostate cancer.
The Selenium and Vitamin
E Cancer Prevention Trial, or SELECT is one of the largest-ever
prostate-cancer prevention studies ever undertaken, involving
32,400 men in the United States, Canada and Puerto Rico.
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, and will be conducted by a network of 400 research sites,
cancer-care centers and physicians known as the Southwest Oncology
Group, or SWOG. Dr. Charles A. Coltman, Jr. heads SWOG.
"We are looking
for quite a few good men to join SELECT because it is an incredibly
important prostate cancer prevention study," said Coltman
in a prepared statement.
"Previous research
with vitamin E and selenium -- in studies focused on other kinds
of cancer -- suggested that these nutrients might 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," says Coltman who also directs
the San Antonio Cancer Institute in Texas.
Men 55 or older; age
50 or older for black men, who have never had prostate cancer
and have not had any other cancer, except nonmelanoma skin cancer,
in the last five years and are generally in good health are eligible
to join SELECT.
Men in the study will
visit a study site once every six months. Upon enrollment, they
will be assigned by chance to one of four groups. One group will
take selenium daily plus an inactive capsule, or placebo, that
looks like vitamin E. Another group will take 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.
Participants 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.
Selenium and vitamin
E are both naturally occurring nutrients. Selenium is a trace
element found in grains, meat and fish. Vitamin E is contained
in vegetable oil, dark green, leafy vegetables and whole-grain
cereal.
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 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.
Based on those unanticipated
results, Dr. Leslie Ford, associate director for clinical research
in NCI's Division of Cancer Prevention says researchers designed
the SELECT trial to determine whether those chance results might
prove to provide real protection from prostate cancer.
"SELECT is the
critical next step for pursuing the promising leads we saw for
the prevention of prostate cancer," said Ford, who oversees
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."
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.
For more information
about the study or prostate cancer, call the NCI'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. Or, visit NCI's Web site at or visit SWOG's Web site at and choose SELECT.
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