By Pat Curry, HealthAtoZ contributing writer
Simply being male and getting older puts you at risk for prostate cancer. But could you cut that risk if you took common vitamins and minerals?
Preliminary evidence suggests that you can. Vitamin E and the mineral selenium have been shown in some small studies to cut the risk of prostate cancer between 30 percent and 60 percent. Now, researchers are giving the vitamin and mineral a second look in the largest-ever prostate cancer prevention trial.
More than a few good men
The National Cancer Institute (NCI) and a network of researchers known as the Southwest Oncology Group (SWOG) are looking for "quite a few good men" to participate in the Selenium and Vitamin E Cancer Prevention Trial, or SELECT, according to Charles A. Coltman Jr., M.D., chairman of SWOG and director of the San Antonio Cancer Institute in Texas.
The study will include a total of 32,400 healthy men of all races and ethnic backgrounds who are age 55 and older (50 and older for African-American men).
"Previous research with vitamin E and selenium - in studies that 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," Coltman says.
During the next 12 years, doctors in medical centers across the United States, Puerto Rico and Canada will follow participating patients to see whether those taking vitamin E and/or selenium develop cancer less frequently than those taking placebos.
The American Cancer Society (ACS) says men who participate in the study not only have a chance to prevent prostate cancer for themselves but also may help their sons and grandsons live free from the disease.
Prostate cancer is the most common cancer among men, except for skin cancer. In 2006, about 234,460 new cases of prostate cancer will be diagnosed in the United States. Though slow-growing and easily treated in the early stage, prostate cancer, unfortunately, usually isn't diagnosed until the disease has advanced. The ACS estimates more about 27,350 will die from the disease in 2006.
Three-fourths of men who are diagnosed are 65 and older. Your risk for developing prostate cancer is higher if your father or brother has had the disease. It is much more common in African-American men than in Caucasian men and less common in Asians and Native Americans.
Early evidence encouraging
The SELECT study is an outgrowth of two studies. In 1996 selenium was studied for the prevention of non-melanoma skin cancer in 1,000 men and women. It wasn't found effective for skin cancer prevention, but investigators did report a 60 percent decrease in the incidence of prostate cancer. Then, in a lung cancer study published in 1998, more than 29,000 male smokers took beta-carotene and vitamin E to determine if these supplements have any lung cancer prevention benefit. Again, the study revealed an unexpected result. Neither of the nutrients showed any effect against lung cancer, but those who took vitamin E had 32 percent less prostate cancer than the general population.
Vitamin E and selenium are antioxidants, which are nutrients believed to help control cell damage that can lead to cancer. Both vitamin E and selenium are normally found in water and food in small amounts. Selenium is especially found in meat, seafood and Brazil nuts. Good sources of vitamin E are vegetables, vegetable oil, nuts and egg yolks.
Because the earlier studies are promising, the Prostate Cancer Research Institute (PCRI) recommends both vitamin E and selenium as part of a diet to reduce the risk of prostate cancer. Seidmon recommends that men start taking vitamin E and selenium supplements by age 40. PCRI is a nonprofit educational and research center in Los Angeles founded by two medical oncologists.
How much to take
If you want to take these nutrients as part of your own health regimen, the daily amounts recommended in the study, 200 micrograms of selenium and 400 International Units of vitamin E are more than what's typically found in a multivitamin.
Some evidence suggests that a diet high in animal fat may increase your risk of prostate cancer and a diet high in fruits and vegetables may decrease the risk. A few studies have suggested that having a vasectomy might increase a man's risk for prostate cancer. However, the NCI says this finding has not been supported.
When should you get screened?
All men with a family history of prostate cancer or breast cancer on their mother's side are advised to have a yearly PSA blood test and digital rectal testing starting between ages 35 to 40, according to the PCRI.
In a digital rectal exam, the doctor uses his finger to feel if the prostate is enlarged, a sign that a cancerous tumor may be present. Also, the PSA test can detect levels of prostate specific antigen, or PSA, which is a hormone in the blood. Normally, the PSA level is between zero and four.
If the annual test shows that the PSA level is increasing, then further evaluation is recommended. Even if it's within the normal range, when the number is increasing, there should be additional testing with an ultrasound and biopsy, the PCRI urges.
If there's no family history of prostate or breast cancer, the PCRI recommends annual testing for all men starting at age 40. The American Urologic Association has a more specific recommendation; it suggests annual testing at age 40 for all black males and age 50 for all white males.
"We know that between 10 percent and 20 percent of all men have occult-stage cancer," says E. James Seidmon, M.D., professor of urology and diagnostic imaging at Temple University Medical School in Philadelphia. In occult-stage cancer, the cancerous cells are present, but there are no symptoms.
"The cancer is there and it's growing, but because it's so slow-growing, we have to wait until we see the rise in PSA to find it. The majority of diagnoses are being made this way," states Seidmon.
This article was reviewed and updated June 2007.
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