Fort Lauderdale, Fla. A drug commonly used to treat enlarged prostates and baldness also cuts the risk of prostate cancer by about 25 percent, researchers said Tuesday. But experts stopped short of recommending that every man at risk for the disease begin taking it.
Prostate cancer is the most common nonskin cancer in the United States with more than 220,000 new cases diagnosed each year, and many more going undetected. It kills about 29,000 each year, second only to lung cancer.
The drug finasteride, approved in 1992 and sold as Proscar to treat enlarged prostates and Propecia to treat baldness, was studied in a seven-year clinical trial sponsored by the National Institutes of Health. More than 18,000 healthy men 55 and older enrolled in the trial got either the drug or a placebo, a look-alike pill with no active ingredients.
The trial was to have run until May 2004 but stopped early, and the results were published Tuesday on the New England Journal of Medicine's Web site because of the significance of the findings.
"Finasteride is the first drug found to reduce the risk of prostate cancer," said Dr. Ian Thompson, of the University of Texas Health Sciences Center, who led the study.
Nonetheless, some doctors are cautious about prescribing the drug because it can cause sexual side effects, such as loss of libido and erectile dysfunction.
And researchers also found that of the men in the study who did develop cancers, a higher percentage taking the drug developed high-grade cancers, meaning they may be more aggressive and more likely to spread beyond the prostate.
The NIH explained the results this way: If you start with 1,000 men age 63, it is estimated that after seven years, 60 of them would develop prostate cancer. Of those 60, 18 would have high-grade disease. If those same 1,000 men took finasteride for seven years, only 45 would get prostate cancer and 22 of them would have high-grade disease.
The NIH press release on the findings said the drug affects the appearance of prostate cancer cells and this may lead to a false estimate of the tumor's grade, which is determined by a pathologist looking at the cells through a microscope.
Dr. Mark Soloway, chairman of the urology department at the University of Miami School of Medicine, said men should discuss their own situation with their doctor, but that men who already have symptoms of enlarged prostate would be good candidates for the drug, as long as they are monitored by their physician.
Soloway said the drug lowers the numbers produced by the PSA test most men get annually to check their prostate health, and cautioned that they not get a false sense of security from that.
Dr. Peter Scardino, a urologist and prostate cancer specialist at Memorial Sloan-Kettering Cancer Center in New York, said in an editorial published Tuesday by the same medical journal that the findings argue against recommending that men begin taking the drug to lower their cancer risk.
Scardino said, however, that the findings do not mean that men taking the drug for treatment of enlarged prostate or baldness should stop.