Mixed ResultsThis good news-bad news is sure to spark a debate over whether doctors should start prescribing finasteride to men as a preventive treatment against prostate cancer. Data from the so-called Prostate Cancer Prevention Trial -- including the conclusion that finasteride may help prevent prostate cancer -- were published Tuesday in the online edition of The New England Journal of Medicine. But an accompanying editorial in the NEJM concludes that "disturbing findings" in the study outweigh the positives, and that doctors should not be prescribing the drug to lower the risk of prostate cancer. Merck currently sells finasteride under two brand names. As Proscar, the drug is used as a treatment for an enlarged prostate gland, a common ailment of aging men. A lower dose of the drug, sold as Propecia, is approved as a hair-loss treatment. Finasteride works by inhibiting an enzyme that converts testosterone into the more potent dihydrotestosterone, the primary male hormone in the prostate. Combined, finasteride sales totaled about $550 million last year. Naturally, finasteride sales could soar if doctors began prescribing the drug to a significant number of men as a way to lower prostate cancer risk. Merck shares were down 45 cents, or 0.7%, at $61.66 in Tuesday morning trading. Prostate cancer is the most common cancer in men after skin cancer, and will affect nearly 221,000 men in the U.S. this year. About 29,000 men will die of the disease, according to the National Cancer Institute.
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