Over the course of the past several years, some studies have shown that the drug finasteride (Proscar and Propecia), commonly prescribed to reduce prostate size or restore thinning hair, may also reduce the risk of prostate cancer. Now, a new review and update of prior studies published in today s New England Journal of Medicine supports this finding, although with some caveats.
This study was led by Dr. Ian Thompson of the cancer therapy and research center at the University of Texas Health Center, San Antonio, as was the original 2003 report. That study, the Prostate Cancer Prevention Trial (PCPT), first reported the significant decrease in total cases of prostate cancer among those on finasteride, but a small increase in growths likely to be more aggressive, based on a scoring system called the Gleason score which assesses various tumor factors after biopsy.The current study analyzed another year of direct evaluation of the almost-19,000 men in the PCPT for incident (newly diagnosed) prostate cancer, and further analyzed Social Security death records to evaluate survival. About half of the group was on finasteride, which works by blocking testosterone metabolism, while the control group (also numbering about 9,400) got placebos instead.
Follow-up through October of 2011, or up to 18 years for the group, revealed a cancer incidence of 15 percent in the control group as compared to 10.5 percent in the finasteride group, a reduction of about 30 percent in total prostate cancer. There was a 17 percent higher incidence of high-grade (Gleason score 9-10) tumors in the finasteride group but the total mortality rates were the same for both groups, and the length of survival after the diagnosis of prostate cancer was also the same.
So what does this all mean? ACSH s Dr. Gilbert Ross had this synopsis: The fear that while the drug reduced the overall risk of prostate cancer, it might be provoking the growth of more dangerous growths seems unsupported by this long-term, prospective randomized study. That conclusion is based on the lack of any difference in long-term mortality or survival between the active and control groups. Meanwhile, the significant reduction in cancers, as well as the beneficial effect on prostate size and symptoms, make finasteride a therapy to consider in men with bothersome symptoms of BPH (enlarged prostate). They should be informed about a possible increase in unpleasant sexual side effects, as might be expected from a drug that interferes with a man s testosterone metabolism. As for prescribing finasteride as generalized chemoprevention for most men, I d probably take a pass on it for now, watching for more evidence.