More Data on Finasteride and Prevention of Prostate Cancer

Friday, October 29, 2010 // Uncategorized

9/4/2008 12:00:00 AM

Finasteride lowers the incidence of prostate cancer, but whether it lowers prostate cancer–associated morbidity and mortality remains unclear.

Recently, the New York Times and other media outlets reported that the drug finasteride (Proscar and generics) prevents prostate cancer. Because patients might inquire about use of finasteride for that purpose, clinicians should be aware of the research that prompted media attention.

In 2003, results of the Prostate Cancer Prevention Trial (PCPT) were published (JW Jul 18 2003). In that study, 18,000 men with normal rectal examinations and prostate-specific antigen levels 3.0 ng/mL were randomized to finasteride or placebo. The 7-year overall incidence of prostate cancer was lower with finasteride than with placebo (18% vs. 24%), but an unexplained small excess of high-grade cancers (determined by prostate biopsies) was observed in the finasteride group (6% vs. 5%). Thus, finasteride therapy to prevent cancer was not embraced.

In 2007, additional analyses of PCPT data suggested that the reported excess of finasteride-associated high-grade cancers was an artifact caused by several factors (JW Oct 11 2007). Now, in “Online First” publications by the new journal Cancer Prevention Research, two groups have refined the 2007 analyses and have concluded that finasteride lowered the incidence of prostate cancer without increasing risk for high-grade cancer. When these researchers looked at radical prostatectomy specimens that were collected after positive needle biopsies, they found that upstaging from low-grade to high-grade cancer was more likely among placebo recipients than among finasteride recipients (i.e., random needle biopsies in placebo recipients were more likely to miss areas of high-grade cancer). The presumed explanation is that finasteride-induced reduction in prostate size results in more accurate sampling when multiple needle biopsies are performed.

Allan S. Brett, MD

Published in Journal Watch General Medicine July 17, 2008



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