An increase in high-grade prostate cancer among men taking the drug finasteride is likely caused by an increased detection of cancers, and not by the development of more high-grade cancers, according to two studies published online September 11 in the Journal of the National Cancer Institute.The Prostate Cancer Prevention Trial (PCPT) was the first long-term randomized trial of a possible drug to prevent prostate cancer. The trial showed a nearly 25 percent reduction in prostate cancer incidence among men who took finasteride compared with a placebo. But men taking finasteride had greater rates of high-grade prostate cancer than men taking placebo (6.4 percent vs. 5.1 percent). It is unclear whether finasteride causes more high-grade prostate cancers or simply creates a situation where more high-grade cancers are detected.
