Effect of finasteride on risk of prostate cancer: how little we really know. 
The Prostate Cancer Prevention Trial (PCPT) reported conclusively that finasteride prevents or delays the detection of prostate cancer.  One perplexing finding was that more high-grade tumors were detected in the finasteride treated group.  It is hard to put this into perspective because of the limited published data on the effects of finasteride on prostate cancer.  The strong possibility exists that the increase in high-grade tumors may be due to a treatment effect, which causes intermediate grade cancers to appear to be high-grade or aggressive tumors.  Confirmation of a spurious tumor grade "inflation" will make the conclusions of this study clearer and define the benefits of finasteride chemoprevention in a more favorable light.