Should finasteride be used to prevent prostate cancer?

Prostate cancer is an important public health problem. Chemoprevention offers an attractive solution because it may lead to decreased disease-specific mortality. Furthermore, because many men are treated radically for prostate cancers that pose little or no threat to life, chemoprevention may also provide an excellent strategy for diminishing treatment-related costs and adverse effects such as erectile and urinary dysfunction. The Prostate Cancer Prevention Trial was a 7-year randomized study of finasteride versus placebo among men aged older than 55 years. All men were intended to have a prostate biopsy at study conclusion. At trial's end, there was a 25% reduction in period prevalence in all prostate cancers (24.4% for placebo vs 18.4% for finasteride). This represents a 6% absolute risk reduction. A larger number of higher-grade cancers were noted among men randomized to finasteride, which post hoc analyses and studies suggest are almost certainly related to previously unrecognized biases in trial design. There continues to be great debate as to the clinical significance of the cancers prevented. It is our opinion that among men who warrant 5-alpha reductase inhibitors (5ARIs) as part of their benign prostatic hyperplasia regimen, cancer prevention should be recognized as an additional benefit of treatment. Furthermore, men with high risk of clinically significant prostate cancer, such as significant family history, abnormal prostate biopsy histologies, and African descent, should be made aware of these findings. Men with significant anxiety or concern about prostate cancer should also be made aware of the risks and benefits of this therapy. Additional trials of antiestrogens, micronutrients, and other 5ARIs, which will mature over the next 2 to 5 years, will better define the role of 5ARIs in prostate cancer chemoprevention.