Chemoprevention of Prostate Cancer

Purpose: Due to the public health impact of prostate cancer including the burden of screening and treatment, there is significant public interest in the potential prevention of this disease. We review the most recent results of large scale randomized clinical trials. Materials and Methods: We review the potential agents, their hypothesized mechanisms of action and challenges for the design of chemoprevention trials, including the 3 large scale trials SELECT (testing selenium and vitamin E), PCPT (testing finasteride) and REDUCE (testing dutasteride). Results: The initial results of SELECT have now been reported and demonstrate no impact of selenium or vitamin E on the risk of prostate cancer. The REDUCE trial results should be available within the year. The results of the PCPT demonstrate a significant (measured relative risk reduction of 24.8%) reduction in the risk of prostate cancer. The initial observation of an excess risk of high grade disease appears to be related to improved detection of cancer and high grade cancer related to the improved sensitivity of prostate specific antigen, digital rectal examination and prostate biopsy for cancer and high grade cancer detection. Modeling studies suggest that with finasteride the risk of high grade cancer is unchanged or reduced. Sexual dysfunction and gynecomastia were observed but the rates were low. Conclusions: Recommendations for the prevention of prostate cancer must be based on outcomes of well designed randomized trials. Men undergoing prostate cancer screening should be informed of the potential for the reduction in risk with finasteride.