Study evaluates CaP risk among finasteride users

Current medical management for BPH includes alpha-blockers and 5- reductase inhibitors.

In the Prostate Cancer Prevention Trial, finasteride, a 5- reductase inhibitor was shown to decrease the risk of developing prostate cancer by 24.8% over 7.2 years. Dr. Murtola and colleagues report in the online version of the European Journal of Cancer, a population based study evaluating the risk of CaP among men undergoing BPH therapy.

The Finnish Cancer Registry was used to identify 25,029 men with newly diagnosed CaP. The Population Register Center of Finland selected 24,723 male age and geographical controls. Information on BPH therapy was obtained from the prescription database of the Social Insurance Institution of Finland. A logistic regression model was used to calculate odds ratios.

A total of 7,715 men had used BPH therapy, and 1,578 had used both -blockers and 5- reductase inhibitors. Finasteride use was greater among cases than controls. Finasteride was associated with an increased CaP risk. The risk was increased among short-term users regardless of length of the analyzed time period. Risk of CaP among finasteride users did not differ from that of the non-users. Finasteride use for less than 4 years was associated with an increased risk for localized CaP. This risk of advanced CaP was not affected by finasteride.

Alpha-blocker use was associated with increased CaP risk. The risk remained elevated regardless of regularity of use or length of the analyzed time period. The risk increase was stronger among men 60 years of age or younger, as compared to 77 years of age and older. Overall, the risk among users of both drug categories was increased compared with that among non-users. When compared to alpha-blocker users, the overall CaP risk in finasteride users was decreased. The significant decrease was observed for regular and irregular users.

This is the first study to evaluate CaP risk among finasteride users in a population-based setting and compare it to that of alpha-blocker users. An increased risk of CaP existed for users of either BPH therapy. The investigators attribute the risk increase to increased detection of latent CaP due to differential diagnostics of BPH. They state that the CaP risk in symptomatic finasteride users is strongly affected by not only the biological effect of finasteride, but by the clinical practices and diagnostics in the management of BPH.

Teemu J. Murtola, Teuvo L.J. Tammela, Liisa Maattanen, Matti Hakama and Anssi Auvinen

Eur J Cancer 2007, 43(4): 775-781

By Christopher P. Evans, MD