Background: Previous studies have demonstrated that 5α-reductase inhibitors (5-ARIs) finasteride and dutasteride decrease overall prostate cancer risk, while the proportion of high risk tumors may be increased. We compared risk of biochemical recurrence and mortality after radical prostatectomy between users of 5-ARIs, alpha-blockers and medication non-users

Materials and Methods: A total of men 1,315 men who underwent radical prostatectomy at the Tampere University Hospital during 1995–2009 were included in the study cohort. Post-operatively, men were followed at six month intervals during the first postoperative year and yearly afterwards. Serum PSA was measured at each visit. Biochemical relapse was defined as PSA becoming detectable after the operation. Information on causes of death was obtained from the Finnish Cancer Registry. Data on medication purchases during 1995–2009 was obtained from national prescription database. Cox proportional regression was used to analyze hazard ratios (HRs) and 95% confidence intervals (95% CI) of biochemical relapse and death.

Results: A total of 117 men had used finasteride or dutasteride, while 372 had used tamsulosin or alfuzosin. During the follow-up 424 men had a biochemical relapse, while 124 died, of which 22 due to prostate cancer. The median follow-up time until biochemical relapse was 3.17 years and until death 5.08 years. Pathological T-stage and tumor Gleason score among users of either drug group did not significantly vary from non-users. However, 5-ARI and alpha-blocker users had more often local lymph node metastases and positive surgical margins. Prediagnostic PSA, Gleason grade, pathological T-stage and marginal positivity were all independent predictors of biochemical recurrence. Risk of biochemical relapse was comparable to non-users among 5–ARI users (HR 1.38; 95% CI 0.86–2.19), but elevated among alpha-blocker users (HR 1.71; 95% CI 1.31–2.25). However, this risk increase was only observed when alpha-blockers were being used after the surgery. Overall mortality and prostate cancer-specific mortality did not differ by medication usage.

Conclusions: Use of finasteride or dutasteride was not associated with prostate cancer grade in this population, although the users had more often local lymph node metastases and positive surgical margins. Nevertheless, the risk of biochemical recurrence and prostate cancer mortality were not affected by 5-ARI use. Our finding of increased risk of biochemical recurrence among alpha-blocker users likely reflects treatment of symptoms of aggressive prostate cancer with alpha-blockers.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):A97.