The effect of erectile function on the use of phosphodiesterase-5 inhibitors after radical prostatectomy in Japanese and US men

OBJECTIVES To compare patterns of phosphodiesterase-5 (PDE-5) inhibitor use between Japanese and U.S. men after radical prostatectomy. METHODS A total of 168 Japanese men and 205 U.S. men with localized prostate cancer who were enrolled in studies of health-related quality-of-life outcomes participated in this study. Sexual function and bother were estimated with validated English and Japanese versions of the University of California-Los Angeles Prostate Cancer Index before and after treatment. Use of PDE-5 inhibitors was self-reported. RESULTS During the 24 months after radical prostatectomy, 71.8% of the U.S. men and 10.1% of the Japanese men used PDE-5 inhibitors. Japanese users reported significantly better sexual function than did non-users before (41 versus 29, P = 0.028) and after (31 versus 9, P = 0.040) surgery. In contrast, the U.S. users reported significantly worse sexual function than did non-users before (59 versus 77, P < 0.001) and after (33 versus 54, P < 0.001) surgery. Postoperative sexual bother did not differ between users and non-users in either group. CONCLUSIONS Japanese men were much less likely to use PDE-5 inhibitors than were U.S. men after radical prostatectomy, despite reporting worse sexual function scores. Cultural differences in patterns of PDE-5 inhibitor use after prostatectomy were evident.