The impact of treatment choice for localized prostate cancer on response to phosphodiesterase inhibitors

Purpose: We determined whether the impact of phosphodiesterase inhibitors on sexual function and sexual bother is different after radical prostatectomy vs radiation therapy for localized prostate cancer. Materials and Methods: We analyzed data from 1,087 men treated for localized prostate cancer with radical prostatectomy or radiation therapy, who had at least 2 years of health related quality of life followup and who reported using a phosphodiesterase type 5 inhibitor after prostate cancer treatment. Sexual function and bother were assessed over time using the UCLA Prostate Cancer Index. Mixed model analysis was used to examine sexual function and sexual bother over time after initiation of treatment with a phosphodiesterase type 5 inhibitor. Response rates were then determined using the criterion of an increase in score of at least half the standard deviation in baseline scores, and multivariate logistic regression was used to identify predictors of improved sexual function and sexual bother in response to phosphodiesterase type 5 inhibitor use. Results: Patients treated with radical prostatectomy and those who received radiation therapy had an improvement in sexual function and sexual bother after initiating phosphodiesterase type 5 inhibitor use. Response rates were similar for both types of treatment, and the only significant predictors of response to phosphodiesterase type 5 inhibitors were higher baseline (pretreatment) sexual function score and lower sexual function before phosphodiesterase type 5 inhibitor use. There was no significant change in response to phosphodiesterase type 5 inhibitors over time. Conclusions: Analysis of these data suggests that choice of treatment for localized prostate cancer is unlikely to have a significant impact on response to phosphodiesterase type 5 inhibitors should they be needed after treatment. However, patients with better pretreatment sexual function are more likely to respond to phosphodiesterase type 5 inhibitors.