Long-term erectile function following permanent seed brachytherapy treatment for localized prostate cancer

Background and purpose: Erectile function (EF) is commonly affected following prostate cancer treatment. We aim to evaluate the long-term EF following seed brachytherapy (BT) treatment. Materials and methods: The study consisted of 366 patients treated with BT at our institution, who completed the IIEF-5 questionnaire and reported no or mild erectile dysfunction (ED) pre-BT. The probability of EF preservation post-BT was estimated using the Kaplan–Meier methods. The difference in EF preservation by patient-, tumour- and treatment-related factors was assessed using the log-rank test. Multivariate Cox regression was used to estimate the effect of each factor on EF preservation. Results: Of the 366 patients, 277 (76%) reported normal EF, and 89 (24%) reported mild ED. The patients were followed-up for a median of 41 months (range: 3–124), and the 5-year actuarial rate of EF preservation was 59%. Age at BT seed implant, presence of medical comorbidities, Gleason score and the biologically effective dose (BED) are associated with EF preservation (P < 0.005). The association for these four factors remains statistically significant in multivariate analysis, with Gleason score having the strongest effect (HR = 3.7; 95% CI = 2.6–5.4). Conclusion: The 5-year actuarial rate of EF preservation post-BT in our cohort is 59%, and is influenced by multiple factors