Association between long-term erectile dysfunction and biochemical recurrence after permanent seed I-125 implant brachytherapy for prostate cancer. A longitudinal study of a single-institution

We aimed to investigate the predictive factor of erectile dysfunction (ED) in prostate cancer (PCa) patients who underwent low-dose permanent I125 seed implant brachytherapy and to investigate if ED could represent a patients reported outcome measures (PROMs) of efficacy of BT and indirectly associated with biochemical recurrence free survival (BRFS). From 2000 to 2012, 176 consecutive patients with low-risk PCa underwent BT. ED was evaluated with the International Index of Erectile Function (IIEF-5). Cox regression analysis was performed to assess significant predictors of mild-to-severe ED and BRFS after BT, including covariates. The 10-year actuarial rate of ED was 66%. Subjects with severe ED had higher values of D90 (183.0 versus 177.0; p < 0.05) and V100% (40.1 versus 31.4; p < 0.05) compared with normal. At the multivariate logistic regression analysis, D90 (OR: 1.10; p < 0.05) was an independent predictor of ED. Multivariate Cox-regression analysis did not demonstrate significant association between erectile preservation and biochemical recurrence (BCR) after 10 years of follow up (HR: 2.15; p = 0.20), while D90 ≤ 180 Gy independently predicted BCR (HR: 4.65; [95%CI: 1.25-17.34]; p < 0.05). Erectile preservation should be addressed as valuable PROMs after permanent seed I125 implant, but it is not associated with better BRFS.