Efficacy of silodosin in patients undergoing brachytherapy: a randomized trial involving a pressure flow study

Purpose The purpose of the study is to investigate the efficacy of an alpha-1 adrenergic receptor antagonist (silodosin) for the treatment of lower urinary tract symptoms (LUTS) associated with interstitial 125 I implantation for prostate cancer. Methods This randomized single-center study involved 105 patients (53 with and 52 without silodosin). Silodosin was postoperatively administered, daily, for 6 months (8 mg/day). Urinary symptoms and pressure flow were evaluated preoperatively and postoperatively at 1, 3, 6, and 12 months. Results At 12 months, interstitial 125 I implantation had induced a significant decrease in prostate volume (28.3 ± 11.1–20.5 ± 8.1 g in the silodosin group and 26.1 ± 9.7–17.7 ± 4.9 g in the controls) and the prostate-specific antigen level (7.1 ± 3.6–1.4 ± 1.7 ng/mL in the silodosin group and 8.1 ± 4.3–1.3 ± 1.2 ng/mL in the controls). Significant improvements in the international prostate symptom voiding subscores at 6 months and quality of life at 3 months were observed in those receiving silodosin. The pressure flow studies demonstrated that silodosin had significantly enlarged the bladder capacity when the first non-voiding contraction was seen at 3 and 12 months (3M: 127.1 ± 74.8 vs. 118.2 ± 83.9 mL, p = 0.001; 12M: 123.7 ± 79.3 vs. 100.3 ± 73.4 mL, p = 0.01); however, there were no improvements in the bladder outlet obstruction index (BOOI) or urinary flow. Conclusions Silodosin temporarily improved LUTS, but did not improve the BOOI after 125 I implantation in the prostate.