Impact of Hormonal and Radiation Therapy on Bladder Outlet Obstruction in High-Risk Localized Prostate Cancer: A...

There are few reports investigating urodynamic changes after radiotherapy and hormonal therapy (HT) for prostate cancer. We prospectively evaluated differences in bladder outlet obstruction (BOO) using pressure-flow studies (PFS) before and after HT and radiotherapy in patients with high-risk localized or locally advanced prostate cancer.

This single-center prospective observational study enrolled 20 consecutive men scheduled for HT followed by intensity-modulated radiotherapy. PFS, uroflowmetry, symptom questionnaire surveys, and magnetic resonance imaging (MRI) were performed at baseline, 6 months, and 24 months after initiation of HT. Radiotherapy was initiated after the 6-month evaluation. The primary endpoint was the change in the bladder outlet obstruction index (BOOI), defined as the difference between baseline and 24 months after initiation of HT.

All patients completed the 24-month protocol. Mean BOOI decreased from 44.3 ± 23.4 at baseline to 26.8 ± 25.0 at 6 months (p < 0.01) and remained significantly reduced at 33.2 ± 29.1 at 24 months (p < 0.05). Prostate volume was reduced significantly by 43% at 6 months (p < 0.01) and by 41% at 24 months (p < 0.01). MRI demonstrated resolution of malignant lesions by 6 months in all patients, with no recurrence at 24 months. Three patients (15%) exhibited a BOOI reduction > 30, and all three had periurethral tumors prior to treatment.

This first prospective PFS-based study demonstrates that combined HT and radiotherapy improve BOO, particularly during HT, likely through reduction of prostate and tumor volume. Patients with periurethral tumors may achieve greater improvement in BOO. These findings underscore the importance of considering treatment-induced BOO changes in therapeutic decision-making.

ClinicalTrials.gov identifier: UMIN-CTR; UMIN000040312.