Long-term Incidence of Hematuria, Urethral Stricture and Bladder Cancer after Radiation Therapy for Prostate Cancer.

INTRODUCTION

Approximately 25% of patients diagnosed with prostate cancer choose radiation therapy as the primary treatment for this malignancy. Urinary tract toxicity after radiation therapy impacts patients years after treatment of the malignancy. We describe the incidence of hematuria, urethral stricture and bladder cancer after radiation therapy, and measure the effect of the radiation therapy modality in patients with prostate cancer.

METHODS

We performed a retrospective review of 886 consecutive patients who received radiation therapy for prostate cancer between 1992 and 2013. Prostate cancer clinical characteristics, radiation therapy treatment modality and events of interest (hematuria, urethral stricture disease and bladder cancer) were recorded. The Kaplan-Meier method was used to estimate the incidence of events of interest and multivariate stepwise Cox regression was performed to analyze associations.

RESULTS

Radiation therapy modalities included external beam radiation therapy (379), brachytherapy (225), combination therapy (35) or post-prostatectomy radiation therapy (adjuvant 47 or salvage 201). Overall the 5 and 10-year risk (95% CI) of hematuria was 23% (19-27) and 42% (36-48), urethral stricture 7% (5-9) and 12% (8-16), and bladder cancer 2% (1-3) and 5% (3-7), respectively. On multivariate regression smoking was associated with hematuria (HR 2.5, p <0.001). Obesity (HR 2.5, p=0.005), combination therapy (HR 3.8, p=0.006) and adjuvant radiation therapy (HR 3.1, p=0.015) were associated with urethral stricture.

CONCLUSIONS

Hematuria, urethral stricture and bladder cancer continue to develop several years after radiation therapy for prostate cancer, thereby warranting continued, long-term followup for these conditions.