Propensity-weighted long-term risk of urinary adverse events after prostate cancer surgery, radiation, or both.

Abstract

Prostate cancer is the second most common cancer in men and has high survivorship, yet little is known about the long-term risk of urinary adverse events (UAEs) after treatment. To compare the long-term UAE incidence across treatment and control groups. Using a matched-cohort design, we identified elderly men treated with external-beam radiotherapy (EBRT; n=44 318), brachytherapy (BT; n=14 259), EBRT+BT (n=11 835), radical prostatectomy (RP; n=26 970), RP+EBRT (n=1557), or cryotherapy (n=2115) for non-metastatic prostate cancer and 144 816 non-cancer control individuals from the population-based Surveillance, Epidemiology, and End Results-Medicare linked data from 1992-2007 with follow-up through 2009. The incidence of treated UAEs and time from cancer treatment to first UAE were analyzed in terms of propensity-weighted survival. Median follow-up was 4.14 yr. At 10 yr, all treatment groups experienced higher propensity-weighted cumulative UAE incidence than the control group (16.1%; hazard risk [HR] 1.0), with the highest incidence for RP+EBRT (37.8%; HR 3.19, 95% confidence interval [CI] 2.79-3.66), followed by BT+EBRT (28.4%; HR 1.97, CI 1.85-2.10), RP (26.6%; HR 2.44, CI 2.34-2.55), cryotherapy (23.4%; HR 1.56, CI 1.30-1.87), BT (19.8%; HR 1.43, CI 1.33-1.53), and EBRT (19.7%; HR 1.11, CI 1.07-1.16). Bladder outlet obstruction was the most common event. Men undergoing RP, RP+EBRT, and BT+EBRT experienced the highest UAE risk at 10 yr, although UAEs accrued differently over extended follow-up. The significant background UAE rate among non-cancer control individuals yields a risk attributable to prostate cancer treatment that is 17% lower than prior estimates. We show that treatment for prostate cancer, especially combinations of two treatments such as radiation and surgery, carries a significant risk of urinary adverse events such as urethral stricture. This risk increases with time since treatment, emphasizing that treatments have long-term effects.