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.