To report the urinary outcome of men treated for prostate cancer with external beam radiotherapy (EBRT) who have pretreatment obstructive urinary symptoms (International Prostate Symptom Score [IPSS] ≥ 15).

We treated 368 patients with EBRT for localized prostate cancer, and pre- and post-radiotherapy (RT) IPSSs were recorded. In total, 80 men had an IPSS ≥ 15, 48% of whom were taking genitourinary (GU) medications before RT. The IPSS was followed over time and analyzed as a pretreatment factor against Radiation Therapy Oncology Group acute and late GU toxicity.

The median follow-up was 44 months. Among men with a pre-RT IPSS ≥ 15, the median IPSS at baseline, first follow-up, and last follow-up was 18 (range, 15 to 34), 17 (range, 0 to 32), and 13 (range, 0 to 34), respectively. The mean patient declines in IPSS from baseline to first and last follow-up were -3.6 points (p < 0.0004) and -6.9 points (p < 0.0001), respectively. At last follow-up, 43 men (54%) took GU medications. Pre-RT IPSS ≥ 15 vs. ≤ 14 was associated with a higher incidence of Grade ≥ 2 acute GU toxicity (64% vs. 42%, p = 0.0005), and 4-year freedom from Grade ≥ 2 late GU toxicity was 38% vs. 64% (p < 0.0001). There was no greatly increased risk of Grade ≥ 3 late GU toxicity for men with IPSS ≥ 15 (4-year freedom from Grade ≥ 3 late GU toxicity of 90% vs. 96%, p = 0.0964).

Although the improvement is not immediate, men with moderate to severe obstructive GU symptoms can have improvement in urinary function after EBRT, without significant risk for severe morbidity.