External Beam Radiotherapy for Prostate Cancer: Urinary Outcomes for Men With High International Prostate Symptom Scores (IPSS)

Abstract

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.