To describe genitourinary (GU) toxicity in men with a history of transurethral resection of the prostate (TURP) treated with external beam radiation therapy (EBRT) for prostate cancer.

Seventy-one men with a history of TURP were treated with EBRT for prostate cancer. The median time from TURP to EBRT was 15 months. The median EBRT dose was 70 Gy, and 21 men (30%) received androgen deprivation therapy (ADT). Acute GU toxicity and late GU toxicity were scored by Radiation Therapy Oncology Group criteria and compared with a cohort of 538 men without prior TURP. The median follow-up for men with TURP and men without TURP was 40 months and 50 months, respectively (p = 0.7605).

The rate of acute Grade 2 GU toxicity or higher was 41%, and was increased with a history of more than 1 TURP (73% vs. 31%, p = 0.0036). The 4-year rate of freedom from late Grade 3 GU toxicity or higher was 84%, and was decreased with ADT (45% vs. 95% without ADT, p = 0.0024). By last follow-up, maximal GU toxicity tended to resolve (p < 0.0001) and there was no worsening of urinary symptom scores (p = 0.6911). Compared to men without a prior TURP, TURP patients had a lower rate of freedom from late Grade 3 toxicity or higher (84% vs. 96%, p = 0.0483). Multivariate analysis suggested a higher rate of late Grade 3 toxicity or higher with TURP (risk ratio, 2.87; p = 0.0612) and EBRT dose of 74 Gy or greater (risk ratio, 2.26; p = 0.0521).

Men treated for prostate cancer with EBRT after TURP have a higher risk of severe GU toxicity; however, the overall incidence is low, and toxicity tends not to persist.