The Long-term Incidence and Quality of Life Outcomes Associated With Treatment-Related Toxicities of External Beam Radiotherapy for Prostate Cancer.

OBJECTIVE:To assess the long-term incidence of treatment-related toxicities and quality of life (QOL) outcomes associated with toxicity after external beam radiotherapy (EBRT) for prostate cancer. METHODS:We identified all men who had EBRT between 1994 and 2017 from Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), a longitudinal, nationwide prostate cancer registry. CaPSURE was queried for patient-reported and International Classification of Diseases-9/10 and Current Procedural Terminology codes. The Medical Outcomes Studies Short Form 36 and the University of California, Los Angeles Prostate Cancer Index were used to provide measures of general health, sexual, urinary, and bowel function. Repeated measures mixed models were used to determine QOL change after onset of toxicity. RESULTS:From a total of 15,332, 1744 (11.4%) men had EBRT. The median follow-up was 7.9years (interquartile range [IQR] 4.3-12.7). The median time to onset of any toxicity including urinary pad usage in 265 (15.4% at 8years) men was 4.3years (IQR 1.8-8.0). The most frequent toxicity was hemorrhagic cystitis (104, 5.9% at 8years) after a median of 3.7years (1.3-7.8), gastrointestinal (48, 2.7% at 8years) after a median of 4.2years (IQR 1.3-7.8), followed by urethral stricture (47, 2.4% at 8years) after a median of 3.7years (IQR 1.9-9.1). Repeated measures mixed models found that onset of hemorrhagic cystitis was associated with change in general health over time. CONCLUSION:EBRT for prostate cancer is associated with distinct treatment-related toxicities which can occur many years after treatment and can affect QOL. These results may help men understand the long-term implications of treatment decisions.