For a study, researchers sought to determine the clinical indicators of radiation cystitis and evaluated the cumulative incidence of general and severe radiation cystitis after external beam radiation therapy (RT) for prostate cancer (PCa).

In the retrospective investigation, 246 patients who underwent external beam radiation treatment at their facility between 2013 and 2016 for localized or locally progressed prostate cancer were included. Among them, 57 underwent adjuvant/salvage radiation therapy, and 189 underwent main radiation therapy. The Common Terminology Criteria for Adverse Events version 5.0 definition of radiation cystitis was used, and grade 3 or above was considered severe radiation cystitis. For the purpose of calculating the cumulative incidence of radiation cystitis, all medical data were examined. In addition, the connection with clinicopathologic characteristics was assessed using univariate and multivariate Cox regression analysis.

After radiation therapy, the average follow-up time was 56 months (range 5–81). Radiation cystitis and severe radiation cystitis had cumulative incidence rates of 5 years of 16.2% and 3.0%, respectively. According to multivariate analysis, radiation therapy in the adjuvant/salvage scenario was the only known risk factor for radiation cystitis (hazard ratio: 2.75, P=0.02).

Compared to radiotherapy as the primary form of treatment, radiation therapy in the post-prostatectomy context was linked to a higher incidence of radiation cystitis.