Does renal failure worsen radiation cystitis following radical prostatectomy?

Objective: To investigate the impact of renal function on the risk, severity, and management of radiation cystitis in patients who underwent postoperative radiation therapy for prostate cancer. Methods: Retrospective data was assessed from patients treated with adjuvant/salvage radiation therapy at a single academic institution between 2006 and 2020. The incidence, severity, and management of radiation cystitis were compared between three groups: CKD 0–2, CKD 3–4, and CKD 5. Associations of clinicopathologic factors with radiation cystitis were assessed in univariate and multivariate Cox regression models. Results: A total of 110 patients who underwent radiation therapy following robot-assisted laparoscopic radical prostatectomy were included. The incidence of radiation cystitis following postoperative radiation therapy was 17% with a median presentation time of 34 months (interquartile range 16–65 months). The incidence of radiation cystitis was 100% in CKD 5 patients compared to 15% in CKD 0–2 and 17% in CKD 3–4 patients (p < 0.001). CKD 5 patients required more treatments, emergency department visits, and longer hospitalization times than CKD 0–4 patients (all p < 0.001). Multivariate analyses identified CKD 5 as the only significant factor associated with radiation cystitis (HR = 10.39, p = 0.026). Conclusion: End-stage renal failure is associated with the risk and severity of radiation cystitis in patients receiving postoperative radiation therapy. Knowledge of the potential morbidity of this complication in this population could guide physicians and patients as they evaluate risks and benefits prior to selecting adjuvant or salvage radiation therapy.