Clinical characteristics of secondary bladder cancer developing after low-/high-dose-rate brachytherapy to treat localized prostate cancer

Background To explore correlations between the clinical attributes of secondary bladder cancer and brachytherapy, we retrospectively reviewed our institutional database on patients with localized prostate cancer who underwent low-dose-rate brachytherapy (LDR-BT) or high-dose-rate brachytherapy (HDR-BT) with or without external beam radiation therapy (EBRT) or radical prostatectomy (RP). Methods From October 2003 to December 2014, 2551 patients with localized prostate cancer were treated at our institution. Of these, data on 2163 were available (LDR-BT alone: n = 953; LDR-TB with EBRT: n = 181; HDR-BT with EBRT: n = 283; RP without EBRT: n = 746). The times of secondary bladder cancer development subsequent to radical treatment, and their clinical characteristics, were studied. Results Age-adjusted Cox’s regression analyses indicated that brachytherapy did not significantly impact the incidence of secondary bladder cancer. However, the pathological characteristics of such cancer differed between patients treated via brachytherapy and RP without EBRT; invasive bladder cancer was more common in such patients. Conclusion The risk for secondary bladder cancer was not significantly increased after brachytherapy compared to non-irradiation therapy. However, brachytherapy patients exhibited a higher incidence of invasive bladder cancer. Therefore, meticulous follow-up is crucial for early detection and treatment of bladder cancer in such patients.