External beam radiotherapy combination is a risk factor for bladder cancer in patients with prostate cancer treated with brachytherapy

• Published in: World journal of urology 2023-05, Vol.41 (5), p.1317-1321
• Main Authors: Minami, Takafumi, Fujita, Kazutoshi, Hashimoto, Mamoru, Nishimoto, Mitsuhisa, Adomi, Shogo, Banno, Eri, Nozawa, Masahiro, Nose, Kazuhiro, Yoshimura, Kazuhiro, Inada, Masahiro, Yokokawa, Masaki, Nakamatsu, Kiyoshi, Uemura, Hirotsugu
• Format: Article
• Language: English
• Subjects: Bladder cancer; Brachytherapy; Brachytherapy - adverse effects; Carcinoma, Transitional Cell - etiology; Cigarettes; Humans; Invasiveness; Male; Medicine; Medicine & Public Health; Nephrology; Oncology; Original Article; Prostate cancer; Prostatic Neoplasms - pathology; Radiation therapy; Retrospective Studies; Risk Factors; Urinary Bladder Neoplasms - epidemiology; Urinary Bladder Neoplasms - etiology; Urinary Bladder Neoplasms - radiotherapy; Urology; Urothelial carcinoma
• ISSN: 1433-8726; 0724-4983; 1433-8726
• DOI: 10.1007/s00345-023-04380-5

Purpose To investigate the risk of bladder cancer (BCa) in patients treated with brachytherapy for prostate cancer (PCa). Methods We retrospectively analyzed 583 patients with PCa who underwent brachytherapy with or without external beam radiotherapy (EBRT). We analyzed the disease-free survival (DFS) of BCa in patients with PCa who underwent brachytherapy with or without EBRT. We performed multivariate Cox regression analyses of DFS using age, EBRT, and Brinkman index (BI) score (number of cigarettes smoked per day × number of years smoking) ≥ 200 as variables for BCa after brachytherapy. Results Fourteen patients (2.4%) developed BCa after brachytherapy with or without EBRT. The percentage of high-grade urothelial carcinoma (UC) was 63.6%. A total of 85.7% of patients had non-muscle invasive BCa, and 14.3% of patients had muscle invasive BCa. DFS was longer in brachytherapy monotherapy than in combination therapy (brachytherapy + EBRT). Multivariate Cox regression analysis showed that a BI score ≥ 200 (Hazard Ratio (HR 8.61; 95% Confidence Interval (CI) 1.12–65.98) and EBRT combination (HR 3.29; 95% CI 1.03–10.52) were significantly associated with BCa development in patients with PCa treated with brachytherapy. Furthermore, patients with BI score ≥ 200 and EBRT combination had a significantly higher risk of BCa compared with patients with BI score