Surgery lengthens survival for collecting duct carcinoma: Analysis of Hospital-Based Cancer Registry data in Japan

Abstract Background To identify the prognosis of Japanese patients with collecting duct carcinoma (CDC). Methods We used a hospital-based cancer registry data in Japan to extract CDC cases that were diagnosed in 2013, histologically confirmed, and determined the first course of treatment. We further investigated treatment modalities and estimated overall survival (OS) by the Kaplan-Meier method. Results A total of 61 CDC patients were identified. The 5-year OS rates for all CDC patients in Japan at 2013 were 23.6% (95% CI: 15.0-37.4), with a median OS of 14 months (95% CI: 12-24). The 5-year OS rate for CDC patients at stages I, III, and IV were 53.0% (95% CI: 29.9-94.0), 35.7% (95% CI: 19.8-64.4), and 3.4% (95% CI: 0.5-23.7), respectively. Noteworthy, the 1-year OS for stage IV patients was 27.6% (95% CI: 0.5-23.7) and the median OS was only 5 months (95% CI: 4-12). We further examined the OS for advanced disease according to treatment modalities. The median OS for chemotherapy alone was significantly shorter than surgery alone (4 months [95% CI: 4-4] vs. 15 months [95% CI: 13-68]; p<0.001). Conclusions Japanese CDC patients face poor prognoses similar to Western countries, especially in advanced cases that receive only chemotherapy. Surgery appears necessary for advanced disease.