The prognostic impact of treatment centralization in patients with testicular germ cell tumors: analysis of hospital-based cancer registry data in Japan

Background To identify the prognostic impact of treatment centralization in patients with testicular germ cell tumors (TGCT). Methods We used a hospital-based cancer registry data in Japan to extract seminoma and non-seminoma cases that were diagnosed in 2013, histologically confirmed, and received the first course of treatment. To compare the 5-years overall survival (OS) rates of patients stratified by institutional care volume, we performed a Cox proportional hazards regression analysis using inverse probability of treatment weighting (IPTW) method to adjust patient backgrounds. Results A total of 1767 TGCT patients were identified. The 5-years OS rates for stage II and III TGCT patients treated at low-volume institutions (< 7 cases) were significantly worse than high-volume institutions (≥ 7 cases) (91.2% vs. 83.4%, p = 0.012). Histological stratification revealed that 5-year OS rates for stage II and III seminoma patients in the low-volume group were significantly worse than the high-volume group (93.5% vs. 84.5%, p = 0.041). Multivariate OS analysis using an IPTW-matched cohort showed that institutional care volume was an independent prognostic factor (hazard ratio 2.13 [95% confidence interval: 1.23–3.71], p = 0.0072). Conclusion Our results indicate that stage II and III TGCT patients experience lower survival rates at low-volume institutions and would benefit from treatment centralization.