Retroperitoneal sarcoma: a 10-year follow-up analysis using hospital-based cancer registry data in Japan

Objectives: We sought clinical characteristics, survival outcomes, and prognostic factors for overall survival of retroperitoneal sarcoma in Japan. Methods: A Japanese hospital-based cancer registry database with a pivotal 10-year follow-up was used to identify and enroll patients, registered from 106 institutions, diagnosed with retroperitoneal sarcoma in 2008-2009. Treating hospitals were divided by hospital care volume; high-volume hospitals and low-volume hospitals were defined as >= 4 and < 4 cases/year, respectively. Results: A total of 91 men and 97 women were included, with a median age of 64 years. The most common histological type was liposarcoma in 101 patients, followed by leiomyosarcoma in 38 patients. The 5-year and 10-year overall survival rates were 44.1 and 28.3%. The majority of patients (n = 152, 80.9%) were treated at low-volume hospitals. High-volume hospital patients had higher 10-year overall survival rates than low-volume hospital patients (51.2% vs 23.2%, P = 0.026). Multivariate analysis revealed age over 60 years, treatment in low-volume hospitals and chemotherapy were independent predictors of unfavorable survival while treatment with surgery was an independent predictor of favorable survival. Conclusions: The possibility of surgical removal was suggested to be the most important prognostic factor for retroperitoneal sarcoma. Better survival was shown in patients treated at high-volume hospitals in our series.