Impact of centralization in primary retroperitoneal sarcoma treatment: analysis using hospital-based cancer registry...

To elucidate the clinicopathological features, hospital-based care volume and prognoses associated with primary retroperitoneal sarcoma (PRS).

Clinical data on PRS cases, diagnosed from 2008 to 2009 (cohort A) and from 2012 to 2015 (cohort B), were obtained from the national hospital-based cancer registry in Japan. Since data on survival, 5 years after PRS diagnosis, were available only for cohort A, patient prognoses were analyzed in this group alone.

The numbers of participating hospitals were 154 in cohort A and 537 in cohort B. In total, 380 and 2011 patients with PRS were identified in cohorts A and B, respectively. The incidence of PRS among all the registered urogenital malignancies was 0.52% (2391/462,866). Liposarcoma was the most commonly observed PRS subtype (55.8%), followed by leiomyosarcoma (19.0%). In cohort A, the 5-year overall survival (OS) was 40.4%. The 5-year OS associated with stage I (n = 107), stages II and III (n = 61), and stage IV (n = 59) disease were 59%, 39%, and 6%, respectively. Only two institutions treated over ten patients per year in each cohort. When institutions were divided by hospital care volume (8 hospitals with ≥ = 3 cases and 149 with < 3 cases/year), there were any statistic differences in the OS.

We presented the distribution and prognoses associated with PRS using a real-world large cohort database. Centralization for PRS management was not established in Japan, while the prognosis did not significantly depend on the treatment volume of hospitals.