Survival Benefit of the Surgical Management of Retroperitoneal Sarcoma in a Reference Center: A Nationwide Study of the French Sarcoma Group from the NetSarc Database

Background. Guidelines recommend that retroperitoneal sarcoma (RPS) be managed in a reference sarcoma center (RSC), but the benefit remains to be demonstrated. This study investigated the impact of initial surgery performed within the NetSarc network on overall survival (OS). Methods. NetSarc is a network of 26 RSCs with specialized multidisciplinary tumor boards (MDTs) that is funded by the French NCI. Since 2010, presentation to an MDT and second pathological review are mandatory for sarcoma patients, and data have been collected in a nationwide database. We extracted data for all patients who received surgery in or outside the network and who presented at a NetSarc center (NSC) for primary nonmetastatic RPS between 2010 and 2017. Results. A total of 2945 patients were included: 1078 (36.6%) underwent the first surgery in an NSC, and 1867 (63.4%) in an out-of-network center. The median number of operations at an NSC during the study period was 23 (range: 3-209), and the corresponding median was 1 (range: 1-2) at out-of-network centers. The diagnostic procedures followed significantly more clinical practice guidelines within NetSarc, where there were significantly more first R0 resections [452 (41.9%) vs. 230 (12.3%)]. The OS was significantly superior for patients treated within NetSarc, with a 2-year OS of 87% vs. 70% (p<0.001). In the multivariate analysis, surgery within an NSC was an independent predictor of OS, with a twofold lower odds ratio of death. Conclusions. In this national study, surgery for primary RPS within an NSC was associated with a better OS.