Background Primary mesenteric soft tissue sarcomas (STS) are rare and limited evidence is available to inform management. Surgical resection is challenging due to the proximity of vital structures... Show moreBackground Primary mesenteric soft tissue sarcomas (STS) are rare and limited evidence is available to inform management. Surgical resection is challenging due to the proximity of vital structures and a need to preserve enteric function.Objectives To determine the overall survival (OS) and recurrence-free survival (RFS) for patients undergoing primary resection for mesenteric STS.Methods The Trans-Atlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) is an intercontinental collaborative comprising specialist sarcoma centers. Data were collected retrospectively for all patients with mesenteric STS undergoing primary resection between 2000 and 2019.Results Fifty-six cases from 15 institutions were included. The spectrum of pathology was similar to the retroperitoneum, although of a higher grade. R0/R1 resection was achieved in 87%. Median OS was 56 months. OS was significantly shorter in higher-grade tumors (p = .018) and extensive resection (p < .001). No significant association between OS and resection margin or tumor size was detected. Rates of local recurrence (LR) and distant metastases (DM) at 5 years were 60% and 41%, respectively. Liver metastases were common (60%), reflecting portal drainage of the mesentery.Conclusion Primary mesenteric sarcoma is rare, with a modest survival rate. LR and DM are frequent events. Liver metastases are common, highlighting the need for surveillance imaging. Show less
Background The current study investigated the role of radiotherapy (RT) in patients with primary nonmetastatic retroperitoneal liposarcomas. Methods A total of 607 patients with localized... Show moreBackground The current study investigated the role of radiotherapy (RT) in patients with primary nonmetastatic retroperitoneal liposarcomas. Methods A total of 607 patients with localized retroperitoneal well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS) underwent surgical resection with or without RT at 8 high-volume sarcoma centers (234 patients with WDLPS, 242 patients with grade 1 to 2 DDLPS, and 131 patients with grade 3 DDLPS; grading was performed according to the National Federation of Centers for the Fight Against Cancer [Federation Nationale des Centres de Lutte Contre le Cancer; FNCLCC]). RT was administered in 19.7%, 34.7%, and 35.1%, respectively, of these 3 cohorts. Overall survival (OS) was estimated using the Kaplan-Meier method, and the incidences of local recurrence and distant metastasis (DM) were estimated in a competing risk framework. To account for bias consistent with nonrandom RT assignment, propensity scores were estimated. Cox univariable analysis of the association between RT and oncological endpoints was performed by applying inverse probability of treatment weighting (IPTW) using propensity scores. Results Age, tumor size, and the administration of chemotherapy were found to be significantly imbalanced between patients who did and did not undergo RT in all cohorts. IPTW largely removed imbalances in key prognostic variables. Although the 8-year local recurrence incidences in patients treated with surgery plus RT versus surgery only were 11.8% and 39.2%, respectively, for patients with WDLPS (P = .011;); 29.0% and 56.7%, respectively, for patients with grade 1 to 2 DDLPS (P = .008); and 29.8% and 43.7%, respectively, for patients with grade 3 DDLPS (P = .025), this significant benefit was lost after IPTW analyses. There were no significant differences noted with regard to DM and OS between irradiated and unirradiated patients across all 3 cohorts. Conclusions Perioperative RT was found to be associated with better local control in univariable unadjusted analysis in all 3 cohorts, but not after accounting for imbalances in prognostic variables. RT did not impact on DM or OS. The appropriate selection of RT in this disease remains challenging. The results of the European Organization for Research and Treatment of Cancer (EORTC)-Soft Tissue and Bone Sarcoma Group (STBSG) 62092-22092 prospective randomized trial are awaited. Show less
