Retroperitoneal sarcomas: patterns of care at diagnosis, prognostic factors and focus on main histological subtypes: a multicenter analysis of the French Sarcoma Group.

BACKGROUND: Retroperitoneal sarcomas (RPS) are heterogeneous. No previous study has investigated the impact of specialized surgery, evaluated locoregional relapse (LRR), abdominal sarcomatosis and distant metastatic relapse as separate events, or considered histological subtypes separately. This study addresses these specific points in a homogeneous cohort of patients with completely resected primary RPS. PATIENTS AND METHODS: We conducted a retrospective analysis of adult patients diagnosed with a RPS between 1 January 1988 and 31 December 2008 and eventually referred to one of 12 centers of the French Sarcoma Group. All cases were centrally reviewed by an expert pathologist. RESULTS: Five hundred eighty-six patients were included. Median follow-up was 6.5 years [95% confidence interval (CI) 5.9-7.1]. Five hundred thirty-seven patients had localized disease and 389 patients (76%) had macroscopically complete resection of the tumor. In this latter group, the 5-year LRR-free survival rate was 46% [41-52] and the 5-year overall survival (OS) rate was 66% [61-71]. In multivariate analysis, gender, adjacent organ involvement, specialization of the surgeon, piecemeal resection and perioperative radiotherapy were independently associated with LRR. Specialization of the surgeon and piecemeal resection were independently associated with abdominal sarcomatosis whereas histology and adjacent organ involvement were independently associated with distant metastasis. Age, gender, grade, adjacent organ involvement and piecemeal resection were significantly associated with OS. Prognostic factors for LRR and OS were analyzed in well-differentiated and dedifferentiated liposarcomas and leiomyosarcomas. Grade 3 was an independent prognostic factor for OS of dedifferentiated liposarcomas. CONCLUSION: This study underlines the crucial role of pretherapeutic assessment and meticulous histological examination of RPS as well as the need to consider histological subtypes separately. Surgery in a specialized center and avoidance of piecemeal resection stand out as the two most important prognostic factors for RPS and highlight the importance of treating these patients in specialized centers.

Retroperitoneal sarcomas: patterns of care in advanced stages, prognostic factors and focus on main histological subtypes: a multicenter analysis of the French Sarcoma Group.

BACKGROUND: Retroperitoneal sarcomas (RPS) are heterogeneous. Advanced stages include unresectable locoregional (LR) disease, abdominal sarcomatosis and distant metastasis. There is no available report assessing palliative chemotherapy in advanced RPS. This study analyzes management and outcome in a large cohort of patients with advanced RPS, considering main histological subtypes separately. PATIENTS AND METHODS: We conducted a retrospective analysis of adult patients diagnosed with a RPS between 1 January 1988 and 31 December 2008 across 12 centers of the French Sarcoma Group. All cases were centrally reviewed by an expert pathologist. RESULTS: Five-hundred eighty-six patients were included, 299 patients received palliative chemotherapy, with a median of two lines (range 0-8). Fifty patients underwent palliative surgery. Two hundred fifty-five patients (85%) were assessable for response after first line of chemotherapy. Among them, 69 patients (27%) had progressive disease, 145 (57%) had stable disease, 37 (14.5%) had partial response and 4 (1.5%) complete response. Median time from first line of palliative chemotherapy to progression was 5.9 months [4.9-7.3] and median overall survival (OS), 15.8 months [13-18]. In multivariate analysis, prognosis factors independently associated with poor OS were male gender, performance status (PS) >1 and grade >1. There was no difference according to stage of disease. Palliative surgery did not appear to add any survival benefit. CONCLUSION: These results emphasize the scarcity of available options for RPS in the advanced setting and the urgent need to develop new strategies. Patients with good PS should be included in clinical trials and best supportive care should be considered in those with poor PS.