[81] Prognosis of Retroperitoneal Sarcomas Owing to Their Histologic Subtypes: A Large Multicentre Retrospective Analysis Fom the French Sarcoma Group

Maud Toulmonde, Agnes Neuville, Philippe Terrier, Dominique Ranchere-Vince, Veronique Brouste, Antoine Italiano, Jean-Michel Coindre. Institut Bergonié, Bordeaux, France; Institut Gustave Roussy, Villejuif, France; Centre Léon Bérard, Lyon, France

Background: Retroperitoneal sarcomas (RPS) are mainly made up of liposarcomas (LPS) and leiomyosarcomas (LMS) that have distinct behaviors. Unclassified pleomorphic sarcomas (UPS) are a heterogeneous group whose proportion in RPS has decreased in time with the recognition that a large part was in fact dedifferentiated LPS. Because of their rarity, these subtypes have been mainly studied and managed as a whole. The aim of this multicentre study was to describe and analyze the behavior and prognosis of the different histological subtypes existing in RPS.
Design: We conducted a retrospective analysis of patients > 18 year-old diagnosed with a RPS in French cancer centers between 01/01/1988 to 31/12/2008.
Results: 313 women and 273 men were included, 57 years-old mean age (range 18-89). The main diagnoses were 244 dedifferentiated liposarcoma (DDLPS, 41.5%), 135 well differentiated liposarcoma (WDLPS, 23%), 109 LMS (18.5%) and 42 UPS (7%). Evolution patterns owing to histology are given in [Table 1]. On multivariate analyses, significant prognostic factors for LR relapse were tumor opening (p=0.01) for WDLPS, expert surgeon (p=0.01) and radiotherapy (p=0.03) for DDLPS. Significant prognostic factors for overall survival were multifocality (p=0.02) and LR involvement (p=0.01) pour WDLPS, grade (p=0.015) for DDLPS, LR involvement (p=0.035) and type of surgery (p=0.018) for LMS.

Evolution Patterns
Nb M0 operated1242198334
Nb R0/R1 (%)103 (80.5)156 (71)75 (90.4)21 (61.8)
Nb LR relapse (%)56 (54)93 (60)31 (41)15 (71)
5-year LRFS53%40%68%25%
10-year LRFS21%24%55%-
5-year MFS96%86%47%73%
5-year OS82%61%61%35%
10-year OS63%31%30%-
Nb: Number; M0: metastasis-free; R0/R1: complete resection, LR: Locoregional; LRFS: locoregional relapse-free survival; MFS: Metastasis-free survival; OS: overall survival.

Conclusions: Our results suggest that independent prognostic factors for local control and survival are different among histologic subtypes that may serve as markers for stratifying options of treatment. We demonstrated an impact of the grade on the survival for DDLPS. Overall, the expertise of the surgeon and the avoidance of tumor rupture at first surgery are main prognostic factors, especially for LPS, and underline that initial treatment of these rare diseases in specialized centers should be mandatory.
Category: Bone & Soft Tissue

Tuesday, March 5, 2013 9:00 AM

Proffered Papers: Section G, Tuesday Morning


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