BACKGROUND: @entity242 ( @entity242 ) are rare @entity5 composed of several well defined histologic subtypes. The aim of this study was to analyze patterns of recurrence and treatment variations in a large population of @entity1 , treated at reference centers. METHODS: All consecutive @entity1 with primary @entity242 treated at 6 European and 2 North American institutions between January 2002 and December 2011 were included. Five, 8, and 10-year overall survival (OS) and crude cumulative incidence (CCI) of local recurrence (LR) and @entity3 ( @entity3 ) were calculated. Multivariate analyses for OS, CCI of LR, and @entity3 were performed. RESULTS: In all, 1007 @entity1 were included. Median follow-up was 58 months (first and third quartile range 36-90). The 5, 8, and 10-year OS were 67% [95% confidence interval (CI), 63, 70), 56% (95% CI, 52, 61), and 46% (95% CI, 40, 53). The 5, 8, and 10-year CCI of LR and @entity3 were 25.9 (95% CI, 23.1, 29.1), 31.3 (95% CI, 27.8, 35.1), 35% (95% CI, 30.5, 40.1), and 21% (95% CI, 18.4, 23.8%), 21.6 (95% CI, 19.0, 24.6), and 21.6 (95% CI, 19.0, 24.6), respectively. Tumour size, histologic subtype, @entity5 grade, multifocality, and completeness of resection were significant predictors of outcome. Patterns of recurrence varied depending on histologic subtype. Different treatment policies at participating institutions influenced LR of well differentiated @entity1821 without impacting OS, whereas discrepancies in adjuvant systemic therapies did not impact LR, @entity3 , or OS of @entity1822 . CONCLUSIONS: Reference centers are critical to outcomes of @entity242 @entity1 , as the management strategy requires specific expertise. Histologic subtype predicts patterns of recurrence and should inform management decision. A prospective international registry is under preparation, to further define our understanding of this disease.

Variability in Patterns of Recurrence After Resection of Primary @entity242 ( XXXX ): A Report on 1007 @entity1 From the Multi-institutional Collaborative @entity242 Working Group.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity242 :: ('MESH:D012509', 'Disease') :: ['Retroperitoneal sarcomas', 'RPS'] @entity5 :: ('MESH:D009369', 'Disease') :: ['malignancy', 'tumors'] @entity1822 :: ('MESH:D007890', 'Disease') :: ['leiomyosarcoma'] @entity3 :: ('MESH:D009362', 'Disease') :: ['DM', 'distant metastasis'] @entity1821 :: ('MESH:D008080', 'Disease') :: ['liposarcoma']
@entity242 :: (MESH:D012509,Disease) :: ['RPS']
