Does synovial sarcoma grade predict oncologic outcomes, and does a low‐grade variant exist?. Issue 8 (6th March 2022) - Fice, Michael
Abstract: Background and Objectives: While historically aggressive, some synovial sarcomas (SS) are clinically indolent. This study sought to determine whether SS grade predicts oncologic outcomes and whether Grade 1 disease might exist. Methods: Thirty‐five cases from 2010 to 2019 were retrospectively reviewed. Clinicopathological data were analyzed and Kaplan–Meier assessed survival. Results: The median patient age was 37 years (interquartile range: 28–51.5). The local control rate was 74.3%, and recurrence‐free survival (RFS) was worse in positive versus negative margin resections ( p = 0.023). The incidence of metastasis was 21.9% ( n = 7) at a median 31 ± 31.7 months, and metastasis‐free survival was 50.0% in Grade 3 SS versus 86.5% in Grade 2 ( p = 0.026). Among a theoretical Grade 1 group, the overall survival (OS) and RFS profiles were improved compared to Grade 2 and 3 SS, respectively ( p = 0.014 and p = 0.030). The Grade 1 group had a 15.8% ( n = 3) metastatic rate and 80% 10‐year survival. Conclusions: Tumor grade appears to predict outcomes in SS. A theoretical Grade 1 group showed improved OS and RFS versus Grades 2 and 3 SS, with metastatic rates and long‐term survival resembling the historical literature for other low‐grade soft tissue sarcomas. Our group continues to support the French Federation of Cancer Centers diagnostic strategy and NCCN treatment guidelines for SS.