Abstract 5857: Systematic literature review of prognostic factors associated with overall survival among advanced synovial sarcoma and myxoid/round cell liposarcoma subjects
Authors: St Laurent Samantha , van den Bosch Judith , Vroling Hilde , Wang Huifen , Pokras Shibani 
Published: June 2022

Abstract
Objective: Synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCLS) are rare subtypes of soft tissue sarcoma. Reported prognostic factors of survival for SS and MRCLS include tumor size/grade, tumor depth, and round cell component specifically for MRCLS. However, these publications refer to both localized and advanced disease, and there is a lack of a systematic review of these factors. The objective is to systematically review prognostic factors associated with overall survival (OS) in subjects with advanced (metastatic or unresectable) SS and MRCLS.
Methods: Literature searches were conducted in PubMed and Embase using search strings for advanced/metastatic SS and MRCLS, and survival, and included English language articles (2000-2020), complemented with clinical trial registry summaries and oncology conference proceedings (most recent 3 years). Studies with multivariable (MV) analyses were prioritized.
Results: Sixteen studies investigated prognostic factors associated with OS (13 SS, 2 MRCLS and 1 SS/MRCLS). Five studies were conducted in the US, two in the UK and three in the EU; three SS studies and one MRCLS study included at least 100 subjects in the analyses. Advanced SS: Among six studies with MV analyses of OS, the factors in the models varied by study. Age was studied in three analyses with older age being associated with worse OS in one analysis. Metastasectomy was included in two analyses and found to be associated with longer OS in one analysis. Larger primary tumor size was associated with shorter survival in two analyses. Other factors associated with worse OS and occurring in one analysis include: males, no chemotherapy/radiotherapy/surgery of primary tumor, extra-pulmonary metastasis, lymph node metastasis, shorter time to metastasis and higher performance status. Univariate analyses showed similar results. Advanced MRCLS: While no MV analyses were conducted, the following factors were investigated in two univariate analyses each but had p-values &gt;0.05: primary tumor grade, primary tumor size, percentage of round cells and location of metastases. Only one study identified factors associated with worse OS: stage IV at diagnosis, ≥3 metastatic lesions at start of first-line therapy and a high number of organs involved during first-line therapy.
Conclusion: Limited evidence exists for prognostic factors of OS among advanced SS and MRCLS subjects. Large tumor size was the most common factor associated with poor OS in MV analyses among advanced SS subjects; other factors associated with poorer prognosis included older age, males, and metastasis characteristics. Among advanced MRCLS subjects, there were very few prognostic factors reported and all stemmed from univariate analyses in a single study, underscoring the scarcity of data available and the need for further explorations with this subtype.
Funding: GSK
Citation Format: Samantha St Laurent, Judith van den Bosch, Hilde Vroling, Huifen Wang, Shibani Pokras. Systematic literature review of prognostic factors associated with overall survival among advanced synovial sarcoma and myxoid/round cell liposarcoma subjects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5857.