Metastasectomy in synovial sarcoma: A systematic review and meta-analysis.

BACKGROUND: Synovial sarcoma (SS) is a malignancy with high metastatic potential. The role of metastasectomy in SS is unclear, with limited data on prognostic factors and clinical outcomes. In this systematic review, we evaluate the survival outcomes post-metastasectomy for patients with SS. METHODS: A systematic review was undertaken following PRISMA guidelines. English studies reporting survival outcomes among adults and children with SS undergoing metastasectomy were evaluated. Databases were searched from inception to May 31, 2021, and included Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. Two reviewers independently undertook literature evaluation and screening, data extraction and grading of studies. Risk of bias assessments utilized the Newcastle-Ottawa Quality Assessment Scale for Cohort Studies and the Joanna Briggs Institute Critical Appraisal Checklist for Case Series. Qualitative data was summarized in descriptive format, and survival outcome data were assessed for meta-analysis. RESULTS: Thirteen retrospective studies, published between 1993 and 2017, were included, four were cohort studies, and nine were case series. A total of 598 patients with SS were included, of whom 462 had metastatic pulmonary disease, and 309 underwent metastasectomy. The median ages of the study cohorts ranged from 14 to 51 years. The median survival period after metastasectomy ranged from 21 to 80 months. Patients who underwent metastasectomy had a lower risk of mortality compared to those who did not (pooled HR 0.26 95% CI 0.14-0.49). The most common prognostic factors associated with survival included a disease-free interval of greater than 12 months and complete resection of the metastases. DISCUSSION: Although the level of evidence is low, retrospective studies support a clinical advantage for metastasectomy in selected patients with metastatic SS. FUNDING: This was not a funded study. REGISTRATION: This protocol has been registered within the international prospective register of systematic reviews (PROSPERO) database (registration ID: CRD42019126906).