The classic prognostic factors tumor stage, tumor size, and tumor grade are the strongest predictors of outcome in synovial sarcoma: no role for SSX fusion type or ezrin expression.

BACKGROUND: The aim of this study was to investigate prognostic factors influencing the survival of synovial sarcoma, including the debated role of SYT-SSX fusion type and the newly suggested immunohistochemical marker ezrin.

PATIENTS AND METHODS: From 1984 to 2005, 45 patients-25 men (56%) and 20 women (44%) with a median age of 31 (range: 2 to 81) years-were diagnosed with a synovial sarcoma. Age at diagnosis, tumor site, tumor size, tumor histology (biphasic vs. monophasic), mitotic count, necrosis, histologic grade, SYT-SSX fusion type, and ezrin immunostaining were analyzed for influence on survival by univariate and multivariate methods.

RESULTS: The median follow-up for all patients was 55 (range: 2 to 238) months. Five patients had metastatic disease at the time of presentation. Five-year disease-specific survivals (DSS) were 67% overall and 72% for the 40 patients presenting with localized disease at diagnosis. Nineteen patients (48%) developed metastases during follow-up. Five-year metastasis-free survival (MFS) for the 40 patients with localized disease at diagnosis was 60% and the 10-year MFS was 52%. Disease stage at presentation, tumor size >5 cm, and histologic grade 3 were univariate significant factors associated with a worse DSS. Age >or=30 years, tumor size >5 cm, necrosis, and histologic grade were univariate significant factors associated with a worse MFS. In multivariate analysis, tumor size and tumor grade remained significant prognostic factors for DSS and MFS. A role of SYT-SSX fusion type could not be confirmed in our patient group. Ezrin showed high expression in glandular and nonglandular epithelioid components in biphasic synovial sarcoma. Variable expression was found in the mesenchymal component of monophasic and biphasic synovial sarcoma. Low versus high ezrin expression levels in monophasic and/or biphasic synovial sarcoma did not correlate with patient outcome.

CONCLUSIONS: Disease stage at presentation, tumor size, and tumor grade were significant predictors of survival in synovial sarcoma. SYT-SSX fusion type was not correlated with survival in our series. Ezrin expression levels were not discriminative in predicting outcome.