Prognostic significance of radiologic and histologic response to neoadjuvant chemotherapy in localized synovial sarcoma.

Abstract

10578 Background: The role of neoadjuvant and adjuvant chemotherapy in localized synovial sarcoma (SS) is still controversial. Histologic response to neoadjuvant chemotherapy is an independent prognostic variable in bone sarcomas. Data regarding the prognostic value of response to noeadjuvant chemotherapy in STS are limited. Methods: 68 patients with localized STS, treated with neoadjuvant anthracycline/ifosfamide-based chemotherapy and assessable for response to chemotherapy were included prospectively in the French Sarcoma Group (GSF) database from 1985 to 2011. All the cases were reviewed by the pathology subcommittee of the GSF. Radiological response to chemotherapy was assessed according to RECIST criteria. Good response was defined as partial response or stable disease according to RECIST and ≤10% recognizable tumor cells in the surgical specimen. Poor response was defined as stable or progressive disease according to RECIST and ≥ 50% recognizable tumors cells in the surgical specimen. All the other cases were defined as intermediate response. Results: Median age was 38 years. Median tumor size was 8 cm (range 2-20). 56% of tumors were located in the limbs and 52% were grade 3. Response to chemotherapy was considered as good in 9 cases (13%), intermediate in 20 cases (29.5%) and poor in 39 cases (57.5%). Median metastasis-free (MFS) and overall (OS) survivals were 45 (95% CI 11-79) and 84 months (95%CI 88-120), respectively. On univariate analysis, grade, tumor size and response to chemotherapy were significantly associated with metastasis-free survival (MFS). Radiological response according to RECIST has no prognostic value. On multivariate analysis, grade was the sole variable independently associated with MFS (HR=3.4, 95% CI 1.5-7.5, p=0.003). On univariate analysis, grade, and response to chemotherapy were significantly associated with overall survival (OS). On multivariate analysis, grade was the sole factor independently associated with OS (HR=2.5, 95% CI 1.2-5.7, p=0.03). Conclusions: Response to neoadjuvant chemotherapy may not have prognostic value in patients with SS. Grade represents the most significant predictive factor of outcome in this setting.