Efficacy of Neoadjuvant Chemotherapy for Synovial Sarcoma: Retrospective Analysis of a Nationwide Database in Japan

Abstract

BackgroundSynovial sarcoma is an aggressive but chemosensitive soft-tissue tumor. We retrospectively analyzed the efficacy of neoadjuvant chemotherapy for synovial sarcoma with data from the nationwide database, Bone and Soft Tissue Tumor Registry in Japan.MethodsThis study included 316 patients diagnosed with synovial sarcoma between 2006 and 2012. Oncologic outcomes were analyzed using a Cox-hazard regression model. The effects of neoadjuvant chemotherapy on outcomes were evaluated using a matched-pair analysis. The oncologic outcomes of patients who did or did not receive neoadjuvant chemotherapy were compared (cx+ and cx-).ResultsMultivariate analysis revealed significant correlations of distant postoperative metastasis (hazard ratio [HR] = 0.01, p<0.001) with overall survival; surgical margin type (marginal resection, HR=0.12, p=0.011 and intralesional resection, HR=0.08, p=0.022 versus wide resection) with local recurrence; and postoperative local recurrence (HR=0.30, p=0.027) and surgical margin (marginal resection, HR=0.31, p=0.023 versus wide resection) with distant relapse-free survival. Before propensity score matching, neoadjuvant chemotherapy was mainly administered for the patients with younger age, deeper tumor locations, larger tumors, more advanced-stage disease, and monophasic-type disease. The 3-year overall survival rates, local control rates and distant relapse-free survival rates were 82.9% / 80.7% (HR = 0.79, p = 0.102), 91.2% / 89.8% (HR = 1.04, p = 0.837) and 76.6% / 75.0% (HR = 0.76, p = 0.307) in the cx+/cx- groups, respectively. After propensity score matching, 172 patients were selected such that the patient demographics were nearly identical for both the groups. The 3-year overall survival rates, local control rates and distant relapse-free survival rates were 80.8% / 81.4% (HR = 0.83, p = 0.563), 93.2% / 89.4% (HR = 0.83, p = 0.491) and 76.9% / 78.7% (HR = 1.01, p = 0.982) in the cx+ and cx- group, respectively.ConclusionThis large-sample study indicated that the margin status and postoperative disease control were associated directly or indirectly with improved oncologic outcomes. However, the efficacy of neoadjuvant chemotherapy for survival outcomes in synovial sarcoma patients was not proven.