The role of neoadjuvant chemotherapy in resectable primary synovial sarcoma

Abstract

Background: The role of neoadjuvant chemotherapy for localized synovial sarcoma is still controversial. This study aimed to explore the influence of neoadjuvant chemotherapy combined with surgery in localized synovial sarcoma through analysis of our hospital's patient records. Patients and Methods: A total of 122 patients diagnosed with synovial sarcoma were enrolled in this study from January 1980 to December 2016 at the Cancer Institute Hospital of The Japanese Foundation for Cancer Research. The impact of neoadjuvant chemotherapy on overall survival was assessed to show how clinicopathological factors (e.g. age, tumor size, treatment, dose intensity, pathological pattern and histological grading) influenced patient prognosis. Results: Among 106 patients, 76 (71.7%) received neoadjuvant chemotherapy and 30 (28.3%) did not. The median follow-up was 39.2 (range=12-286) months. The 5-year and 10-year overall survival rates were 65.4% and 58.4% respectively. The tumor size and histological grade influenced the patient's overall survival (p<0.05). Among the patients with grade 2 tumor, tumor size did not influence prognosis. Neoadjuvant chemotherapy improved the overall survival of patients who had grade 3 tumors. Conclusion: Treatment with neoadjuvant chemotherapy proved beneficial for high-risk patients with grade 3 synovial sarcoma but was not effective for those with low-risk and grade 2 tumor. Tumor size and histological grade were important factors in patient prognosis but had no connection with pathological patterns. Synovial sarcoma is a high-grade malignant tumor, it accounts for approximately 5-10% of all soft-tissue sarcomas, and mainly develops in the para-articular regions in adolescents and young adults (1). The combination of surgery and chemotherapy has resulted in about a 60% 5-year survival rate (2, 3), but the 10- year survival rate remain surprisingly low. Therefore, identification of appropriate therapy for this sarcoma type is urgently needed. Neoadjuvant chemotherapy is commonly performed for high-grade soft-tissue sarcoma to reduce the risk of local and metastatic recurrence (4). Compared with other soft-tissue sarcomas, synovial sarcoma is considered to be a chemosensitive tumor. As evidenced by the results of clinical trials conducted on adult (5-8) and pediatric (9, 10) patients. However, in previous studies, it has been reported that several factors influenced the prognosis of patients with synovial sarcoma. Treatment using neoadjuvant chemotherapy in patients with resectable synovial sarcoma remains controversial. Synovial sarcoma is characterized by a chromosomal translocation between chromosomes 18 and X, generating oncoproteins such as synovial sarcoma translocation, chromosome 18-synovial sarcoma X chromosome breakpoint 1 and 2 (SS18-SSX1 and SS18-SSX2) (11, 12). This translocation is present in greater than 95% of cases and is likely to be the oncogenic driving event in the development of this tumor (6). Pathologically, synovial sarcoma is mainly divided into two types: Monophasic and biphasic. According to The French Federation of Comprehensive Cancer Centers (FNCLCC) grading system, by tumor differentiation score, this tumor is classified either as histological grade 2 or 3 (13). Our study sought to clarify the prognostic factors or the influence of neoadjuvant chemotherapy for patients with resectable synovial sarcoma. To analyze the influencing factors for the prognosis of patients with this tumor type, 106 patients with resectable synovial sarcoma were enrolled in a single-center study over 35 years and the overall survival rate was assessed.