Soft tissue sarcomas can develop from soft tissues like fat, muscle, nerves, fibrous tissues, blood vessels, or deep skin tissues. There are approximately 50 types of soft tissue sarcomas, including synovial sarcoma, a cancer of the connective tissue around joints.
Synovial sarcoma accounts for approximately 6% to 10% of all soft tissue sarcomas. Approximately one third of synovial sarcomas occur in childhood and the peak incidence is in the third decade of life, with 70% of sarcomas occurring in patients younger than 40 years old. The majority of patients who develop metastatic soft tissue sarcomas are currently incurable, with 75% to 80% of patients not surviving past two to three years. First line therapy typically involves radiotherapy and chemotherapy, as well as surgical resection where possible. There are limited additional treatment options for unresectable, recurrent and metastatic synovial sarcoma, which is nearly always fatal, and systemic therapy is mainly used to provide palliation and slow disease progression.