Risk Factors Including Age, Stage and Anatomic Location that Impact the Outcomes of Patients with Synovial Sarcoma

Synovial sarcoma is a high-grade soft tissue sarcoma that inflicts mostly children and young adults with high mortality rate; however, the risk factors that impact the outcomes remain incompletely understood. We have identified the synovial sarcoma cases from the Kaiser Permanente Northern California cancer registry between 1981 and 2014. Kaplan–Meier plots were used to display disease-free survival (DFS) and overall survival (OS); log-rank tests and Cox proportional hazard models were used to determine the impact of clinical factors on DFS, OS, and disease-specific survival. Tumor size > 5.0 cm and age > 50 years were associated with higher risk of presenting with stage IV disease. Median OS for patients with stage IV was 1.3 years and 7.8 years for early-stage disease. For patients with early-stage disease, tumor size > 5.0 cm was significantly associated with worse DFS, sarcoma-specific morality, and OS. Compared to extremity primary, patients with head and neck and trunk primary had approximately three-fold higher sarcoma-specific mortality and lower OS. There was no significant difference in DFS or OS among three histologic subtypes. Pre-operative and/or post-operative chemotherapy was not associated with improvement in DFS or OS. Twenty-six patients relapsed with predominantly lung metastasis, thirteen of whom received metastatectomy with a median OS of 7.8 years, compared to 2.3 years for patients who did not receive metastatectomy. In conclusion, age older than 50 years and tumor size > 5.0 cm are risk factors for presenting with stage IV disease. For early-stage patients, trunk and head and neck primary as well as tumor size > 5.0 cm are risk factors for decreased OS