Synovial Sarcoma: The Influence of Clinicopathological Variables on Overall Survival in a UK Population

Introduction
Synovial sarcoma accounts for 5%-10% of malignant soft-tissue tumours. Curative treatment includes surgery, with radiotherapy and/or chemotherapy. With no specific treatment regimen for synovial sarcoma, the primary aim of this research was to describe the characteristics of a regional synovial sarcoma population in the UK, and to investigate clinicopathological variables associated with overall survival.

Methods
Ninety-four patients with synovial sarcoma from the East Midlands Sarcoma Service database were pseudo anonymised and clinicopathological variables extracted. Kaplan-Meier and Cox regression statistical analyses were used to identify variables affecting overall survival.

Results
Mean age at diagnosis was 42 years (range 8 – 83 years). Over half (n=50, 53%) of patients had a tumour in the lower limb. Thirty-seven (39.6%) had a tumour size of <5cm. Sixteen (17%) patients had local recurrence, and under half (n=40 43.5%) developed metastatic disease. Most patients (n=63, 63%) were initially treated with surgery. The majority (n=58, 61.7%) had a monophasic subtype, and the overall survival of the whole cohort was 83 months (95% CI 39.1-127.8). Increasing tumour size and distant recurrence (metastasis) had a significantly negative impact on median overall survival (p = 0.0001). Patients who underwent surgery and radiotherapy had a significantly better median overall survival (p = 0.02). Multivariable analysis identified adjuvant radiotherapy (p = 0.039), lower limb tumour (p = 0.033), and tumour size (<5 cm p = 0.006, 5-10 cm p = 0.0001, >10 cm p = 0.013) as significant survival predictors.

Conclusion
Adjuvant radiotherapy is a novel independent prognostic marker for synovial sarcoma.