(P 387) TREATMENT PATTERNS AND PROGNOSTIC FACTORS IN LOCALISED SYNOVIAL SARCOMA: A RETROSPECTIVE STUDY FROM A TERTIARY CANCER CENTRE IN INDIA

Objective: Synovial sarcoma (SS) is an uncommon subtype of soft tissue sarcoma, predominantly affecting adolescents and young adults. Although chemo-sensitive histology, the optimal role and timing of chemotherapy remain unclear. This study aimed to analyze clinical characteristics, treatment outcomes, and prognostic factors in patients with localized SS treated at a tertiary care centre in India.

Methods: We retrospectively reviewed 111 patients with histologically confirmed, localized SS treated at Tata Memorial Hospital, Mumbai, India, between 2010 and 2019. Clinical, pathological, and treatment data were collected. Survival outcomes: overall survival (OS) and disease-free survival (DFS) were assessed using Kaplan-Meier analysis and log-rank tests. Prognostic factors were evaluated through univariate analysis.

Results: The median age was 31 years, with a slight male preponderance. The most common site was the lower extremity (55.8%), and monophasic histology predominated (46.8%). About 63% of tumors were more than 5 cm size. Surgery was performed on 88.3% of patients, with 56.7% received chemotherapy (either perioperative or adjuvant) and 63.9% received radiotherapy. The 5-year OS and DFS rates were 62.2% and 54.1%, respectively. Poorly differentiated histology, larger size and higher ECOG performance status were associated with worse outcomes. Adjuvant chemotherapy was associated with improved OS compared to perioperative chemotherapy (HR 0.494, p = 0.043). Radiotherapy was also associated with better OS (HR 1.736, p = 0.033).

Conclusion: Multimodality treatment achieves favorable long-term outcomes in localized synovial sarcoma. Tumor differentiation, gender, and use of adjuvant therapy significantly impact prognosis. The apparent benefit of adjuvant over perioperative chemotherapy in this cohort warrants further
validation in prospective, multicenter studies.