Oncologic Outcomes in Patients with Localized, Primary Head and Neck Synovial Sarcoma

Background: this study aims to evaluate the survival outcomes of patients suffering from head and neck synovial sarcoma (HNSS), especially in relation to patients with a localized disease at diagnosis. Methods: this retrospective chart review includes 57 patients diagnosed with primary HNSS between 1981 and 2020 who presented with a localized disease at diagnosis. Overall survival (OS) from diagnosis, local recurrence-free survival (LRFS), and metastasis-free survival (MFS) from the end of the primary tumor treatment are estimated. The Kaplan-Meier method, the log-rank test, and the Cox proportional hazards regression are used. Results: the 5-year OS, LRFS, and MFS are estimated at 80.4% (95% CI: 66.6%, 88.9%), 67.7% (95% CI: 50.0%, 80.4%), and 50.6% (95% CI: 34.4%, 64.8), respectively. Compared to patients undergoing surgical resection alone, those receiving radiation therapy (RT) with surgery have better LRFS (HR: 0.03, 95% CI: 0.001, 0.57), and those undergoing neo/adjuvant chemotherapy with surgery and RT have better MFS (HR: 0.10, 95% CI: 0.01, 0.95). Moreover, among the patients with tumors ≥ 4 cm, those subject to neo/adjuvant chemotherapy have significantly better MFS (5-year MFS: 53.2%, 95% CI: 29.0%, 72.5%) than those treated with surgery and RT alone (5-year MFS: 20.0%, 95% CI: 0.8%, 58.2%) (LR-p = 0.003). Conclusions: overall, the prognosis of HNSS patients looks favorable. Perioperative RT significantly improves local control, and perioperative chemotherapy plays a vital role in delaying metastasis formation in patients with primary HNSS when diagnosed with a localized disease. Importantly, we recommend that systemic therapy should be considered for HNSS patients with tumors ≥ 4 cm.