An Institutional Review of Patients Presenting with Localized Primary Intrathoracic Synovial Sarcoma
Introduction
Although intrathoracic sarcomas are common, primary intrathoracic synovial sarcoma (SS) subtype is a rare entity. Given the rarity of the diagnosis, the limited literature on these tumors are comprised predominantly of case reports or small case series mainly characterizing the clinicopathological and immunohistochemical features. The objective of this study was to evaluate multiple survival outcomes for patients with intrathoracic SS presenting with localized disease at the time of diagnosis.
Methods
We conducted a retrospective review of 68 patients diagnosed with intrathoracic SS between 1997-2020. Kaplan-Meier method and log-rank test were used to estimate the progression-free survival (PFS), overall survival (OS), local recurrence-free survival (LRFS) and metastasis-free survival (MFS). The hazard ratios were estimated by using Cox-proportional hazards regression.
Results
Median follow-up time, age at diagnosis, and primary tumor size were 32 months (range: 3-218 months), 44 years (range: 18-77), and 7.3 cm (range: 1-23), respectively. Among the entire cohort of 68 patients, distribution of female (57%) patients were higher than males (43%). Most of the patients were White (n= 62, 91%) in this study. Lung was the most common primary tumor site (n = 47, 69%), followed by mediastinum (n = 15, 22%), lung with involvement of pleura (n = 3, 4%), and inner chest wall (n = 3, 4%). 65 out of 68 (96%) patients had primary tumor resected from whom 18 (28%) and 36 (55%) had received neo/adjuvant radiotherapy and chemotherapy, respectively. Median PFS, OS, and MFS were 1.1, 3.3, and 1.2 years, respectively. The median LRFS was not reached. Based on the multivariable analysis, patients who had positive margin after resection had worse PFS (HR: 3.11; 95% CI: 1.50, 6.45, LR p=0.0117) than those with negative margin. Moreover, patients with 5-10 cm tumor size had worse OS (HR: 2.78; 95% CI: 1.09, 7.09; LR p=0.0120) than those with less than 5 cm tumor size.
Conclusion
Outcomes associated with intrathoracic SS remain poor. Our findings indicate that regardless of specific tumor location within the thorax, patients with 5-10 cm primary tumor size, and/or positive resection margin have especially poor survival.