Treatment Approaches and Outcomes for Primary Mediastinal Sarcoma: Analysis of 976 Patients.

BACKGROUND: Primary mediastinal sarcomas are rare and deadly. Our objective was to describe the clinicopathological features, treatment strategies, and overall survival outcomes for a contemporary cohort of patients diagnosed with primary mediastinal sarcoma in the United States.

METHODS: We queried the National Cancer Database for cases of mediastinal sarcoma diagnosed from 2004 to 2012. Five-year overall survival (OS) was examined using the Kaplan-Meier method. Differences in OS were assessed using log-rank analysis and Cox proportional hazards regression.

RESULTS: The mean age of diagnosis was 53 years (range, 0 to 90) with a male predominance (59.2%). The most common histological subtype was hemangiosarcoma (27.1%). Fewer than half of patients underwent surgery (48.9%), and 19.7% of patients had no treatment. For all patients, OS was 14.8%. The best unadjusted OS was seen in patients treated with surgery and radiation (40.1%); untreated patients had the worst unadjusted OS (4.2%). Of those who underwent surgery (n = 477, 48.9%), OS was significantly better for those who achieved an R0 resection (30.1% versus 18.9%; p = 0.002). In multivariable analysis, surgery combined with radiation therapy was again associated with the best survival (HR, 0.24; 95% CI, 0.16 to 0.36). Other factors associated with improved OS included younger age, fewer comorbidities, and leiomyosarcoma histology. Worse OS was associated with poorly differentiated or undifferentiated grade, metastases, treatment in the New England region, and having Medicaid or no insurance. Sex and tumor size had no effect on OS.

CONCLUSIONS: The 5-year OS for primary mediastinal sarcoma is poor. Surgical resection can be successful and should be considered whenever possible.