Characterization of alveolar soft part sarcoma using a large national database.

Background: Alveolar soft part sarcoma is a rare, histologic subtype of soft tissue sarcoma that remains poorly defined. We aimed to describe patient characteristics and treatment patterns and to examine factors associated with survival for patients with alveolar soft part sarcoma.

Methods: After identifying patients with alveolar soft part sarcoma in the National Cancer Database, we recorded their clinicopathologic characteristics. Univariable log-rank survival analysis and Cox proportional hazards model were employed. For context, survival comparisons were included for patients with other sarcoma subtypes.

Results: Overall, 293 patients with alveolar soft part sarcoma were identified. Interestingly, patients with head and neck tumors were least likely to present with distant disease (40%, P = .025). The majority of patients underwent resection (n = 183, 63%). Among those, no predictors of lesser survival were identified other than the presence of metastases (hazard ratio 6.04, P ≤ .001). Patients with stage IV alveolar soft part sarcoma who underwent resections experienced improved survival relative to similar patients with more common subtypes of soft tissue sarcomas (P ≤ .001).

Conclusion: Alveolar soft part sarcoma is exceedingly rare, and patients often present with metastases. Primary tumors can occur anywhere in the body, and location impacts the rates of metastases at presentation. Resection is associated with a favorable survival advantage when compared to other, more common histologic subtypes of soft tissue sarcomas.