Predictors of survival in carcinoma ex pleomorphic adenoma.

BACKGROUND Carcinoma ex pleomorphic adenoma (Ca ex PA) is a high-grade carcinoma arising from benign pleomorphic adenoma. This is the first population-level analysis of prognosis and prognostic features of parotid Ca ex PA. METHODS The Surveillance, Epidemiology, and End Results (SEER) database (1988-2009) was used to identify 278 patients with parotid Ca ex PA. RESULTS Extraparenchymal extension of the primary tumor was associated with cervical metastasis (35.7% vs 2.9%; p < .001). Independent predictors of disease-specific survival (DSS) were race (hazard ratio [HR], 7.12; 95% confidence interval [CI], 2.56-19.82), distant metastases (HR, 18.99; 95% CI, 5.06-71.21), and multiple metastatic lymph nodes (HR, 9.48; 95% CI, 4.14-21.71). Patients with multiple cervical lymph node metastases had decreased 5-year DSS compared with patients with ≤1 positive lymph node (42.7% vs 85.9%; p < .001). CONCLUSION The presence of 2 or more cervical lymph node metastases identifies patients with Ca ex PA with a poor prognosis.