Clinical outcome of patients with carcinoma ex pleomorphic adenoma of the parotid gland: a comparative study from a single tertiary center.

BACKGROUND Carcinoma ex pleomorphic adenoma (CXPA) of the parotid gland is a high-grade cancer and the prognosis of this cancer has not been compared with non-CXPA high-grade primary parotid cancer. METHODS Retrospective medical chart review of patients with surgically treated high-grade primary parotid cancer (21 CXPA and 52 non-CXPA) was performed with correlation with disease-specific survival, locoregional recurrence, and distant recurrence. RESULTS Despite having similar stage of cancer and extent of surgical resection, patients with CXPA had a lower disease-specific survival compared to non-CXPA high-grade primary parotid cancer (p = .02). Salivary duct cancer (SDC) was the commonest histologic variant in both cohorts and around 40% of patients with SDC died of distant recurrence that occurred within 3 years from diagnosis. CONCLUSION CXPA of the parotid gland is a more aggressive cancer compared to non-CXPA high-grade primary parotid cancer. SDC was associated with a high chance of delayed distant recurrence, which contributed directly to the mortality of this cancer.