Prognostic factors for squamous cell cancer of the parotid gland: An analysis of 2104 patients

BACKGROUND: Parotid gland squamous cell cancer (SCC) occurs as metastasis from cutaneous SCC or primary malignancy. There is limited data on incidence, prognosis, and treatment outcomes. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database (1988-2009) identified 2104 adult patients with parotid SCC. RESULTS: SCC is the second most common parotid malignancy, and its incidence is increasing (annual percentage change 1.7%; ptrend = .004). Age ≥85 years, tumor size ≥4 cm, extraparenchymal extension, cervical metastases, and distant metastases were independently associated with disease-specific mortality. Compared to no surgery, surgery was associated with improved 5-year disease-specific survival (DSS; 44.4% vs 71.0%; p < .001), whereas radiation alone was similar to no treatment (47.0% vs 41.6%; p = .28). CONCLUSION: Surgery and adjuvant radiation therapy (RT) are associated with improved survival compared to radiation alone and no treatment. Patients ≥85 years of age account for nearly 20% of all patients and have a poor prognosis independent of treatment.