Determinants of survival in parotid gland carcinoma: A population-based study

To determine survival and factors influencing survival for parotid gland cancer. Cases of parotid gland malignancy were extracted from the SEER database for 1988 to 1998. Kaplan-Meier survival analysis was conducted for the most common tumor histologies. Cox proportional hazards modeling was conducted to determine the influence of age, gender, histopathology, grade, size, regional modal status, extraglandular extension, and radiation therapy on survival. Subset analysis was conducted for mucoepidermoid carcinoma according to grade. Nine hundred three patients were identified with a mean age of 59.2 years. Mean follow-up was 51.8 months. Mean 5-year and 10-year actuarial survivals for the entire cohort were 87.8 months, 66.6% and 49.7%, respectively. Mean tumor size at diagnosis was 2.7 cm; 38.0% of patients had extraglandular extension of the tumor, 26.8% of patients had positive nodal disease, and 59.4% of patients received radiation therapy. Tumor histology did predict survival, with squamous cell carcinoma and acinar cell carcinoma exhibiting the poorest and best survivals, respectively. Stratified Cox proportional hazards modeling revealed that increasing age, tumor size, grade, extraglandular extension, and nodal positivity significantly negatively influenced survival (all P ≤. 001); radiation therapy conferred a survival benefit (P =. 090), whereas gender did not significantly affect survival. Increasing tumor grade, nodal disease, and extraglandular extension carried particularly high hazards ratios. Survival in parotid gland malignancy is influenced by multiple factors. Patients with multiple poor prognostic features such as extraglandular extension, aggressive tumor histologies, and nodal disease will exhibit poorer survivals and may be candidates for more aggressive treatment protocols.