Predictors of survival in parotid adenocarcinoma not otherwise specified: a National Cancer Database study of 3155 patients

Background: Parotid adenocarcinoma not otherwise specified (PANOS) is a common parotid cancer, but studies specifically on this subject are limited. Methods: We conducted a retrospective review of the National Cancer Database. Results: Ten percent of all parotid cancers were PANOS (n = 3155). Median age was 67 years. Most patients were men (62.8%) with high-grade histology (67.2%). Regional metastasis was common (35.9%), whereas occult nodal metastasis (20.2% overall) was less frequent in non-high-grade lesions (8.5% vs 31.6%; p <.001). Distant metastasis was rare (7.9%). Five-year overall survival (OS) was 47%. In multivariate analysis, age, regional metastasis, distant metastasis, high-grade, and T classification were predictors of lower survival. Patients with stage III to IV disease receiving surgery and radiotherapy had a better OS than those receiving surgery alone (51% vs 41%; p <.001). Conclusion: PANOS is an aggressive disease with frequent regional metastasis and low survival. Numerous variables are associated with worse survival.