Variations in the association of grade with survival across the head and neck cancer landscape.

Abstract

Although pathologic tumor grade is a well-established prognostic risk factor that impacts staging and treatment decisions across multiple cancer types, its role in head and neck squamous cell carcinoma (HNSCC) is less certain. HNSCC patients diagnosed from 2010 to 2015 and undergoing primary surgery in the National Cancer Data Base were identified. Propensity score matching and multivariable Cox regression were performed. Among 27 041 HNSCC patients, 13 941 had oral cavity cancers (OCC). Intermediate-grade (hazard ratio [HR] 1.16, 95% CI 1.07-1.26, P < .001) and high-grade (HR 1.38, 95% CI 1.26-1.52, P < .001) tumors had worse survival than low-grade tumors. This magnitude was comparable to other well-established prognostic factors, including margin positivity, extranodal extension, and lymphovascular invasion. By contrast, there was no association between grade and survival in larynx/hypopharynx or HPV(-) oropharynx cancer. The prognostic impact of pathologic grade is highly variable across head and neck subsites and is the strongest among OCC patients.