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

ABSTRACT

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: The prognostic impact of pathologic grade is highly variable across head and neck subsites and is the strongest among OCC patients.