Impact of Extranodal Extension in Patients With Regional Metastases of Head and Neck Cutaneous Squamous Cell Carcinoma.

Abstract

Extranodal extension (pENE) is common in metastatic head and neck cutaneous squamous cell carcinoma (HNcSCC), but its independent prognostic value is unclear. This study assessed whether pENE extent influences survival. A retrospective cohort of patients with metastatic HNcSCC treated surgically at Chris O'Brien Lifehouse (2015-2023) was analyzed. pENE was defined as tumor extension beyond the nodal capsule or soft-tissue deposits. Survival was assessed using Kaplan-Meier and Cox regression models. Of 585 patients, 81.5% had pENE, most commonly > 15 mm. Extensive pENE was associated with worse overall and disease-free survival on univariate analysis, but not after multivariable adjustment. Independent predictors of poorer outcomes included age, nodal size, nodal number, perineural invasion, and positive margins. pENE strongly correlated with nodal burden. pENE is highly prevalent in metastatic HNcSCC but lacks independent prognostic significance. More discriminatory, HNcSCC-specific nodal staging criteria are needed.