Significance of Preoperative Imaging‐Detected Extranodal Extension in Pathological Extranodal Extension‐Positive Head and Neck Squamous Cell Carcinoma Treated With Postoperative Chemoradiotherapy

BACKGROUND: The Head and Neck Cancer International Group (HNCIG) recently proposed standardized classifications for imaging-detected extranodal extension (iENE) and pathological ENE (pENE). We evaluated the prognostic value of iENE in pENE-positive head and neck squamous cell carcinoma (HNSCC) treated with postoperative chemoradiotherapy (CRT). METHODS: Patients with pENE-positive HNSCC who underwent postoperative CRT were retrospectively analyzed. iENE and pENE were re-classified using HNCIG criteria. Recurrence-free survival (RFS) and overall survival (OS) were analyzed using Kaplan-Meier and Cox proportional hazards models. RESULTS: Ninety-two patients were included. iENE grades 2-3 were associated with significantly worse outcomes than grades 0-1 (3-year RFS: 68.5% vs. 31.5%, log-rank p = 0.0002; 3-year OS: 85.0% vs. 63.2%, log-rank p = 0.02). In multivariable analysis, iENE was the only independent prognostic factor for RFS and OS. CONCLUSION: Preoperative iENE is a prognostic factor in pENE-positive HNSCC after postoperative CRT, with grades 2-3 identifying a very high-risk population.