Predictors of extra nodal extension in oral squamous cell carcinoma: A retrospective analysis

ABSTRACT Background: Extranodal extension (ENE) has emerged as the strongest predictor of recurrence in oral squamous cell carcinoma (OSCC) and the only operator-independent predictor of treatment intensification in the form of adjuvant chemoradiation. Objectives: The primary objective was to identify various clinical and pathological predictors of pathological ENE (pENE) in surgically resected OSCC, and the secondary objective was to determine accuracy of clinical ENE (cENE) in predicting pathological ENE (pENE). Materials and Methods: In this retrospective analysis, we included all biopsy proven patients with OSCC who underwent surgery with appropriate neck dissection from April 2018 - December 2022 at the Department of Otolaryngology-Head-and-Neck Surgery, All India Institute of Medical Sciences Rishikesh, India. Tumors were staged according to the American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) 8 th edition tumor, node and metastasis (TNM) classification. Clinical and pathological variables were subjected to univariate and multivariate analyses. Results: We enrolled 299 patients in this study. Pathological bone invasion (BI), presence of perineural invasion (PNI), total number of positive lymph nodes, and lymph node ratio (LNR) were found to be independent predictors of pENE in both univariate and multivariate analyses. Post hoc analysis showed that ≥ 5 positive lymph nodes and LNR of ≥ 0.1 were significantly associated with pENE. Clinical ENE (cENE) exhibited a high specificity (92.9%) and negative predictive value (89.4%) for pENE. Conclusion: Clinical tumor characteristics are poor predictors of pENE. BI, PNI, and pathological nodal parameters, namely, total number of positive nodes and lymph node ratio, are the major predictors of pENE.