Tumor Infiltrating Lymphocytes as a Determinant of Lymph Node Metastasis in Oral Squamous Cell Carcinoma

Abstract Background Tumor-infiltrating lymphocytes (TILs) represent the host immune response and may influence metastatic behavior in oral squamous cell carcinoma (OSCC). Objective To evaluate the diagnostic accuracy of stromal TILs in predicting clinical and pathological lymph node metastasis in OSCC. Methods Analytical cross-sectional study including 170 OSCC patients. Stromal TILs were quantified on H&E sections and classified into high vs. low groups. Their association with clinical nodal staging and pathological nodal metastasis was studied. ROC analysis assessed predictive performance. Results Low stromal TILs were significantly associated with pathological nodal metastasis ( p < 0.001) and with clinical nodal positivity ( p < 0.001). Among clinically N0 patients, 76.9% of occult nodal metastasis occurred in low-TIL tumors. ROC analysis showed moderate accuracy overall (AUC 0.603) and better performance in N0 patients (AUC 0.676). Conclusion Stromal TILs are inversely associated with nodal metastasis in OSCC and may improve the accuracy of clinical nodal staging, especially in N0 disease.