Lymphatic invasion as a prognostic indicator in surgically treated tongue squamous cell carcinoma.

OBJECTIVE: Tongue squamous cell carcinoma is associated with a substantial risk of recurrence after primary surgical treatment. Accurate identification of pathological prognostic factors is therefore essential to optimize postoperative management and risk stratification. This study aimed to identify clinicopathological factors associated with recurrence and overall survival (OS), with particular emphasis on the prognostic significance of lymphatic invasion. METHODS: The data of 96 patients who underwent primary surgical treatment for tongue squamous cell carcinoma between 2013 and 2022 at Chiba University Hospital were retrospectively collected. Recurrence-free survival and OS, measured from the date of initial treatment, were estimated using the Kaplan-Meier method and compared using the log-rank test. A multivariate Cox proportional hazards regression model including lymphatic invasion, T classification, and N classification was performed to evaluate factors associated with recurrence. RESULTS: Lymphatic invasion and a positive horizontal margin were significantly associated with poorer recurrence-free survival in univariable analysis (p = 0.016 and p = 0.040, respectively). In multivariate Cox proportional hazards regression analysis, lymphatic invasion remained independently associated with recurrence after adjustment for T and N classification (hazard ratio [HR], 2.44; 95% confidence interval [CI], 1.11-5.38; p = 0.026). For overall survival, lymphatic invasion, venous invasion, perineural invasion, positive horizontal margin, and DOI were significantly associated with OS in univariable analysis (p = 0.011, 0.014, 0.020, 0.011, and 0.048, respectively). CONCLUSION: Lymphatic invasion was independently associated with recurrence after adjustment for T and N classification. Assessment of lymphatic invasion may provide additional prognostic information for postoperative risk stratification.