Predictors of nodal metastasis in thin tongue tumours (depth of invasion <5 mm) - revisited.

Various predictors of nodal metastasis and threshold values for depth of invasion (DOI) have been reported in early-stage tongue cancer . This study aimed to evaluate the predictors of nodal metastasis in patients with thin tongue tumours (DOI <5 mm). A retrospective analysis was conducted using data collected prospectively from 240 patients with thin tongue tumours, categorized as node-positive or node-negative. Univariate and multivariate analyses were performed to identify predictors of nodal metastasis, and receiver operating characteristic (ROC) curve analysis was used to determine the predictive power of DOI and tumour size. DOI was not found to be significantly associated with nodal metastasis (P = 0.31). However, tumour size (P = 0.028) and lymphovascular invasion (LVI) (P < 0.001) were identified as independent predictors of nodal metastasis. ROC curve analysis for DOI revealed weak predictive power (AUC = 0.545), whereas tumour size showed moderate predictive power (AUC = 0.642). These findings indicate that DOI is not predictive of nodal metastasis in thin tongue tumours, but tumour size and LVI are significant predictors, with tumour size >15 mm being a critical threshold.