Abstract: Objective: Measuring the depth of invasion and tumor volume of tongue lesions in patients with cN0 stage by preoperative MRI, and further exploring the predictive value of depth of invasion and tumor volume in cervical lymph node metastasis and prognosis. Methods: 74 patients clinically diagnosed as cN0 stage tongue squamous cell carcinoma who underwent surgery in the Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University were collected. The tongue lesions were reconstructed, then the depth of invasion and volume were measured by IKT-SNAP and 3D slicer software. The ROC curve between the depth of invasion, tumor volume and cervical lymph node metastasis was drawn by R language, and the cutoff value was determined. The correlation between clinical parameters and cervical lymph node metastasis was analyzed by logistic regression, and the independent risk factors affecting the prognosis of patients were analyzed by univariate and multivariate COX regression. Results: Tumor volume of 6.3 cm3 and invasive depth of 14mm as a cutoff value to predict lymph node metastasis; Multivariate analyses revealed that depth of invasion was highly correlated with lymph node metastases and the prognosis of oral cancer (P < 0.05); Kaplan-Meier analysis showed that patients with invasive depth ≥ 14mm had a poor prognosis (P < 0.05). Conclusion: Depth of invasion based on preoperative MRI has the capability to independently predict the lymph node metastases and the prognosis of oral cancer, while three-dimensional Tumor volume did not show the same effect.

Key words: Tongue squamous cell carcinoma, MRI, tumor volume, depth of invasion, cervical lymph node metastasis