Assessing the magnetic resonance imaging in determining the depth of invasion of tongue cancer.

OBJECTIVES: To assess the magnetic resonance imaging (MRI) in predicting tumour's depth of invasion (DOI) of tongue cancer by comparing to pathology and to determine the cut-off value of MRI-derived DOI for lymph node metastasis. PATIENTS AND METHODS: In a retrospective analysis, 156 patients with newly diagnosed tongue cancer were included. Tumour's DOI was compared between MRI measurement and pathology by Pearson correlation coefficient and paired t test. The accuracy of MRI-derived DOI was compared to the pathological DOI. The relationship between MRI-derived DOI and cervical lymph node metastasis was calculated by receiver operating characteristic curve. RESULTS: Tumour's DOI was well correlated between MRI measurement and pathology with correlation coefficients of 0.77. MRI-derived DOI was 3.4 mm (28%) larger than pathology. The accuracy of MRI in deciding pathological DOI was 67.9%. The cut-off value of MRI-derived DOI was 10.5 mm for lymph node metastasis of tongue cancer. CONCLUSION: Magnetic resonance imaging can be used as a reference to determine tumour's DOI of tongue cancer. Tumour with MRI-derived DOI larger than 10.5 mm deserves simultaneous neck dissection at initial surgery.