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 pairedttest. 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.