Correlating MRI and histologic tumor thickness in the assessment of oral tongue cancer

OBJECTIVE. Tumor thickness in oral tongue cancer is an important independent prognostic factor for local recurrence, nodal metastasis, and patient survival. An accurate preoperative assessment of tumor thickness is therefore essential for optimal treatment planning. The aim of our study was to evaluate the accuracy of MRI findings for the preoperative measurement of tumor thickness. SUBJECTS AND METHODS. Eighteen patients with oral tongue cancer underwent preoperative MRI of the tongue. After surgery, the glossectomy specimens were serially sectioned. The radiologic tumor thickness of contrast-enhanced T1-weighted and T2-weighted images was compared with the histologic tumor thickness using our proposed tumor thickness staging classifications. These included stage I (tumor less than or equal to 3 mm), stage II (> 3 mm but less than or equal to 9 mm) and stage III (> 9 mm). RESULTS. The overall accuracy in assessment of proposed tumor thickness staging using contrast-enhanced T1-weighted and T2-weighted images was 83% and 56%, respectively. The radiologic tumor thickness as measured on contrast-enhanced T1-weighted and T2-weighted images had significant correlation with histologic tumor thickness (R = 0.938 and 0.941, respectively). CONCLUSION. MR images provide satisfactory accuracy for the measurement of tumor thickness and staging of oral tongue cancer. Preoperative MRI is recommended to assist in treatment planning for patients with this disease.