Magnetic resonance determination of tumor thickness as predictive factor of cervical metastasis in oral tongue carcinoma

Objectives: To establish an accurate and reproducible means of measuring tumor thickness as a preoperative prognostic factor for cervical metastasis in oral tongue carcinoma. Study Design: Retrospective review. Methods. Charts from 30 patients were reviewed, and the correlation between histopathological and magnetic resonance imaging (MRI) findings of actual tumor thickness or reconstructed tumor thickness measured between a reconstructed mucosal line and the deepest extent of the tumor was investigated. Magnetic resonance images were acquired on a 1.5 T-scanner with a T2-weighted sequence in the axial plane using 3-mm-thick sections and a 256 X 256 matrix. The correlation between N stage and tumor thickness acquired by histopathological scrutiny or MRI was also assessed. Results: The correlation between histopathological and MRI examinations was more significant in terms of reconstructed than actual tumor thickness. No cervical metastasis was detected in patients with tumors of less than 6 mm of reconstructed thickness in the MRI examination. The difference in cervical metastasis between the two groups, namely, less than 6 or more than 6 mm, was statistically significant (P = .0051). Conclusions: Magnetic resonance imaging examination provides useful data for prognostic assessment and planning strategies with which to treat oral tongue carcinoma. The preoperative decision as to whether to attempt neck dissection could be based on a tumor thickness of 6 mm for patients with oral tongue carcinoma.