MRI-derived tumor thickness: an important predictor of outcome for T4a-staged tongue carcinoma.

The objectives of this paper are to evaluate the heterogeneity of magnetic resonance imaging (MRI)-derived tumor thickness within tumors of the same T4a-staged tongue carcinoma and to elucidate the effects of tumor thickness on treatment outcomes. A sequential and prospectively maintained head and neck cancer database was retrospectively searched for newly diagnosed tongue carcinoma treated with surgery between 2003 and 2006. Fifty-eight patients with newly diagnosed T4a-staged tongue carcinoma were included in this study. Tumor thickness was obtained from preoperative magnetic resonance imaging. The mean MRI-derived tumor thickness was 22.29 mm. The patients with long tumor thickness (>26 mm) were associated with a significantly poor disease-specific survival (P = 0.015). The 2-year disease-specific survival rates were 72% in patients with short tumor thickness and only 27% in patients with long tumor thickness within the same T4a-staged disease. A substantial variation in MRI-derived tumor thickness was present within the same T4a-staged tongue carcinoma, and tumor thickness represented an important prognostic factor.