Diagnostic accuracy of magnetic resonance imaging (MRI) in the assessment of tumor invasion depth in oral/oropharyngeal cancer

The purpose of the present study was to evaluate the diagnostic value of MRI for measuring invasion depth in oral/oropharyngeal carcinoma. We retrospectively reviewed pathologic specimens and MRI findings of 114 patients who were diagnosed with squamous cell carcinoma of the oral cavity and oropharynx. Invasion depths were evaluated in pathologic specimens and by MRI. The mean histologic and MRI invasion depths were 13.57 ± 8.476 and 15.24 ± 10.700 mm, respectively. The overall Pearson's correlation coefficient for histologic and MRI (T1W-MRI) invasion depths was 0.825, which was statistically significant (P < 0.001). Pearson's correlation coefficients for histologic and MRI invasion depths in oral tongue, tongue base, and tonsil cancers were 0.949, 0.941, and 0.578, respectively. The MRI invasion depth was significantly different according to nodal status in cancers of the oral tongue (P = 0.001∗) and tongue base (P = 0.003∗). With MRI, the invasion depth cutoff values for determining positive nodes were 9.5 and 14.5 mm in cancers of the oral tongue and tongue base, respectively. Preoperative MRI is an accurate method for measuring tumor invasion depth in oral tongue and tongue base cancers. Furthermore, it has predictive value for nodal metastasis in the oral tongue and tongue base.