Role of Computed Tomography in Prediction of Depth of Invasion and Cervical Lymph Node Metastasis in Oral Cancer

The primary aim is to determine the accuracy of contrast-enhanced computed tomography (CT) in evaluation of depth of invasion (DOI) and detection of cervical node metastasis. We also analysed the relation between radiographic DOI (rDOI) and cervical lymph node metastasis.

We have retrospectively reviewed 201 oral squamous cell carcinoma (SCC) patients. The rDOI was compared with histological DOI. Sensitivity, specificity, accuracy, and negative (NPV) and positive (PPV) predictive values were evaluated for CT scan in predicting nodal metastasis. The relation between rDOI and lymph node metastasis was analysed using ROC curve.

rDOI correlated significantly with histologic DOI for oral tongue, buccal mucosa, gingiva, and mucosal lip SCC (P < 0.05) and for tumours with rDOI > 5 mm. The sensitivity, specificity, PPV, NPV and accuracy rate of CT scan were found to be 84.71%, 50.86%, 55.81%, 81.94% and 65.17%, respectively. Tumours with rDOI > 16 mm had significant (P < 0.001) chance of having neck node metastasis.

CT-derived DOI correlates significantly with pathological DOI although both are not similar. CT scan can predict nodal metastasis in fairly accurate manner using the four radiographic criteria used in this study. Radiographic depth of invasion can be used as predictor of cervical node metastasis.