Multidetector CT Evaluation of Oral Cavity and Oropharynx Malignant Tumours

Squamous cell carcinoma is the most frequent malignancy of oral cavity and oropharyngeal region, accounting for 5 % of all malignant tumors worldwide. Geographic variations in incidence and mortality have been observed due to prevalence of known aetiological riskfactors, such as tobacco and alcohol use. By mapping out the extent of disease, cross-sectional imaging completes the picture given by clinical examination and also evaluate lymph node involvement and bone invasion in oral cavity and oropharynx malignancy. CT and MR imaging are the imaging modalities useful in the evaluation of the oral cavity and oropharynx malignant tumours. CT is useful to look for bony erosions and also to assess lymph node metastasis in the neck using contrast CT with 5-mm axial sections. The aim of the study was to compare the sensitivity of CT with clinical staging in tumor extent, lymph node involvement and bone erosion in oral cavity and oropharyngeal malignant tumors. Over a period of 24 months, 67 patients histopathologically proven to have carcinoma of oral cavity and oropharynx and underwent contrast enhanced computed tomography scan of neck in Department of Radio-diagnosis, K. S Hegde Medical Hospital were included in the study. All patients with oral cavity tumours underwent Puffed-cheek technique at the time of image acquisition. The clinical examination findings were obtained from patients records. Correlation of clinical examination and CT findings with histopathology findings with respect to tumor extent, nodal involvement and bone invasion was done by sensitivity, specificity, PPV, NPV and by overall accuracy. Out of 67 patients studied, 52 were males and 15 were females and the mean age of the study population was 55 years. The most common primary site of malignancy was found to be buccal mucosa (52 %). The sensitivity of clinical examination for tumor extension was 82 %, for lymph nodal involvement 50 % and for bone invasion 50 %. The sensitivity of CT for tumor extension was 96 %, for lymph nodal involvement 92 % and for bone invasion 89 %. When compared to clinical examination CT was found to be more sensitive in predicting lymph nodal involvement and bone invasion. CT performed slightly better than clinical examination to assess tumor extension. The CT scan showed high efficiency in excluding bone involvement when compared to clinical examination and this provides a good guidance for surgery.