Pre-operative contrast enhanced computer tomographic evaluation of cervical nodal metastatic disease in oral squamous...

This prospective study was undertaken to evaluate the contrast enhanced computed tomography (CECT) criteria in detecting cervical lymph node metastasis in 50 patients with an oral squamous cell carcinoma (OSQCC).

A total of 50 patients with OSQCC who underwent clinical assessment, routine CECT scanning of cervical lymph node and radical neck dissection were analyzed. Radiologic criteria for diagnosing nodal metastasis in this imaging study were: A nodal size of 1 cm, the presence of central lucency despite the size of the lymph node and grouping of lymph nodes. These criteria were based on modified American Joint Committee on Cancer Radiological Nodal Staging Guidelines.

Chi-square test/Fisher Exact test has been used to find the significant association of findings. Diagnostic statistics viz.: Sensitivity, specificity, positive predictive value (PPV), negative predictive value, and diagnostic accuracy were obtained. The results were considered significant when P value was less than 0.05.

On using a nodal size of 1 cm and the presence of central nodal necrosis (CNN) as radiological criteria for nodal metastasis CT scanning staged 23 of the 27 histopathologically positive necks, providing accuracy of 88%, sensitivity of 92%, and specificity of 84% in detection of nodal metastasis. A significant relationship between the incidence of CNN, different nodal densities, and primary tumor differentiation was observed.

The nodal size cut-off of 1-1.5 cm had a maximal sensitivity of 90.91% and PPV of 86.96%. Furthermore, observation of nodal densities in the absence of frank CNN on the CT scan may be necessary especially in low grade primary tumor. CT assessment of cervical node metastasis was found acceptable, although adjuncts like ultrasound guided fine needle aspiration may further increase efficacy of CT scan in nodes lesser than 1 cm in size.