COMPUTED-TOMOGRAPHY EVALUATION OF NECK NODE METASTASES FROM NASOPHARYNGEAL CARCINOMA

Purpose: To study the role of computed tomography in the pre-therapy e valuation of nasopharyngeal carcinoma. Methods and Materials: The comp uted tomography of 119 new patients of nasopharyngeal carcinoma were e valuated independent of clinical findings for neck node metastases, an d then compared with clinical findings. Contrast enhanced axial scans were obtained at 5 mm intervals with the infraorbitomeatal line parall el to the gantry. Scans were obtained from the supra-sellar cistern to the C5 or C6 vertebra for the evaluation of the base of skull, nasoph arynx, paranasopharyngeal space and the upper and mid neck. Result: Th e present study confirmed the disparity of nodal extent documented by clinical palpation and computed tomography. Of the 37 patients who hav e no clinically palpable node (NO), computed tomography showed nodal i nvolvement in 11 (29.7%) of them, and they were up-staged from N0 to N 1. Computed tomography showed multiple or bilateral nodes in seven (58 .3%) of the 12 patients with AJC N1 disease and they were hence up-sta ged to N2. All together, there were 28 (23.5%) patients who have no co mputed tomography evidence of nodal involvement by tumor. In agreement with clinical experience, the most commonly involved nodal groups wer e the upper internal jugular and upper spinoaccessary, followed by the lateral retropharyngeal. The percentage of nodes which were not clini cally palpable was roughly the same for different regions (15-30%), ex cept, as expected, that all the retropharyngeal nodes were not palpabl e. The risk of harboring retropharyngeal node was proportional to the size of the largest node in the ipsilateral neck. Conclusion: A signif icant proportion of patients with clinically negative neck (N0) or AJC N1 disease will be upstaged by computed tomography, thus supporting i ts routine use in pre-therapy evaluation of nasopharyngeal carcinoma.