Clinical utility of CT and FDG PET/CT in assessing the neck in node-positive head and neck cancer after chemoradiotherapy.

Abstract

6082 Background: Concurrent chemoradiotherapy has been widely accepted to treat locoregional advanced head and neck cancer, but the need for subsequent neck dissection remains controversial. Our objective was to determine whether CT or fluorodeoxyglucose (FDG) PET/CT is superior in the evaluation of persistent nodal disease after chemoradiotherapy in patients with node-positive head and neck squamous cell carcinoma (HNSCC). Methods: Study entry criteria included node-positive HNSCC treated with concurrent chemoradiotherapy, a local complete response, and post-treatment CT and FDG PET/CT studies 11 weeks after chemoradiotherapy. Fifty-eight patients with 68 node-positive necks were eligible. Nodes larger than 1 cm (minor axis), or with central necrosis on CT, or any visually hypermetabolic nodes on FDG PET/CT were considered clinically positive. Regardless of PET/CT findings, necks with positive CT were subjected to neck dissection, whereas those with negative CT were observed without neck dissection. Results: Seventeen necks showed positive CT, 13 and 4 of which underwent neck dissection and fine needle aspiration cytology, respectively, resulting in pathologic evidence of persistent nodal disease in 5 necks. Four of 51 necks with negative CT developed regional recurrence. Diagnostic accuracy of CT and PET/CT is shown in table. In general, the negative predictive value (NPV) was equivalent between CT and FDG PET/CT, whereas FDG PET/CT was better than CT in the specificity and accuracy. Conclusions: In patients with HNSCC, both CT and FDG PET/CT after chemoradiotherapy have a high NPV for excluding residual regional disease and avoiding unnecessary neck dissection. Although the NPV is similarly high, PET/CT has superior utility compared with CT because the number of false positive findings is less in PET/CT than CT. [Table: see text]