[18F]-FDG PET/CT imaging for detection of nodal metastases in patients with squamous cell carcinoma of the pharynx and larynx: comparison with CT

Our aim was to investigate the diagnostic accuracy of fluorine-18-labeled fluorodeoxyglucose positron emission tomography computed tomography (FDG-PET/CT) relative to CT for detecting neck lymph node metastases in patients with squamous cell carcinoma (SCC) of the hypopharynx, oropharynx, and larynx. Thirty-four patients with SCC of the hypopharynx (n = 20), oropharynx (n = 5), and larynx (n = 9) who underwent neck dissection (29 bilateral, 5 unilateral; a total of 355 nodal levels) were assessed. Two observers determined the long-axis diameter and maximum standardized uptake value (SUVmax) of all visible neck nodes. Results of FDG-PET/CT were compared with those of corresponding histopathologic examinations according to the neck-level system. Histopathology revealed metastases in 70 of 355 nodal levels. Using a best discriminative SUVmax cutoff of 3.65, sensitivity, specificity, and accuracy of FDG-PET/CT on a level-by-level basis were 72.9, 96.8, and 92.1 %; those for CT were 52.9, 98.6, and 89.6 %. Differences in sensitivity and accuracy were significant (p < 0.01). The best cutoff SUVmax on the ipsilateral side was 4.61, with corresponding figures of 81.6, 100, and 94.7 %; that on the contralateral side was 2.41, with figures of 60, 88.4, and 85.4 %. FDG-PET/CT with SUVmax is useful for preoperative evaluation of neck-node metastasis from SCC of the pharynx and larynx, especially on the ipsilateral side.