18F fluorodeoxyglucose PET/CT in head and neck squamous cell carcinoma with negative neck palpation findings: a prospective study

Abstract

Purpose: To assess the clinical usefulness of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and CT/magnetic resonance (MR) imaging in detecting occult neck metastasis in patients with head and neck squamous cell carcinoma and negative neck palpation findings.

Materials and methods: This prospective study was approved by the institutional review board, and written informed consent was obtained from all enrolled patients. In total, 91 patients with head and neck squamous cell carcinoma and negative neck palpation findings were assessed prospectively with (18)F-FDG PET/CT and CT/MR imaging. Histopathologic analysis of neck dissection samples served as the standard of reference. Diagnostic values of (18)F-FDG PET/CT and CT/MR imaging were compared by using the McNemar test and logistic regression with generalized estimating equations.

Results: Of 91 patients, 38 (42%) had metastasis in 43 neck sides and 70 levels of the neck. (18)F-FDG PET/CT demonstrated nodal metastasis more sensitively on a per-level basis than did CT/MR imaging (69% vs 39%, P < .001). CT/MR imaging demonstrated nodal metastasis with low sensitivity at all levels (0%-38%) except level II (55%), while (18)F-FDG PET/CT had generally high sensitivity at all levels (63%-100%) except level VI (0%). On a per-patient basis, the sensitivities of (18)F-FDG PET/CT and CT/MR imaging were 71% and 50%, respectively (P = .011). (18)F-FDG PET/CT accurately depicted CT/MR imaging false-negative findings in nine of 19 patients but yielded false-negative results in 11 patients. Use of (18)F-FDG PET/CT reduced the probability of occult neck metastasis to 12%.

Conclusion: (18)F-FDG PET/CT is superior to CT/MR imaging in depicting occult cervical metastatic nodes in patients with negative neck palpation findings. The improved detection and nodal staging may promote appropriate therapeutic planning in these patients.