18F FDG PET/CT versus CT/MR Imaging and the Prognostic Value of Contralateral Neck Metastases in Patients with Head and Neck Squamous Cell Carcinoma

To evaluate whether contralateral neck metastasis (CNM) from previously untreated head and neck squamous cell carcinoma (HNSCC) can be accurately detected at combined computed tomography (CT)/magnetic resonance (MR) imaging and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT and assess the prognostic value of CNM.This prospective study was approved by the institutional review board, and written informed consent was obtained from all enrolled patients. In total, 160 patients with HNSCC were preoperatively evaluated with FDG PET/CT and CT/MR imaging. Histopathologic results of neck dissection samples served as the reference standard for all cases. McNemar test and logistic regression with generalized estimating equations were used to compare the diagnostic value of FDG PET/CT and CT/MR imaging, and Cox proportional hazard modeling was used to assess the prognostic value of CNM.Of the 160 enrolled patients, 94 (58.8%) had a neck metastasis on 231 sides and with 974 levels, and 20 patients (21.3%) had a contralateral neck metastasis. FDG PET/CT was significantly more sensitive than CT/MR imaging according to per-patient (91.5% vs 73.4%; P.001), per-side (91.1% vs 69.6%; P.001), and per-level analyses (78.9% vs 53.0%; P.001). On the per-side basis, FDG PET/CT was also significantly more sensitive and accurate than CT/MR imaging when evaluating the contralateral neck (85.0% vs 45.0%, P = .008, and 91.6% vs 80.3%, P = .008, respectively). However, at univariate analysis, CNM was significantly associated only with cancer-specific death (P = .001) and overall survival (P = .015).CNM from HNSCC can be detected at FDG PET/CT with higher sensitivity and accuracy than at CT/MR imaging.