18F-FDG PET/CT versus CT/MR imaging for detection of neck lymph node metastasis in palpably node-negative oral cavity cancer

Purpose Subclinical lymph node (LN) metastasis is associated with poor survival outcome in oral cavity squamous cell carcinoma (OCC), which alleges elective neck LN dissection. Preoperative detection of metastatic LNs may improve prognosis and proper management of OCC. We examined the clinical usefulness of fluorine 18-fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET)/computed tomography (CT) for the detection of occult neck LN metastasis in OCC patients in comparison with conventional CT/magnetic resonance (MR) imaging. Methods A total of 178 OCC patients with negative neck palpation findings were assessed prospectively with F-18-FDG PET/CT and CT/MR imaging. Histopathological analyses of neck dissection samples served as reference. Diagnostic values of F-18-FDG PET/CT versus CT/MR imaging were compared with the McNemar test and logistic regression with generalized estimating equations. Results Forty-two patients (23.6%) had metastasis in 44 sides and 58 levels of the neck. The sensitivity for detection of occult metastasis was higher for F-18-FDG PET/CT than that for CT/MR imaging on a per-patient (69.1% vs 35.7%), per-side (70.5% vs 36.4%), and per-level (62.1% vs 29.3%) basis (all P <= 0.001). However, the specificity for metastatic detection was higher for CT/MR imaging than that for F-18-FDG PET/CT (all P < 0.005). F-18-FDG PET/CT improved detection of occult metastasis up to 33.4% in these patients compared to CT/MR imaging. Conclusions F-18-FDG PET/CT can better detect occult neck metastasis than CT/MR imaging, which may potentially impact the clinical management of OCC patients.