18F-fluorodeoxyglucose positron emission tomography to evaluate cervical node metastases in patients with head and neck squamous cell carcinoma:: A meta-analysis

Background Positron emission tomography using F-18-fluorodeoxyglucose (F-18-FDG PET) has been proposed to enhance preoperative assessment of cervical lymph node status in patients with head and neck squamous cell carcinoma (HNSCC). Management is most controversial for patients with a clinically negative (cN0) neck. We aimed to assess the diagnostic accuracy of F-18-FDG PET in detecting lymph node metastases in patients with HNSCC. Methods We performed a meta-analysis of all available studies of the diagnostic performance of F-18-FDG PET in patients with HNSCC. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves using hierarchical regression models. We also compared the performance of F-18-FDG PET with that of conventional diagnostic methods (ie, computed tomography, magnetic resonance imaging, and ultrasound with fine-needle aspiration) by analyzing studies that had also used these diagnostic methods on the same patients. Results Across 32 studies (1236 patients), F-18-FDG PET sensitivity was 79% (95% confidence interval [CI] = 72% to 85%) and specificity was 86% (95% CI = 83% to 89%). For cN0 patients, sensitivity of F-18-FDG PET was only 50% ( 95% CI = 37% to 63%), whereas specificity was 87% (95% CI = 76% to 93%). Overall, LR+ was 5.84 (95% CI = 4.59 to 7.42) and LR- was 0.24 (95% CI = 0.17 to 0.33). In studies in which both F-18-FDG PET and conventional diagnostic tests were performed, sensitivity and specificity of F-18-FDG PET were 80% and 86%, respectively, and of conventional diagnostic tests were 75% and 79%, respectively. Conclusion F-18-FDG PET has good diagnostic performance in the overall pretreatment evaluation of patients with HNSCC but still does not detect disease in half of the patients with metastasis and cN0.