Background: Traditional imaging techniques have limited efficacy in detecting occult cervical lymph node (LN) metastases in head and neck squamous cell carcinoma (HNSCC). Positron emission tomography/computed tomography (PET-CT) has demonstrated potential for assessing HNSCC, but the literature on its efficacy for detecting cervical LN metastases is scarce and exhibits varied outcomes, hindering comparisons. Aim: To compare the efficacy of CT, MRI, PET-CT, and US for detecting LN metastasis in HNSCC with clinically negative neck lymph nodes. Methods: A systematic search was performed using Web of Science, PubMed, Scopus, Embase, and Cochrane databases. Studies comparing CT, MRI, PET-CT, or US to detect cervical metastases in HNSCC were identified. The quality of the studies was assessed using the QUADAS-2 instrument. The positive likelihood ratios (+LR) and negative likelihood ratios (-LR), sensitivity (SEN), specificity (SPE), and diagnostic odds ratio (DOR), with 95% confidence intervals (C.I.), were calculated. Analysis was stratified according to lymph node and patient basis. Results: Fifty-seven studies yielded 3791 patients. At the patient level, PET-CT exhibited the highest diagnostic performance, with a SEN of 74.5% (95% C.I.: 65.4-81.8%) and SPE of 83.6% (95% C.I.: 77.2-88.5%). PET-CT also demonstrated the highest +LR of 4.303 (95% C.I.: 3.082-6.008) and the lowest -LR of 0.249 (95% C.I.: 0.168-0.370), resulting in the highest DOR of 15.487 (95% C.I.: 8.973-26.730). In the evaluation of diagnostic parameters for various imaging modalities on node-based analysis results, MRI exhibited the highest SEN at 77.4%, and PET demonstrated the highest SPE at 96.6% (95% C.I.: 94.4-98%). PET-CT achieved the highest DOR at 24.353 (95% C.I.: 10.949-54.166). Conclusions: PET-CT outperformed other imaging modalities across the majority of studied metrics concerning LN metastasis detection in HNSCC.
Keywords: CT; HNSCC; MRI; PET-CT; cervical lymph node metastases; ultrasound.