Diffusion-weighted MRI versus PET/CT in evaluation of clinically N0 neck in patients with HNSCC. Systematic review and meta-analysis study

Background: Evaluation of a clinically N0 neck is essential in cases of head and neck squamous cell carcinoma (HNSCC) in order to determine whether the neck needs treatment or not.Purpose: The study was designed to compare the efficacy of DW-MRI with that of PET/CT scans in the preoperative evaluation of clinically N0 neck in cases of HNSCC.Methods: A systematic search was performed by the PubMed/MEDLINE to identify and select the relevant studies published within the last 20 years (up to 20/01/2014). Reported sensitivities, specificities, Positive Likelihood Ratio, Negative Likelihood Ratio and Diagnostic Odds Ratio were metaanalyzed. QUADAS criteria were used to evaluate the methodologic quality of the studies.Results: Six studies met the inclusion criteria and were analyzed. Only one study evaluated DW-MRI whereas 5 studies evaluated PET/CT comprising a total sample size of 329 patients. Sensitivity was homogeneous across studies (P = 0.202), whereas specificity was heterogeneous across studies (P = 0.050). The overall sensitivity, specificity and accuracy rates of DW-MRI in evaluation of a clinically N0 neck were 100%, 71% and 85% respectively whereas PET/CT scans’ overall sensitivity, specificity and accuracy were 68%, 84% and 78% respectively.Conclusions: The available evidence suggests that DWI is more sensitive than PET/CT in the preoperative evaluation of cN0 neck in patients with HNSCC. PET/CT exam has low sensitivity and a positive test would not help the clinician in the management of the patient with clinically N0 disease and therefore, it should not be routinely used in neck nodal status work-ups