Verification of the Efficacy of New Diagnostic Criteria for Retropharyngeal Nodes in a Cohort of Nasopharyngeal Carcinoma Patients

Abstract

Background: A multistage approach to diagnose lateral retropharyngeal nodes (LRPNs) of nasopharyngeal carcinoma (NPC) had been proposed and warranted for validation. Methods: From 2012 to 2017, we collected NPC cases with LRPNs before radiotherapy-based treatments. The responsive nodes or those that progressed during follow-up were positive. The proposed criteria for the multistage approach delimited LRPNs with a minimal axial diameter (MIAD) ≥ 6.1 mm were positive and if the mean standard uptake value ≥ 2.6, or if the maximal coronal diameter ≥ 25 mm and maximal axial diameter ≥ 8 mm with nodes MIAD < 6.1 mm were also positive. The outcomes were compared with the MIAD cutoff value ≥ 6 mm (traditional method). Chi-squared test was used to compare two areas under the curve (AUC) of receiver operating characteristic curves. Results: A total of 67 eligible NPC cases and 155 LRPNs (72 positive and 83 negative) were analyzed. The accuracy, specificity, and sensitivity of the traditional method were 0.91, 0.93, and 0.89, respectively. The values for the multistage approach all reached 0.94. The AUC was significantly greater for the multistage approach compared with that for the traditional method (p = 0.023). Conclusion: The results of LRPN data in this cohort of patients support the advantage of the multistage approach.