PET-CT Versus EUS Lymph Node Detection in Esophageal Cancer Patients: Implications for Dilatation Requirement

Abstract

For the staging of esophageal cancer, endoscopic ultrasound (EUS) is the most sensitive modality to detect local and distant lymph nodes (LN). Dilatation of stenotic cancers to assess the celiac axis is often challenging and has a perforation risk up to 25%. Integrated positron emission tomography computed tomography (PET-CT) has reported incremental improvement for nodal staging over PET and CT alone. The aim of this study is to compare the detection of celiac LN by PET-CT and EUS. We specifically sought to determine whether a negative PET-CT could prevent the risks involved in dilatation at the time of EUS. Aim: To compare the detection of celiac lymph nodes by PET-CT and EUS. Methods: We retrospectively reviewed all staging EUS performed for esophageal carcinoma from January 2005 to December, 2008. Only patients treated with esophageal dilation with concomitant PET-CT reports were included in the analysis. Successful dilatations were defined by passage of the EUS scope into the stomach. Positive celiac LN detection by EUS was defined by the presence of any LN <2 cm away from the celiac axis with classic sonographic features of size >1.0 cm, round, and hypoechoic with distinct margins. Positive LN detection by PET-CT was defined by positive imaging by both modalities. Results: During the study period, 93 esophageal cancer patients underwent EUS; 34 also underwent dilation. 27 (79%) dilatations were successful. 10/27 patients were excluded (no PET-CT). Of the remaining 17 patients, 12 patients had both a negative EUS and PET-CT, 4 had a positive EUS and negative PET-CT, and 1 had a negative EUS and a positive PET-CT. In this cohort of patients with both EUS and PET-CT, and the negative predictive value for PET-CT was only 75%. Conclusion: PET-CT has a poor NPV and therefore a negative PET-CT does not eliminate the need for esophageal dilatation to assess celiac lymph nodes during EUS for esophageal cancer staging. Larger prospective studies comparing EUS and PET-CT are needed to determine the true accuracy of both staging modalities.