Background: Malignant esophageal masses can be staged with endoscopic ultrasound (EUS) using the TNM staging classification. Several criteria for differentiating between intraesophageal (T1-2) and extraesophageal (T3-4) masses have been described, but highly accurate staging remains difficult.
Methods: This is a blinded evaluation of four specific EUS criteria in 24 patients with esophageal malignancy who underwent esophageal resection after neoadjuvant chemotherapy. Radial EUS was used to evaluate the first 12 patients and curved linear EUS was used in the second half of the group. Using the histology of the resected specimens, the sensitivity, specificity, and accuracy of the EUS criteria after chemotherapy were determined for predicting intraesophageal or extraesophageal invasion.
Results: There was no difference in the accuracy rates with radial or linear EUS. Two ultrasound criteria, muscularis disruption and irregular mass border, were found to have low accuracy rates (44% and 50%). The maximal thickness (overall or extraesophageal) of the esophageal mass was found to be highly accurate (79% and 87%) in predicting intraesophageal or extraesophageal extension. pT3-4 masses had a thickness of 16.0 +/- 2 mm, significantly greater than pT1-2 masses, 8.2 +/- 1 mm (p < .01). Using receiver operator characteristics (ROC) curve analysis, mass thickness was found to be more accurate (91% and 94%) than a subjective assessment of staging (73%) (p < .07).
Conclusions: The EUS measurement of a malignant esophageal mass maximal thickness can accurately predict extraesophageal extension.