Usefulness of endoscopic ultrasonography (EUS) in diagnosing esophageal infiltration of thyroid cancer

Pre-operative evaluation of esophageal infiltration is sometimes difficult in patients with advanced thyroid cancer even with recent imaging modalitie s. We evaluated the accuracy of endoscopic ultrasonography (EUS) in diagnos ing esophageal infiltration of thyroid cancer. Twenty-nine patients with ad vanced thyroid cancer underwent EUS and other imaging examinations before s urgery. The diagnostic accuracy of EUS was compared with that of magnetic r esonance imaging (MRI) and esophagography based on pathologic findings in 2 7 of the 29 cases. EUS clearly demonstrated the 5-layer structure of the es ophageal wall. EUS detected cancer invasion into the muscularis propria of the esophagus correctly in 8 of 10 patients diagnosed pathologically with m uscular infiltration. EUS was significantly more accurate than MRI and esop hagography (88.9% vs 63.0% and 66.7%, respectively). The specificity of EUS was also significantly better than the specificities of MRI or esophagogra phy (94.1% vs 58.8% and 64.7%, respectively). The sensitivity, positive pre dictive value and negative predictive value of EUS tended to be better than those of MRI and esophagography. EUS is useful in evaluating the esophagea l infiltration of thyroid cancer. This method has the further advantage of detecting the exact depth of cancer invasion into the esophageal wall. (J. Endocrinol. Invest. 24: 564-569, 2001) (C) 2001, Editrice Kurtis.