Can EUS elastography improve lymph node staging in esophageal cancer?

Abstract

Endoscopic ultrasound (EUS) elastography can assess the hardness of tissue by measuring its elasticity. Few data have been published on EUS elastography for lymph node (LN) staging in patients with esophageal cancer. This study analyzes the value of elastography as an additional diagnostic tool for LN staging. Forty patients (mean age 68 years) with known esophageal cancer (34 Barrett's carcinoma, 6 squamous cell carcinoma) were included prospectively. On conventional EUS, suspicious LNs were assessed using sonomorphologic criteria, and EUS elastography was then used to assess their tissue hardness. The sonomorphologic criteria and elastographic images for the LN were later reviewed on recorded video clips by an endosonographer blinded to the histology results. The proportions of color pixels in LNs in selected patients were assessed using computer analysis of the elastography images. Fine-needle aspiration was performed in all of the LNs, and the histological/cytological results were used as the gold standard. Twenty-one of the 40 LNs examined (52.5 %) were positive for neoplasia, confirmed by histology/cytology. The first assessment by the examiner during the procedure, based on sonomorphologic criteria, showed sensitivity of 91.3 % and specificity of 64.7 %. EUS elastography alone had sensitivity of 100 % and specificity of 64.1 %. When computer analysis of the elastographic images was added, the specificity improved significantly to 86.7 %, with a slight decrease in sensitivity to 88.9 %. EUS elastography is easily included in clinical staging and, particularly with computer-aided pixel analysis, significantly improves the specificity of LN staging.