Endoscopic ultrasound-guided elastography in the nodal staging of oesophageal cancer

AIM:To assess quantitative endoscopic ultrasound (EUS)guided elastography in the nodal staging of oesophagogastric cancers.METHODS:This was a single tertiary centre study assessing 50 patients with established oesophago-gastric cancer undergoing EUS-guided fine needle aspiration biopsy (FNAB) of lymph nodes between July 2007 and July 2009.EUS-guided elastography of lymph nodes was performed before EUS-FNAB.Standard EUS characteristics were also described.Cytological determination of whether a lymph node was malignant or benign was used as the gold standard for this study.Comparisons of elastography and standard EUS characteristics were made between the cytologically benign and malignant nodes.The main outcome measure was the accuracy of elastography in differentiating between benign and malignant lymph nodes in oesophageal cancers.RESULTS:EUS elastography and FNAB were performed on 53 lymph nodes.Cytological malignancy was found in 23 nodes,one was indeterminate,one was found to be a gastrointestinal stromal tumor and 25 of the nodes were negative for malignancy.On 3 occasions insufficient material was obtained for analysis.The area under the curve for the receiver operating characteristic curve for elastography strain ratio was 0.87 (P<0.0001).Elastography strain ratio had a sensitivity 83%,specificity 96%,positive predictive value 95%,and negative predictive value 86% for distinguishing between malignant and benign nodes.The overall accuracy of elastography strain ratio was 90%.Elastography was more sensitive and specific in determining malignant nodal disease than standard EUS criteria.CONCLUSION:EUS elastography is a promising modality that may complement standard EUS and help guide EUS-FNAB during staging of upper gastrointestinal tract cancer.