Assessment for diagnosis of lymph node metastasis in esophageal cancer using endoscopic ultrasound elastography

BACKGROUND: We performed endoscopic ultrasound real-time tissue elastography to more accurately diagnose lymph node metastasis of esophageal cancer. The aim of this study was to evaluate the ability of EUS elastography to distinguish benign from malignant lymph nodes in esophageal cancer patients. METHODS: The present study had two steps. As the first step (study 1), we developed diagnostic criteria for metastatic lymph nodes using elastography and verified the validity of the criteria. Three hundred and twenty-two lymph nodes from 35 patients treated by surgical resection were included in the study. As the second step (study 2), we preoperatively examined the lymph nodes of esophageal cancer patients with EUS elastography and compared its diagnostic performance with that of the conventional B-mode EUS images. A total of 115 lymph nodes from 31 patients were included. RESULTS: In study 1, lymph nodes were considered malignant if 50 % or more of the node appeared blue, or if the peripheral part of the lesion was blue and the central part was red/yellow/green. The sensitivity and specificity of the elastography were 79.7 and 97.6 % with an accuracy of 93.8 %, which was significantly higher than the values for conventional B-mode imaging. In study 2, the sensitivity and specificity of the EUS elastography were 91.2 and 94.5 % with an accuracy of 93.9 %, which was also significantly higher than the values for conventional B-mode EUS imaging. CONCLUSIONS: The present study demonstrated that EUS elastography is useful for diagnosing lymph node metastasis of esophageal cancer.