P1.03-044 EUS-Guided Sampling of Mediastinal Lymph Nodes and Abdominal Lesions in Lung Cancer

Abstract

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS–TBNA) was introduced to provide access to mediastinal and hilar lymph nodes. However, it is difficult to use EBUS to approach the aortopulmonary window and paraesophagaeal stations. Transesophageal endoscopic ultrasound (EUS) was introduced to provide access to this area. In addition, transgastroduodenal endoscopic ultrasound can evaluate abdominal lesions. Endoscopic ultrasound fine needle aspiration (EUS-FNA) was performed under conscious sedation with the administration of intravenous midazolam and pethidine hydrochloride. It was performed with a convex array echoendoscope connected to an ultrasound scanning system. Lymph nodes of paraesophageal, subcarinal, lower paratracheal, subaortic, and upper paratracheal regions were evaluated from esophagus. Left adrenal gland and right adrenal gland were evaluated from stomach and duodenum, respectively. Abdominal lesions were also evaluated from stomach and duodenum. After obtaining tissue via EUS-FNA, the tissue was reviewed immediately (rapid on-site cytopathological evaluation: ROSE) by a cytopathologist. Subsequent punctures in the same patient were not performed before confirming the results of ROSE so as to minimize the complications. As to the lymph node level, the lower mediastinum and the aortopulmonary window are particularly important for detection by transesophageal EUS, whereas pretracheal and hilar lymph nodes are out of reach because of the interposition of air from the trachea and bronchi. EUS was chosen to assess the posterior mediastinum nodes (#5, 7, 8, or 9) but not the anterior ones. A final diagnosis was obtained by EUS-FNA in 76 patients. The lesions sampled were mediastinal lymph nodes (n=64; #5, 7, 8, or 9), abdominal lymph nodes (n=8), and adrenal gland (n=4). Repeat tumor biopsies from patients with acquired resistance were initially obtained through research efforts to ascertain mechanisms of resistance, but are now recommended to help select second-line therapies. However, such biopsies are associated with both risk and discomfort and may not always supply enough tumor tissue for genetic analyses. Although EUS–FNA does not provide access to pretracheal and hilar lymph nodes, EUS-FNA is an accurate, safe, and minimally invasive modality for evaluating mediastinal lymphadenopathy and abdominal lesions in patients suspected of having lung metastases.