Added value of EUS-B-FNA to bronchoscopy and EBUS-TBNA in diagnosing and staging of lung cancer.

Background: Bronchoscopy and EBUS are standard procedures in lung cancer work-up but have low diagnostic yield in lesions outside the central airways and hilar/mediastinal lymph nodes. Growing evidence on introducing the EBUS endoscope into the oesophagus (EUS-B) in the same session as bronchoscopy/EBUS gives access to new anatomical areas that can be safely biopsied. Objective: To summarize the current evidence of the added value of EUS-B-FNA to bronchoscopy and EBUS-TBNA in lung cancer work-up. Methods: A narrative review. Results: Few randomized trials or prospective studies are available. Prospective studies show that add-on EUS-B-FNA increases diagnostic yield when sampling abnormal mediastinal lymph nodes, para-oesophageal lung and left adrenal gland. A large retrospective series on EUS-B-FNA from retroperitoneal lymph nodes suggests high diagnostic yield without safety concerns, as do casuistic reports on EUS-B-FNA from mediastinal pleural thickening, pancreatic lesions, ascites fluid and pericardial effusions. No study has systematically assessed both diagnostic yield, safety, patient reported outcomes, adverse events and costs. Conclusion: The diagnostic value of add-on EUS-B to standard bronchoscopy and EBUS in lung cancer work-up appears very promising without safety concerns, giving the pulmonologist access to a variety of sites out of reach with other minimally invasive techniques. Little is known on patient-reported outcomes and costs. Future and prospective research should focus on effectiveness aspects to clarify whether overall benefits of add-on EUS-B sufficiently exceed overall downsides.

Using the Endoscope for Endobronchial Ultrasound in the Esophagus.

EUS-B is a procedure using the echoendobronchoscope in the esophagus and stomach. The procedure is a minimally invasive, safe, and feasible approach that pulmonologists can use to visualize and biopsy structures adjacent to the esophagus and stomach. EUS-B gives access to many structures of which some may also be reached by EBUS (mediastinal lymph nodes, lung or pleural tumors, pericardial fluid) while others cannot be reached such as retroperitoneal lymph nodes, ascites, and lesions in the liver, pancreas or left adrenal gland. The procedure is a pulmonologist- and patient- friendly version of the gastroenterologists' EUS using the thin EBUS endoscope that the pulmonologist already masters. Thus EUS-B training should be easy and a natural continuation of EBUS. With the patient under conscious sedation and in the supine position, the echoendoscope is introduced either through the nostril or mouth into the oropharynx. Then the patient is encouraged to swallow while the endoscope is slowly bent posteriorly and introduced into the esophagus and stomach. Using the ultrasonic image, the operator identifies the six landmarks by EUS-B and EUS: the left liver lobe, abdominal aorta (with the celiac trunk and superior mesenteric artery), left adrenal gland, and mediastinal lymph node stations 7, 4L, and 4R. Biopsies can be taken from suspected lesions under real-time ultrasonographic guidance- fine needle aspiration (EUS-B-FNA) using a technique similar to that used with EBUS-TBNA. The biopsy order is M1b-M1a-N3-N2-N1-T (M = metastasis, N = lymph node, T = tumor) to avoid iatrogenic upstaging. Pre- and post-procedural observation is similar to that of bronchoscopy. EUS-B is safe and feasible in the hands of experienced interventional pulmonologists and provides a significant expansion of the diagnostic possibilities in providing safe, fast, and thorough diagnosis and staging of lung cancer.