Mediastinal lymph node cryobiopsy guided by endobronchial ultrasound: a comprehensive review of methods and outcomes

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is the preferred initial method to diagnose and stage non-small cell lung cancer. EBUS-guided transbronchial cryobiopsy (EBUS-TBC) is a newer technique with the potential to address the limitations of EBUS-TBNA. Only a few studies have explored this technique and compared its diagnostic yield to that of EBUS-TBNA. This review aims to summarize the existing literature and provide insights into the optimal yield and technique for performing EBUS-TBC. A comprehensive search of the PubMed database was conducted for studies published up to May 2024 related to EBUS-TBC. The PICO framework (Participants, Intervention, Comparison, and Outcome) was used to evaluate the diagnostic yield, techniques employed, and associated complications. Eleven studies involving 857 patients were identified. In these trials, EBUS-TBC was performed after EBUS-TBNA at the same lymph node station. Techniques varied among bronchoscopists, with most procedures conducted under moderate sedation. The TBNA needle sizes ranged from 19G to 22G. Three trials used a needle knife for the initial mucosal incision, while others utilized the initial puncture site for cryoprobe insertion. Nine studies employed a 1.1-mm Erbe cryoprobe, with a median freezing time of 4 seconds (range, 3-7 seconds). The overall diagnostic yield of EBUS-TBC was 91.9%, compared to 76.6% for EBUS-TBNA alone, with EBUS-TBC yielding larger specimens. Mild bleeding was the most common complication reported. The addition of EBUS-TBC to EBUS-TBNA enhances the diagnostic yield without significantly increasing complications. The larger biopsy samples obtained can be particularly valuable for next-generation sequencing in lung cancer and for improving diagnostic accuracy in benign diseases and rare malignancies like lymphoma.