Is the diagnostic yield of mediastinal lymph node cryobiopsy (cryoEBUS) better for diagnosing mediastinal node involvement compared to endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)? A systematic review

Abstract

Introduction: New tools such as cryobiopsy of mediastinal lymph nodes (cryoEBUS) have been described to improve the diagnostic usefulness of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). The literature suggests that this novel procedure could be associated with greater diagnostic usefulness than conventional EBUS-TBNA.

Methods: To develop a systematic analysis and meta-analysis on the diagnostic diagnostic yield and safety of cryobiopsy of hilar and mediastinal adenopathies compared to EBUS-TBNA.

Results: Seven studies that had included a total of 555 patients were considered in this review, with 365 (65.7%) of these patients having an etiology of malignant lymph node involvement. The overall diagnostic usefulness of cryoEBUS was higher compared to EBUS-TBNA (92% vs. 80%). However, when the results were analysed according to the specific aetiologies of the adenopathies, cryoEBUS was especially useful in cases of lymphomas or non-pulmonary carcinomas (83% vs. 42%) and in cases that were benign (87% vs. 60.1%), with no significant differences being found in specific cases of lung cancer. For lymphoma, cryoEBUS was diagnostic in 87% of cases compared to 12% for EBUS-TBNA and in addition, also allowed the characterisation of every lymphoma subtype. Genetic studies and immunohistochemical determination of PD-L1 was possible in almost all (97%) of the samples obtained by cryoEBUS, while this was only possible in 79% of those obtained by EBUS-TBNA. The most frequent complication was light bleeding, which was described in up to 85% of cases in some series.

Conclusion: CryoEBUS could represent a promising technique in the diagnostic algorithm used for mediastinal and hilar involvement. Although cryoEBUS did not significantly improve the diagnosis of lung cancer compared to EBUS-TBNA, the results were significantly better in patients with benign pathologies and other tumour types, including lymphomas. In addition, it seems that the samples obtained by cryoEBUS better defined the histological subtypes of lymphoma and allowed complete molecular characterisation in cases of lung cancer. The technique has proven to be safe and no serious complications were described after the procedure.

Keywords: Cryobiopsy; Diagnostic usefulness; Endobronchial ultrasound; Lymphadenopathy; Puncture biopsy; Safety.