Ultrasound-guided transbronchial cryobiopsy of mediastinal and hilar lesions: a multicenter pragmatic cohort study with real-world evidence.

Background: Limited data exist on the reliability, efficacy and safety of ultrasound-guided transbronchial cryobiopsy for suspicious mediastinal and hilar lesions. This study shares findings from implementing this method and compares the results with those of the standard endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA).

Methods: Patients undergoing diagnostic bronchoscopy for mediastinal or hilar lesions in four Swiss centres were included. The study aims to assess the diagnostic yield and safety of EBUS-guided cryobiopsy compared with EBUS-TBNA. Tunnelling to the target lesion was performed using an electric needle knife (70.8%), a 19 G- (12.4%) or a 22 G needle (16.8%). Cryobiopsies were obtained with a freezing time of 4-7 s (18.2% with a 1.7 mm probe) or 6-10 s (81.8% with a 1.1 mm probe).

Results: Altogether, 137 patients were enrolled with a median follow-up of 89 days. The overall diagnostic yield was 56.2% for EBUS-TBNA and 91.2% for cryobiopsies (p<0.001). Cryobiopsies increased the diagnostic yield for benign disorders (+28.5%), uncommon tumours (+5.9%) and other metastatic cancer (+0.6%), but not for lung cancer (+0%). For lung cancer (n=27), immunohistochemistry was obtainable in 40.7% of EBUS-TBNA (median of 3 probes [IQR 3 to 3]), significantly lower than cryobiopsy's 88.9% yield (median of 4 probes [IQR 3 to 5]) (p<0.001). Adverse events were found in 23.4% of participants; 10.2% had mild to moderate bleeding, 0.7% had pneumonia, and 0.7% (one) of patients had pneumothorax following pneumomediastinum. No deaths or mediastinum infections were observed.

Conclusion: Cryobiopsy of mediastinal and hilar lesions improves the diagnostic yield compared with EBUS-TBNA while maintaining a favourable safety profile.