Introduction: Recent studies have shown that combined use of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and cryobiopsy provides a higher diagnostic yield for mediastinal lesions as compared with EBUS-TBNA alone. Currently, cryoprobes with diameters of 1.1mm and 1.7mm have been reported to be used for mediastinal cryobiopsy.

Methods: We conducted a randomized controlled trial to evaluate and compare the diagnostic safety and efficacy profile the 2 cryoprobes in mediastinal disease. Consecutive patients with mediastinal lesions (≥ 1 cm in the short axis) were prospectively enrolled. After 4 passes of needle aspiration, participants underwent mediastinal cryobiopsy with 1.1 mm- and 1.7 mm- cryoprobes in a randomized order. The main endpoints included procedural success rate, diagnostic yield, and safety.

Results: A total of 137 patients were recruited and randomized. Both 1.1 mm- and 1.7 mm- probe-cryobiopsies added diagnostic value to EBUS-TBNA. (94.2% vs 75.9%; p < 0.001; 92.0% vs 75.9%; p < 0.001; respectively). Supplementing EBUS-TBNA with either 1.1 mm- or 1.7 mm- probe-cryobiopsy resulted in no differences in overall diagnostic yield (94.2% vs 92.0%; p = 0.48). Nevertheless, direct comparison revealed a significantly improved overall diagnostic yield with 1.1 mm- cryoprobe relative to 1.7 mm- cryoprobe, primarily due to technical failures associated with the latter (88.3% vs 79.6%; p = 0.048). Additionally, 1.1 mm- and 1.7 mm- cryoprobes yielded mediastinal specimens of similar size. Both approaches were safe, with no serious adverse events reported.

Conclusions: 1.1 mm- cryoprobe demonstrates better performance in transbronchial mediastinal cryobiopsy vs 1.7mm cryoprobe, making it a viable adjunct to traditional needle biopsy.