Learning Curve for Transbronchial Lung Cryobiopsy in Interstitial Lung Disease Diagnosis: A Multicenter Experience.

Background: Transbronchial lung cryobiopsy (TBLC) is increasingly used to diagnose interstitial lung disease (ILD). However, the learning curve associated with this technique remains unclear. Methods: This retrospective analysis included the first 100 patients suspected of having ILD for whom TBLC was performed by six physicians (three chief physicians and three attending physicians) across three centers in China. The diagnostic yield, procedural information, and complications were compared between consecutive groups of patients. Logistic regression was employed to analyze the median diagnostic yields across ten subgroups of operative experience, categorized in intervals of ten patients, to delineate the learning curve. Results: The overall multidisciplinary discussion (MDD)-based diagnostic rate for ILD after TBLC was 75% (450 of 600 procedures). The diagnostic yield increased with time. Learning curves revealed that chief physicians achieved proficiency after approximately 60 procedures and attending physicians after approximately 90. The sample biopsy was larger for chief physicians than for attending physicians (median, 19 mm2 vs. 15.25 mm2, P<0.001). The complication rates were acceptable, with no significant difference between the chief and attending physicians over their first 100 procedures. Conclusions: TBLC is a safe and effective diagnostic approach for ILD, but operators require extensive training to achieve proficiency. Senior physicians reached competency earlier than junior colleagues (after several dozen procedures), underscoring the importance of structured training programs and standardized protocols for facilitating safe implementation.