Transbronchial Lung Cryobiopsy and SurgicAl LuNg Biopsy: A Prospective MultI-CEntre Agreement Study (CAN-ICE).

Transbronchial cryobiopsies (TBCB) for the diagnosis of interstitial lung disease (ILD) have shown promising results but prospective studies with matched surgical lung biopsy (SLB) yielded conflicting results. We aimed to assess within- and between-center diagnostic agreement between TBCB and SLB at both the histopathologic and multidisciplinary discussion (MDD) levels in patients with diffuse ILD. In a multicenter prospective study, we obtained matched TBCB and SLB in patients referred for SLB. After blinded review by three pulmonary pathologists, all cases were reviewed by three independent ILD teams in a MDD. MDD was performed first with TBC, than with SLB in a second session. Within center and between center diagnostic agreement was evaluated by percentage and correlation coefficient. Twenty patients were recruited and underwent contemporaneous TBCB and SLB. Diagnostic agreement within center between TBCB-MDD and SLB-MDD was reached in 37 of the 60 (61.7%) paired observations, resulting in a k of 0.46 (95%CI 0.29-0.63). Diagnostic agreement increased amongst high-confidence/definitive diagnosis at TBCB-MDD (21 of 29 (72.4%)), but not significantly, and was more likely amongst cases with a SLB-MDD diagnosis of idiopathic pulmonary fibrosis (IPF) than fibrotic hypersensitivity pneumonitis (fHP) (13 of 16 (81.2%) vs 16 of 31 (51.6%), p=0.047). Between center agreement for cases was markedly higher for SLB-MDD (k = 0.71; 95%CI 0.52-0.89) than TBCB-MDD (k = 0.29; 95%IC 0.09-0.49).This study demonstrated moderate TBCB-MDD/SLB-MDD diagnostic agreement which was insufficient to reliably distinguish fHP from IPF. The between centre agreement for TBCB-MDD was only fair, while it was substantial for SLB-MDD. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02235779.