Late Breaking Abstract - Transbronchial lung cryobiopsy for interstitial lung disease diagnosis: results of the COLDICE Study

Transbronchial lung cryobiopsy (TBLC) is a novel technique for sampling lung tissue for interstitial lung disease (ILD) diagnosis. Despite increasing use, the diagnostic accuracy of TBLC compared to surgical lung biopsy (SLB) remains unclear. Methods: We conducted a prospective, multicenter study investigating agreement between TBLC and SLB. ILD patients referred for lung biopsy after central screening underwent sequential TLBC and SLB, under one anesthetic. Blinded analysis of samples was conducted by 3 pathologists, individually and by consensus. At multidisciplinary discussion (MDD), deidentified cases were discussed twice with either TBLC or SLB along with clinical and radiology data, in random non-consecutive order. Primary endpoints were agreement of TBLC and SLB for 1) “definite/probable usual interstitial pneumonia (UIP)”, “indeterminate for UIP” and “alternative diagnosis” histopathologic patterns; and for 2) MDD diagnoses. Concordance and kappa values were calculated. Results: 65 patients (30 males; age 66±9yrs; FVC 84±14%; DLCO 63±13%) were enrolled. TBLC (7.1±1.9mm) and SLB samples (47±15mm) were taken from two separate ipsilateral lobes. Histopathological agreement between TBLC and SLB was 70.8%, weighted κ 0.70 (95%CI 0.55-0.86); agreement at MDD was 76.9%, κ 0.62 (95%CI 0.47-0.78). For TBLC with high/definite diagnostic confidence at MDD (39/65, 60% cases), 94.9% were concordant with SLB diagnoses. In the 26 with low-confidence/unclassifiable TBLC diagnoses, SLB reclassified only 6 to alternative high/definite MDD diagnoses. Conclusion: High agreement between TBLC and SLB for pathologic and MDD diagnoses support the clinical utility of TBLC in ILD diagnostic algorithms.