Using Bronchoscopic Lung Cryobiopsy and a Genomic Classifier in the Multidisciplinary Diagnosis of Diffuse Interstitial Lung Diseases

Abstract

Background: Challenges remain for establishing a specific diagnosis in cases of interstitial lung disease (ILD). Bronchoscopic lung cryobiopsy (BLC) has impacted the diagnostic impression and confidence of multidisciplinary discussions (MDDs) in the evaluation of ILD. Reports indicate that a genomic classifier (GC) can distinguish usual interstitial pneumonia (UIP) from non-UIP.

Research question: What is the impact of sequentially presented data from BLC and GC on the diagnostic confidence of MDDs in diagnosing ILD?

Study design and methods: Two MDD teams met to discuss 24 patients with ILD without a definitive UIP pattern. MDD1 sequentially reviewed clinical-radiologic findings, BLC, and GC. MDD2 sequentially reviewed GC before BLC. At each step in the process the MDD diagnosis and confidence level were recorded.

Results: MDD1 had a significant increase in diagnostic confidence, from 43% to 93% (P = .023), in patients with probable UIP after the addition of GC to BLC. MDD2 had an increase in diagnostic confidence, from 27% to 73% (P = .074), after the addition of BLC to GC. The concordance coefficients and percentage agreement of categorical idiopathic pulmonary fibrosis (IPF) and non-IPF diagnoses were as follows: GC vs MDD1: 0.92, 96%; GC vs MDD2: 0.83, 92%; BLC1 vs MDD1: 0.67, 83%; BLC2 vs MDD2: 0.66, 83%.

Interpretation: GC increased diagnostic confidence when added to BLC for patients with a probable UIP pattern, and in appropriate clinical settings can be used without BLC. In contrast, BLC had the greatest impact regarding a specific diagnosis when the likelihood of UIP was considered low following clinical-radiographic review.

Keywords: bronchoscopy; cryobiopsy; genomic classifier; interstitial lung diseases; multidisciplinary discussion.

Figure 1

Organizational scheme. MDD = multidisciplinary discussion.

Figure 2

Comparison of diagnostic confidence for MDD1 (left) and MDD2 (right). IPF = idiopathic pulmonary fibrosis; UIP = usual interstitial pneumonia. See Figure 1 legend for expansion of other abbreviation.

Figure 3

Cohen’s κ and overall agreement of categorical clinical diagnosis of IPF or non-IPF between the genomic classifier and histopathology in each group with the final multidisciplinary discussion diagnosis in the same group. GC = genomic classifier. See Figures 1 and 2 legends for expansion of other abbreviations.

Figure 4

Overall agreement of categorical clinical diagnosis of IPF or non-IPF between the genomic classifier and histopathology in patients with a radiologic pattern of UIP or probable UIP with the final MDD diagnosis in the same group. See Figure 1 and 2 legends for expansion of abbreviations.