Usefulness of transbronchial lung cryobiopsy when choosing treatment for chronic fibrosing interstitial lung disease: Descriptive research

Abstract Background: Although transbronchial lung cryobiopsy (TBLC) is widely used in diagnostic algorithms for various interstitial lung diseases (ILD), its real-world utility in the therapeutic decision-making strategy for ILD patients remains unclear. Methods: We analyzed medical records of 40 consecutive patients with idiopathic or fibrotic hypersensitivity pneumonitis who underwent TBLC. A TBLC-based usual interstitial pneumonia (UIP) score was used to assess three morphologic descriptors: i) patchy fibrosis, ⅱ) fibroblastic foci, and ⅲ) honeycombing. Results: In our 40 patients with ILD, the most frequent radiological feature was indeterminate for UIP (45.0%). Final diagnosis included idiopathic pulmonary fibrosis (22.5%), fibrotic nonspecific interstitial pneumonia (5.0%), fibrotic hypersensitivity pneumonitis (35.0%), and unclassifiable ILD (37.5%). Linear mixed-effects analysis showed that declines in the slopes of %FVC and %DL CO in patients with TBLC-based UIP ‘Score ≥2’ were significantly steeper than those of patients with ‘Score ≤1’. During follow-up of patients with ‘Score ≥2’ (n = 24), more than half of them received combination therapy (i.e., anti-inflammatory and anti-fibrotic agents). Moreover, in the groups receiving an anti-fibrotic agent, many patients received anti-fibrotic agent administration within 6 months after the TBLC procedure. Among the groups with combination therapy, most patients received an anti-fibrotic agent within 6 months of the multi-disciplinary discussion-based diagnosis. Conclusions: TBLC-based UIP score ≥2 indicated the increased possibility of a progressive fibrosis course that may prove helpful in predicting progressive pulmonary fibrosis/progressive fibrosing ILD even if disease is temporarily stabilized due to anti-inflammatory agents. Patients may benefit from early introduction of anti-fibrotic agents by treating clinicians.