Impact of combined cryobiopsy plus genomic classifier testing on diagnosis of interstitial lung diseases

SESSION TITLE: Diffuse Lung Disease: Reimagining the Standard of Care SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/10/2023 12:00 pm - 12:45 pm PURPOSE: Due to the progressive nature of Idiopathic Pulmonary Fibrosis (IPF), a prompt diagnosis and initiation of therapy are critical. The 2022 clinical practice guidelines on IPF regarded transbronchial lung cryobiopsy (TBLC) as an acceptable alternative to surgical lung biopsy. However, it was determined that there was as of yet insufficient evidence to make a recommendation for or against genomic classifier (GC) testing for the purpose of diagnosing UIP/IPF. With this study, we report our experience with combined TBLC and GC testing in interstitial lung disease patients at our center. METHODS: We identified 83 cases of interstitial lung disease in which both TBLC and GC testing were performed. Data was collected from each patient through a review of the UCLA Health Electronic Health Record. Specific data collected included the radiologic classification of Interstitial Lung Disease (Probable UIP, Indeterminate for UIP, Alternate Diagnosis) as determined by a chest radiologist, the TBLC result (UIP, Probable UIP, Indeterminate for UIP, Alternate Diagnosis) as determined by a lung pathologist, and the GC result (positive or negative for UIP). RESULTS: Among the 83 patients that underwent both TBLC and GC, 35 subjects had high-resolution chest CT (HRCT) indeterminate for UIP, 17 had probable UIP, and 31 had an alternate diagnosis suggested. The overall diagnostic yield of TBLC alone was 46%, including 25 alternate diagnoses and 13 with UIP (11 probable UIP and 2 UIP). The diagnostic yield of GC alone was 36%, with 30 positive GC tests. The combination of TBLC and GC yielded a diagnosis in 61% (51/83). Among the 35 cases with indeterminate HRCT, TBLC alone yielded a diagnosis in 23% (8/35), GC alone was 40% (14 positive), and the combination yielded a diagnosis in 49% (17/35), 13 with UIP, 2 with alternate diagnoses, and 2 with UIP plus an alternate diagnosis. CONCLUSIONS: Among patients with ILD, the combination of TBLC and GC has a higher diagnostic yield than either test used alone, including patients where HRCT is indeterminate for UIP. Additional information obtained from TBLC, combined with clinical context, would also be utilized in a multidisciplinary discussion to yield a final diagnosis and potentially provide greater confidence in a diagnosis, but that could not be measured by this study. CLINICAL IMPLICATIONS: The 2022 ATS/ERS/JRS/ALAT practice guidelines on IPF determined that TBLC is an acceptable mode for tissue diagnosis, but there was as of yet insufficient evidence to make a recommendation for or against GC testing. In this study, we find that TBLC alone may be insufficient to diagnose UIP, possibly because pathology is heterogenous and peripheral. The Envisia GC test detects more UIP, but when negative does not provide guidance for alternate diagnoses. This study provides evidence for the utility of combined TBLC plus GC testing for the diagnosis of ILD, especially when HRCT is indeterminate for UIP. DISCLOSURES: No relevant relationships by Olawale Amubieya No relevant relationships by Shailesh Balasubramanian No relevant relationships by Augustine Chung No relevant relationships by Tamas Dolinay No relevant relationships by Catherine Durant No relevant relationships by Gregory Fishbein No relevant relationships by Tao He Faculty for fellows' education project relationship with Medtronic Please note: Current by Catherine Oberg, value=Consulting fee Consultant relationship with Intuitive Please note: Current Added 12/04/2022 by Catherine Oberg, source=Web Response, value=Consulting fee Consultant relationship with Noah Medical Please note: September 2022 Added 12/04/2022 by Catherine Oberg, source=Web Response, value=Consulting fee No relevant relationships by Scott Oh No relevant relationships by Lila Pourzand No disclosure on file for Zohra Prasla No relevant relationships by Allison Ramsey No disclosure on file for Reza Ronaghi No relevant relationships by Richard Watson Consultant relationship with Veracyte Please note: 05/15/2022 Added 04/07/2023 by Stephen Weigt, source=Web Response, value=Consulting fee Speaker/Speaker's Bureau relationship with Boehringer Ingelheim Please note: 1/1/22 - present Added 04/07/2023 by Stephen Weigt, source=Web Response, value=Honoraria Research funding relationship with CareDx Please note: 12/1/21-Present Added 04/07/2023 by Stephen Weigt, source=Web Response, value=Grant/Research Support