Feasibility of Endobronchial Ultrasound Guided Miniforceps Biopsy for PD-L1 Expression and Quantitative Tissue Analysis.

Background: Testing for targeting programmed death ligand 1 (PD-L1) is standard of care for patients with newly diagnosed non-small cell lung cancer (NSCLC) but is only approved for use with core biopsy specimens. Endobronchial ultrasound guided miniforceps biopsy (EBUS-MFB) is an approach to obtain core biopsy material but data assessing the ability of EBUS-MFB to adequately test for PD-L1 is lacking. We evaluate the feasibility of EBUS-MFB to acquire adequate tissue for PD-L1 testing and look to compare the quality of specimens between EBUS-MFB and endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) using a standard method of tissue analysis.

Methods: Twenty patients with suspected non-small cell lung cancer undergoing bronchoscopy were recruited for enrollment. For each patient with NSCLC diagnosed on rapid onsite pathology with EBUS-TBNA, EBUS-MFB was performed. PD-L1 immunostaining was completed to assess for adequacy. A comparison of tissue collection was performed using the total surface area measured by digital imaging.

Results: Among 20 patients, 65% were male with a mean age of 66 years with a total procedure time of 50 min and an average of 14 biopsy passes per procedure. 15 (75%) patients were diagnosed with NSCLC, and PD-L1 analysis was successfully performed in 12 of the 15 (80%). The mean total tissue area obtained by the MFB technique was 9.757 mm² compared to 6.941 mm² with TBNA (p = 0.427).

Conclusion: In this feasibility study, EBUS-MFB was successful in performing PD-L1 testing in 80% of patients with NSCLC.