Abstract
Background: A sufficient amount of tissue is required for the evaluation of tumor programmed death-ligand 1 (PD-L1) expression. However, in many cases, we must test PD-L1 expression using small tissues by bronchoscopy.
Objection: We analyzed the usefulness of transbronchial biopsy (TBB) to test PD-L1 expression in lung cancer tissue.
Methods: Expression of PD-L1 was assessed in tumor specimens by using an automated immunohistochemical assay (PD-L1 IHC 22C3 pharmDx; Dako) for 55 TBB specimens and 22 surgical specimens at Hokkaido University Hospital. Evaluation of PD-L1 expression was as follows; No = tumor proportion score (TPS) <1% / Low = TPS 1-49% / High = TPS≧50%.
Results: Of the 55 TBB cases, 33 samples were obtained by endobronchial ultrasonography with a guide sheath (EBUS-GS)-TBB, 18 samples by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and 4 samples by endobronchial biopsy. In all 55 TBB cases, more than 100 tumor cells were recognized in the specimens, and evaluation of PD-L1 expression was possible. Evaluation of PD-L1 expression in 55 cases was No / Low / High = 19/17/19 samples (35/30/35%), in 22 cases of surgical samples was No / Low / High = 10/5/7 samples (45/23/32%). There was no significant difference between TBB specimens and surgical specimens. Tumor tissues by TBB were well-tolerated to evaluate PD-L1 expression. There was no difference in tumor PD-L1 expression between EBUS-GS-TBB, EBUS-TBNA and endobronchial biopsy.
Conclusions: Our study suggests TBB as a promising method to evaluate PD-L1 expression in lung cancer.
Footnotes
Cite this article as: European Respiratory Journal 2018 52: Suppl. 62, PA2806.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2018