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Kazuo Tsuchiya



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    MA13 - Interventional Pulmonology (ID 914)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Interventional Diagnostics/Pulmonology
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 10:30 - 12:00, Room 206 AC
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      MA13.03 - Heterogeneity Analysis of EBUS-TBNA-Derived Specimens for Evaluation of PD-L1 Expression and Copy Number Alterations in Patients with NSCLC (ID 12664)

      10:40 - 10:45  |  Author(s): Kazuo Tsuchiya

      • Abstract
      • Presentation
      • Slides

      Background

      Most patients with non-small cell lung cancer (NSCLC) are diagnosed at advanced stages and only small biopsy specimens are available for diagnosis in the majority of the patients. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a useful diagnostic modality and is becoming more relevant and essential procedure in the real-world clinical setting. However, it is poorly elucidated whether EBUS-TBNA-derived small specimens are suitable for evaluation of biomarkers such as PD-L1 alterations, because heterogeneity of PD-L1 expression limits the power as a guide to select patients who are likely to benefit from the PD-1/PD-L1 blockade therapy. In addition, PD-L1 copy number alterations (CNAs) have been proposed to potentially complement the predictive performance of PD-L1 expression. We here evaluated the utility of EBUS-TBNA-derived specimens in the assessment of PD-L1 protein and CNAs focusing on the heterogeneity with other biopsy/resected samples.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      PD-L1 protein expression and CNAs in 71 EBUS-TBNA specimens of NSCLC were assessed. Corresponding 68 transbronchial biopsy (TBB) specimens, 13 resected primary tumors, and 6 resected metastases were comparatively analyzed. PD-L1 expression on tumor cells was assessed by immunohistochemistry (E1L3N). Positivity of ≥1% was used as the cut-off. PD-L1 CNAs were assessed with fluorescent in situ hybridization, and were classified into three categories: amplification, polysomy, and disomy. Concordance between EBUS-TBNA and other specimens were calculated.

      4c3880bb027f159e801041b1021e88e8 Result

      The median age was 68 years (38-90 years). The cohort comprised 48 men (67.6%), 15 never-smokers (21.1%), and 39 adenocarcinomas (54.9%). The concordance of PD-L1 positivity between EBUS and the other specimens was moderate; κ=0.63 for EBUS vs TBB, κ=0.68 for EBUS vs the resected primary tumors, and κ=1.00 for EBUS vs the resected metastases. The concordance of PD-L1 CNA statuses was comparable with that of PD-L1 expression: κ=0.60 for EBUS vs TBB, and κ=0.74 for EBUS vs the resected primary tumors. When the PD-L1 copy number was assessed as a continuous variable, the correlation was also good/moderate: ρ=0.60 for EBUS vs TBB specimens, ρ=0.56 for EBUS vs the resected primary tumors, and ρ=0.80 for EBUS vs the resected metastases. Intratumorally, PD-L1 expression was significantly heterogeneous in whole sections of resected tumors, but PD-L1 CNAs was less heterogeneous than protein expression.

      8eea62084ca7e541d918e823422bd82e Conclusion

      EBUS-TBNA-derived specimens can be used for the assessment of PD-L1 alterations including CNAs. The concordance of PD-L1 CNAs between EBUS-TBNA and TBB/resected specimens were comparable with that of PD-L1 expression. However, spatial heterogeneity should be taken into account to interpret both PD-L1 protein expression and CNAs.

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