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Lama Sakr



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    MA09 - Lung Cancer Surgical and Molecular Pathology (ID 908)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Pathology
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 15:15 - 16:45, Room 202 BD
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      MA09.09 - EBUS-TBNA in Assessing PD-L1 Expression in NSCLC (ID 13471)

      16:15 - 16:20  |  Author(s): Lama Sakr

      • Abstract
      • Presentation
      • Slides

      Background


      Pembrolizumab is the only immunotherapy approved as a first line agent for metastatic NSCLC in patients with high programmed death‐ligand 1 (PD‐L1) expression. The standard samples for PD-L1 testing are considered surgical or core biopsies. In this study, our primary objective is to identify the adequacy of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) tumor samples in detecting PD-L1 expression.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Between July 2016 and April 2017 a total of 1352 consecutive cases of non-small cell lung cancer (NSCLC) were identified. 29 specimens were deemed inadequate (less than 100 viable tumor cells) and were excluded. 1323 specimens analyzed included surgical samples (N=238), small biopsy (N=744) and cytology cell blocks (N=341). Cytology cell blocks were from EBUS-TBNA (N=190), fine needle aspiration (FNA) (N=61) and pleural/pericardial fluid (N=90). PD-L1 expression was examined by staining with Dako PD-L1 IHC 22C3 pharmDx kit. A Tumor Proportion Score (TPS) was categorized as <1%, 1-49% and ≥ 50% tumor cells.

      4c3880bb027f159e801041b1021e88e8 Result

      Most of the 1323 specimens (84%) were non-squamous carcinomas. Overall yield for TPS > 50% was 36%. Rate of PD-L1 positivity was no different in non-squamous (37%) compared to squamous (32%). Diagnostic yield of PD-L1 for different sample types varied substantially (Table 1). The EBUS-TBNA samples had the highest yield for TPS ≥ 50% (p=0.025).

      TPS Surgical resection Small biopsy EBUS-TBNA FNA Fluid cytology Total
      Adequacy 100% 99% 98% 96% 92% 98%
      ≥ 50% 69 (29) 269 (36) 84 (44) 21 (34) 38 (42) 481
      1-49% 87 (37) 274 (37) 57 (30) 22 (36) 22 (24) 462
      <1% 82 (35) 201 (27) 49 (26) 18 (30) 30 (33) 380
      Total 238 744 190 61 90 1323
      8eea62084ca7e541d918e823422bd82e Conclusion

      Our results show that cytology cell blocks could be considered as a valuable resource for PD-L1 testing in advanced NSCLC. Future studies are warranted to explore clinical correlation of PD-L1 on EBUS-TBNA samples and immunotherapy outcome.

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