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M. Okamoto
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P2.02 - Biology/Pathology (ID 616)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.02-072 - Reliability of Small Biopsy Samples for Tumor PD-L1 Expression in Non-Small-Cell Lung Cancer (ID 8728)
09:30 - 09:30 | Author(s): M. Okamoto
- Abstract
Background:
Programmed death 1 immune checkpoint inhibitor antibody has been effective in patients with PD-L1 positive advanced NSCLC. However, surgically resected specimens or core-needle biopsy samples were used to estimate drug potency in past clinical trials.The aim of this study is to prospectively investigate small sample reliability for NSCLC to determine the PD-L1 expression status.
Method:
We prospectively enrolled patients who underwent diagnostic biopsy by any procedures (under rigid bronchoscopy, flexible bronchoscopy, CT & US-guided core-needle, excisional method) from March 2017 to March 2018 (ongoing study). Pathologically confirmed non-small cell lung cancer (NSCLC), PD-L1 expression was evaluated in our institution using companion diagnostic PD-L1 immunohistochemistry：PD-L1 IHC 22C3 pharmDx (Daco) with autostainer Link 48, detecting a driver mutation in parallel. We evaluated: 1) the total number of tumor cells and sample size; 2) compared PD-L1 expression for each procedure using tumor proportion score: TPS (＜1%, 1～49%, 50%≦), 3) the concordance rate of PD-L1 expression status by biopsy and surgical materials; and 4) the efficacy of administration for PD-1 immune checkpoint inhibitor antibody.
Result:
During the first three months 44 cases of PD-L1 expression were evaluated. 33 cases were sampled by bronchoscopy (6 under rigid scope with BF 1T260, 17 TBBs using 1T260/P260F in 4/13 cases, 10 TBNAs), and 7 cases were CT-guided core-needle biopsy. The TPS (＜1%, 1～49%, 50%≦) was 8/6/10 for TBB, 3/4/2 for TBNA, and 4/0/3 for CT-guided. Four cases harboring EGFR mutation showed a lower PD-L1 expression (＜10%).
Conclusion:
Utilizing smaller samples to evaluate PD-L1 expression, and the frequency of TPS were comparable to past clinical trials using larger samples. Smaller samples might be an accurate alternative to assess PD-L1 expression. Current data will be updated at the conference.
