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Narine Nadira
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P1.09 - Pathology (Not CME Accredited Session) (ID 941)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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P1.09-01 - PD-L1 Testing On NSCLC Cytology Samples in a UK Teaching Hospital (ID 12435)
16:45 - 18:00 | Author(s): Narine Nadira
- Abstract
Background
Immunotherapy, specifically pembrolizumab, is now approved in the UK as first-line therapy in patients with advanced non-small cell lung cancer (NSCLC) and no activating EGFR mutation or ALK translocation if high PD-L1 expression (≥50%) can be demonstrated on tumour samples. Furthermore, second line treatment is approved with PD-L1 expression ≥1%. Initial studies were performed exclusively on histological samples. We present our experience of PD-L1 testing purely on cytology samples.
a9ded1e5ce5d75814730bb4caaf49419 Method
Prospectively maintained cytology databases were analysed to identify all lung cancer cytology samples from our institute tested for PD-L1 expression between January 2017 and March 2018. Cell blocks from endo-bronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) performed using rapid on-site evaluation (ROSE), FNA of other sites, pleural fluid and bronchial brush samples were prepared and immunohistochemistry performed on sections using the Dako 22c3 antibody to determine PD-L1 expression.
4c3880bb027f159e801041b1021e88e8 Result
A total of 99 samples were tested for PD-L1. There was sufficient material for PD-L1 testing in 95% (n=94). Male 62%, female 38%, age range 26-84. EBUS-TBNA accounted for 79% of samples, percutaneous Fine Needle Aspirate (FNA) 11%, pleural fluid samples 7%, bronchial brush 2% and endoscopic ultrasound FNA 1%. Table-1 provides a breakdown of the methods of sample acquisition with adequacy rates and PD-L1 expression.
Table 1 PD-L1 samples Adequate Inadequate Negative Positive Positivity EBUS 78 76 2 19 57 1-50%
31
≥50%
26
FNA 11 9 2 2 7 1-50%
2
≥50%
5
Pleural fluid 7 6 1 0 6 1-50%
5
≥50%
1
Bronchial brush 2 2 0 0 2 1-50%
0
≥50%
2
EUS FNA 1 1 0 1 0 1-50%
0
≥50%
0
Total 99 94 5 22 72 1-50%
38
≥50%
34
Overall PD-L1 expression was highly (≥50%) positive in 34/94 (36%), low (≥1-50%) positive in 38/94 (40%), and negative in 22/94 (23%). The proportion of patients expressing high (≥50%) PD-L1 positivity in the different pathological subtypes were: adenocarcinoma 23/62 (37%), squamous cell carcinoma 8/21 (38%), NSCLC-NOS 3/9 (33%).The proportion of patients with low (≥1-50%) PD-L1 positivity were: adenocarcinoma 27/62 (44%), squamous cell carcinoma 9/21 (43%), NSCLC-NOS 2/9 (22%).
Neither of 2 neuroendocrine NSCLC tested expressed PD-L1
Our experience demonstrates that cytological samples obtained at our institute are suitable for PD-L1 testing with an adequacy rate of 95%.
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