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M. Deavers
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P3.02c - Poster Session with Presenters Present (ID 472)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.02c-064 - Higher PD-L1 Expression Correlates with Solid and High Grade Lung Adenocarcinomas: Implications for Immunotherapy Selection (ID 5690)
14:30 - 14:30 | Author(s): M. Deavers
- Abstract
Background:
Evidence of likely response to immunotherapy, including programmed death ligand-1 (PD-L1) expression, assumes more importance in selecting immunotherapy as a first line therapy over conventional therapy. However, PD-L1 expression is heterogeneous and known to be underestimated on small biopsies. Correlation of PD-L1 expression with clinicopathologic features may provide additional useful information in this setting. In phase II clinical trials (POPLAR study) survival benefit from atezolizumab correlated PD-L1 expression in either tumor cells or tumor-infiltrating immune cells assessed by immunohistochemistry with clone SP142 for patients with previously treated non-small cell lung carcinoma (NSCLC). To our knowledge the clinicopathologic features of NSCLC have not been reported for subsets defined by PD-L1 expression in either tumor cells or tumor-infiltrating immune cells.
Methods:
A total of 125 adenocarcinomas and 38 squamous cell carcinomas were included in the study. PD-L1 immunohistochemistry with the SP142 clone was performed on whole tissue sections and scored according to percent of PD-L1-positive tumor cells (TC0 for <1%, TC1 for 1-4%, TC2 for 5-49%, and TC3 for ≥50%) and percent tumor area with PD-L1-positive tumor-infiltrating immune cells (IC0 for <1%, IC1 for 1-4%, IC2 for 5-9%, IC3 for ≥10%).
Results:
Adenocarcinoma cases which scored either TC1/2/3 or IC1/2/3 include the majority (22 of 34; 65%) with high histologic grade, a minority (15 of 46; 33%) with low histologic grade, the majority (25 of 36; 69%) with solid subtype, and a minority for most other subtypes. Compared to the adenocarcinoma TC0 and IC0 subset, the TC1/2/3 or IC1/2/3 subset correlated with higher histologic grade (p = .0051, χ[2] test for trend) and solid subtype (p = .0006, Fisher’s exact test). Compared to the adenocarcinoma TC0/1 or IC0/1 subset, the TC2/3 or IC2/3 subset correlated with higher histologic grade (p = .0021, χ[2] test for trend), solid subtype (p = .0001, Fisher’s exact test), and higher smoking pack-years (p = .012, Mann-Whitney test). No other clinicopathologic variable, including survival, correlated with subsets for either adenocarcinoma or squamous cell carcinoma.
Conclusion:
Lung adenocarcinoma subsets defined by PD-L1 expression in either tumor cells or tumor-immune cells correlated with high histologic grade, solid subtype, and high smoking pack-years. Our results suggest that high histologic grade and solid subtype may provide useful supplementary information for the decision to treat with atezolizumab, particularly for first line therapy, when PD-L1 mmunohistochemistry is negative on small biopsies or samples are insufficient for testing.
