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B. Nelson
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P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.04-067 - Clinical Characteristics Associated with PDL1 Positive Status in Resected NSCLC (ID 1077)
09:30 - 09:30 | Author(s): B. Nelson
- Abstract
Background:
Multiple different PD1 and PDL1 targeting antibodies have been developed for the treatment of NSCLC. Identifying the population most likely to benefit from PD1/PDL1 direct therapy has focused on PDL1 immunohistochemistry (IHC) of the tumor cells. However, each therapeutic agent has a different companion diagnostic test therefore it is difficult to consistently ascertain the PDL1 status of an individual patient. We proposed to evaluate clinical predictors of PDL1 positive status based on consensus PDL1 immunohistochemistry.
Methods:
Patients with resected Stage II lung adenocarcinoma who underwent adjuvant chemotherapy at the BC Cancer Agency were selected for this study. A tissue microarray (TMA) with matched primary and lymph node was constructed. IHC directed towards PD-L1 was performed with 2 different primary antibody clones: E1L3N (Cell Signaling Technology) and SP142 (Spring Bioscience). PDL1 consensus score was considered positive if there was concordance with both antibodies. Clinical characteristics were abstracted by retrospective chart review.
Results:
Eighty cases of NSCLC were identified and used in TMA construction. 19 primary tumors (24%) were PD-L1 positive by consensus scoring. Lymph node metastases showed a concordant PD-L1 score in 92% cases. Patients were categorized as PDL1 positive based on consensus score of the primary tumor. Baseline characteristics based on PDL1 primary tumor status negative/positive: female 64%/47%, median age 61/65 (NS). Current smoker at the time of diagnosis 34%/58% (p=0.07). The 7 EGFR mutation positive and 2 ALK positive patients were PDL1 negative. PDL1 positivity was examined by pack years of smoking: >10 pk yrs 69%/90% (p=0.13), >20 pk yrs 62%/79% (p=0.26), >30 pk yrs 39/63% (p=0.11) and tumor differentiation: well 13%/5%, moderate 48%/21%, poorly 39%/74% (p=0.03).
Conclusion:
PDL1 positive status is associated with poorly differentiated tumors and demonstrates a trend towards current smokers. This is consistent with the concept that smoking related malignancies and poorly differentiated tumors are more antigenic and therefore require immunosuppression via PDL1 to remain undetected by the immune system.
