Author of

• 31780

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  P2.17 - Treatment of Early Stage/Localized Disease (ID 189)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Treatment of Early Stage/Localized Disease
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31793

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    P2.17-11 - Evaluating PD-L1 as a Prognostic Biomarker in Surgically Resectable Non-Small Cell Lung Cancer (ID 1959)

    10:15 - 18:15  |  Author(s): Cesar Gamarra
    • Abstract

    Background
    

    Identifying biomarkers that can predict which early stage non-small cell lung cancers (NSCLCs) are likely to recur following surgical resection is critical to improving survival outcomes. Programmed Cell Death Ligand-1 (PD-L1) is an immune regulatory protein expressed on tumor cells that inhibits T effector response against tumors. Therefore, high PDL-1 expression on tumor cells may enable evasion of the anti-tumor response and be associated with worst outcomes. We conducted a meta-analysis to determine if PDL-1 expression is associated with survival in surgically resected early stage NSCLCs.

    Method
    

    PubMed was searched to identify eligible studies comparing survival of surgically resected stage I-III NSCLC patients according to PD-L1 tumor expression. Included studies were grouped according to measurement criteria of PDL-1 expression: 1%, 5%, 50% cutoffs or as a continuous variable expressed as H-score. The latter is calculated from the percentage of cells expressing PDL1 multiplied by the intensity of staining. Meta-analysis was performed using a linear mixed-effects model to determine overall survival (OS). I² was used as a measure of heterogeneity across studies.

    Result
    

    Of the 519 articles queried, 31 articles met eligibility criteria, accounting for 6,713 patients. Nine studies (n=2,407) used H score, where higher PD-L1 expression was associated with worse OS (hazard ratio [HR]_meta: 1.68, 95% confidence interval [CI]: 1.17-2.41, I²= 15.45%). Five studies used a 1% cutoff (n=1,073), 14 studies reported using a 5% value (n=2,310) and 6 studies (n=1,572) used a 50% cutoff for evaluating high vs. low PD-L1 expression. PD-L1 expression was not statistically significantly associated with survival according to these cutoffs and there was high inter-study heterogeneity (HR_meta: 1.47, 95% CI 0.89-2.41; I²= 17.57%; HR_meta: 1.09, 95% CI 0.79-1.52; I²= 35.49%; HR_meta: 1.21, 95% CI 0.61-2.40; I²= 58.26% for 1%, 5%, 50%, respectively).

    Conclusion
    

    Higher PD-L1 expression in early stage NSCLCs as measured by H scores was associated with worse post-surgical survival. The measurement of PD-L1 expression as a continuous variable (i.e. H score) may provide more accuracy for predicting survival outcomes over percentage cutoffs. Future research is needed to validate PD-L1 expression as a predictive biomarker of survival for early-stage NSCLCs undergoing surgical resection.