Author of

• 17398

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  P2.01 - Poster Session with Presenters Present (ID 461)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Biology/Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 17464

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    P2.01-066 - PD-L1 Tumor Expression and Its Effect on Overall Survival among Patients with Resected Non-Small Cell Lung Cancer (NSCLC) (ID 6110)

    14:30 - 14:30  |  Author(s): M.Y. Teo
    • Abstract

    Background:
    Anti-PD1 monoclonal antibodies have demonstrated survival advantage over conventional chemotherapy in progressive metastatic non-small cell lung cancer (NSCLC). The prognostic role of tumoral expression of PD-L1 in NSCLC remains conflicting. We performed this study to evaluate the impact of PD-L1 expression as a prognostic marker in non-metastatic NSCLC.
    
    Methods:
    NSCLC patients (pts) who underwent curative resection between 1998 and 2006 in St. James’s Hospital, Dublin were included. PD-L1 status was assessed using Ventana SP124 antibody on archival FFPE surgical tumor specimens, arrayed on tissue microarrays (TMAs) with triplicate 0.6 mm cores. PD-L1 was scored as positive if membranous staining was present in >1% of tumor cells aggregated across the replicate cores to address heterogeneity. Clinical characteristics of the pts were obtained from the hospital electronic database including age, gender, histological subtype, smoking status, grade, tumor size, nodal status, stage and survival data.
    
    Results:
    One-hundred and forty-seven patients from our institutional database were included, of which 92 (63.0%) were males, with a median age of 65 years (range: 42-82). 53.1% (n=78) with squamous histological subtype, 43.5% (n=60) were ex-smoker and 50.3% (n=74) had Stage I disease. PD-L1 positivity vs negativity among non-smoker, ex-smoker and current smoker were 13.0% vs 20.9%, 47.8% vs 43.3% and 39.1% vs 35.8% respectively, (p=0.708). PD-L1 expression by IHC was significantly higher in squamous NSCLC compared to non-squamous NSCLC (34.7% vs 14.6%, p=0.030). We also noted increased PD-L1 positivity with rising tumor T stage (T1 vs T2 vs T3 vs T4: 7.1% vs 30.6% vs 0% vs 60%, p=0.023) and grade of differentiation (G1 vs G2 vs G3: 11.1% vs 19.6% vs 44%, p=0.039). There was no correlation between nodal status and PD-L1 expression (N0 vs N1 vs N2: 25.5% vs 25% vs 26.3%, p=0.995). PD-L1 expression appears to be independent of overall disease stage (I vs II vs III: 27.3% vs 22.7% vs 25.0%, p=0.921). The median overall survival for PD-L1 positive vs negative pts was 22.1 vs 20.8 months with HR of 0.64 (95% CI: 0.34-1.12, p=0.123). Overall survival rates of pts with PD-L1 positive vs negative tumors at 2 years were 47.8% vs 44.8% and at 5 years were 43.5% vs 26.9%.
    
    Conclusion:
    In our cohort, PD-L1 expression was not associated with poorer survival among resected NSCLC pts. Tumour size and grade of differentiation appear to correlate with PD-L1 expression which warrants further validation in future studies.