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Susanna Cappia



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    EP1.09 - Pathology (ID 199)

    • Event: WCLC 2019
    • Type: E-Poster Viewing in the Exhibit Hall
    • Track: Pathology
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/08/2019, 08:00 - 18:00, Exhibit Hall
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      EP1.09-13 - Clinic-Pathological and Molecular Features of PD-L1 Analyses in Advanced NSCLC: A Real Life Single Center Experience (Now Available) (ID 2559)

      08:00 - 18:00  |  Author(s): Susanna Cappia

      • Abstract
      • Slides

      Background

      Programmed death ligand 1 (PD-L1) immunohistochemistry (IHC) is the most rapid, less expensive and routinely applied predictive assay for treatment with immune checkpoint inhibitors (ICI) in advanced non small cell lung cancer (NSCLC). We analyzed a real-life single center activity of PD-L1 characterization together with pathological features, molecular status determination and patients’ clinical response to ICI.

      Method

      From January 2017 to July 2018 all advanced NSCLC tumor tissue analyzed for PD-L1 expression and molecular status determination in the Pathology Unit of San Luigi Hospital, Orbassano (Turin) were selected. PD-L1 analysis was performed using 22C3 PharmDX on Dako Autostainer, while ALK rearrangement was assessed by FISH and EGFR mutations by direct pyrosequencing. Furthermore in a majority of cases (60%) a 22-gene panel was evaluated by Ion Torrent PGMTM Next Generation Sequencing (NGS). The PD-L1 IHC assay results were analyzed with cut-off values of >50% (strong positive), 1-49% (weak positive), and <1% (negative). Clinical data of response to ICI were acquired for 65 patients.

      Result

      510/532 (96%) cases were adequate for PD-L1 determination and molecular analyses; 169 (33%) were histological, 269 (53%) core biopsies and 72 (14%) cytological samples; 375 (74%) were from primitive lesion, while 135 (26%) were from metastatic sites. Of the 22 inadequate samples for PD-L1 analysis half of them were cytological specimens. PD-L1 was strong positive in 91 (18%) cases, weak positive in 137 (27%) cases and negative in 285 (56%) cases. Specimens with higher expression (>50%) derived preferentially from histological samples (e.g. surgical specimens) and from external hospitals referred to our Central Hub. EGFR and ALK positive cases were more frequently PD-L1 negative or weak positive (13% and 2%, respectively), although not reaching statistical significance. Instead, KRAS and TP53 mutated cases were significantly associated with negative or weak positive PD-L1 expression (14% and 22%, chi-square p=0.0006 and p=0.01, respectively). Among the 65 patients with clinical data of response to ICI, 37/65 (57%) were responders (partial response + stable disease) while 28/65 (43%) had progressive disease. No significant differences in terms of clinic-pathological or molecular features were found between these two groups, maybe due to the limited number of cases.

      Conclusion

      Our analyses suggest that integration of PD-L1 testing in the pathological and molecular characterization of advanced NSCLC is feasible with a very high adequacy, enabling a wide ICI administration to these patients.

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