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H. Koeppen



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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
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      P2.01-043 - Pathologist Agreement Rates of PD-L1 Tumor and Immune Cell Quantitation Using Digital Read, Field-Of-View, and Whole Tumor Image Analysis (ID 4041)

      14:30 - 14:30  |  Author(s): H. Koeppen

      • Abstract

      Background:
      PD-L1 agents have shown clinical efficacy. Recent reports have demonstrated the predictive value of PD-L1 immunohistochemistry (IHC) assessment from immune (IC) and tumor cells (TC) in non-small cell lung carcinoma (NSCLC). While assessing percent staining of TC is a task familiar to pathologists, assessment of IC is novel and possibly challenging. As noted in other studies, digital pathology (DP) with image analysis (IA) has the potential to reduce inter-reader (IR) variation in specific situations. However, the impact of DP IA on IR variation in the setting of PD-L1 IHC scoring is unknown as are the effects of different IA approaches (field-of-view [FOV] vs whole tumor [WT]).

      Methods:
      A cohort of 60 NSCLC formalin-fixed paraffin-embedded tissue samples was stained with PD-L1 IHC (SP142). Three pathologists underwent training for IHC-based manual assay and DP IA interpretation. Three scorers independently and blindly scored each case using digital read (DR, no IA but digital assessment on computer monitor), FOV IA, and WT IA. Data was analyzed using pair-wise overall percent agreement rates (OPA) derived from assay threshold categorical bins.

      Results:
      For IC scoring, WT IA significantly improved IR agreement and reproducibility rates as compared to DR and FOV-based approaches (table 1). TC WT IA also showed similar improvements.

      TC-DR (%) TC-FOV (%) TC-WTA (%) IC-DR (%) IC-FOV (%) IC-WTA (%)
      R1-R2 83.1 (71.5-90.5) 89.8 (79.5-95.3) 98.3 (91.0-99.7) 89.1 (77.0-95.3) 91.5 (81.6-96.3) 100.0 (93.9-100.0)
      R2-R3 94.5 (85.1-98.1) 87.3 (76.0-93.7) 100.0 (93.5-100.0) 76.7 (62.3-86.8) 88.4 (75.5-94.9) 100.0 (93.5-100.0)
      R1-R3 82.1 (70.2-90.0) 85.7 (74.3-92.6) 98.2 (90.6-99.7) 83.9 (72.2-91.3) 95.5 (84.9-98.7) 100.0 (93.6-100.0)
      Table 1: NSCLC IR OPA rates. PD-L1 IHC scoring threshold 1% (TC1/IC1), R = Reader (95% confidence interval)

      Conclusion:
      Compared to DR and FOV IA, WT IA significantly improved pathologists’ PD-L1 IR rates for TC and IC scoring in NSCLC samples. Further studies regarding accuracy and reproducibility are being performed in a larger cohort.