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Asghar Naqvi



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    P1.09 - Pathology (Not CME Accredited Session) (ID 941)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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      P1.09-04 - Optimization of PD-L1 Testing Specimen Flow in the Greater Hamilton, Ontario Region (ID 12767)

      16:45 - 18:00  |  Author(s): Asghar Naqvi

      • Abstract

      Background

      Immunotherapy targeted at the programmed cell death 1 (PD-1) receptor and its ligand (PD-L1) is a new treatment option for non-small-cell lung cancer (NSCLC). Immunohistochemistry (IHC) for the PD-L1 protein has been shown to predict response. The 22C3 IHC assay is the only clinically validated PD-L1 test. We present the Hamilton, Ontario, Canada experience of local PD-L1 analysis using the 22C3 assay including both histology and cytology specimens.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      All data for requests for PD-L1 testing from within Hamilton were collected for one year. Unstained slides were cut for IHC analysis. Both histology and formalin fixed cytology specimens were accepted. Slides were sent for PD-L1 staining centrally at Dynacare in Bowmanville, Ontario, Canada. IHC interpretation was done in Hamilton. The assay was positive if ≥50% of tumour cells (TCs) had any intensity staining. The assay was negative if no TCs had staining. The assay was interpreted as low positive if 1-49% TCs had any intensity staining. Samples with less than 100 cells were considered inadequate. Turn around-time was defined as the accession date to PD-L1 sign out date.

      4c3880bb027f159e801041b1021e88e8 Result

      401 samples were evaluated; 108 cytology(C) and 293 histology(H). 36% of samples tested positive (43%:C;33%:H); 20% of samples tested low positive (14%:C;23%:H); 39% of samples tested negative (29%:C;42%:H); 5% were insufficient for evaluation (15%:C;1%:H). Chi-squared analysis identified a statistically significant (χ2 < 0.02) difference in the distribution of test results comparing histology and cytology. The mean turn-around-time (TAT) was 28.9 days (range 12-144). TAT varied by hospital of origin. TAT for PD-L1 results from the hospital with dedicated thoracic pathologists was on average 10 days shorter than from other Hamilton hospitals. TAT in our hospital with dedicated thoracic pathologists improved with time from a mean of 49 days to a mean of 22 days while TAT from other hospitals did not improve over the course of the year.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our cohort mirrors findings in the literature and demonstrates that the 22C3 assay for PD-L1 can be done on both histology and cytopathology specimens; however, the insufficient rates are higher for cytopathology. Cytopathology specimens have a higher PD-L1 positivity rate, a finding that may reflect differences in tumour biology and/or stage in this subgroup. Turnaround times were different based on the hospital of origin, and suggest centralized specimen collection or use of dedicated thoracic pathologists may be advantageous. Correlation with clinical outcomes on our cytology cases will be presented in a separate abstract.

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    P2.09 - Pathology (Not CME Accredited Session) (ID 958)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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      P2.09-08 - Clinical Outcomes of Histology Versus Cytology PD-L1 22C3 Antibody Testing in Advanced Non-Small Cell Lung Cancer (ID 13490)

      16:45 - 18:00  |  Author(s): Asghar Naqvi

      • Abstract

      Background

      Immune checkpoint inhibitors (CPIs) are now an accepted standard of care along the treatment algorithm for advanced non-small cell lung cancer (NSCLC). PD-L1 expression using 22C3 immunohistochemistry (IHC) help determine the line of therapy in which CPI are used. Previous studies demonstrated that PD-L1 expression is comparable on cytology versus solid biopsy/histology specimens. We assess the clinical outcomes between patients with PD-L1 expression ≥50% (high positive) tested using cytology versus histology specimens.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      This retrospective cohort study includes specimens processed between January 2015 to June 2017 on samples dating back to March 2014. Patients were included in the study if they were seen by a medical oncologist for consideration of systemic treatment for advanced NSCLC. Clinical characteristics were extracted from electronic medical records. Overall survival (OS) was defined as time from diagnosis of advanced NSCLC to death and compared by method of PD-L1 analysis (cytology versus histology), adjusting for age, ECOG, weight loss, and receipt of palliative intent radiotherapy, targeted therapy, and CPI.

      4c3880bb027f159e801041b1021e88e8 Result

      148 (30.8%) of 481 samples tested ≥50% for PD-L1 expression. Amongst those, 32 and 37 patients fulfilled eligibility criteria with cytology and histology samples respectively. Baseline characteristics of the two groups are comparable in age, gender, ECOG, histological subtype, and receipt of CPIs. The cytology group had a significantly higher number of patients with baseline pleural effusion (10 vs 4 patients, p=0.035) and receipt of any systemic therapy (28 vs 22 patients, p=0.009). The histology group received more palliative intent radiation (24 vs 13, p=0.044).

      There was no difference in OS between the cytology and histology groups. Median OS in the cytology group was 11.9 versus 8.0 months in the histology group; adjusted HR 0.98 (95% CI 0.43-2.26). Amongst patients who received systemic therapy, survival was longer if patients were exposed to CPI during their course of treatment regardless of cytology or histology groups; adjusted HR 0.45 (95% CI 0.22 – 0.90).

      8eea62084ca7e541d918e823422bd82e Conclusion

      In advanced NSCLC, CPI treatment guided by specimens analyzed by cytology versus histology were equivalent in survival. Regardless of sample source, patients exposed to CPI in any line of therapy had significantly longer survival than patients without exposure to CPI amongst patients testing high positive for PD-L1. Ongoing analyses are comparing clinical outcomes in patients with other expressions of PD-L1.

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