Publication-only abstracts (abstract number preceded by an "e"), published in conjunction with the 2018 ASCO Annual Meeting but not presented at the Meeting, can be found online only.
Lower prevalence of PD-L1 expression in advanced non-small lung cancer in Brazil.
Metastatic Non-Small Cell Lung Cancer
Lung Cancer—Non-Small Cell Metastatic
2018 ASCO Annual Meeting
J Clin Oncol 36, 2018 (suppl; abstr e21140)
Author(s): Ana Caroline Gelatti, Fernando Moura, Ana Maria Franco Gaiger, Mariana Petaccia de Macedo, Lisandro Ferreira Lopes, Facundo Zaffaroni, Vladmir Claudio Cordeiro De Lima, Gustavo Werutsky, Luiz H. Araujo, Samira Mascarenhas, Clarissa Mathias, Christina Shiang, Patricia Pacheco Viola, Mauro Zukin; Grupo Brasileiro de Oncologia Torácica, Porto Alegre, Brazil; Hospital Israelita Albert Einstein, São Paulo, Brazil; Laboratório Biomarker e Patologistas Reunidos, Porto Alegre, Brazil; Diagnostic Molecular Pathology Laboratory, AC Camargo Cancer Center, São Paulo, Brazil; Grupo Hermes Padrino e Laboratório Diagnostika, São Paulo, Brazil; Latin American Cooperative Oncology Group, Porto Alegre, Brazil; A.C. Camargo Cancer Center e Grupo Brasileiro de Oncologia Torácica, São Paulo, Brazil; Grupo Brasileiro de Oncologia Torácica, Rio De Janeiro, Brazil; Nucleo de Oncologia da Bahia e Grupo Brasileiro de Oncologia Torácica, Salvador, Brazil; Laboratório de Anatomia Patológica, Hospital Israelita Albert Einstein, São Paulo, Brazil; Americas Centro de Oncologia Integrado e Grupo Brasileiro de Oncologia Torácica, Rio De Janeiro, Brazil
Background: Immune checkpoint inhibitors improved outcomes of patients with advanced non-small cell lung cancer (NSCLC). KEYNOTE-024 trial demonstrated that immunotherapy was superior to platinum-based chemotherapy in the first-line setting. However, only 30% of screened patients had programmed death receptor ligand-1 (PD-L1) expression above 50%. The prevalence of biomarkers in NSCLC may vary through different regions worldwide. Our study aims to describe the prevalence of PD-L1 expression in Brazil. Methods: Immunohistochemistry for PD-L1, antibody 22C3 PharmDx Dako, was performed in 4 reference laboratories in Brazil, from Aug/2017 to Dec/2017, in consecutive cases of advanced NSCLC considered for treatment with immunotherapy. Adequate samples had > 100 tumor cells per slide evaluable. PD-L1 staining was scored as < 1%, 1-49% or ≥50% positive membrane staining within tumor cells. Data were described using summary statistics. Categorical variables were compared using Pearson's chi-square test and adjusted residuals. All p-values < 0.05 were deemed to be statistically significant. Results: PD-L1 expression was assessed in 1018 cases of aNSCLC. Median age was 67 yo, 53.84% of the patients were older than 65 yo and 55.01% were male. Regarding histology, 53.93% had adenocarcinoma, 13.36%, squamous, 26.72%, unspecified NSCLC, 3.83%, other histologies, and 2.16%, losses. Of the 1018 cases, 16.6% presented PD-L1 expression ≥50%, 22%, 1-49%, and 61.39%, < 1%. There was no association between PD-L1 expression and sex or age (p = 0.594 and p = 0.708, respectively). The histological subtype showed association with PD-L1 expression (p = 0.0455). Among adenocarcinomas, 66.48% had no PD-L1 expression, 18.03%, had 1-49%, and 15.48%, ≥50%. Among squamous cell carcinomas, 55.15% did not show PD-L1 expression, 25% had 1-49%, and 19.85%, ≥50%. Conclusions: Our results indicate a lower prevalence of PD-L1 expression in NSCLC in Brazil. Possible reasons for this discrepancy are inadequate sample handling, pre-analytical issues, or epidemiology of the biomarker, all of which may impact the results of PD-L1 expression outside clinical trials. Real world data is needed to better understand the prevalence of this test worldwide.
1. Pembrolizumab (pembro) versus platinum-based chemotherapy (chemo) as first-line therapy for advanced/metastatic NSCLC with a PD-L1 tumor proportion score (TPS) ≥ 1%: Open-label, phase 3 KEYNOTE-042 study.