455P Population-level impact of EGFR mutation testing in non-squamous NSCLC

Abstract

Background: The impact and outcomes of EGFR mutation testing and targeted therapies are not well studied at the population level. We carried out a pre‐planned observational study of prospectively archived data to examine trends in the uptake of EGFR mutation testing and targeted therapy, and their impact on outcomes of patients with non‐squamous NSCLC. Methods: We assembled a population‐based cohort of 1857 non‐squamous NSCLC patients presenting over a 40 month period in the catchment area of a regional EGFR mutation testing laboratory. Electronic data repositories were linked to compile individual patient data about EGFR mutation testing, dispensing of targeted therapy, mortality outcomes, demographics and clinical factors. Results: EGFR mutation testing increased markedly during the period of study, from <5 to 67% (P<0.05), coincidently with significant reductions in the number of patients who were prescribed erlotinib or gefitinib (13.7 to 10.6%, P<0.05). For the cohort as a whole, overall survival measured from diagnosis differed significantly between groups stratified according to their EGFR mutation testing status (P<0.0001). For patients with negative EGFR mutation tests, overall survival was shorter than those with positive tests (HR=0.57 (95% CI, 0.48‐0.75)) but longer than untested patients (HR=0.75 (95% CI, 0.68‐0.87)). For a subgroup of 231 patients treated with erlotinib or gefitinib, those with positive EGFR mutation tests had longer duration of treatment (HR=0.49 (95%CI, 0.35‐0.62); P<0.0001) and overall survival from the start of treatment (HR=0.48 (95%CI, 0.36‐0.64); P<0.0001) or from diagnosis (HR=0.55 (95%CI, 0.40‐0.72); P<0.0006) as compared to untested patients who were treated. Uptake of testing was incomplete (≤67%) but more likely among females, younger or Southeast Asian patients, or those with advanced‐stage disease, pathological diagnoses or who presented later in the study period. Conclusions: EGFR mutation testing improves the utilisation and effectiveness of EGFR targeted therapies, and is associated with gains in overall survival, at the population level. Population‐based outcomes from treatment with erlotinib or gefitinib are comparable to those achieved in randomized controlled trials.