Impact of Asian ethnicity on outcome in metastatic EGFR-mutant non-small cell lung cancer.

Aim: To determine factors associated with survival in de novo stage IV, non-small cell lung cancer (NSCLC) patients possessing epidermal growth factor receptor mutations (EGFRmut ) receiving tyrosine kinase inhibitors (TKI) in the first-line setting.

Methods: The Glans-Look Lung Cancer Database was used to retrospectively review stage IV EGFRmut NSCLC patients diagnosed 2010-2016 receiving first-line TKI. Patients with overall survival times in the upper quartile (≥34 months) were designated "long-term survivors" (LTS), the remaining deemed "average-term survivors" and characteristics between these groups were compared in univariate analysis, and multivariable models constructed to determine predictors of outcome.

Results: Of 170 eligible patients, median overall survival was 21 months. LTS were significantly more likely to be of Asian ethnicity, be never-smokers and not possess brain or bone metastases at diagnosis. Asian and non-Asian patients were comparable, save for an increased propensity of Asian patients to be never smokers and have normal-range BMI. Multivariable analysis revealed Asian ethnicity [hazard ratio (HR) = 0.65; P = 0.016] and never-smoking history (HR = 0.65; P = 0.034) as indicators of improved outcome, and presence of brain metastasis at diagnosis an indicator of poor outcome (HR = 2.21; P < 0.001).

Conclusions: Analysis of this population-based cohort identifies never-smoking history and absence of brain metastasis along with Asian ethnicity as an independent prognosticators of favorable outcome, and reveals Asian patients to be clinicopathologically similar to non-Asian patients. These findings suggest Asian patients represent a unique subpopulation within EGFRmut NSCLC who may possess different biological underpinnings of NSCLC.