In the adjusted model which was modified for age, sex, premium level, comorbidities, anti-neoplastic agents, cancer treatments, CT regimen before EGFR-TKI and concomitant drugs, lung cancer patients with COPD still remained at a higher risk of death (HR 1.05, 95% CI 1.01–1.08, p = 0.012). The gene discussed is EGFR; the disease is cancer.