One hundred six patients with lung adenocarcinoma bore EGFR ex20ins near loop, six patients started first-generation EGFR-TKI therapy as first-line treatment, five patients received second-/third-generation EGFR-TKI therapy as first-line therapy, and chemotherapy or immunotherapy was administered as a first-line strategy in 37 patients. This evidence concerns the gene EGFR and lung adenocarcinoma.