EGFR and lung adenocarcinoma: Between May 2014 and December 2016, a total of 4,889 advanced lung adenocarcinoma patients with the EGFR mutation receiving TKIs (including 1,778 gefitinib, 1,599 erlotinib, and 1,512 afatinib) as first-line therapy were included in our study (Figure 1).