Baseline characteristics
Of the total 334 older advanced NSCLC patients, 232 (69.5%) patients (172 females and 60 males) aged >=65 years at EGFR-TKI treatment initiation were included in the study (Figure 1 ). Their median age was 73 years (range = 65–88 years). On the basis of the TNM Classification of Malignant Tumors, 8thedition, 8 (3.4%), 46 (19.8%), 121 (52.2%), and 57 (24.6%) patients presented with stage III, stage IVA, stage IVB, and recurrent disease, respectively. At EGFR-TKI treatment initiation, 156 (67.2%) patients were administered gefitinib; 38 (16.3%), erlotinib; 10 (4.3%), afatinib; and 28 (12.1%), osimertinib. During the overall clinical course, 66 (29.0%) patients, including those initially treated with first- or second-generation EGFR-TKIs, were administrated osimertinib (Table 1 ).