EGFR and bone metastasis: The formula (Table 3) included PS (PS0: 0 points, PS 1/2: 48 points, PS 3/4: 100 points), morphology (adenocarcinoma: 0 points, non-adenocarcinoma: 94 points), EGFR mutation (exon 19 deletion: 0 points, L858R: 19 points), stage (IIIB: 0 points, IV: 76 points), TKI use (afatinib: 0 points, erlotinib: 48 points, gefitinib: 76 points), lung metastasis (77 points), brain metastasis (40 points), bone metastasis (56 points), pleural metastasis (62 points), adrenal metastasis (49 points), and distant lymph node metastasis (33 points).