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). Here, EGFR is linked to adenocarcinoma.