To determine whether EGFR-TKI treatment is associated with SBM, herein, we conducted a separate study. Of the patients without BM at the diagnosis of stage IIIB-IV NSCLC enrolled in Figure 2C right, 105 patients had mutated-EGFRs, 33 treated with EGFR-TKIs (TKI group) and 72 treated with non-TKI regimen (non-TKI group) as first-line treatment, respectively. More SBM was observed in TKI group (54.5%, 18/33) than in non-TKI group (29.2%, 21/72). As shown in Table 5, the administration of EGFR-TKIs as the 1st-line setting was associated with SBM (HR = 2.10, 95% CI = 1.15-3.82, P = 0.015) after adjusting for gender (HR = 2.38, 95% CI = 1.28-4.55, P = 0.007), age, smoking history and histological subtype.