EGFR and bone metastasis: Multivariate analysis revealed that acquired EGFR amplification [HR = 0.676, 95% CI (0.489–0.935), p = 0.018] and EGFR 19del mutation [HR = 0.561, 95% CI (0.433–0.726), p < 0.001] were independent prognostic factors for PFS, whereas EGFR 19del mutation [HR = 0.667, 95% CI (0.490–0.907), p = 0.010], a history of lung cancer surgery [HR = 0.611, 95% CI (0.415–0.900), p = 0.006] and no bone metastasis [HR = 0.703, 95% CI (0.516–0.958), p = 0.026] were independent prognostic factors for OS.