EGFR and bone metastasis: Among the 33 potential prognostic factors analyzed in univariate analysis, the female gender (HR 0.684, 95% CI: 0.493–0.949, p = 0.023), EGFR Mutation of Exon 19 (HR 0.601, 95% CI: 0.416–0.867, p = 0.007) and the presence of synchronous bone metastasis (HR 0.631, 95% CI: 0.444–0.896, p= 0.010) were significantly associated with a lower risk of death.