There are several limitations in the current study. First is the nature of the retrospective study; patient selection, especially the lump of histological subtypes of NSCLC, is a potential bias. Our additional analyses targeting the lung adenocarcinoma patients showed the comparable results (Supplementary Tables 1 and 2). Moreover, a higher proportion of patients with adenocarcinoma histology received the EGFR testing compared to those with SCC (71.4% vs. 39.6%) is the second limitation; however this limitation implies that the influence of the presence of mutated-EGFRs on SBM occurrence compared to that of WT-EGFR had been possibly underestimated because patients with lung SCC have a smaller chance of harboring mutated-EGFRs (1-3%) and of experiencing BM than those with lung adenocarcinoma . The possibility of EGFR mutation discordance between the primary and metastatic sites may influence our results and represents another limitation. Based on the report indicating that the heterogeneous distribution of EGFR mutations is extremely rare in lung adenocarcinoma , we used the EGFR mutation status determined from primary or metastatic lung cancer specimens as a surrogate of the entire eligible population. Fourth, not all of the enrolled patients, such as those with early-stage disease, received intensively periodic brain imaging assessments after their NSCLC diagnosis. Furthermore, other driving oncogenes, such as KRAS and ALK mutations, were not factored into the analysis, largely because KRAS mutations were not common in our patient population (3.8%)  and ALK rearrangements were not routinely tested during the study period. Moreover, because few cases had the T790M mutation (n = 5) in our study, we could not address the potential influence of T790M on the BM development. In addition, we recognized that our findings were limited to externally generalize to NSCLC patients who visited and received their major managements for lung cancer at our institutes, not to the Taiwan population. All the previously mentioned limitations may have influenced the clinical findings in the current study. To further elucidate this issue, large-scale studies cross populations are warranted.