The Correlation Between EGFR Mutation Status and the Risk of Brain Metastasis in Patients with Lung Adenocarcinoma

To explore the correlation between epidermal growth factor receptor (EGFR) mutation status and the risk of brain metastasis (BM) in patients with lung adenocarcinoma, the clinical data of 100 patients with pathologically confirmed lung adenocarcinoma and known EGFR mutation status at exon 18, 19, 20, or 21 were analyzed retrospectively. The incidence of BM was similar between patients with wild-type EGFR and those with EGFR mutations (p = 0.48). However, among patients with EGFR mutations, the incidence of BM was significantly higher in patients with mutation at exon 19 than in patients with mutation at other sites (p = 0.007). Besides, among patients with heterochronous BM, 66.7 % had EGFR mutations. Regarding brain-metastasis-free survival (BMFS), patients with EGFR sensitive mutations (mutation at exon 19/21/and dual mutation) had significantly shorter BMFS compared with patients with wild-type EGFR (p = 0.018). For patients treated only with chemotherapy, BM was an unfavorable prognostic factor. Patients with BM had worse overall survival compared with those without BM (p = 0.035). However, in patients with BM and EGFR sensitive mutations, those treated with tyrosine kinase inhibitors (TKIs) had significantly longer overall survival compared with those treated with chemotherapy only (p = 0.0081). In conclusion, among patients with EGFR mutations, those mutated at exon 19 had the highest incidence of BM. Furthermore, patients with EGFR mutations are more likely to develop heterochronous BM. The BMFS was significantly shorter in patients with EGFR sensitive mutations. TKIs improved the survival of patients with lung adenocarcinoma and BM who harbored EGFR sensitive mutations.