Association between EGFR mutation types and incidence of brain metastases in postoperative patients with stage I–III NSCLC

Objective: This retrospective study aims to clarify the association between epidermal growth factor receptor ( EGFR ) mutation types and brain metastasis incidence in early-stage non-small-cell lung cancer after surgery. Methods: Patients pathologically diagnosed with stage I to III non-small-cell lung cancer were consecutively enrolled from January 2010 to January 2017 and reviewed. First-generation TKIs were selected as postoperative therapy for those with EGFR mutations, and platinum-based chemotherapy was used as postoperative therapy for patients with negative wild-type gene mutations. A Kaplan–Meier approach was used to calculate the cumulative incidence of brain metastasis and overall survival. Candidate prognostic factors were checked by log-rank test. Results: A total of 669 patients were eligible for the study, comprising 309 who were EGFR (+), and 360 who were EGFR (−). Patients with any type of EGFR mutation have a significantly higher risk of developing brain metastases compared to those with EGFR wild-type (hazard ratio=1.957, P=0.012). The incidence of brain metastasis was 17.1% higher in patients with the 19Del mutation than in those with the L858R mutation (13.6%), other mutations (13.3%), or wild-type EGFR (6.1%). Moreover, those with 19Del mutations showed the greatest increase in incidence of brain metastasis (hazard ratio=3.009, P=0.001); those with L858R mutations showed a smaller increase (hazard ratio=2.750, P=0.003). Conclusions: EGFR mutations are predictive factors for the cumulative incidence of brain metastasis. EGFR -mutant non-small-cell lung cancer patients may need more frequent brain magnetic resonance imaging to detect earlier occurrence of brain metastases, allowing for timely and effective treatment to improve patient prognosis.