The prognostic effect of the epidermal growth factor receptor gene mutation on recurrence dynamics of lung adenocarcinoma

Abstract

OBJECTIVES: The prognostic effects of epidermal growth factor receptor (EGFR) gene mutation on lung adenocarcinoma recurrence have not been well established. The relationship between EGFR gene mutation and recurrence dynamics of lung adenocarcinoma was investigated. METHODS: A total of 527 patients with complete resection for adenocarcinoma were reviewed retrospectively. EGFR gene mutation was analysed by polymerase chain reaction followed by bidirectional direct sequencing in recurred patients. Patients were divided into the EGFR gene mutation group (M) or the wild-type EGFR gene group (W). Recurrence types and disease-free intervals (DFIs) of the 2 groups were compared. DFIs were calculated by the Kaplan–Meier method and compared using the log-rank test and Cox proportional hazard model. RESULTS: EGFR gene sequencing was performed in 115 recurrent adenocarcinoma patients. Sixty-six patients had EGFR mutations and 49 patients had wild-type EGFR. The median DFI of the 2 groups were significantly different (M: 20.3 months, W: 15.1 months, P = 0.012). EGFR gene mutation was the only prognostic factor for DFI [hazard ratio (HR) = 0.639, 95% confidence interval (CI) = 0.428–0.954, P = 0.029]. The proportion of loco-regional recurrences and distant metastases of both groups were similar (P = 0.50). In subgroup analysis, EGFR gene mutation (HR = 0.534, 95% CI = 0.339–0.839, P = 0.007) was a significant prognostic factor for DFI of distant metastases. CONCLUSIONS: Lung adenocarcinoma with EGFR gene mutations had longer DFI than those with wild-type EGFR gene, especially with regard to distant metastasis. EGFR gene mutation was a prognostic factor for lung adenocarcinoma.