Abstract
PURPOSE: Metastasis of non-small cell lung cancer (NSCLC), indicating hematogenous dissemination, is more frequent in patients harboring epidermal growth factor receptor (EGFR) mutations, who respond dramatically to EGFR-tyrosine kinase inhibitors (TKIs). METHODS: Based on the proposed association of miliary pulmonary metastasis and EGFR mutations in the previous studies, we conducted a retrospective study to assess survival of NSCLC with miliary pulmonary metastases in 223 patients harboring EGFR mutations who were treated with single agent EGFR-TKIs. RESULTS: Progression-free survival (PFS) and overall survival (OS) with single agent EGFR-TKIs were 11.7 months [95% confidence interval (CI) 9.6-13.7] and 23.7 months (95% CI 20.3-26.9), respectively. Patients with and without miliary pulmonary metastases were matched using propensity scores (n = 29 per group) based on clinical characteristics. After matching, the PFS were 8.2 months (95% CI 5.2-15.0) and 14.3 months (95% CI 9.6-30.0) (p = 0.02) in patients with and without miliary pulmonary metastases, respectively. Conversely, the OS were 15.3 months (95% CI 10.6-19.4) and 27.9 months (95% CI 22.0-33.0) (p = 0.003) in patients with and without miliary pulmonary metastases, respectively. By multivariate analysis, miliary pulmonary metastasis was associated with poor prognosis (p = 0.0035). CONCLUSION: The prognosis of patients with advanced NSCLC harboring EGFR mutations with miliary pulmonary metastasis demonstrated significantly worse outcomes compared to those without miliary pulmonary metastasis.