P3.02b-063 Analysis of Survival in EGFR-Mutation-Positive Advanced Non-Small-Cell Lung Cancer Patients with Miliary Pulmonary Metastasis: Topic: EGFR Clinical

Miliary pulmonary metastasis of non-small-cell lung cancer (NSCLC) indicates hematogenous dissemination and is more frequent in patients harboring EGFR mutations, and dramatic responses are often observed after treatment with EGFR-tyrosine kinase inhibitors (TKI). The relevance between miliary pulmonary metastasis and EGFR mutation has been suggested; therefore, we analyzed the survival in patients with miliary pulmonary metastasis harboring EGFR mutations treated with EGFR-TKI. We retrospectively analyzed 269 patients diagnosed with advanced or recurrent NSCLC treated with EGFR-TKI between 2005 and 2015 identified from the electronic database at our hospital. OS and PFS were estimated using the Kaplan–Meier method. We analyzed the survival in all eligible patients and performed propensity score matching based on clinical characteristics. A total of 215 NSCLC patients harboring EGFR mutations and treated with EGFR-TKIs were included in the study. Patients had a median age of 61 years (38–88 years). With regard to EGFR-TKIs, gefitinib was administered in 167 patients (77.7%), erlotinib in 30 (14.0%), and afatinib in 1 (0.5%). PFS for EGFR-TKI was 12.5 months [95% confidence interval (CI) 9.6–13.8 months) and OS was 23.7 months (95% CI: 20.3–27.2). A total of 31 patients with miliary pulmonary metastasis were identified; propensity matching identified 29 patients from each group with similar clinical characteristics. PFS between miliary pulmonary metastasis and matched control groups was 8.2 months (95% CI, 5.2–5.0) vs. 14.3 months (95% CI, 9.6–30.0) (p = 0.02), and OS was 15.3 months (95% CI, 11.0–20.3 months) vs. 27.9 months (95% CI, 22.0–33.0 months) (p = 0.003). The response rates did not show any significant difference between the two groups. The prognosis of patients with advanced NSCLC harboring EGFR mutations with miliary pulmonary metastasis demonstrated significantly worse outcome compared with those without miliary pulmonary metastasis.