Brain metastases in lung adenocarcinoma: impact of EGFR mutation status on incidence and survival
Brain metastases (BM) represent a frequent progression site in lung adenocarcinoma. This study was designed to analyse association between epidermal growth factor receptor (EGFR) mutation status and frequency of BM and survival in routine clinical practice.
Patients and methods
We retrospectively analysed medical records of 629 patients with adenocarcinoma in Slovenia who were tested for EGFR mutations in order to analyse cumulative incidence of BM, time from diagnosis to development of BM (TDBM), time from BM to death (TTD) and medial survival.
Out of 629 patients, 168 (27%) had BM, 90 patients already at the time of diagnosis. Additional 78 patients developed BM after a median interval of 14.3 months; 25.8 in EGFR positive and 11.8 in EGFR negative patients, respectively (p=0.002). EGFR mutations were present in 47 (28%) patients with BM. Curves for cumulative incidence of BM in EGFR positive and negative patients demonstrate a trend for higher incidence of BM for EGFR mutant patients at diagnosis (19% vs 13%, p = 0.078), but no difference later during the course of the disease. Patients with BM at diagnosis had statistically longer TTD (7.3 months) than patients who developed BM later (3.1 months). TTD for EGFR positive patients with BM at diagnosis was longer than in EGFR negative patients (12.6 vs 6.8, p=0.005), while there was no impact of EGFR status on TTD of patient who developed BM later.
ConclusionsExcept for a non-significant increase of frequency of BM at diagnosis for EGFR positive patients, EGFR status had no influence upon cumulative incidence of BM. EGFR positive patients had longer time to CNS progression. While EGFR positive patients with BM at diagnosis had longer survival, EGFR status had no influence on TTD for patients who developed BM later during the course of disease.