Epidermal Growth Factor Receptor Mutations and Brain Metastasis in Patients with Nonadenocarcinoma of the Lung

Objective: This study explored the potential association between epidermal growth.factor receptor. (EGFR) mutation status and brain metastasis in patients with nonadenocarcinoma nonsmall cell lung cancer. (NSCLC).

Patients And Methods: We analyzed clinical data from 286 patients with nonadenocarcinoma NSCLC, who were tested for EGFR mutations and underwent brain magnetic resonance imaging at diagnosis. We examined the relationship between EGFR mutation and brain metastasis at initial presentation.

Results: Of the 286 patients, 20 patients (7.0%) had EGFR mutations. EGFR mutations were more frequent in younger patients (11.1% in patients =64 years vs. 3.3% in patients >64 years: P = 0.01), females (21.4% vs. 3.5% in males: P <0.001), never-smokers (25.0% vs. 3.4% in smokers: P < 0.001), and tumors with nonsquamous histology (25.0% vs. 4.1% in squamous histology: P < 0.001). At diagnosis, the frequency of EGFR mutations was significantly different in patients with metastasis to different sites (4.0% [no metastases] vs. 10.4% [extracranial metastases] vs. 40.0% [brain metastases], P < 0.001). The strong association between EGFR mutation and brain metastasis remained significant in multivariate analysis (adjusted odds ratio [OR] = 9.68, 95% confidence interval [CI] =2.32-40.45; P = 0.002). Associations were also found for EGFR mutation status with nonsquamous histology (adjusted OR = 4.46, 95% CI = 1.46-13.56; P = 0.008).

Conclusion: This study indicates that the likelihood of nonadenocarcinoma patients having EGFR mutant tumors may differ according to brain metastasis and squamous cell histology.