Phase II trial of gefitinib alone without radiation therapy for Japanese patients with brain metastases from EGFR-mutant lung adenocarcinoma

Abstract Background Brain metastases (BM) are a common in patients with lung cancer. Although whole-brain radiation therapy (WBRT) is the standard therapy, it may have a risk of decline in cognitive function of patients. In this study, we evaluated the efficacy of gefitinib alone without radiation therapy for the treatment of patients with BM from lung adenocarcinoma. Materials and methods Eligible patients had BM from lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutations. Gefitinib was given at 250 mg orally once a day until tumor progression or unacceptable toxicity. Results Forty-one patients were enrolled. The response rate was 87.8%. No patient experienced grade ≥4 toxicity. The median progression-free survival time was 14.5 months (95% CI, 10.2–18.3 months), and the median overall survival time was 21.9 months (95% CI, 18.5–30.3 months). In compared with L858R, exon 19 deletion was associated with better outcome of patients after treatment with gefitinib in both progression-free ( p = 0.003) and overall survival ( p = 0.025). Conclusion Favorable response of BM to gefitinib even without irradiation was demonstrated. Exon 19 deletion was both a predictive and prognostic marker of patients with BM treated by gefitinib.