Antitumor effects of gefitinib for metastatic brain tumors from lung carcinomas with EGFR mutation

Patients with lung cancer harboring epidermal growth factor receptor (EGFR) mutation respond remarkably well to tyrosine kinase inhibitors of the EGFR (EGFR-TKI). We examined the relation of the EGFR mutation and the efficacy of EGFR-TKI for metastatic brain tumors from lung cancer. Forty-one patients with brain metastases from lung cancer were treated in our hospital from January 2007 to October 2010. Among them, 9 patients were examined on their EGFR mutation of tumors using the PNA-LNA PCR clamp method, and were treated with gefitinib, given orally at a daily dose of 250 mg. The drug efficacy for brain tumors was evaluated with MRI and CT. Seven patients had EGFR mutation (4 in exon 19, and 3 in exon 21). Five patients showed partial response, 3 remained stable, and one had progressive disease. All 5 patients who showed partial response had EGFR mutation. One patient who had progressive disease had no EGFR mutation. Three patients (case 1, 2 and 6) among 5 patients who showed partial response were well controlled only with gefitinib (without radiation). This study suggests that the efficacy of EGFR-TKI for metastatic brain tumors from lung cancer is related to the EGFR mutation of tumor. (author)