Activity of pemetrexed and high-dose gefitinib in an EGFR-mutated lung adenocarcinoma with brain and leptomeningeal metastasis after response to gefitinib

About 20% to 40% of patients with non-small cell lung cancer (NSCLC) will develop brain metastases during the natural course of their disease. The prognosis for such patients is very poor with limited survival. In addition to the standard whole brain radiation therapy (WBRT), some studies have shown that chemotherapy drugs and/or epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) can improve the outcome of these patients. Here, we report a stage IIIA patient who developed multiple brain metastases one year after operation. Oral gefitinib with concurrent WBRT were given as first-line therapy. Complete response and a 50-month progression-free survival (PFS) were obtained. Double dosage of gefitinib (500 mg per day) together with pemetrexed were given as the second-line therapy after the patient developed new brain lesions and leptomeningeal metastasis during the maintenance therapy of gefitinib. The PFS for the second-line therapy was six months. In total, the patient obtained an overall survival of 59 months since the first diagnosis of brain metastases. Mutational analysis showed a 15-nucleotide deletion and a missense mutation in exon 19 of the EGFR gene, and a missense mutation at codon 12 of the K-ras gene. These underlying genetic changes might partially explain the long-term survival of this patient after brain metastases when treated with concurrent or sequential therapies of EGFR-TKI, radiotherapy and chemotherapy.