Rates of central nervous system (CNS) metastases in patients with advanced non-small cell lung cancer (NSCLC) and somatic EGFR mutations initially treated with gefitinib or erlotinib versus chemotherapy.

7607 Background: The impact of tumor genotype and targeted therapies on the control and development of CNS metastases from NSCLC has not been extensively studied. We recently reported a lower than expected rate of CNS progression in patients with advanced NSCLC and somatic EGFR mutations initially treated with gefitinib or erlotinib. This retrospective study was undertaken to investigate the impact of gefitinib or erlotinib versus chemotherapy on the risk of CNS progression in EGFR mutant advanced NSCLC patients. Methods: Patients with stage IV or relapsed NSCLC with somatic EGFR mutations seen at the DFCI between 8/00 and 2/10 who were initially treated with gefitinib or erlotinib or chemotherapy without receiving gefitinib or erlotinib for at least 6 months were identified from a prospective trial. The cumulative risk of CNS progression was calculated using death as a competing risk. Results: 129 EGFR mutant patients were eligible (99 EGFR-TKI, 30 chemotherapy). 21 patients (21%) in the EGFR-TKI group a...