However, for the advanced EGFR mutant NSCLC patients with prior CNS involvement, the time to occurrence of CNS progression was significantly prolonged after first-line erlotinib compared with gefitinib (30.0 months vs 15.8 months, P = 0.024), indicating the greater potential of erlotinib at slowing development of established CNS metastases from NSCLC than gefitinib. This evidence concerns the gene EGFR and non-small cell lung carcinoma.