In this open-label , phase II study , patients with resected stage IIIA-N2 NSCLC harbouring EGFR mutations ( either exon 19 deletion or L858R point mutation ) were assigned randomly to receive pemetrexed ( 500mg/m ( 2 ) ) and carboplatin ( AUC = 5 ) , administered every 21days for 4 cycles , followed with or without gefitinib ( 250mg/day ) for 6months .