Erlotinib maintenance showed a favourable ICER in patients with PS = @ ( @,@ / QALY ) , in patients with adenocarcinoma ( @,@ / QALY ) and in patient with objective response to induction ( @,@ / QALY ) , but it is not cost-effective in patients with PS = @ , in patients with non-adenocarcinoma or with stable disease after induction chemotherapy .