It has been suggested that some clinical parameters, including women, no smoking history and a histologic diagnosis of adenocarcinoma, are associated with favorable outcomes of gefitinib therapy. We will conduct a phase II study in docetaxel pretreated advanced NSCLC patients treated with gefitinib or irinotecan according to these clinical parameters in order to determine whether in patients with favorable clinical parameter(s) gefitinib will produce difference outcomes from patients without favorable clinical parameter treated with irinotecan.