Phase 2 Study of S-1 as 2nd Line Therapy in Advanced Non-Small Cell Lung Cancer

All patients will receive S-1 orally at a dose of 30 mg/m2 twice daily (BID) for 14 days followed by a 1-week recovery period, repeated every 3 weeks. The study may go to the second stage only if the stage 2 criteria are met, where 3/30 (10%) or more patients must have achieved a confirmed response (CR or PR) in stage 1.The study may go to the third stage only if at least 8/50 patients (16%) must have achieved a confirmed response in stage 2