Belotecan (Camtobell, CKD-602, Chong Kun Dang Pharm., Korea) is a new camptothecin derivative, that exhibits anticancer effects by inhibiting topoisomerase I. The investigators will have a randomized prospective multicenter trial of Belotecan/Cisplatin versus Etoposide/Cisplatin in patients with previously untreated, extensive-stage small cell lung cancer.