 In a prior phase I study of carboplatin in combination with bendamustine for previously untreated small cell lung cancer patients, the recommended dose for phase II studies was bendamustine 100 mgm2 on day 1 and 2, carboplatin AUC 5 on day 1, respectively 16. In consideration of previously treated subjects, however, the dose of bendamustine was decided on 80mgm2 in this study protocol with concerning about the toxicities, especially to severe cytopenia. 