Patients received amrubicin ( 70-74 years old , 40-45 mg/m ( 2 ) ; 75 years old , 40 mg/m ( 2 ) ) intravenously on days 1 to 3 every 3 weeks for 4 to 6 cycles or carboplatin ( area under the curve of 5 intravenously on day 1 ) and etoposide ( 80 mg/m ( 2 ) intravenously on days 1 to 3 ) every 3 weeks for 4 to 6 cycles .