Patients were randomly assigned to receive GS ( oral S-1 60mg/m ( 2 ) daily on days 1-15 every 3weeks and gemcitabine 1,000 mg/m ( 2 ) on days 8 and 15 ) or gemcitabine ( 1,000 mg/m ( 2 ) on days 1 , 8 , and 15 every 4weeks ) .