DFS tended to be better with S-1 ( median 146 ( 90 per cent c.i. 88 to 284 ) months versus 105 ( 70 to 284 ) months in the gemcitabine group ; P = 0188 ) , with a similar pattern for overall survival : 215 ( 95 per cent c.i. 144 to 423 ) and 180 ( 133 to 428 ) months respectively ( P = 0293 ) .