However , an analysis of age groups revealed the benefits of DEXA in children younger than @ years ( the event-free survival ( EFS ) was @ and @ % , respectively ( p = @ ) ; the overall survival ( OS ) was @ and @ % , respectively ( p = @ ) ; therapy-induced mortality was @ % ( DEXA ) andl @ % ( MePRED ) ( p = @ @ ) ; the rate of isolated extramedullary relapses was @ % ( DEXA ) and @ % ( MePRED ) ( p = @ ) .