The present invention belongs to the field of improved personalized medicine.More precisely, the present inventionrelates to a method for progressively optimizing the 5 -FU dose administeredby continuous infusion in patients treated by aFOLFIRI regimen or a similar regimen, based on the 5 -FU plasmaticconcentration measured during the previous 5 -FU continu-ousinfusion and on a herein described decision algorithm. The present inventionalso relates to a method for treating a cancer pa-tientin which the 5 -FU dose administered in continuous infusion in each FOLFIRI orsimilar treatment cycle is optimized usingthe decision algorithm according to the invention.
