Real-World Impact of an In-House Dihydropyrimidine Dehydrogenase ( DPYD ) Genotype Test on Fluoropyrimidine Dosing, Toxicities, and Hospitalizations at a Multisite Cancer Center.

genotyping prompted fluoropyrimidine modifications in most carriers. Pretreatment testing reduced toxicities and hospitalizations compared with reactive testing, thus normalizing the risk to that of wild-type patients, and should be considered standard practice.