As mentioned above, we aim to delineate the available pharmacogenomic information related to fluorouracil (FU) and DPYD, an association pair that regularly raises questions regarding the application of pharmacogenomic testing.Based on the available information by the WHO, cancer remains the second leading cause of death worldwide, with colorectal cancer affecting approximately 1.8 million patients.On the contrary, the rather crucial issue of the toxicity of the antineoplastic treatment has not been adequately addressed although adverse drug reactions constitute a common phenomenon in cancer therapy.

Delving deep into the complex pharmacokinetics of the drug, the rate-limiting step of FU metabolism is dependent on dihydropyrimidine dehydrogenase (DPD), which metabolizes at least 80% of the administered dose.Although difficult to precisely estimate, the occurrence of such toxicities is not at all rare, affecting up to as many as 60% of the patients under FU treatment. Taking into account that patients with cancer are usually prescribed other agents with overlapping adverse reactions, the issue of increased vigilance of these patients is often underlined.

These types of Guided Reassurance can help a lot in oncology. They are the ways to cure the problem from the basics.