5-fluorouracil (5-FU) is used for adjuvant(postoperative) and neoadjuvant (preoperative) cytostatic therapy of colorectal cancer. Dose is usually determined by body surface (mg/m2) in spite of the fact that a linear relationship between the dose and systemic clearance has not been proven so far.
Kinetically guided therapy has only been developed for adjuvant therapy based on AUC (area under the curve of plasma concentrations in time after the start of 5-FU i.v.infusion) that is well correlated with toxicity.