ABSTRACT
Anticancer drugs represent a class of agents suitable for therapeutic drug monitoring, as acute toxicity often occurs at dosages similar to those required for therapeutic efficacy. The selection of a therapeutic endpoint for assessing the clinical pharmacodynamics (PD) of anticancer drugs is also critical, as 1 year of disease-free survival may differ significantly from 5 years of disease-free survival for most tumors. The standard use of combination chemotherapy limits the ability to define PD relationships for individual anticancer drugs. Several studies have demonstrated that systemic exposure to certain anticancer drugs is correlated with either their toxicity, their efficacy, or both. It should be acknowledged that not all studies have found a significant PD relationship for anticancer drugs and their efficacy or toxicity. 5-Fluorouracil is one of the most commonly used anticancer drugs, with activity in a variety of solid tumors including colorectal, breast, and head/neck carcinomas.
