Pretreatment Serum Folate Levels and Toxicity/Efficacy in Colorectal Cancer Patients Treated With 5-Fluorouracil and Folinic Acid

The pretreatment serum folate level did not conclusively influence 5-FU toxicity and antitumor efficacy. However, high folate levels showed a trend toward a greater incidence of severe toxicities but also lower rates of disease recurrence and mortality. These results provide promising hypothesis-generating data warranting further investigation. The predictive value of pretreatment folate status should be a priority for study in cancer patients receiving 5-FU-based chemotherapy and should be considered a potentially confounding factor in clinical trials and a modifiable parameter in treatment.