Evaluation of serum iron levels during FOLFOX4 and FOLFIRI therapies.

FOLFOX4 and FOLFIRI are effective regimens for the treatment of advanced colorectal cancer, and their use together with molecular targeting drugs has recently become more common. In the present study, we evaluated the changes in the serum iron levels of patients undergoing FOLFOX4 or FOLFIRI therapy alone or in combination with bevacizumab (BV). The serum iron level was increased 48 h after therapy and was restored to baseline 2 weeks afterwards in colorectal cancer patients who received FOLFOX4 or FOLFIRI alone or in combination with BV. This transient increase in serum iron was observed repeatedly during chemotherapy. The serum iron level was 71.66±28.96 μg/dl (mean ± standard deviation) before treatment and significantly increased to 186.82±83.17 μg/dl (p<0.001) 48 h after therapy. A transient increase in serum iron levels was also observed when FOLFIRI was administered to a patient after tumor resection. In contrast, no decrease in blood hemoglobin, no increase in liver enzymes and no increase in urinary iron excretion were observed. Based on these results, it can be concluded that an increase in serum iron may be induced by a transient change in iron distribution within the body after FOLFOX4/FOLFIRI therapy with or without BV.