[Pharmacokinetic modulating chemotherapy for rectal carcinoma metastases to the liver and lung--a case report].

Pharmacokinetic modulating chemotherapy (PMC) is a new therapeutic regimen for advanced colorectal carcinoma, in which high serum 5-FU concentrations are attained through the inhibition of 5-FU degradation by simultaneously administered uracil. A 67-year-old woman, presented with unresectable multiple hepatic and pulmonary metastases following abdominoperineal resection of rectal carcinoma, was successfully treated by the PMC. The patient was initially treated by 600 mg/m2/day of 5-FU infusion, once a week, and subsequently 5-FU doses were increased to 750 mg/m2/day and then to 1,200 mg/m2/day. Hepatic metastases responded at the dose of 750 mg/m2/day and pulmonary metastases responded at the dose of 1,200 mg/m2/day. The patient remains partial response (>21 months). 5-FU serum concentrations were higher at night time and the peak concentration of 5-FU was obtained at 3 a.m. 5-FU Cmax of 600 mg/m2/day, 750 mg/m2/day and 1,200 mg/m2/day were 254, 329, 531 ng/ml, respectively. The experience of this case, together with literature review, suggests that pulmonary metastases are more resistant to 5-FU than hepatic metastases in patients with colorectal carcinoma. The high serum 5-FU concentrations at night suggest the chronomodulating nature of PMC and are effective for metastatic colorectal carcinoma.