Rationale for the administration of systemic 5-FU in combination with heated intraperitonal oxaliplatin.

BACKGROUND

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin (OX) is the standard of care for selected patients with peritoneal carcinomatosis of colorectal origin. Because 5-FU is mandatory to improve efficacy of OX when used by systemic route, several teams now empirically combine intravenous (IV) 5-FU with HIPEC OX, but this practice has yet to be supported by preclinical data. Using a murine model, we studied the impact of IV 5-FU on peritoneal absorption of HIPEC OX.

METHODS

Under general anesthesia, 24 Sprague-Dawley rats were submitted to 4 different doses of IV 5-FU (0, 100, 400 and 800 mg/m2) and a fixed dose of HIPEC OX (460 mg/m2) perfused at 40 °C during 25 min. At 25 min, samples in different compartments were harvested (peritoneum, portal vein and systemic blood) and the concentrations of 5-FU and OX were measured by high performance liquid chromatography.

RESULTS

Peritoneal absorption of OX was significantly higher (17.0, 20.1, 34.9 and 38.1 nmol/g, p < 0.0001) with increasing doses of 5-FU (0, 100, 400 and 800 mg/m2, respectively). Peritoneal absorption of OX reached a plateau between 400 and 800 mg/m2 of IV 5-FU.

CONCLUSION

IV 5-FU enhances peritoneal absorption of HIPEC OX. The most efficient dose of IV 5-FU to be used in combination with HIPEC OX seems to be 400 mg/m2.