5-fluorouracil (5-FU) and 5,10-methylene tetrahydrofolate (5,10-CH2FH4) as adjuvant therapy in an experimental rodent colon carcinoma model.

Eradication of micrometastases is the goal for adjuvant therapy following a radical surgical procedure for cancer. We report an experimental study with 5,10-methylenetetrahydrofolate (5,10-CH2FH4) modulation of 5-fluorouracil (5-FU) cytotoxicity in adjuvant treatment. A colon adenocarcinoma cell suspension was inoculated intrahepatically in a rodent experimental model. Intravenous 5-FU (30 mg/kg) in combination with 5,10-CH2FH4 (15 mg/kg or 30 mg/kg) was administered after 1, 2, 3, 4 and 7 days. 5-FU alone reduced the tumor take to fifty percent compared to one hundred percent tumor take in control animals (p < 0.05), while 5-FU in combination with 5,10-CH2FH4 (regardless of folate-dose) eliminated tumor take (p < 0.0001). This makes 5,10-CH2FH4 a promising agent for modulation of 5-FU cytotoxicity in adjuvant cancer treatment.