A comparative study of oral tegafur and intravenous 5-fluorouracil in patients with metastatic colorectal cancer.

A randomized study was conducted in patients who had measurable metastatic colorectal cancer to compare the relative efficacy and toxicities of oral tegafur (1 gm/m2/days 1-21) with those of 5-fluorouracil (5-Fu, 500 mg/m2/days 1-4, then 250 mg/m2 on days 6, 8, 10, 12). The treatment courses were repeated every 4 weeks. Patients not responding to 5-Fu treatment were switched to tegafur. Randomization was stratified for presence or absence of liver metastasis and performance status. Partial responses were observed with 5-Fu, 6/32 (19%), tegafur, 7/35 (20%), and in patients who had been switched to tegafur after failing on 5-Fu, 1/20 (5%) with patients evaluable for response. Neutropenia was more common with 5-Fu (32% vs. 1% of treatment courses). Nausea occurred in about half the treatment courses; vomiting occurred in only 22%. Mucositis and diarrhea were more common with 5-Fu and severe in patients with liver function impairment. Neurologic toxicities due to tegafur were mild and occurred in less than 10% of the treatment courses. Oral tegafur and I.V. 5-Fu were equally effective against colorectal cancer, but tegafur was associated with minimal myelosuppression, which makes it suitable for use in combination with myelosuppressive antitumor agents.