A comparative study was performed to evaluate the efficacy and safety of 5'-DFUR and tegafur in recurrent breast cancer. The oral daily dosage of 5'-DFUR was 1,200 mg and that of tegafur was 800 mg, both drugs being administered every day for more than 4 weeks.
Results: Cases evaluable for anti-tumor effect were 50 with 5'-DFUR and 38 with tegafur. The response rate was 28.0% (14/50) with 5'-DFUR while that with tegafur was 15.8% (6/38). In the cases with no prior fluorinated pyrimidine therapy, 5'-DFUR was significantly superior to tegafur in the response rate. Effective cases determined within 8 weeks numbered 9 out of 50 cases with 5'-DFUR, showing a tendency to be more than those of tegafur, 1 out of 38 cases. This indicates that the appearance of response for 5'-DFUR seems to be faster. The duration of PR tended to be longer with 5'-DFUR than with tegafur. As for the safety, there was no difference between the two groups except for a high incidence of diarrhea in 5'-DFUR. 5'-DFUR tended to be superior to tegafur in its usefulness judged from the angles of efficacy and safety. From the above results, 5'-DFUR can be regarded as having a better efficacy than tegafur for the treatment of recurrent breast cancer, with a fast-appearing anti-tumor effect and a long durability for continuous treatment.