Randomized controlled trial comparing oral doxifluridine plus oral cyclophosphamide with doxifluridine alone in women with node-positive breast cancer after primary surgery

Purpose: We compared the therapeutic usefulness of doxifluridine (5′-DFUR) alone and a combination of 5′-DFUR plus cyclophosphamide (CPM), both of which are considered effective against advanced and recurrent breast cancer, to determine which treatment is more beneficial as postoperative adjuvant chemotherapy. Patients and Methods: A total of 1,131 women with node-positive primary breast cancer were randomly assigned after primary surgery to receive 5′-DFUR alone or 5′-DFUR plus CPM. All patients initially received 5′-DFUR in an oral dose of 1,200 mg/d for 4 weeks, starting 4 weeks after surgery. Chemotherapy was then not given for 2 weeks. Patients in the 5′-DFUR group subsequently received five 4-week cycles of treatment consisting of oral 5′-DFUR (1,200 mg/d) for the first 2 weeks and no chemotherapy for the next 2 weeks. Those assigned to the 5′-DFUR plus CPM group also received oral CPM 100 mg/d for the first 2 weeks and no chemotherapy for the next 2 weeks. Women 50 years or older concurrently received 20 mg/d of tamoxifen for 2 years in both groups. Results: Of the 1,088 eligible women, 546 were assigned to receive 5′-DFUR alone and 542 were assigned to receive 5′-DFUR plus CPM. Overall disease-free survival was significantly better in women who received 5′-DFUR plus CPM than in those who received 5′-DFUR alone (log-rank test, P = .021). Toxic effects occurred in 20.0% of patients (109 of 546) in the 5′-DFUR group and 32.3% of patients (175 of 542) in the 5′-DFUR plus CPM group (χ2 test, P < .001). Conclusion: Combination therapy with 5′-DFUR plus CPM is more effective in preventing recurrence than 5′-DFUR alone.