EASTERN-COOPERATIVE-ONCOLOGY-GROUP RANDOMIZED TRIALS OF OBSERVATION VERSUS MAINTENANCE THERAPY FOR PATIENTS WITH METASTATIC BREAST-CANCER IN COMPLETE REMISSION FOLLOWING INDUCTION TREATMENT

Purpose: To investigate the value of maintenance treatment for patient s with metastatic breast cancer whose disease is in complete remission (CR). Patients and Methods: One hundred ninety-five women (141 eligib le) whose disease was in CR or in CR except for bone metastases follow ing six cycles (6 months) of doxorubicin-containing induction treatmen t were randomized to receive cyclophosphamide, methotrexate, fluoroura cil, prednisone, tamoxifen, and halotestin [CMF(P)TH] or observation. In a previous pilot study, patients in CR after 24 months of induction treatment were randomized to continue chemotherapy for 4 more years o r stop chemotherapy. Results: Among patients randomized to CMF(P)TH, l ife-threatening toxicity included leukopenia in 3%, thrombocytopenia i n 3%, cardiac in 2%, and diabetes in 1%, The median time to relapse fr om randomization was 18.7 months on CMF(P)TH and only 7.8 months on ob servation (P < .0001), The median time to death was 32.2 months on CMF (P)TH and 28.7 months on observation (P = .74), Similar results were s een in the pilot study (median time to relapse, 12.6 and 6.4 months; m edian survival, 37.7 and 24.2 months; study too small for statistical significance). Maintenance treatment wets always the most significant covariate in time-to-relapse models. Conclusion: There is definite tox icity associated with CMF(P)TH maintenance treatment, When CR was obta ined on induction, maintenance treatment with CMF(P)TH was never signi ficant in survival models. However, maintenance treatment was always t he most significant covariate in the time-to-relapse models, which mot ivates its consideration for appropriately informed patients. (C) 1998 by American Society of Clinical Oncology.