Fluorouracil, Doxorubicin, and Cyclophosphamide Followed by Tamoxifen as Adjuvant Treatment for Patients with Stage IV Breast Cancer with No Evidence of Disease

Abstract

We conducted a single‐institution study to determine whether local therapy plus six cycles of chemotherapy with 5‐fluorouracil, doxorubicin, and cyclophosphamide (FAC) followed by 5 years of tamoxifen is superior to local treatment alone in terms of disease‐free survival (DFS) and overall survival (OS) in patients with stage IV breast cancer with no evidence of disease (stage IV‐NED breast cancer). Patients with breast cancer were eligible if they had histologic proof of a locoregional or distant recurrence that had been curatively resected, irradiated, or both and had no other evidence of disease. Patients who had received prior anthracycline therapy were not eligible. All patients received six cycles of intravenous FAC, with cycles repeated every 3 weeks. After completion of chemotherapy, patients whose tumors had not previously demonstrated resistance to tamoxifen and had positive or unknown estrogen receptor status received tamoxifen 20 mg by mouth daily for 5 years. Patients in this study were compared with a historical control population (patients with stage IV‐NED breast cancer who never received systemic therapy) as well as with the patients in two previously reported trials of chemotherapy for stage IV‐NED disease. Forty‐seven patients were registered, but only 45 were evaluable. There was a highly statistically significant difference ( p < 0.001) in OS and DFS among the four groups, with patients in our most recent study having the best OS and DFS at 3 years compared with the control group (84% vs. 55% and 66% vs. 11%, respectively). When patients in all four groups were analyzed together in search of prognostic factors, we found that patients whose primary tumors had negative axillary lymph nodes had a statistically significant improvement in OS and DFS ( p < 0.01) compared with patients with positive axillary lymph nodes. No survival differences were found between patients with positive and those with negative hormone receptor status. This study demonstrates a benefit in terms of OS and DFS for patients with stage IV‐NED breast cancer who receive doxorubicin‐based adjuvant chemotherapy. The benefit was greater on patients with node‐negative primary tumors. In patients with stage IV‐NED disease, doxorubicin‐based chemotherapy should be considered standard treatment after adequate local control is achieved.