Disease-Free Survival Advantage of Adjuvant Cyclophosphamide, Methotrexate, and Fluorouracil in Patients With Node-Negative, Rapidly Proliferating Breast Cancer: A Randomized Multicenter Study

Abstract

PURPOSE: According to one of the most recent key scientific questions concerning the use of biomarkers in clinical trials, we investigated whether node-negative breast cancer patients, defined as high-risk cases on the basis of tumor cell proliferation, could benefit from cyclophosphamide, methotrexate, and fluorouracil (CMF) adjuvant therapy. PATIENTS AND METHODS: Two hundred eighty-one patients with negative nodes and rapidly proliferating tumors, defined according to thymidine labeling index (TLI), were randomized to receive six cycles of CMF or no further treatment after surgery ± radiotherapy. RESULTS: The 5-year disease-free survival (DFS) was 83% for patients treated with CMF compared with 72% in the control group (P = .028). Adjuvant treatment reduced both locoregional and distant metastases. When clinical outcome was analyzed in cell kinetic subgroups characterized according to tertile criteria, compared with patients in the control arm, 5-year DFS was significantly higher after adjuvant CMF in patients with TLI values in the second (78% v 88%, respectively; P = .037) and third tertiles (58% v 78%, respectively; P = .024). CONCLUSION: The results from this randomized clinical study indicate that patients with node-negative, rapidly proliferating tumors significantly benefit from adjuvant CMF.