Ten-year results of a randomized trial evaluating prolonged low-dose adjuvant chemotherapy in node-positive breast cancer: a joint European Organization for Research and Treatment of Cancer-Dutch Breast Cancer Working Party Study. Cooperating Investigators.

Abstract

To investigate whether treatment with prolonged low-dose adjuvant chemotherapy could improve survival of patients with axillary node-positive breast cancer. Four hundred fifty-two patients with axillary node-positive breast cancer who received postoperative irradiation were prospectively randomized in a trial (European Organization for Research and Treatment of Cancer [EORTC] 09771) that compared surgery followed by prolonged low-dose chemotherapy versus surgery alone. Chemotherapy was given for a period of 2 years and consisted of monthly courses of cyclophosphamide 50 mg/m2 orally on days 1 to 14, methotrexate 15 mg/m2 intravenously on days 1 and 8, and fluorouracil 350 mg/m2 intravenously on days 1 and 8 (CMF). At a median follow-up time of 10 years, the overall survival duration was significantly prolonged in the chemotherapy arm (hazards ratio, 0.75; 95% confidence interval, 0.56 to 0.99; P = .04). Ten-year overall survival rates (+/- SE) were 59% (+/- 3.6%) for the chemotherapy arm and 50% (+/- 3.7%) for the control arm. Time to local relapse was significantly prolonged in the chemotherapy arm (hazards ratio, 0.63; 95% confidence interval, 0.42 to 0.94; P = .02). Patients with one to three positive axillary nodes and patients with estrogen receptor-negative tumors especially benefited from chemotherapy. Toxicity was observed in 93% of patients. We conclude that prolonged low-dose adjuvant CMF can significantly prolong overall survival in patients with node-positive breast cancer. However, considering the fact that toxicity was still considerable despite reducing the dose of chemotherapy by 50%, we believe that conventionally dosed short-term regimens are preferable in the treatment of node-positive breast cancer.