A pilot study of continuous infusional 5-fluorouracil, doxorubicin and cyclophosphamide in breast cancer

The purpose of this study was to evaluate the toxicity and activity of continuous infusional 5-fluorouracil (5-FU) given at three dose levels in combination with cyclophosphamide and doxorubicin (FAC) in women with breast cancer. Thirty-nine patients with either primary tumours >3 cm prior to surgery (n = 24) or metastatic disease (n = 15) received cyclophosphamide 600 mg/m2 and doxorubicin 50 mg/m2 as an intravenous bolus every 3 weeks for six courses. Continuous infusional 5-FU was delivered via a central venous line for a maximum of 18 weeks at dose levels of 100 mg/m2 per day (n = 6), 150 mg/m2 per day (n = 3) and 200 mg/m2 per day (n = 30). At the 200 mg/m2 per day dose level, 36% of patients required dose delays and 23% dose reductions; there was one death due to neutropenic sepsis. Hickman line complications occurred at all dose levels, particularly thrombosis (18%) and infection (33%). The response rate was 62% (95% confidence interval (CI) 32-84) for metastatic disease, including five complete responses (CRs). The response rate for primary tumours prior to surgery was 81% (95% CI 57-95) including six clinical CRs. Infusional FAC is an active regimen and has an acceptable toxicity profile. It does not, however, appear to offer any significant advantage over other chemotherapy regimens. This study does not support the further evaluation of infusional 5-FU at these doses in combination with doxorubicin and cyclophosphamide.