Treatment of metastatic breast cancer with continuous infusional 5 fluorouracil

Background: Single agent continuous infusional 5 fluorouracil (CI-5FU) via a central venous catheter (CVC) is usually reserved for breast cancer patients who have previously failed one or more chemotherapy regimens. The patients are usually heavily pre-treated with later stage disease. Previously published studies of CI-5FU have reported response rates as high as 54%. It is considered an approach with an acceptable side effect profile in such patients. Aims: To evaluate the efficacy and toxicity of CI-5FU in previously treated metastatic breast cancer. Methods: A retrospective review of advanced breast cancer patients treated with CI-5FU between October 1992 and October 1996 was performed. Response to treatment, toxicity, CVC complications and patient survival were analysed. Results: Twenty-four patients with metastatic breast cancer were treated with CI-5FU. All had received previous chemotherapy, including 19 patients (79%) with prior 5FU exposure and eight patients (33%) who had previous high dose chemotherapy with autologous stem cell transplantation. The median duration of CI-5FU treatment was 3.1 months. Nineteen patients had evaluable disease, three (16%) of whom demonstrated a partial response and four patients had stable disease. There were no complete responses. All responses occurred in soft tissue sites with no objective evidence of response in liver or bone metastases. The survival rate at one year was 21% (five of 24) and the median survival of all patients was 6.1 months. Five patients (21%) stopped treatment due to treatment related morbidity (two CVC complications and three CI-5FU side effects). Diarrhoea, nausea, and palmar-plantar erythrodysaesthesia were the major side effects of chemotherapy. CVC complications requiring intervention, the most notable of which were infection and thrombosis, occurred in 11 patients (46%). There were no treatment related deaths. Conclusions: Single agent CI-5FU has modest activity in women with previously treated advanced breast cancer. The efficacy is lower than in previously published series. This may reflect patient selection factors. The toxicity was mainly related to CVC complications. Important issues relating to quality of life need to be objectively measured in future studies of CI-5FU.