Prolonged infusions of 5-fluorouracil (5-FU) have been used since the
early 1960s, but recently there has been a major resurgence of interes
t, partly because of the advent of electronically controlled portable
infusion pumps. This paper looks at the published data on continuously
infused 5-FU in breast cancer. As a single agent, bolus 5-FU has a re
sponse rate of around 25%; this includes many patients in older series
who were chemotherapy naive. The overall response rate across all the
studies with continuously infused 5-FU is 29%. However, the majority
of these patients were heavily pretreated, and response rates of up to
54% have been reported. What is more encouraging is the response rate
in combination chemotherapy - even for pretreated patients with metas
tatic disease, response rates up to 89% have been found. However, this
level of benefit brings a new toxicity - palmar-plantar erythrodysaes
thesia; and of course myelotoxicity still remains a problem in the com
bination regimens. Randomised trials to assess the role of infusional
5-FU are now indicated.