Intermittent continuous infusion of fluorouracil and low-dose oral leucovorin in pretreated breast cancer: a pilot study.

Aims and background: There is evidence that fluorouracil (FU), when administered by protracted venous infusion, has antitumor activity in pretreated breast cancer. The aims of the study were to assess, in a population of heavily pretreated breast cancer patients (greater than or equal to 2 lines of chemotherapy previously administered), the feasibility and activity of a new combination of oral L-leucovorin and continuous FU infusion. Methods: Patients were treated with the following combination: oral L-leucovorin, 5 mg/m(2) days 1 through 14, plus FU, 250 mg/m(2) days 1 through 14, with cycles repeated every 21 days. Results: Since November 1994, 22 patients have entered the study and 20 are assessable for response and side effects. Major patient characteristics were: ECOG performance status, 0-2; median age, 56 years (range, 41-70); sites of metastasis, bone 9, lung 8, liver 2, pleura 7; 2 or more metastatic sites, 18. A total of 74 cycles has been administered (median/patient, 3 cycles). Five partial remissions (25%), 4 disease stabilizations and 11 disease progressions have been observed. Median time to progression was 3 months (range 1-6+). Grade I-II mucositis was observed in 8 patients and grade III-IV in 6 patients. Other side effects have included diarrhea and thrombocytopenia. Conclusions: The schedule has demonstrated moderate activity in heavily pretreated breast cancer, with mucositis as the dose-limiting toxicity.