Comments on the use of leucovorin as a potentiator of 5-fluorouracil

The emerging role of 5-fluorouracil and leucovorin in the treatment of advanced breast cancer. A review

Considerable interest has been generated by the clinical experience with 5-fluorouracil + leucovorin based regimens in colorectal cancer. Consequently, this combination was tested in other tumors in which 5-fluorouracil has some activity (gastric, pancreatic, head and neck and breast cancer). This review summarizes the interesting results reported so far in advanced breast cancer. Up to now, more than 300 patients have been treated with chemotherapeutic regimens based on this attempt at biochemical modulation of 5-fluorouracil's activity. Overall, a median response rate of 26% was achieved by nine studies performed in 245 mainly pretreated patients with an acceptable degree of toxicity. Moreover, two additional studies explored the clinical activity of this combination as first-line chemotherapy for advanced disease with impressive results. Current efforts to further improve the therapeutic index of this combination will also be briefly discussed.