THERAPY OF PATIENTS WITH METASTATIC BREAST-CANCER WITH 5-FLUOROURACIL, LEUCOVORIN AND CARBOPLATIN

Thirty-four women with metastatic breast cancer were treated at the National Cancer Institute of the National Institutes of Health, with a regimen of leucovorin (L), 500 mg/m2 i.v. over 30 min, followed in 1 h by 5-fluorouracil (5-FU), 375 mg/m2 i.v. bolus on days 1-5, and carboplatin (CBDCA), 50-100 mg/m2 i.v. bolus on days 2-4, every 28 days. All patients had received previous combination chemotherapy with at least one regimen (29 patients with 5-FU-containing regimens). CBDCA, 100 mg/m2 on days 2-4, resulted in grade 4 neutropenia in 10 out of 11 patients associated with sepsis in all 10 patients. CBDCA, 75 mg/m2 (seven patients) and 50 mg/m2 (15 patients), resulted in grade 4 neutropenia in six and eight patients, and neutropenic sepsis in five and two cases, respectively. Grade 4 thrombocytopenia occurred in 10, five and two patients receiving 100, 75 and 50 mg/m2 of CBDCA, respectively. Other toxicities included grade 3/4 mucositis in 18 patients and grade 3/4 diarrhea in 10 patients. Twenty nine patients were evaluable for response, with one pathologic complete response (3%), two partial responses (6%), 18 stable disease (53%) and eight (24%) progressive disease. Sites of response included bone, viscera and soft tissue. The median time from entry on study to progression, for responders, was 15 months. When platinum-DNA adduct formation in peripheral white blood cells was analyzed in 27 patients at 24 h after drug administration, a significant correlation between adduct level and CBDCA cumulative dose was found. However, no statistically significant correlation was found between platinum-DNA adduct formation and disease response, survival or toxicity in this study. The results presented here suggest that the combination of 5-FU, L and CBDCA is tolerable at a CBDCA dose of 50 mg/m2 days 2-4; however, higher doses of CBDCA are poorly tolerated due to hematologic toxicity. At the CBDCA dose level of 50 mg/m2 on days 2-4, no significant disease responses were observed. We conclude that higher doses of CBDCA are highly toxic and limited our ability to deliver adequate doses of L-modulated 5-FU.