Purpose: We studied sequential dose-dense doxorubicin, paclitaxel, and 5-fluorouracil (A-T-F) before high dose chemotherapy (HDC) with autologous peripheral blood stem cell support (PBSCT). Our aims were to determine the maximum tolerated dose (MTD) of 5-FU in the dose-dense regimen and to determine the impact of dose-dense chemotherapy on HDC/PBSCT.
Methods: Patients with Stage IIIB or Stage II or IIIA breast cancer with > or = 4 involved ipsilateral lymph nodes were treated with nine cycles of chemotherapy at 14-day intervals. The regimen was doxorubicin at 80 mg/m2 x 3, followed by paclitaxel at 140 mg/m2 over 96 h x 3, then 5-FU at doses of 1285, 1470, or 1655 mg/m2 by continuous intravenous infusion over 72 h x 3. Patients then underwent a G-CSF-stimulated peripheral blood stem cell (PBSC) apheresis prior to receiving HDC with autologous PBSCT.
Results: We identified 1285 mg/m2 as the MTD of 5-FU in this regimen. 5-FU-related DLTs included hand-foot syndrome, mucositis, and facial edema with somnolence. Unexpectedly, 3/19 treated patients developed congestive heart failure that prevented planned HDC. Compared to standard dose doxorubicin-containing adjuvant therapy, the dose-dense regimen also decreased CD34+ PBSC yields by about 40% (p = 0.049), requiring that 50% of patients have a supplemental bone marrow harvest. There was no difference in time to neutrophil, platelet, and red blood cell recovery after HDC.
Conclusions: This regimen resulted in an unacceptably high rate of cardiac toxicity and is not recommended for further testing. It may be feasible to use a different schedule of 5-FU-containing dose-dense chemotherapy, particularly for the induction therapy of high-risk primary breast cancer prior to novel targeted therapies.