Analysis of dose-response relationships in the setting of high-dose ifosfamide, carboplatin, and etoposide and autologous hematopoietic stem cell transplantation: implications for the treatment of patients with advanced breast cancer.

Dose intensity appears to play a role in the treatment of breast cancer. Although many reports have been published regarding dose intensity using nonmyeloablative doses, little data have been presented in the setting of high-dose chemotherapy and autologous hematopoietic stem cell transplantation. The results of a retrospective review of a phase I/II trial evaluating the effect of escalating doses of ifosfamide/carboplatin/etoposide on survival of patients with locally advanced and metastatic breast cancer are discussed here. Patients were divided by ifosfamide dose: low dose (6,000 to 14,400 mg/m2) and high dose (17,100 to 24,000 mg/m2). Three-year event-free survival was no different between the two dose groups in patients with locally advanced disease (71% [low] v 56% [high]). In patients with metastatic disease, however, although the difference did not meet statistical significance, there did appear to be a trend toward improved survival with increased dose intensity (8% [low] v 25% [high]). Our results show that dose intensity may be important in inflammatory and metastatic breast cancer. This trend was seen in both anthracycline-responsive and -refractory patients. While further study of dose intensity in this setting is warranted, dose-intensive high-dose therapy with autologous hematopoietic stem cell transplantation can be considered for patients with advanced breast cancer.