[Retrospective analysis of dose intensity of epirubicin in breast cancer]

In breast cancer the efficacy of epirubicin-based chemotherapy is possibly related to the actual dose intensity applied. We retrospectively determined the administered dose intensity and the relative toxicity and efficacy of an epirubicin-containing regimen in patients with primary or metastatic breast cancer.

Fluorouracil, epirubicin, and cyclophosphamide (FEC) were either given at a standard dose of 500/50/500 mg/m2 (FE50C) or at an intensified dose of 500/75/500 mg/m2 (FE75C) every 3 weeks. Of the 66 patients treated, 63 were evaluable; 43 had metastatic breast cancer, and 20 patients with an increased risk of relapse received FEC as an adjuvant treatment.

Dose intensity and absolute dose of adjuvant treatment were 81 and 70% for FE50C and 96 and 88% for FE75C. In metastatic breast cancer, the dose intensity for FE50C was 94% and for FE75C 92%. In a retrospective comparison, the 4-year overall survival following adjuvant FE50C and FE75C was 40 and 48%, respectively (p = 0.47). The dose intensification led to a higher response rate of 34 vs. 44%. There were no significant differences in response duration and survival time. The toxicity profiles were comparable between FE50C and FE75C.

In general, the doses applied were lower than initially planned. Higher doses of epirubicin did not result in a significant increase of toxicity. Despite the limitations of a retrospective analysis, our observations support the importance of adherence to the planned dose intensity as a prerequisite for optimal treatment of patients suffering from breast cancer. As our results could be related to selection bias, dose-intensified anthracycline-containing regimens should be further evaluated in prospective trials.