Neutrophil-guided dosing of anthracycline–cyclophosphamide-containing chemotherapy in patients with breast cancer: a feasibility study

The aim of this study was to investigate whether neutrophil-guided dose escalation of anthracycline–cyclophosphamide-containing chemotherapy (ACC) for breast cancer is feasible, in order to optimize outcome. Breast cancer patients planned for 3-weekly ACC were enrolled in this study. The first treatment cycle was administered in a standard BSA-adjusted dose. The absolute neutrophil count was measured at baseline and at day 8, 11 and 15 after administration of ACC. For patients with none or mild (CTC grade 0–2) neutropenia and no other dose-limiting toxicity, we performed a 10–25 % dose escalation of the second cycle with the opportunity to a further 10–25 % dose escalation of the third cycle. Thirty patients were treated in the adjuvant setting with either FE100C (n = 23) or AC (n = 4), or in the palliative setting with FAC (n = 3). Two out of 23 patients (9 %) treated with FEC did not develop grade 3–4 neutropenia after the first treatment cycle. Dose escalation was performed in these two patients (30 % in one and 15 % in the other patient). During dose escalation, there were no complications like febrile neutropenia. No patients treated with FAC or AC could be escalated, since all of them developed grade 3–4 neutropenia. We conclude that asymptomatic grade 3–4 neutropenia is likely to be achieved in the majority of patients with breast cancer treated with ACC according to presently advocated BSA-based dose levels. Escalation of currently advocated ACC doses without G-CSF, with a target of grade 3–4 neutropenia, is feasible, but only possible in a small proportion of patients. EudraCT 2010-020309-33.