Background Chemotherapy-induced neutropenia is the main dose-limiting toxicity, with high morbidity, mortality and associated costs. Febrile neutropenia (FN) rates vary considerably between studies.

Purpose To know neutropenic complications (NC) incidence in our breast cancer patients treated with Doxorubicin-Cyclophosphamide (AC) and Doxorubicin-Cyclophosphamide-sequential Docetaxel (AC-T) schemes; determine their consequences; analyse sample's characteristics and myeloid growth factors use.

Materials and methods Patients with breast cancer treated over 20 months were selected retrospectively. 107 patients treated with AC or AC-T comprised the sample. Descriptive variables were obtained.

Results 97% of patients were in stage I, II or III; 95.8% received chemotherapy for the first time; 98% started treatment at full dose. 35.5% (95CI 27 to 45) of patients developed NC and 24.3% (95CI 17 to 33.2) suffered FN. 36% of NC were due to first AC cycle. No patient received primary prophylaxis with myeloid growth factors even when docetaxel was started. Secondary prophylaxis was administered in subsequent cycles after patient developed the first NC (it was administered to 91,3% of patients who developed FN and 78% of patients with NC without fever). Apart from two cases, no patient on secondary prophylaxis developed a NC again. Filgrastim and/or Peg-filgrastim were used. 77% of patients with FN were hospitalised (mean= 5±3 days) and 7% had to be attended in the emergency department (ED). 25% of patients with NC without fever were treated in the ED. Next cycle was delayed in 31.5% of NC (mean= 6.6±2.8 days); dose was reduced to 79.5%±4.4% of the scheduled dose in 39.4%; chemotherapy was finished in 7.9%. 5% of the sample received a relative dose intensity (RDI) <85% due to NC.

Conclusions The risk of NC in our patients is higher than reported in literature. According to current recommendations, primary prophylaxis with myeloid growth factors would be indicated in our patients.