RESUMO
OBJECTIVE: The primary outcome of the current study is, whether there is a protective effect of prior chemotherapy or of prior granulocyte colony-stimulating factor (G-CSF) on the next cycle blood cell counts. METHODS: Hematologic toxicity was evaluated, based on a randomized phase III study in breast cancer patients (n = 167) with >20% risk of febrile neutropenia. The primary endpoint was the nadir blood cell counts for patients treated with G-CSF given during all 6 chemotherapy cycles or limited to the first 2 chemotherapy cycles only. RESULTS: For the present analyses, 47 patients were eligible. In the G-CSF 1-6 arm, the median white blood cell count (WBC) and absolute neutrophil count (ANC) nadir slowly decreased from 10.8 × 109/L in cycle 1 to 7.5 × 109/L in cycle 6 and from 7.1 × 109/L to 5.5 × 109/L, respectively. The median WBC nadir in the G-CSF 1-2 arm decreased from 1.2 × 109/L in cycle 3 to 0.9 × 109/L in cycle 6 and the ANC nadir showed a grade 4 neutropenia of 0.1 × 109/L in cycles 3-6. All patients had ANC recovery to normal levels (≥1.5 × 109/L) without delay on day 1 of the next cycle. CONCLUSION: We conclude that there is no protective effect of prior G-CSF or prior chemotherapy use on nadir blood cell counts in subsequent cycles.