Abstract
BACKGROUND
Severe neutropenia, a common consequence of chemotherapy, may result in infectious complications and hospitalizations. Preventive treatment with colony‐stimulating factors is limited because of the inability to predict which patients will develop neutropenic complications. To the authors' knowledge, the current study is the first large prospective validation of a risk model in patients with early‐stage breast carcinoma.
METHODS
Patients with Stage I–III breast carcinoma who were receiving adjuvant chemotherapy (n = 624) were assigned to risk groups based on first‐cycle absolute neutrophil count (ANC) nadirs of < 0.5 × 10^9^/L. Filgrastim (a recombinant human granulocyte–colony‐stimulating factor) was administered from Cycle 2 onward to high‐risk patients. Dose intensity and rates of neutropenic complications, including febrile neutropenia and hospitalization resulting from it, were calculated for each group and compared. High‐risk patients were matched by chemotherapy regimen, stage of disease, age, and baseline ANC to historic‐control patients and outcomes were compared within the matched pairs.
RESULTS
Both risk groups were found to have a similar proportion of patients receiving > 85% of the dose intensity (95.8% vs. 94.4%). The rate of febrile neutropenia and hospitalization in the low‐risk group (n = 264) was 2.6% (95% confidence interval [95% CI[], 0.7–4.5%) and 0.8 (95% CI, ‐0.3–1.9%), respectively. The high‐risk group was 2.6 times more likely to receive a full dose of chemotherapy, but no higher risk of neutropenic complications was reported compared with the matched controls.
CONCLUSIONS
The risk‐related prophylactic administration of filgrastim facilitated the delivery of planned chemotherapy to the high‐risk group of patients. However, further research is needed to confirm the results obtained in the current study in a randomized trial, if feasible, and in other chemotherapy and disease settings. Cancer 2003;98:222–8. © 2003 American Cancer Society.
DOI 10.1002/cncr.11516