Targeted filgrastim support in patients with early-stage breast carcinoma: toward the implementation of a risk model.
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 x 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.
Rivera
Edgardo
E
Department of Breast Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-0056, USA. erivera@mail.mdanderson.org
Erder
M Haim
MH
Moore
Timothy D
TD
Shiftan
Thomas L
TL
Knight
Chris A
CA
Fridman
Moshe
M
Brannan
Carol
C
Danel-Moore
Laurence
L
Hortobagyi
Gabriel N
GN
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D000069585:Filgrastim; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D009503:Neutropenia / Q000139:chemically induced / Q000517:prevention & control*; D011446:Prospective Studies; D011994:Recombinant Proteins; D012307:Risk Factors
D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D000069585:Filgrastim