Pretreatment haematological laboratory values predict for excessive myelosuppression in patients receiving adjuvant FEC chemotherapy for breast cancer.

BACKGROUND: A predictive model that identifies patients at risk of excessive neutropenia following chemotherapy would be valuable in guiding the use of supportive therapies. PATIENTS AND METHODS: We conducted a retrospective analysis of 741 patients who had received adjuvant 5-fluorouracil, epirubicin, cyclophosphamide (FEC) chemotherapy for breast cancer. The cause of every schedule alteration was identified. The ability of pretreatment haematological indices to predict for excessive myelosuppression was assessed.
RESULTS: Pretreatment absolute neutrophil count (ANC) and absolute lymphocyte count (ALC) were strongly associated with the risk of neutropenic events (NEs), febrile neutropenia (FN) or receiving suboptimal chemotherapy dose intensity (DI<85%). The timing and pattern of NEs suggest that they reflect intrinsic chemosensitivity rather than cumulative toxicity and that FN results from chance infection rather than protracted myelosuppression. By combining quintiles on the basis of the rank order of ANC and ALC, we defined five groups of patients with variable risks of NE (18%-52%), DI<85% (9%-36%) and FN (4%-21%).
CONCLUSIONS: Pretreatment differential white blood cell count can be used to identify patients at increased risk of significant myelosuppression with FEC chemotherapy. Patients in the highest risk group have a risk of FN>20% and would qualify for primary prophylaxis with granulocyte colony-stimulating factor support under current guidelines.