First Cycle Neutrophil Count and Subsequent Chemotherapy Dose Delivery in Breast Cancer Patients Receiving Adjuvant Chemotherapy

Background: Chemotherapy-induced neutropenia is a major dose-limiting toxicity of systemic cancer chemotherapy, and it is associated with substantial morbidity, mortality, and costs. The ability to predict the group of patients who are at high risk for neutropenic complications might help to reduce the morbidity due to febrile neutropenia and increase the likelihood of delivering full chemotherapy dose on time. In addition, hematopoietic growth factors could be administered to patients who need them and allow more efficient use of medical resources. Methods: The study included 120 female patients with breast cancer, treated in adjuvant setting with FAC chemotherapy regimen. Chemotherapy was delayed if the ANC was less than 1500 cells/μL on the planned first day of the cycle. Dose delays would be for 1 week. The chemotherapy dose was reduced if the patient experienced an episode of febrile neutropenia. Dose reductions usually consist of a 20% reduction in dosage of all chemotherapy drugs. Results: Out of the 120 patients in the study, 58 patients experienced neutropenic complications (febrile neutropenia or dose delayed) accounting for 48.3% of total sample size. In univariate analysis, there was statistically significant association between first cycle ANC nadir and neutropenic complication (p = 0.0001). There was also statistically significant association between pretreatment first cycle ANC (p = 0.001), pretreatment platelets count (p = 0.054), first cycle platelets count nadir (p = 0.041), number of involved lymph nodes (p = 0.031) and the occurrence of varies neutropenic complications. However, in multivariate analysis, ANC nadir was only the independent risk factor for occurrence of neutropenic. Conclusions: The first cycle absolute neutrophil counts nadir provides useful information on the risk of future neutropenia, febrile neutropenia and dose delay or reduction with estimated sensitivity and specificity, which were 64.5% and 77.6%, respectively. Other factors such as pretreatment absolute neutrophil count, number of involved LN, pretreatment platelet count and first cycle platelet nadir can be used to predict occurrence of neutropenic complications in breast cancer patients undergoing chemotherapy. Further studies are needed among different populations with different tumor types and different treatment regimens to confirm the results and explore other factors which may contribute to occurrence of neutropenic complications.