Purpose: This study assessed the incidence of chemotherapy-induced neutropenia and febrile neutropenia (FN) while identifying their associated factors.

Methods: A prospective cross-sectional study was conducted among 113 female chemotherapy-naïve breast cancer patients over a 2-year period. Socio-demographic, clinical and haematological data were obtained via semi-structured interviews and from medical case files. Blood samples for complete blood count parameters were collected 2 weeks after each course of chemotherapy. The National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 was used to assess FN, neutropenia and their severity.

Results: The incidence of neutropenia and FN among the patients was 31.9% and 5.3%, respectively. Throughout all courses of chemotherapy (n = 502), there were 57 (11.4%) neutropenic episodes with 6.6% mild, 3.4% moderate and 1.4% severe neutropenia. The incidence of neutropenia decreased with increasing chemotherapy courses, with a rate of 14.2% and 4.9% after the first and last course, respectively. Factors associated with the risk of developing neutropenia include increasing age (p = 0.014), Eastern Cooperative Oncology Group performance score ≥ 1 at presentation (p = 0.033) and presence of bone metastasis (p = 0.002).

Conclusion: One in three breast cancer patients in this study developed neutropenia while on chemotherapy but no independent risk factors were identified for FN among these patients. This study has, therefore, provided the preliminary data necessary for further independent validation of the identified risk factors for FN in a more robust and well-designed study within our clinical practice setting in Nigeria.