The association between chemotherapy-induced febrile neutropenia and breast cancer subtype in Japanese patients.

Background Chemotherapy-induced febrile neutropenia is a common and potentially lethal side effect; therefore, predicting febrile neutropenia development is important. Objective This study examined the risk factors for febrile neutropenia development according to breast cancer subtype among Japanese patients receiving chemotherapy. Methods This single-center retrospective study evaluated 60 outpatients who received chemotherapy for breast cancer (epirubicin plus cyclophosphamide or docetaxel plus cyclophosphamide). Their characteristics were evaluated to identify factors associated with febrile neutropenia development. Results Thirty-three patients developed febrile neutropenia and 27 patients did not. The risk of developing febrile neutropenia was significantly associated with estrogen receptor negativity (p < 0.05). Logistic regression analysis further confirmed that estrogen receptor negativity was an independent risk factor for febrile neutropenia development (odds ratio: 4.35, 95% confidence interval: 1.05-18.0). Moreover, the highest rate of febrile neutropenia was observed in patients with hormone receptor (estrogen and/or progesterone receptor)-negative/human epidermal growth factor receptor 2-positive breast cancer. Conclusion In addition to the known risk factors for febrile neutropenia, our findings revealed that the risk of developing chemotherapy-induced febrile neutropenia is associated with the hormone receptor-negative/human epidermal growth factor receptor 2-positive subtype in Japanese patients with breast cancer.