Evaluation of the Efficacy of Neutrophil-Lymphocyte Ratio as a Predictor of Fever During Period of Neutropenia Induced by Perioperative Chemotherapy for Breast Cancer

Febrile neutropenia (FN) is a critical adverse event in cancer chemotherapy and affects clinical outcomes, such as reduction of the relative dose intensity. In this study, we retrospectively investigated the factors involved in FN occurrence using three periods of blood test results from patients. We enrolled 114 patients receiving anthracycline-based chemotherapy as perioperative breast cancer treatment. We collected the data on the blood test results containing neutrophile-lymphocyte ratio (NLR) at the start of the initial chemotherapy (baseline), 7 days after the initial chemotherapy (day 7), and at the start of the next chemotherapy, and also calculated the rate of change between each blood test value. Patients were divided into two groups according to whether they had or had not experienced fever during the chemotherapy course, and the data were compared between the groups. A total of 35 patients experienced at least one episode of fever. The fever group showed a significantly greater NLR reduction rate from baseline to day 7 (fever group: 87.6％ vs. non-fever group: 67.3％, P = 0.013) and a markedly rebound from day 7 to the next chemotherapy (1326.8％ vs. 611.1％, P = 0.008). From receiver operating characteristic analysis, the cutoff values for the change ratio of NLR were 83.0％ as decrease on day 7 and 995.0％ as increase on the next chemotherapy (AUC = 0.645 – 0.657). It would be thought that following up on the changes in NLR during chemotherapy, as well as neutrophil counts, is important for predicting FN occurrence.