Incidence of febrile neutropenia with use of docetaxel plus cyclophosphamide (TC) for breast cancer.

Abstract

e12073 Background: Incidence of febrile neutropenia (FN) is reported as 5% in breast cancer patients receiving TC (Jones et al., JCO 2006), which would not justify the usage of prophylactic granulocyte colony stimulating factors (G-CSF). We previously showed that the incidence of FN may be as high as 23% in a small study. (N = 130, Soni et al., ASCO 2011). In the current study, we determined the incidence of FN in a larger cohort (N = 415), and evaluated the usage of G-CSF and its relation to FN, age, stage, and hormonal status. Methods: We retrospectively reviewed the electronic medical records from patients diagnosed with breast cancer who received at least one standard dose cycle of adjuvant TC between 2010-2016 at a university-based breast oncology practice. Chi-square or Fisher’s exact tests were used to assess differences between groups. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multiple logistic regression models. Results: We identified in total 415 patients who received adjuvant TC. Median age at diagnosis was 58 (range: 25-86), the majority had stage I or II (N = 382; 92.1%) disease, and 315 (75.9%) were ER+, 277 (66.8%) PR+, 42 (10.1%) HER2+, 22 (5.3%) triple-positive, and 81 (19.5%) triple-negative. Prophylactic G-CSF was utilized in 247 patients (59.5%), and unknown for 43 (10.4%). Overall 39 (9.4%) patients experienced febrile neutropenia. Incidence of FN among those receiving G-CSF was 4.5% versus 17.6% among those who did not (p < 0.001). Use of G-CSF significantly lowered risk of FN, OR (95%CI): 0.20 (0.10-0.43) adjusted for age at diagnosis and stage. Use of G-CSF on incidence of FN did not differ significantly by age, stage, or hormonal status. Conclusions: Our data confirms a high rate of FN in patients receiving TC without G-CSF prophylaxis. Our institutional high rate of G-CSF use ( > 50%) reduced the incidence of FN to 4.5% and the observed significant difference in FN incidence between the non G-CSF group and G-CSF group suggests that prophylaxis may be considered when administering TC. Age, stage, and hormonal status do not seem to affect the usage of G-CSF or incidence of FN in our population.