Full-dose chemotherapy in early stage breast cancer regardless of absolute neutrophil count and without G-CSF does not increase chemotherapy-induced febrile neutropenia

Does giving full-dose adjuvant chemotherapy to patients with early stage breast cancer (ESBC) regardless of the day-before absolute neutrophil count (ANC) lead to an increased incidence of chemotherapy-induced febrile neutropenia (CIFN)? What factors may predispose patients to CIFN? This was a retrospective chart review conducted on all patients receiving adjuvant chemotherapy for ESBC at a mid-sized community hospital in Toronto, Ontario, Canada between September 2005 and August 2011. Day-before CBC data were collected along with other patient characteristics. CIFN was confirmed by hospital records. One hundred fifty-four patients met the inclusion criteria. Overall, 830 cycles of chemotherapy were analyzed. Univariate and multivariate logistic regression analyses were used to identify risk factors for CIFN. Twenty-two episodes of CIFN were observed. There was no significant difference in day-before ANC between patients who developed CIFN relative to those who did not. The day-before ANC was < 1.5 x 10(9)/L for 88 cycles of chemotherapy. ANC analyzed as a continuous variable showed that the odds ratio (OR) for CIFN was 0.97 (95 % CI 0.82-1.13, p = NS). The pseudo R (2) statistic, which is a measure of variability accounted for by a regression model, was only 0.0008, indicating that ANC explained less than 1 % of the variability in the risk of CIFN. The most significant predictor of CIFN was the chemotherapy regimen, with docetaxel (Taxotere)/cyclophosphamide demonstrating the highest risk (OR 7.1, 95 % CI 1.4-34.9, p = 0.016). Full-dose adjuvant chemotherapy may be given to patients with ESBC regardless of the day-before ANC, without significantly increasing the risk of CIFN. The chemotherapy regimen is the most significant predictor for CIFN.