Abstract
Background: The efficacy of adjuvant chemotherapy with FEC-D (5-fluorouracil–epirubicin–cyclophosphamide followed by docetaxel) is superior to that with FEC-100 alone in women with early-stage breast cancer. As the use of FEC-D increased in clinical practice, health care providers anecdotally noted higher-than-expected toxicity rates and frequent early treatment discontinuations because of toxicity. In the present study, we compared the rates of serious adverse events in patients who received adjuvant FEC-D chemotherapy in routine clinical practice with the rates reported in the PACS-01 trial. Methods: We retrospectively reviewed all patients prescribed adjuvant FEC-D for early-stage breast cancer at 4 regional cancer centres in Ontario. Information was collected from electronic and paper charts by a physician investigator from each centre. Data were analyzed using chi-square tests, independent samples t-tests, one-way analysis of variance, and univariate regression. Results: The 671 electronic and paper patient records reviewed showed a median patient age of 52.2 years, 229 patients (34.1%) with N0 disease, 508 patients (75.7%) with estrogen or progesterone receptor–positive disease (or both), and 113 patients (26%) with HER2/neu–overexpressing breast cancer. Febrile neutropenia occurred in 152 patients (22.7%), most frequently at cycle 4, coincident with the initiation of docetaxel [78/152 (51.3%)]. Conclusions: Primary prophylaxis with hematopoietic growth factor support was used in 235 patients (35%), and the rate of febrile neutropenia was significantly lower in those who received prophylaxis than in those who did not [15/235 (6.4%) vs. 137/436 (31.4%); p < 0.001; risk ratio: 0.20]. In routine clinical practice, treatment with FEC-D is associated with a higher-than-expected rate of febrile neutropenia, in light of which, primary prophylaxis with growth factor should be considered, per international guidelines. Adoption based on clinical trial reports of new therapies into mainstream practice must be done carefully and with scrutiny.