A population-based study on the patterns of use of different chemotherapy regimens in Swiss patients with early breast cancer

BACKGROUND
There is considerable heterogeneity in the use of chemotherapy in early breast cancer (BC), despite international recommendations issued from the NCCN, NIH and the St.Gallen bi-annual conference.

METHODS
We included 1,535 patients from seven Swiss cancer registries between 2003 and 2005 receiving chemotherapy for stage I to III BC. Chemotherapy was categorised into (a) FAC/FEC, anthracyclines followed by CMF or anthracycline-taxane combinations (FAC-T) (781 patients) and (b) other chemotherapy regimens such as CMF/AC (EC) (754 patients). Predictors for choosing FAC-T over non-FAC-T chemotherapy were separately determined in all patients and in ER-negative patients (n = 496) by multivariate logistic regression analysis.

RESULTS
The use of FAC-T increased significantly over time, from 44% in 2003 to 55% in 2005. BC stage III (versus stage I-II) and nodal positivity were the predominant predictors for using FAC-T chemotherapy in the adjusted model (odds ratio (OR) 4.1, 95%-confidence intervals (CI) 2.6-6.3 and OR 3.0, 95%-CI 2.0-4.4, respectively). In high-risk ER-negative BC patients, poor histological differentiation was more important to choose FAC-T chemotherapy (OR 3.8, 95%-CI 1.9-7.5) than tumour stage or nodal status. The use of FAC-T chemotherapy varied substantially among the seven geographic regions, from 20% in rural Grisons-Glarus to 73% in Zurich.