There is little information available on the patterns of chemotherapy regimens administered in daily practice to patients with early stage and metastatic or recurrent breast cancer. To determine the trends in type of chemotherapy regimens used in beast cancer patients, newly diagnosed breast cancer patients in the period 2000-2008 who received chemotherapy were identified from the Eindhoven Cancer Registry (ECR) and linked to the PHARMO RLS, including data on, e.g., in- and outpatient drug use. Chemotherapy regimens were classified based on the received combinations and sequences. Trends in the distribution of adjuvant chemotherapy regimens (for early-stage breast cancer) and palliative chemotherapy regimens (for metastatic or recurrent breast cancer) were determined and stratified by Her2/neu status when possible. In this study, 422 patients diagnosed with early-stage breast cancer received adjuvant chemotherapy. The use of CMF (cyclophosphamide, methotrexate, and 5-fluorouracil) decreased from90% in 2000 to almost none since 2005. Administration of regimens that included anthracyclines increased from 4% in 2000 to 96% in 2005, but decreased to 68% in 2008. The use of trastuzumab- and taxane-containing regimens (with or without anthracyclines) increased from 2005 onwards to 24% and 34%, respectively, in 2008. Among the 82 breast cancer patients who received palliative chemotherapy at diagnosis or after breast cancer recurrence, the use of CMF and anthracyclines (without taxanes) decreased, while the use of taxanes (with or without anthracyclines) increased (26% in 2008). Trastuzumab was used as palliative chemotherapy from 2003 onwards, with 22% of the metastatic breast cancer patients receiving trastuzumab-containing regimens in 2008, andbevacizumab was administered since 2007 with 19% of the patients receiving bevacizumab-containing regimens in 2008. In conclusion, major changes have taken place in the chemotherapeutic treatment of patients with early and recurrent breast cancer. Thesechanges reflect the key findings from large clinical trials, as incorporated in the Dutch guidelines.