OBJECTIVES: To determine the trends in type of chemotherapy regimens administered to early stage or metastatic breast cancer patients in daily practice, as this information is lacking in published literature. METHODS: Newly diagnosed breast cancer patients in the period 2000-2008 who received chemotherapy were selected from the Dutch ECR-PHARMO cohort. The ECR (Eindhoven Cancer registry) records data on all newly diagnosed cancer patients in the Southeastern Netherlands whereas the PHARMO RLS (PHARMO Record Linkage System) includes data on, among other things, 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 breast cancer) were determined and stratified by Her2/neu status when possible. RESULTS: In this study, 422 patients diagnosed with early stage breast cancer received adjuvant chemotherapy. The use of CMF decreased from 90% in 2000 to almost none since 2005. Administration of anthracyclines (without taxanes) increased from 4% in 2000 to 94% in 2005, but lowered to 60% in 2008, being replaced by both trastuzumab and taxanes (with or without anthracyclines).  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 (0% and 15% in 2008, respectively), 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, and bevacizumab was administered since 2007 with 19% of the patients receiving bevacizumab containing regimens in 2008.  CONCLUSIONS: Key findings on chemotherapeutic treatment for breast cancer patients from large clinical trials have been incorporated in the Dutch guidelines resulting in major changes in patient care.