OBJECTIVES: Few recent data are available on breast cancer treatment costs, especially by stage of the disease at diagnosis. This study was designed to estimate the management costs in breast cancer for the first 5-year period following diagnosis. Costs have been distinguished by stage of severity. METHODS: A patient-level analysis was performed from a French physician survey database, collecting data on patient demographics, cancer history from diagnosis and treatment patterns. Data were extracted for all breast cancer cases with at least 1 year of follow-up after diagnosis using data collected from 2011 to 2012. Cost analyses were conducted from a health care payers' perspective adjusting for stage (stages I-IV) at diagnosis and year from diagnosis.  RESULTS: 1,157 patients were included in the analysis. The stages at diagnosis distribution was respectively from stage I to IV 29.7%, 39.2%, 15.0% and 16.1%. The mean (SD) age at inclusion was 62.5 (12.4) and the mean (SD) time from diagnosis was 5.0 years (5.1). The mean annual cost (SD) over the 5-year period after diagnosis was ranging from 4,293€ (9,526€) for stage I to 12,111€ (19,070€) for stage IV. The mean (SD) annual costs for the 1st year after diagnosis were estimated at 11,647€ (9,883€), 13,226€ (11,575€), 17,254€ (14,535€) and 24,003€ (24,888€), respectively for stage I to IV at diagnosis. The main cost contributors in early stages were radiotherapy and surgery while cytotoxic treatments, hormonotherapy and supportive care droved it for the late stage. The mean annual costs for the following years after diagnosis (2nd to 5th year) decreased, ranging from 1,827€ (8,964€) for Stage I to 5,370€ (10,662€) for stage IV. CONCLUSIONS: : The mean annual cost was strongly related to the clinical stage at diagnosis and the year from diagnosis. These estimates could be useful to populate models that explore impact of treating and preventing breast cancer.