Résumé : BackgroundIn 2003, US breast cancer incidence rates fell. Recent French data reveal also a decline in 2005-2006. This study aims to present the trends in breast cancer incidence by age and to identify the respective impact of mammography screening and use of hormone replacement therapy (HRT) in the French context.MethodsBreast cancer incidence rates were calculated from the new cases of breast cancer among affiliates of the general scheme of the French National Health Fund between 2000 and 2006. Data concerning HRT and mammograms were extracted from the reimbursement databanks of the National Health Fund and from the National Screening Programme.ResultsBreast cancer incidence decreased between 2003 and 2006 only for women aged 50 or above. The strongest declines were observed among the 55-59 and 60-64-year-old groups (12.9 and 7.7%, respectively). We observed a slight decline in the age groups of 50-54 and 65-69 (0.7 and 2.1%, respectively). Volumes of mammograms increased continuously between 2000 and 2006 from 1,600,000 to 3,470,000 for women aged 50-74 years old. In 2004, the National Screening Programme achieved complete geographic coverage. At the same time, the number of HRT users has dropped by 62% between 2001 and 2006. We observed the highest prevalence of HRT and the highest decrease in breast cancer incidence rates in the age group of 55-59.ConclusionsThe recent reduction in breast cancer incidence in France for women aged 50 years or above, in 2005-2006, was accompanied by a substantial reduction in HRT prescriptions after 2002 for all age groups. The drop in HRT parallels the drop in breast cancer incidence for the women between the ages of 55-59 and 60-64. The high-level of development of screening in France during the same period could not account for the reduction in breast cancer incidence.