A modelling study to evaluate the costs and effects of lowering the starting age of population breast cancer screening

Background: Increased breast cancer incidence between 45 and 50 years of age requires reconsideration of the current starting age of routine mammography. Our aim was to evaluate the quantitative benefits, harms, and cost-effectiveness of lowering the starting age of breast cancer screening in the Dutch general population. Methods: Economic modelling with a lifelong perspective compared biennial screening 48-74 and 46-74 to the current Dutch screening program (50-74). Tumour deaths prevented, years of life saved (YOLS), false positives, radiation-induced tumours, costs and incremental costseffectiveness ratios (ICERs) were evaluated. Results: Starting the screening at 48 vs. 50 led to an increase in: the number of small screen detected tumours (4.0%), tumour deaths prevented (5.6%), false positives (9.2%), YOLS (5.6%), radiation-induced tumours (14.7%), and costs (4.1%). Starting the screening at 46 vs. 48 increased the number of small screen detected tumours (3.3%), tumour deaths prevented (4.2%), false positives (8.8%), YOLS (3.7%), radiation-induced tumours (15.2%), and costs (4.0%). The ICER was €5,600/YOLS for 48-74 scenario and €5,600/YOLS for 46-74. Conclusions: Women could benefit from lowering the starting age of screening as more breast cancer deaths will be averted. Starting regular breast cancer screening earlier is also cost-effective. As the number of additional expected harms is relatively small in both alternative scenarios and the difference in ICERs is not large, introducing two additional screening rounds is justifiable