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

Background: Because the incidence of breast cancer increases between 45 and 50 years of age, a reconsideration is required of the current starting age (typically 50 years) for 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 for women aged 48-74 years and for women aged 46-74 years with the current Dutch screening programme, which screen women between the ages of 50 and 74 years. Tumour deaths prevented, years of life saved (YOLS), false-positive rates, radiation-induced tumours, costs and incremental cost-effectiveness ratios (ICERs) were evaluated. Results: Starting the screening at 48 instead of 50 years of age led to increases in: the number of small tumours detected (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 instead of 48 years of age increased the number of small tumours detected (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 5600/YOLS for the 48-74 scenario and 5600/YOLS for the 46-74 scenario. Conclusions: Women could benefit from lowering the starting age of screening as more breast cancer deaths would be averted. Starting regular breast cancer screening earlier is also cost-effective. As the number of additional expected harms is relatively small in both the scenarios examined, and the difference in ICERs is not large, introducing two additional screening rounds is justifiable.