Aims: Most breast screening programmes worldwide have replaced Screen-Film mammography (SFM) with Full-field Digital Mammography (FFDM). While FFDM provides significant technical and practical advantages over SFM in the provision of population screening programs, whether this move has had beneficial effects on health outcomes remains unclear. An increase in screen-detection rates is only beneficial if the additional cancers detected would have otherwise presented at a later stage and caused morbidity and premature mortality. An indirect measure of this is an observed decrease in interval cancer rates.
Methods/Results: This study compares health outcomes before, during and after the transition from SFM to FFDM in women in NSW, Australia. We linked data to capture women’s journeys from screened/unscreened to cancer diagnosis/no cancer diagnosis to treatment/no treatment and to dead/alive. For the period 1988 to 2016, women screened by Breastscreen NSW and/or diagnosed with breast cancer in NSW Cancer Registry records’ were linked with NSW Admitted Patient Data, and NSW Mortality Data.
We will present the results of our evaluation on whether the transition from SFM to FFDM was associated with changes in screen-detected cancer rates, interval rates, positive predictive values, recall rates and false positive recall rates. We will evaluate changes in breast cancer tumour characteristics for screen-detected and interval cancers and differences in breast cancer treatment and breast cancer mortality rates. We will conduct analyses stratified by age, breast density, and initial and subsequent screening examinations.
Conclusion: This research will evaluate incremental benefits and harms of changes in breast cancer screening programs that can be translated to health policy recommendations as well as the information provided to women invited to screen. The innovative approach of estimating benefits and harms using rates of screen-detected cancers and interval cancers will allow for more timely and rigorous evaluation of changes in screening technologies and practice.