European guidelines on breast cancer screening and diagnosis

Should tailored screening with automated breast ultrasound, in addition to mammography (either digital breast tomosynthesis or digital mammography), vs. mammography alone be used in organised population-based screening programmes for early detection of breast cancer in asymptomatic women with high mammographic breast density?

The GDG agreed that the balance of desirable and undesirable effects favours not implementing automated breast ultrasound (ABUS) for screening women with high mammographic breast density with a negative mammography (either DBT or DM) but the evidence is uncertain. The overall certainty of the evidence is very low because of the uncertainty in the estimates for breast cancer incidence, interval breast cancers, and the number of women called back for another exam (recall rate). Other critical outcomes were not measured in the studies.

The evidence shows that there may be more breast cancers detected in the first round of screening (0.7 more per 100) of which 0.6 are invasive. This benefit is large, but it is uncertain. However, there may be a large number of women who are incorrectly called back for another exam or biopsy (15% more women when adding ABUS). There would also be large costs associated with ABUS, but the overall cost-effectiveness could vary across settings. While ABUS may be acceptable to some women, it is probably not acceptable to payers because of the high costs. It is probably not feasible to implement because of the greater needs for training and time to use ABUS and the lack of reimbursement. In the short and mid-term, the addition of ABUS to current screening protocols is likely not feasible, but it could be feasible in the long term if there are improvements in the technology. Given the lack of accessibility and feasibility, the GDG agreed that at a health care level, adding an ABUS would increase health inequities.
 

The studies included women with BI-RADS C and D. There are likely fewer benefits in women with BI-RADS C and therefore the recommendation may be considered even stronger in this group. 

The acceptability of not providing ABUS may vary amongst women. Therefore, when asked it will be important to share information about classification of breast density, availability of ABUS, and the benefits and harms of ABUS for women with high mammographic breast density and a negative mammography. 

Research priorities include:

• more research into measuring and classifying breast density,
• information to provide to women and communication,
• studies evaluating different screening frequencies and age to stop screening in women with high mammographic breast density.
• The role of Artificial Intelligence should be further investigated.
• The creation of an European consortium for a screening database would be beneficial in evaluating the efficacy of additional tests (e.g. MRI, ABUS, abMRI).