Screening programmes play a crucial role in early breast cancer detection. Mammography remains the best method to detect breast cancer in an early stage. Mammography is a technique of imaging which produces a 2D image of the 3D organ. Digital breast tomosynthesis is a pseudo-3D imaging technique based on a series of low dose images of the breast from different angles and therefore has the potential to overcome the tissue superposition issue thus improving detection of breast lesions.
Should screening using digital breast tomosynthesis vs. digital mammography be used in organised screening programmes for early detection of breast cancer in asymptomatic women?
For asymptomatic women with an average risk of breast cancer, the ECIBC's Guidelines Development Group (GDG) suggests using either digital breast tomosynthesis (DBT) or digital mammography (DM) in the context of an organised screening programme.
Conditional recommendation for either the intervention or the comparison
Very low certainty of the evidence
Women with high mammographic breast density are likely to benefit most from the increased detection capability of DBT. The GDG developed a specific recommendation for this subgroup on the use of DBT vs. DM in the context of an organised screening programme.
Considerations for implementation and policy making
- Evidence will be emerging from ongoing and newly starting screening trials on tomosynthesis that may influence the current recommendations
- The GDG identified variability in the quality of DBT machines currently available and their methods of capturing images. The Malmo study used a machine that has a wide-angle form of DBT image capture and may result in different breast cancer detection rates and also used a single view DBT format
- The GDG notes that new quality assurance standards of technologies and screening programmes must be considered in choosing DBT over DM. The GDG emphasised that specific standards for synthesised 2D imaging, and their use in comparison to previously captured DM screening images will be necessary in order to implement this recommendation
- There will be significantly increased data storage needs for screening programmes using DBT as compared to DM
- The GDG noted that health equity in access to screening should be considered for countries choosing DBT-based screening programmes, due to different resource settings and the capacity for different countries to be able to pay for DBT over DM which may lead to increased health inequities
Monitoring and evaluation
- Quality control/standardisation of the technology for better image storage should be undertaken
- Standards should be developed for the image quality of tomosynthesis
- Screening monitoring and evaluation programmes should be able to distinguish test done with DBT and with DM, stratified standard indicators should be computed
- Evidence will be emerging from ongoing and newly starting screening trials on tomosynthesis that may influence the current recommendations.
- Collecting evidence relevant to implementation challenges of DBT-based screening programmes. To do that, screening programmes should be able to produce stratified indicators (see monitoring and evaluation considerations).
- Research regarding distribution of tumour grade/biology/prognostic measures in the additionally detected cancers might help in clarifying the amount of possible overdiagnosis.
- Further research is needed to build the evidence on benefits and harms of DBT vs DM through comparison of direct outcomes, including impacts of interval cancer incidence, stage of breast cancer at detection and mortality reduction.
- Research investigating the cost-effectiveness of a breast cancer screening programme using DBT is needed to inform decision-making on breast cancer screening.
- Research is needed to define the quality parameters that need to be fulfilled for DBT-based breast cancer screening programmes to be implemented.