Comparison of supplemental breast cancer imaging techniques-interim results from the BRAID randomised controlled trial

Summary

Gilbert FJ, Payne NR, Allajbeu I, Yit L, Vinnicombe S, Lyburn I, Sharma N, Teh W, James J, Seth A, Suaris T, Aggarwal R, Al-Attar M, Savaridas S, Antoniou A, Pharoah P, Duffy S. Lancet. 2025 May 31;405(10493):1935-1944. doi: 10.1016/S0140-6736 (25) 00582-3. Epub 2025 May 21. PMID: 40412427.

The Breast screening—Risk Adapted Imaging for Density (BRAID) RCT sought to identify the best supplementary imaging modality for women with dense breasts and a negative screening mammogram. Women with Breast Imaging Reporting and Data System (BI-RADS) breast density grades C-D were invited to participate, and randomised to 4 arms: abbreviated MRI, automated whole breast ultrasound (ABUS), contrast-enhanced mammography (CEM), or ‘standard or care’ (full-field digital mammography) in a 1:1:1:1 ratio. The primary outcome was cancer detection rate, defined as percentage of women with a positive result on supplementary imaging that resulted in histologically confirmed breast cancer. Secondary outcomes include recall rates and tumour characteristics. 

9361 women were recruited from 10 UK sites, and randomised to the 4 arms (abbreviated MRI, n=2240; ABUS, n=2235; contrast-enhanced mammography, n=2235 and full-field digital mammography only, n=2568). The original trial was designed with 3000 participants per arm, equating to >90% power; this was revised due to COVID-19 but remained powered at 80%. Randomisation across all 4 arms proved logistically impossible for participating sites, therefore initial comparisons were made across supplementary imaging and a contemporaneous cohort of women with BI-RADS breast density grades C-D from one site (n=18107) was used to report cancer detection rates in the standard of care arm. 

6305 women received supplementary imaging and were included in this interim analysis (MRI, n=2130; ABUS, n=2141; CEM, n=2035). Cancer detection rate per 1000 examinations was: Abbreviated MRI 17·4 (95% CI 12·2–23·9, n=37); ABUS 4·2 (1·9–8·0, n=9); CEM 19·2 (13·7–26·1, n=39).  Detection rates for abbreviated MRI were significantly higher than for ABUS (p=0·047) and non-significantly higher than for CEM (p=0·62).  Cancer detection rate within the contemporaneous cohort receiving full-field digital mammography only was 8.4% (7.2-9.9) per 1000 examinations. Supplementary imaging demonstrated a significantly higher cancer detection rate than the standard of care, with the greatest differences noted with abbreviated MRI (p<0.0001). Recall rates were the same following abbreviated MRI and CEM (9.7%, 8.4-11.0) and both were significantly higher than ABUS rates (4.0%, 3.2-4.9) and standard of care (5.4%, 5.1-5.8) (p<0.0001). Average size of invasive cancers detected by abbreviated MRI and CEM were 10mm and 11mm respectively, whilst the average size of cancers detected by ABUS was 22mm.  

In summary, abbreviated MRI and CEM detected three times as many invasive cancers compared with ABUS, with detected cancers being half the size. Supplemental imaging may lead to earlier detection of cancer when screening women with dense breasts.  However, the cost & health benefits, especially breast cancer specific mortality, as well as the potential harm from over diagnosis, remains to be determined. 

Summary authors:

Miss Katherine Fairhurst: Honorary Lecturer Oncoplastic Breast Surgery University of Bristol, Consultant Oncoplastic Breast Surgeon North Bristol NHS Trust

Dr Huma Irshad: Speciality Doctor Breast Surgery at Mid Cheshire Hospitals NHS Foundation Trust UK

Dr Mhairi Mactier: Medical Doctor at NHS Health Scotland