CEM shows promise for screening high-risk breast cancer patients
Contrast-enhanced mammography (CEM) has shown promise for women at higher risk of breast cancer, with follow-up screening showing greater specificity and accuracy.
Cancer detection rates remained consistent during repeat screening, while specificity improved compared with baseline examinations.
Specificity shows how accurately a test identifies people who do not have the disease, helping to reduce unnecessary follow-up procedures.
Researchers at Memorial Sloan Kettering Cancer Center analysed 6,911 contrast-enhanced mammography screens carried out among 2,756 women between 2015 and 2021.
Contrast-enhanced mammography, or CEM, combines standard mammography with an injected contrast agent that highlights areas of increased blood flow. Cancerous tumours often develop a greater blood supply.
The team compared 1,575 baseline screens with 3,336 incidence screens.
The researchers classified a screen as baseline if the woman had no previous CEM or had not undergone breast MRI in the previous three years.
Incidence screens were follow-up examinations carried out after previous screening.
After adjusting for the number of screens each woman received, the researchers found no statistically significant difference in cancer detection rates between the groups.
However, specificity reached 91.5 per cent during incidence screening, compared with 83.4 per cent for baseline screening.
Overall accuracy was also higher for incidence screening, at 91.4 per cent compared with 83.5 per cent.
“The ability of contrast-enhanced mammography to help detect cancer during prevalence screening in women at increased risk for breast cancer is maintained in subsequent incidence screens, with better specificity and accuracy,” the research team wrote.
Baseline screening detected 19 cancers per 1,000 examinations, compared with 11.6 per 1,000 incidence screens.
Sensitivity, which measures how well a test identifies people who have a disease, was 87.1 per cent for baseline screening and 86.1 per cent for incidence screening.
Contrast enhancement alone helped detect 18 of the 30 cancers found during baseline screening and 36 of the 62 found during incidence screening.
The researchers also identified 14 interval cancers across the examinations, with no evidence of a difference between the two groups.
An interval cancer is diagnosed after a screening result appears normal but before the next scheduled examination.
The retrospective study used previously collected clinical records rather than following participants in a newly designed trial.
The researchers described CEM as a reasonable screening tool for women with dense breasts.
Dense breasts contain more fibrous and glandular tissue, which can make cancer more difficult to detect with standard mammography.
CEM has previously shown greater sensitivity than ultrasound, digital mammography and digital breast tomosynthesis, according to the article.
Digital breast tomosynthesis takes several low-dose X-ray images from different angles to create a three-dimensional view of breast tissue.
The technique also takes less time and generally costs less than breast MRI, with previous research suggesting its performance is not inferior to MRI.
CEM is currently used for some screening purposes outside its approved indications.
The researchers said it could also help address health inequalities affecting women who face barriers to accessing MRI.
“In addition, women have reported a preference for CEM over MRI,” they wrote.
The researchers said a future article would provide full details about the interval cancers identified in the study.
An accompanying editorial said the technique could become a practical part of breast cancer screening for selected groups, although challenges remain around wider adoption.
“Whether this potential ultimately translates into widespread implementation will depend on future studies evaluating not only diagnostic performance, but also patient outcomes, health care utilisation, and real-world feasibility across diverse practice settings,” wrote Dr Vivianne Aguilera Freitas of the University of Toronto.
