What Are the Outcomes from Continued Screening Contrast-Enhanced Mammography?
Standard mammography reduces breast cancer mortality but is less sensitive in women with dense breasts. Contrast-enhanced mammography (CEM) combines mammography with intravenous iodinated contrast. CEM thereby depicts tumor-associated blood flow and provides functional information similar to breast MRI.
Most studies have evaluated CEM during an initial (prevalence) screening examination and have shown very promising results. Less is known about its performance during subsequent (incidence) screening rounds. In a recent retrospective study from Memorial Sloan Kettering Cancer Center, investigators evaluated CEM examinations performed between 2015 and 2021. Most women were at increased risk for breast cancer and had dense breast tissue1. The authors compared cancer detection rate, sensitivity, specificity, and cancer characteristics from first screens vs. those with a prior comparison CEM or MRI.
Key Findings
- CEM maintained high sensitivity and cancer detection rates during both prevalence and incidence screening rounds.²
- Specificity and overall accuracy improved significantly during incidence screening compared with the initial examination.³
- More than half of cancers were seen only because of contrast enhancement.⁴
- CEM continued to detect predominantly invasive, node-negative cancers during subsequent screening rounds.5
These findings suggest that CEM remains an effective supplemental screening tool over repeated examinations. The improved specificity seen during incidence screening may reduce unnecessary recalls while maintaining high cancer detection.
There were limitations to this study. It was a retrospective, single-center analysis involving primarily women with a personal history of breast cancer, which may limit generalizability. Larger prospective studies, including the ongoing CMIST trial, are needed to further define the role of CEM in risk-based screening. CEM is currently only FDA approved for diagnostic use, not screening. Contrast-enhanced biopsy capability is necessary for centers performing CEM. In this study, biopsies were performed using MRI guidance, but not all women having CEM can tolerate MRI: direct CEM-guided biopsy should be available.
In an accompanying editorial, Freitas et al. noted that these findings support CEM as a practical screening option, particularly for women who cannot undergo breast MRI or in settings where MRI access is limited. Because low-energy images mimic standard mammography, CEM can be performed instead of standard mammography rather than as a supplement.
Detailed Results
¹ Most women had dense breast tissue. Dense breasts (BI-RADS C or D) were present in 83.1% of women undergoing prevalence screening and 88.2% of women undergoing incidence screening. Of 1575 prevalence screens, 941 (59.7%) were in women with a personal history of breast cancer, as were 2894/5336 (54.2%) of incidence screens.
² Sensitivity remained stable at 86.1% (30/35) during prevalence screening and 87.1% (62/71) during incidence screening (P=.60). Cancer detection rates (CDR) were 19.0 per 1,000 examinations during prevalence screening and 11.6 per 1,000 examinations during incidence screening (P=.65).
³ Specificity increased from 83.4% (95% CI, 81.6–85.4%) during prevalence screening to 91.5% (95% CI, 90.7–92.2%) during incidence screening (P=.008). Overall accuracy increased from 83.5% to 91.4% (P=.01).
⁴ Contrast enhancement alone showed 60% (18/30) of cancers during prevalence screening and 58% (36/62) during incidence screening. Incremental CDR due to contrast was 11.4/1000 for prevalence screening and 6.7/1000 for incidence screening.
5 There was no significant difference in tumor subtype between screening rounds (P=.50). Most cancers were invasive (70.0% during prevalence screening and 61.2% during incidence screening), and lymph node positivity remained low (5.9% vs. 6.1%). Mean invasive tumor size was 8 mm (range 6-11 mm) for prevalence screens and 7 mm (range 4-10 mm) for incidence screens. The interval cancer rate was 5/1292 (3.9/1000) for prevalence screens and 9/4828 (1.9%) for incidence screens.