The combination of contrast-enhanced mammography (CEM) and digital breast tomosynthesis (DBT) led to enhanced detection of second malignancies in comparison to DBT alone in women with a past history of breast cancer, according to interim findings from a three-year prospective trial.
For the study, researchers reviewed data from 1,273 women (mean age of 63.6 years at baseline) with a personal history of breast cancer (PHBC) who had DBT and CEM in the year one analysis. According to the study, 819 women had DBT and CEM at year two and 227 participants completed the imaging at year three. The researchers noted that 48.2 percent of the entire study cohort had dense breasts.
In year one, the researchers found that DBT alone detected breast cancer in 20 out of 1273 participants (or 15.7 per 1000 screenings) versus 29 out of 1,273 women (or 22.2 per 1000 screenings) for the combination of CEM and DBT, according to the interim study results recently published in Radiology. The study authors noted an area under the curve (AUC) of 76 percent for DBT alone in comparison to 88 percent for CEM/DBT for the first year of the study.
In years two and three, DBT alone detected four cases of breast cancer out of 1,046 participants (or 3.8 per 1000 screenings) in contrast to eight out of 1,046 women (or 7.6 per 1000 screenings) with CEM/DBT, according to the researchers. For the second and third years of the study, the authors noted a 93 percent AUC for CEM/DBT in comparison to 72 percent for DBT alone.
“Adding annual CEM to digital breast tomosynthesis (DBT) in women with PHBC substantially increased early cancer detection. … The low cancer yield at DBT, which was only 3.8 per 1000 in incident years (years 2 and 3), suggested that some of the cancers that usually would have been seen were detected in the prior year at CEM,” wrote lead study author Wendie Berg, M.D., Ph.D., a professor of radiology at the University of Pittsburgh School of Medicine, and colleagues.
Three Key Takeaways
- Enhanced detection of second malignancies. Combining contrast-enhanced mammography (CEM) with digital breast tomosynthesis (DBT) led to increased detection of second malignancies in women with a history of breast cancer compared to DBT alone. This is particularly significant for early detection and management of recurrent breast cancer.
- Improved diagnostic performance. The addition of CEM to DBT resulted in higher sensitivity, as indicated by a higher area under the curve (AUC) throughout the study, with a 21 percent higher sensitivity rate (93 percent vs. 72 percent) in comparison to DBT alone for the second and third years of the study. Researchers also noted eight invasive cancers detected only with CEM were 1 cm or smaller.
- Recall rates and screening efficacy. Although the combination of CEM/DBT initially showed higher recall rates compared to DBT alone in the first year, recall rates declined for both approaches in subsequent years. Despite higher recall rates initially, the combination approach led to improved cancer detection without sacrificing sensitivity over time, supporting its potential as an supplemental screening method for women with a personal history of breast cancer.
The researchers noted that of the 18 breasts that had CEM-only detected lesions, 72 percent were invasive, and 50 percent were in women with dense breasts. The study authors also found that CEM was more effective at diagnosing smaller breast cancer lesions.
“The median invasive tumor size of the largest cancer for each breast was 6 mm (range, 1–21 mm) for those seen only at CEM and 9 mm (range, 1–18 mm) for those seen at both DBT and CEM,” pointed out Berg and colleagues. “Eight of the invasive cancers seen only at CEM were 1 cm or smaller and node negative (five of these had pathologic nodal staging, and three were clinically node negative), representing a 73% increase in the detection of such tumors from 11 seen at DBT to 19 after adding CEM.”
(Editor’s note: For related content, see “Is Contrast-Enhanced Mammography a Viable Option for Diagnosing Invasive Lobular Carcinoma?,” “Study: Contrast-Enhanced Mammography Changes Surgical Plan in 22.5 Percent of Breast Cancer Cases” and “Mammography Study: AI Improves Breast Cancer Detection and Reduces Reading Time with DBT.”)
Recall rates were higher with the combination of CEM/DBT in the first year of the study (14.7 vs. 8.1 for DBT alone) but the researchers noted recall declines for both approaches in the second (9.0 vs. 3.9) and third years (7.9 vs. 3.5).
“Our interim results, while preliminary, support the use of CEM for annual supplemental screening in women with PHBC,” added Berg and colleagues.
In regard to study limitations, the authors acknowledged the possibility of patient selection bias contributing to the high breast cancer yield in the first year of the study. Noting that the research was performed at multiple facilities within one health care system, the researchers conceded that broader extrapolation of the study findings may be limited. They also said that a lack of prospective reporting of low-energy findings and related recalls prohibited evaluation of standalone CEM specificity.
