Contrast-Enhanced Digital Mammography: Offering Patients High Sensitivity and Reliable Specificity
Around the globe, breast cancer remains the most common form of cancer in women. In 2018, 2,088,849 women received a breast cancer diagnosis, this number equals more than 25 percent of all the cancers diagnosed in women for that year (excluding non-melanoma skin cancer). Diagnosing breast cancer is the first step in treatment; however, even the full-field digital mammography (FFDM) screenings are unable to detect all the different breast cancers that are putting women’s lives at risk. Today, relatively new diagnostic techniques are filling the gaps left by FFDM screenings. One of these newer imaging techniques is contrast-enhanced digital mammography (CEDM).
Contrast-Enhanced Digital Mammography is More Sensitive than FFDM
Since full-field digital mammography is not capable of detecting all forms of breast cancer, researchers have been conducting studies to find new diagnostic techniques with wider capabilities. One method being used to detect these elusive forms of cancer is the contrast-enhanced digital mammography, which is also referred to as contrast-enhanced mammography (CEM) and contrast-enhanced spectral mammography (CESM). This CEDM technique was first introduced in 2003 (by Lewin et al.) and was approved for use as an add-on in a diagnostic setting by the FDA in 2011.
Radiology Business Publishes Results of New CEDM Breast Cancer Detection Report
Radiology Business published the results of some new findings related to contrast-enhanced digital mammography. The authors examined the benefits of replacing full-field digital mammography with contrast-enhanced digital mammography for women who are at high risk of developing breast cancer and for those with dense breast tissue. The authors gathered their study data from baseline CEDM breast cancer screening examinations performed from December 2012 to April 2016.
Breast Cancer Detection Report: Contrast-Enhanced Digital Mammography:
- 904 Patients Were Reviewed
The total number of patient files reviewed was 904. In all instances, the contrast-enhanced digital mammography was either performed for the purpose of a clinical study or was ordered by the patient’s referring physician. Nearly 80 percent of the 904 patients had breast tissue that was considered dense and almost 30 percent had a family history of breast cancer. A little more than 40 percent of these patients had a personal history with the disease.
- The CEDM Procedure Results
Each patient’s mammography examination occurred within three minutes of the dye being injected. Final Breast Imaging Reporting and Data System (BI-RADS) scores were a three for 2.8 percent of the patients, a 4 or 5 for 5.2 percent and a one or two for 92 percent of the patients. The authors found that the contrast-enhanced digital mammography helped the providers diagnose 15 cancers in 14 of the patients. In addition, the contrast enhancement used during the examination helped with detecting six of the eight cancers previously missed when low-energy images were used.
When considering sensitivity, contrast-enhanced digital mammography’s sensitivity-level is 87.5 percent, almost 40 percent higher than that of full-field digital mammography’s level, which is only 50 percent. Furthermore, CEDM has an impressive specificity of almost 94 percent.
- False-Positives and Contrast Material Reactions
The authors stated that there were false-positive findings, but these were comparable to the benchmarks established for breast MRIs and standard digital mammograms. Reactions to the contrast material occurred in 1.7 percent of the examinations, while one patient experienced a moderate reaction, all others were mild (e.g., hives, nausea, etc.).
- Research Limitations: From the Authors
The research had limitations in that it was composed largely of women at an increased risk of breast cancer and of women with dense breasts. The authors stated that the CEDM’s performance with non-dense breasts and/or for women who are not considered high risk for breast cancer may be different from their findings. In addition, this was a single-institution study.
How Contrast-Enhanced Digital Mammography Differs from Full-Field Digital Mammography
Whereas, FFDM only uses digital x-ray attenuation for screening purposes, contrast-enhanced digital mammography differs in that it uses both digital x-ray and iodine. CEDM takes advantage of the fundamental difference in using iodine to highlight the areas within the breast tissue that could be an indication of breast cancer while performing digital x-ray attenuation of the patient’s breast tissue.
How CEDM Detects Breast Cancer
Since there is an association between breast cancer and tumoral angiogenesis (the development of new blood vessels), the CEDM technique tracks the uptake of the iodine-based contrast agent in the breast tissues. This tracking method allows for the detection of the new blood vessels that are being developed by the cancer.
The Contrast-Enhanced Digital Mammography Procedure
During a CEDM procedure, the patient receives an iodinated intravenous (IV) contrast dye, which is the same type of dye that is used when performing the typical computed tomography (CT) scan. Once the contrast dye has dispersed, a digital mammogram is performed. The contrast dye that is used during this procedure allows the radiologist to see some of the cancers that are unable to be seen with the typical FFDM.
Contrast-enhanced digital mammography may be used to determine the extent of disease for someone who has just been diagnosed with breast cancer, for screening women who are at higher risk of developing cancer, to evaluate a newly found breast lump as well as help prevent needless biopsies.
Will Contrast-Enhanced Digital Mammography Ever Replace Full-Field Digital Mammography?
Studies involving the use of CEDM to provide patients who have dense breasts their annual mammogram screenings continue. The FDA currently considers breast cancer screening with contrast-enhanced digital mammography ‘off-label.’ However, due to its ability to detect tumors in women who have extremely dense breasts and cancers that cannot be seen with FFDM, the hope is that at some point this procedure will replace full-field digital mammography, at least for those women who have dense breasts and are at a higher risk for developing breast cancer.