Dr. Barbieri is Editor in Chief, OBG Management; Chair, Obstetrics and Gynecology, at Brigham and Women’s Hospital, Boston, Massachusetts; and Kate Macy Ladd Professor of Obstetrics, Gynecology, and Reproductive Biology at Harvard Medical School, Boston.
Dr. Barbieri reports no financial relationships relevant to this article.
A pragmatic, low-resource utilization screening approach for women with dense breasts There are no published randomized clinical trials that provide high-quality evidence on what to do if dense breasts are identified on mammography.3 Authors of observational studies have evaluated the potential role of supplemental imaging, including ultrasound and magnetic resonance imaging (MRI), in the management of dense breast tissue (see “Supplemental breast cancer screening modalities” below). Supplemental imaging involves complex trade-offs, balancing the potential benefit of identifying occult early breast cancer lesions not identified by mammography with the risk of subjecting many women without cancer to additional testing and unnecessary biopsies.
A pragmatic, low-resource utilization plan for women with dense breasts involves emphasizing that mammography is the best available screening tool and that annual or biennial mammography is the foundation of all current approaches to breast cancer screening. Supplemental imaging is unnecessary with this approach because there is no evidence that it reduces breast cancer mortality. There is, however, substantial evidence that using supplemental imaging for all women with dense breasts will result in little benefit and great costs, including many unnecessary biopsies.1,4 Women with dense breasts also could consider annual clinical breast examination.
Supplemental breast cancer screening modalities
Ultrasound and magnetic resonance imaging (MRI) are available as supplemental imaging, although ultrasound is the only supplemental imaging test that is specifically approved for women with dense breasts. Among the clinically available imaging modalities, MRI can detect the greatest number of cancers.
Ultrasound In women with dense breasts, ultrasound can detect another 3 to 4 cancers that were not detected by mammography. However, ultrasound imaging generates many false positive results that lead to additional biopsies. According to one analysis, compared with mammography alone, mammography plus ultrasound would prevent 0.36 breast cancer deaths and cause 354 additional biopsies per 1,000 women with dense breasts screened biennially for 25 years.1
Ultrasound commonly is used to follow up an abnormal mammogram to further evaluate masses and differentiate cysts from solid tumors. Ultrasound is also a useful breast-imaging tool for women who are pregnant. In 2012, the US Food and Drug Administration approved an automated breast ultrasound device to be used for supplemental imaging of asymptomatic women with dense breasts and a mammogram negative for cancer. This device may facilitate the use of ultrasound for supplemental imaging of women with dense breasts on mammography.
Magnetic resonance imaging MRI can detect the greatest number of cancers of any clinically available modality.
It is almost never covered by insurance for women whose only breast cancer risk factor is the identification of dense breasts on mammography. The cost of MRI testing is, however, typically covered for women at very high risk for breast cancer.
Women who are known to be at very high risk for breast cancer should begin annual clinical breast examinations at age 25 years and alternate between screening mammography and screening MRI every 6 months or annually. These women include:
carriers of clinically significant BRCA1 or BRCA2 mutations
carriers of other high-risk genetic mutations such as Cowden syndrome (PTEN mutation), Lai-Fraumeni syndrome (TP53 mutation), and Peutz-Jeghers syndrome
genetically untested women with a first-degree relative with a BRCA mutation.
Women who had thoracic radiation before age 30 also should be considered for this screening protocol beginning 8 to 10 years after the radiation exposure or at age 25 years.2
References 1. Sprague BL, Stout KN, Schechter MD, et al. Benefits, harms and cost-effectiveness of supplemental ultrasonography screening for women with dense breasts. Ann Intern Med. 2015;162(3):157–166. 2. CRICO Breast Care Management Algorithm. CRICO; Cambridge, Massachusetts; 2014. https://www.rmf.harvard.edu/~/media/Files/_Global/KC/PDFs/Guidelines/cricormfbca2014_locked.pdf. Accessed July 19, 2015.
A high-resource utilization screening approach There are no randomized trials to help guide recommendations about how to respond to a finding of dense breasts on mammography. In addition to breast density, many factors influence breast cancer risk, including a patient’s:
age
family history
history of previous breast biopsies
many reproductive factors, including early age of menarche and late childbearing.
Women with both dense breasts and an increased risk of breast cancer may reap the greatest benefit from supplemental imaging, such as ultrasonography. Therefore, a two-step approach can help.
Step 1: Assess breast cancer risk. This can be accomplished using one of many calculators. Three that are commonly used are the:
National Cancer Institute (NCI) Breast Cancer Surveillance Consortium (BCSC) calculator5
NCI Breast Cancer Risk Assessment Tool, Gail model (BRCAT)6
IBIS Breast Cancer Risk Evaluation Tool (Tyrer-Cuzick model).7
The BCSC calculator uses age, race/ethnicity, first-degree relatives with breast cancer, a history of a breast biopsy, and breast density to calculate a 5-year risk of developing breast cancer.
