What You Need to Know About Advances in Mammograms and other Breast Cancer Screening
Kathleen A. Ward, MD, Radiology, who specializes in breast imaging, including mammography, MRIs and ultrasound. She answers questions on the latest developments in breast cancer screening.
What type of breast cancer screening is recommended and when should it start?
Screening mammography is the only imaging modality that has been proven to decrease mortality from breast cancer. Since the introduction of screening mammography, the death rate from breast cancer has declined in the United States by 30 percent.
There has been much confusion about when, how often and how long women should undergo screening mammography since the U.S. Preventative Services Task Force (USPSTF) initially released its revised guidelines in 2009. The proposed changes in screening onset and intervals have in part resulted from concern about the number of false-positive results requiring additional imaging or biopsies.
No one disputes the benefits of routine mammography screening, and the USPSTF readily admits that delaying the start of mammography screening and increasing the interval between screenings will result in an increased number of deaths from breast cancer.
As a radiologist with more than 30 years' experience in mammography, I support the guidelines of the Society of Breast Imaging and the American College of Radiology. Annual mammographic screening for breast cancer should begin at age 40 (and earlier in select high-risk patients) and should continue as long as a woman is in good health and will act upon any abnormal results of screening.
What advances have been made in breast cancer screening?
Recent studies have evaluated the role of supplemental screening with whole breast ultrasound in women with dense breast tissue at increased risk of developing breast cancer. Adding supplemental screening with whole breast ultrasound to screening mammography in this patient population was found to increase the detection of invasive breast cancer from approximately 8 women per 1,000 women screened to nearly 12 women per 1,000 women screened with a yield of an additional 4 cancers found per 1,000 women screened. Of the additional cancers detected by ultrasound alone, the lesions were overwhelmingly small and node-negative, meaning they did not show signs of having spread to lymph nodes.
Approximately half of women in the United States have heterogeneously or extremely dense breast tissue that limits the sensitivity of mammography and the detection of smallbreast masses. The use of supplemental whole breast ultrasound has also been advocated in women with dense breast tissue who have no additional risk factors for developing breast cancer, however, such supplemental screening will also substantially increase the number of false positive results resulting in more additional imaging and more benign biopsies, a consequence that is more acceptable to high-risk patients.
Finally, adding a single breast MRI examination in these high-risk patients with dense breasts following three years of combined mammography and ultrasound screening identified additional breast cancers, the majority of which were also early stage invasive cancers that had not spread to lymph nodes.
Supplemental screening with whole breast ultrasound is also a good option in high-risk women for whom MRI screening may be appropriate but who cannot undergo MRI for any reason, including size and claustrophobia.
What is 3D mammography and when is it used?
Since mammography is the only imaging modality that has been proven to decrease mortality from breast cancer, major efforts have been made to build on its success. Digital breast tomosynthesis (DBT), or 3D mammography, is a special type of digital mammography that produces 3-dimensional images of the breasts using low dose X-rays obtained at different angles.
The breast is positioned in the same manner as during conventional full field digital mammography (2D mammography), but the X-ray tube moves in a circular arc around the breast, with the information received then sent to a computer that produces a 3D image. Imaging of each breast takes less than 10 seconds per view, similar to conventional mammography.
While digital breast tomosynthesis is especially useful in women with dense breasts irrespective of risk, all women may benefit from the improved visualization of suspicious lesions afforded by tomosynthesis technique.
What are the benefits of 3D mammography or DBT?
Digital breast tomosynthesis has not only been shown to increase the early detection of invasive breast cancer by 40 percent or more compared to conventional full field digital mammography, but has also been reported to decrease recall or call back imaging by up to 40 percent, with a nearly 50 percent increase in positive predictive value (PPV) for subsequent recall imaging and a 20 percent higher yield of malignancy in women for whom biopsy is recommended.
DBT should reduce the need for short interval follow up imaging studies and should also lead to fewer biopsies in patients with benign lesions. Specifically, masses, areas of architectural distortion and asymmetric densities associated with invasive breast cancer are much better visualized with DBT, with no significant change in the detection of ductal carcinoma in situ (DCIS), or Stage 0 breast cancer.
When should women who are at greater risk of breast cancer start having annual mammograms?
The vast majority of women who develop breast cancer (70 to 80 percent) are at average and not elevated risk and should begin yearly mammograms at age 40. However, women at increased risk of developing breast cancer may need to begin annual mammographic screening earlier.
- Women with certain BRCA1 or BRCA2 mutations and their untested first-degree relatives (mothers, sisters, or daughters) should start yearly mammographic screening by age 30, but not before age 25 due to an increased risk-benefit ratio signaling that the risk from radiation to the breast outweighs the benefits of mammographic imaging.
- Women with a 20 percent or greater lifetime risk for developing breast cancer on the basis of family history and women who have mothers or sisters diagnosed with premenopausal breast cancer should begin yearly mammographic screen by age 30, but again not before age 25, or 10 years earlier than the age of diagnosis of the youngest affected relative, whichever is later.
- Women with histories of mantle radiation for Hodgkin’s disease should begin annual mammographic screening starting eight years after such radiation therapy, but not before age 25.
- Women with biopsy-proven lobular neoplasia (LCIS and ALH), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS or Stage 0 breast cancer), invasive breast cancer or ovarian cancer should undergo annual mammographic examination from time of diagnosis, regardless of age.
How can you tell if you need your risk assessed or if you are a candidate for the genetics evaluation program at Loyola?
Participation in Loyola’s genetic evaluation program would be beneficial for any patient if the patient or a relative is diagnosed with breast cancer at an early age, diagnosed with bilateral breast cancer or more than one cancer (especially ovarian, uterine and colon cancer), has a male family member diagnosed with breast cancer, or has a known gene mutation or syndrome that causes susceptibility to developing breast cancer, such as BRCA1 and BRCA2 mutations, Lynch syndrome and Li-Fraumeni syndrome.
When is a breast MRI used for screening, and how is it used in diagnosis?
Breast MRI may be used as a high-risk screening tool and has diagnostic indications in select patients, particularly in the evaluation of the extent of disease in patients with newly diagnosed breast cancer, the evaluation of postlumpectomy patients with surgical margins positive for residual disease, the evaluation of treatment response to neoadjuvant chemotherapy, as well as in the evaluation of patients with either suspected breast cancer recurrence or metastatic cancer of unknown primary suspected to be of breast origin when clinical, mammography and ultrasound findings are negative or inconclusive.
Breast MRI may play a role in the evaluation of patients with breast augmentation with silicone or saline implants and/or free injections of silicone or other materials in whom mammography may be difficult. Non-contrast breast MRI can determine silicone breast implant integrity and detect silicone implant rupture.
It is important to note that MRI should not replace diagnostic mammography and ultrasound in the evaluation of focal breast complaints, including palpable masses, or in the evaluation of lesions identified on screening mammography.
Supplemental screening with MRI to date is reserved for high-risk patients due to the significant number of false-positive findings. Such patients include:
- Women who are proven BRCA mutation carriers and their untested first-degree relatives.
- Women with a greater than 20 percent lifetime risk for developing breast cancer on the basis of family history.
- Women with histories of mantle radiation treatment for Hodgkin’s disease.
Screening MRI of the opposite breast may be performed in patients with newly diagnosed breast cancer and a normal opposite breast examination by conventional imaging and physical examination. Screening breast MRI may be considered in women with between 15 and 20 percent lifetime risk for developing breast cancer on the basis of a personal history of breast or ovarian cancer or biopsy-proven lobular neoplasia or atypical ductal hyperplasia. Screening breast MRI is not recommended in women with less than 15 percent lifetime risk of breast cancer.
Recent studies have been directed to developing a less expensive, quicker breast MRI screening examination with promising results thus far. It should be noted that breast MRI is currently not meant to replace screening mammography. To date, only mammography screening has been shown to decrease mortality from breast cancer, and therefore, mammography remains the gold standard for breast cancer screening.
Kathleen Ward, MD, FACR, is a leader in radiological medicine and research. Dr. Ward was awarded the 2012 Chicago Radiological Society Gold Medal for Distinguished Service.
Loyola Medicine offers mammography at several locations, including:
- Loyola Outpatient Center on the campus of Loyola University Medical Center in Maywood
- Loyola Center for Health at Burr Ridge
- Loyola Center for Health at North Riverside
- Loyola Center for Health at Oakbrook Terrace
- Loyola Center for Health at Orland Park
- Gottlieb Memorial Hospital in Melrose Park
To make an appointment call 888-584-7888.