Screening Innovations: Opportunity in Perspective

If the history of medical innovation has taught us anything, the technology that will replace the traditional screening mammogram has most likely already been invented. You just can’t expect that anyone will recommend it to you, nor should you expect insurance to cover it. Years of clinical study and millions of dollars will be needed to verify the results, convince referring doctors and assure insurance coverage.

And, if you think that hospitals, imaging centers and all breast experts will enthusiastically and rapidly embrace the new technology when mammography’s replacement is clinically proven, you’d be sadly mistaken. There is up to a 17 year lag in the adoption of new medical devices, even when they are clinically proven.(1)

If you were to ask most doctors their opinion of the best breast cancer screening tool, most would say—without hesitation—the mammogram. They say this because they have been told that mammography is the only screening technology that has been proven to save lives in numerous clinical studies. But that doesn’t mean other screening technologies aren’t going to be shown to be better at saving lives… or shown to provide superior detection when used in conjunction with mammography. Other technologies just aren’t yet supported by as many clinical studies as the mammogram, which is now a 40 year-old technology. Clinical studies are extremely expensive and take much time, but we are able to evaluate their promise based on the few studies that are available or in progress, practitioner experience with the technology and a little bit of common sense.

Here are the technologies that are either challenging the traditional mammogram as the gold standard, or that are used in conjunction with mammography to provide a greater chance for early detection and/or improve diagnostic capabilities:

Anatomical Imaging Tests

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Anatomical tests produce images of the body’s internal anatomy. The advantages of these tests is that they are typically covered by insurance, less expensive to conduct and are widely available. The disadvantages are that they cannot detect the metabolic activity within the body and/or are highly dependent on the skills of the individual administering or interpreting the test.

TOMOSYNTHESIS

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Breast tomosynthesis, known to most as 3D mammography, has been available commercially outside the United States since 2008. The FDA approved tomosynthesis in 2011. Numerous European and American clinical studies have demonstrated that adding tomosynthesis to a screening mammogram increases the cancer detection rate by about 40% and significantly lowers recall rates.(2) Tomosynthesis is a profound innovation that is improving the mammogram as a breast cancer screening tool.

 But will you be having one? Years after FDA approval, the majority of imaging centers and hospitals who offer screening mammograms do not offer tomosynthesis. Adoption also varies by region, with the percentage of practices using it in the northeastern region at 36.9% while the adoption rate in the south is just 18.4%.(3)

FAST BREAST MRI

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On August 1, 2014, the Journal of Clinical Oncology published a proof-of-concept study. Fast Breast MRI, a three-minute MRI screening protocol for breast cancer, was shown to be as good as a regular breast MRI (that takes 21 minutes) and more accurate than digital mammography. It detected 11 invasive breast cancers that escaped detection on regular mammography, according to Christiane A. Kuhl, MD from the University Hospital of Aachen in Bonn, Germany. The researchers also found that although the test was highly sensitive, over-diagnosis was not an issue. FAST breast MRI “is a huge step forward in breast cancer screening,” according to Elizabeth A. Morris, MD, chief of breast imaging services at the Memorial Sloan Kettering Cancer Center in New York City. “Data clearly demonstrate that FAST breast MRI could be the standard for breast cancer screening. It is safe, does not induce cancers, and can find more cancers than mammography.”

The proof-of-concept study consisted of 443 women who were at mild to moderate risk for breast cancer. Each had a digital mammogram, and the women within the group who had dense breasts had also undergone ultrasound screening.  Yet, the FAST breast MRI screening identified 11 cancers (7 invasive and 4 DCIS) that were missed on both the mammogram and ultrasound. Another study, the ACRIN 6666 trial (JAMA 2012;307:1394-1404) showed similar results to Dr. Kuhl’s study, detecting another 15 cancers per 1000 that were not detected with mammography or ultrasound.

AUTOMATED WHOLE BREAST ULTRASOUND

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In April, 2012 the FDA approved Automated Whole Breast Ultrasound (AWBUS) as an adjunctive test to mammography. Where available, it is recommended for women with dense breast tissue and for whom a mammogram alone is not adequate. Unlike handheld ultrasound, which takes a lot of time, AWBUS is completed faster and with greater ease.

According to a 2010 study of 4,419 women, “AWBUS resulted in a significant cancer detection improvement compared with mammography alone.” Breast cancer detection doubled from 23 to 46, and the AWBUS was instrumental in detecting smaller, more invasive cancers of 10 mm or less.(4,5)

Functional Imaging Tests

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Functional imaging tests detect metabolic activity within the body, such as the blood feeding a tumor. The advantages are that they are highly sensitive and accurate at detecting cancer and metastatic cancer—with fewer false positives—and are often used for women who are not candidates for breast MRI. The drawbacks are that they are expensive, require the injection of a radiotracer (increased radiation to the entire body—not localized to just the breasts) and are not available in as many locations as standard imaging tests. In addition, the test must be scheduled at certain times within the patient’s menstrual cycle.

MOLECULAR BREAST IMAGING (MBI)

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Molecular Breast Imaging (MBI) is a functional imaging test designed to highlight metabolic activity, versus anatomical tests like mammography. As a result, it can often find cancers that mammograms or 3D mammograms may miss, including within dense breast tissue. It is recommended as a secondary diagnostic tool, and offers several advantages over ultrasound and MRI. A study conducted by the Mayo Clinic and published in the American Journal of Roentgenology (2015) confirmed that MBI yields superior imaging and low radiation exposure for women with dense breast tissue, detecting an additional 8.8 cancers per 1000 women screened. The sensitivity of mammography combined with MBI was an impressive 90.5% for women with dense breast tissue. (~6 mSv)

BREAST-SPECIFIC GAMMA IMAGING (BSGI)

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This test is also metabolic in nature and designed to show the metabolic activity of breast lesions. Like MBI, it is not affected by breast density, is complementary to mammography and ultrasound, and is clinically proven to improve breast cancer detection. However, due to differences in equipment, BSGI requires a higher radiation dose than MBI. Like other forms of functional imaging, BSGI is also used in treatment planning. (5.9 to 9.4 mSv)

POSITRON EMISSION MAMMOGRAPHY (PEM)

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Positron Emission Mammography (PEM) is the breast application of a high-resolution PET scanner. It is more typically used with cancer staging, pre-surgical planning and to monitor treatment. A large, multicenter study showed PEM and MRI to be equally sensitive and specific for the detection of primary lesions, but PEM was shown to be more specific than MRI for the detection of secondary, smaller lesions. (6.2 to 7.1 mSv)