Almost 50 percent of women in the U.S. have dense breast tissue. However, many aren’t aware that they have dense breasts or what having dense breasts means. Dense breasts often show up on mammograms as indistinguishable from cancerous tumors, making it incredibly difficult to identify cancer. The lack of differentiation can lead to false negatives and a delayed diagnosis, which can significantly alter a patient’s prognosis. Additionally, according to the American College of Radiology, women with dense breast tissue are at an increased risk of developing breast cancer.
To date, Breast Density Notification Laws have been passed in 28 states. The intent of these laws is to give women the information needed to help them and their referring doctor decide if additional screening is necessary. The notification laws vary by state, but in general require physicians in the affected states to notify patients of their breast density after getting a mammogram. Many physicians, however, still rely on mammograms, which may lead them to miss many cancers, or detect them later with a resultant poorer prognosis.
A recent clinical study that was published in the August issue of the American Journal of Roentology (AJR) found molecular breast imaging (MBI) to be an effective secondary screening method for women with dense breast tissue. Mammograms alone have a published cancer detection rate of about four cancers per thousand (4.1/1000); in other words, mammograms alone only catch four cancers per thousand women screened[i]. The study highlighted MBI’s high incremental cancer detection rate of 7.7 cancers per thousand (7.7/1000) when added to mammography screening. In summary, when a MBI is performed after a mammogram, almost 8 additional cancers are detected that the mammogram did not detect alone in women who have dense breast tissue. The study found MBI identified an additional 13 malignant tumors per 1,696 women screened with dense breast tissue after having their mammogram reported negative. Approximately 85 percent of these cancers identified using MBI were invasive and confirmed as node negative, indicating that they were detected at an early stage and therefore had a more favorable prognosis[ii].
According to Dr. Robin Shermis, a practicing physician who regularly recommends MBI to patients with dense breasts and one of the AJR study authors, this technology helps identify cancers that would have otherwise gone missed on a mammogram, it fits seamlessly into the workflow and is a comfortable experience for patients, so it is an obvious choice.
Molecular imaging uses a small injection of a radiopharmaceutical that allows the camera in the MBI device to provide a detailed picture of what’s happening at a cellular level and metabolic level. This cellular activity is detected by the preferential cellular uptake that enables the cameras to detect cancerous lesion despite the tissue density of the patient’s breasts that are undetectable by mammography. The small amount of diagnostic dose of radiation that patients are exposed to is less than annual background radiation from natural sources like the radon gas from the soil and cosmic rays. While people are naturally concerned about radiation, no scientific study has demonstrated any harm from these low radiation levels[iii]. Furthermore, the hypothetical risks must be weighed against the substantial benefit, an increase of four times of detecting breast cancer at an early stage when it’s most treatable and prognosis is much more favorable.
In independent studies published in AJR in 2015, researchers found when used in women with dense breast tissue, MBI increases detection rates by almost 400 percent when added to mammography (8.8/1000) and had a 50 percent reduction in biopsies compared to other screening modalities, such as ultrasound and MRI. [iv] Due to earlier detection, MBI decreases the diagnosis cost per cancer detected by 15 percent compared to a mammogram alone.[v]
Dianne Anderson, a patient of Dr. Shermis, praised the technology: “I am a strong advocate of finding out if you have dense breast tissue and getting an MBI to get a definitive answer. It’s just a quick injection in your arm, some light compression and you are done. It was not at all painful or uncomfortable, and I was able to chat with the technicians while waiting for the machine to complete the scans. Having previously had biopsies and mammograms, MBI is not nearly as painful or stressful.”
MBI is a safe, fast, reliable and accurate secondary screening tool that puts the patient first. Giving patients the power of being certain is an invaluable privilege that we do not take lightly and MBI is the most effective screening tool to do so.
[ii] Robin Shermis, et. al., “Supplemental Breast Cancer Screening With Molecular Breast Imaging for Women With Dense Breast Tissue,” American Journal of Roentology (August 2016)
[iii] Hendee WR, O’Connor MK. Radiation risks of medical imaging: separating fact from fantasy. Radiology. 2012;264(2):312–2
[iv] DJ Rhodes, et. al., “Journal club: molecular breast imaging at reduced radiation dose for supplemental screening in mammographically dense breasts,” American Journal of Roentology (February 2015)
[v] Hruska CB, Conners AL, Jones KN, et al. Diagnostic workup and costs of a single supplemental molecular breast imaging screen of mammographically dense breasts. AJR 2015; 204:1345–1353