For the Mammography Patient with Dense Breast Tissue
Note: The information contained here was provided by Mercy Women’s Center in Oklahoma City, Oklahoma, with kind permission to reproduce the content for all interested parties (see Mercy Women’s Center contact information at end of article).
Mammography has been the cornerstone of early breast cancer detection for several decades, and annual screening has saved many lives over the years. Yet, mammograms do not identify all breast cancers.
Traditionally, mammograms have been credited with finding 90 percent of breast cancers. However, this detection rate refers to lumps that can already be felt by the patient or her doctor. When talking about early cancers that cannot be felt, only women with low density mammograms can rely on this 90 percent detection rate. When all women with all levels of density are considered, only 70 percent of nonpalpable breast cancers are detected by mammography. And, when we confine the discussion to women with “dense” breast tissue, the detection rate drops below 50 percent.
Dense breast tissue means that the tissue is white on X-ray, as opposed to the black that is seen when the breasts are made up mostly of fatty tissue. The problem is that cancer appears as the same level of white as dense breast tissue. So, the whiter the background, the harder it is to see a cancer. It’s a matter of camouflage.
While you may hear the generalization that young women have dense breast tissue and older women do not, exceptions to this rule are quite common. There are premenopausal women whose low density mammograms are very accurate, and there are many postmenopausal women whose high-density mammograms remain a lifelong problem for early detection.
An additional concern is that breast density is, in and of itself, a risk factor for the development of breast cancer. Women with extremely dense breast tissue are four times more likely to be diagnosed with breast cancer as women with low density mammograms. This elevated risk is often comparable to having a strong family history for breast cancer. So, women with high-density breast tissue, and thus an increased risk for the development of breast cancer, are the very group for whom mammography is least effective.
There are two ways to improve breast cancer detection:
Ultrasound and Breast MRI. Although we have used ultrasound for diagnostic purposes for many years, we now use it to screen women with marked breast density to improve the cancer detection rate. When added to mammography in women with a below-50-percent detection level due to density, ultrasound will increase the detection rate to 80 percent or above.
Even better detection is accomplished through breast MRI, the only other modality besides mammography that the American Cancer Society recommends for high-risk screening. Breast MRI is minimally impacted by breast density, and when added to annual mammograms, the detection rate (sensitivity) is 95 percent.
In head-to-head comparisons, breast MRI will detect twice as many cancers as mammography; however, it is not an either/or situation. We do not advise stopping mammography in those individuals who choose to utilize breast MRI. Mammograms are still the best way to detect “calcium clusters” even in dense breast tissue; and, since calcium can be one of the earliest signs of a breast cancer, women who undergo routine MRI should continue with their annual mammograms.
Are ultrasound and/or breast MRI covered by insurance?
When used for appropriate diagnostic purposes (when there is a problem to be worked out), both ultrasound and MRI are covered expenses. However, routine asymptomatic screening can be a different matter. Insurers are only required (by law) to cover mammographic screening. Breast MRI has been a covered expense in some instances for asymptomatic screening, but only in women with strong genetic predispositions.
In 2007, however, the American Cancer Society revised its screening guidelines to include annual breast MRI starting at age 30 in women who fall into several categories of risk. While most of these categories deal with genetic syndromes, one category for MRI screening includes women at a calculated risk of “greater than 20-25 percent lifetime” for the development of breast cancer. This recommendation will prompt increasing coverage for MRI screening by insurers.
However, “breast density” as a single risk factor for breast cancer was not considered enough to warrant MRI screening by the American Cancer Society, and “more research” was recommended. In our experience, we find as many unsuspected breast cancers in this high-density group with MRI as we do when using MRI based on traditional risk factors. Certainly, when breast density is added to other known risk factors, most patients do qualify for breast MRI screening.
These new developments in screening guidelines for breast MRI require mathematical models to calculate lifetime risks. Many breast cancer risk models are available.
Even with a calculated lifetime risk for breast cancer in excess of 20-25 percent, wherein the American Cancer Society threshold for annual MRI is met, insurance coverage is not assured. And, insurers rarely pre-authorize a screening breast MRI. However, if you prove to be at an elevated risk, then add the presence of breast density interfering with detection and raising overall risk further, plus nodularity on clinical exam, insurance coverage is usually justified. If denied, payment options are available.
True or false?
Annual mammograms will find 90 percent of breast cancers.
True … IF your breasts are “low density.” In fact, this 90 percent number got its start from old studies dealing with women whose cancers were already large enough to be felt on exam. But that’s not the purpose of mammography where we try to find cancer before it can be felt. So, for the minority of women with a low-density pattern, the “90 percent” figure is true, but for the majority, it is …
False. In screening mammography studies, even with the latest digital equipment, the overall detection rate for early breast cancer is 70 percent. This sensitivity level applies to all women when grouped together with all levels of density. However, when those women with extremely dense breast tissue are studied separately, the detection rate drops below 50 percent in all published studies.
Dr. Alan Hollingsworth (author) contact information:
If you want to learn more about risk assessment, make an appointment to see Dr. Alan Hollingsworth in Oklahoma City, Medical Director of Mercy Women’s Center (405-936-5455). His medical practice is limited to breast cancer risk assessment (mathematical modeling), genetic testing, and high-risk surveillance for breast cancer. Included in this consultation is a review of your personal mammographic density, as well as options concerning the frequency of breast MRI (every one, two or three years).
About Mercy Women’s Center
Mercy was the first facility in Oklahoma to switch to digital mammography and one of the first in the nation to launch a breast MRI program. With the addition of the risk assessment and genetic counseling team, services under one roof at Mercy Women’s Center are as complete as can be found anywhere. At our breast center, we believe that care should be individualized, so if mammography is going to be limited in your case, this brochure may help you understand ways to improve early detection.
Mercy Cancer Center
Mercy Health Center offers comprehensive, compassionate care for all cancer patients. A team of Mercy physicians and medical professionals work together to diagnose and treat cancer, as well as provide care after cancer, along with emotional support throughout the cancer journey.
Mercy Breast Radiologists:
Rebecca Stough, MD;
Angela McCoy, MD;
Charles Brekke, MD;
Carol O’Dell, MD.
Nancy Pennington, MD
WOMEN’S CENTER
4300 McAULEY BLVD.
OKLAHOMA CITY, OK 73120
(405) 752-3500
www.mercyok.net