Tissue Breast Density
Reporting breast density within the letter to the patient is now mandated by VA law. Therefore, this website has been established by Peninsula Radiological Associates (PRA), the radiologists of the Riverside Health System, as a resource for area referring clinicians. The text from the bill is in italics below. The wording in capital letters is what the patient receives by law. Resources should you receive a phone call are included below. Please contact us if you have further questions.
Curt Stoldt, D.O. Director of Mammography
Such guidelines shall also require the licensed facility or physician’s office where mammography services are performed to (i) include information on breast density in mammogram letters sent to patients pursuant to regulations implementing the Mammography Quality Standards Act promulgated by the U.S. Food and Drug Administration, and (ii) include in letters sent to patients who have dense breast tissue, as determined by the interpreting physician based on standards promulgated by the American College of Radiology, the following notice:
“YOUR MAMMOGRAM DEMONSTRATES THAT YOU MAY HAVE DENSE BREAST TISSUE, WHICH CAN HIDE CANCER OR OTHER ABNORMALITIES. A REPORT OF YOUR MAMMOGRAPHY RESULTS, WHICH CONTAINS INFORMATION ABOUT YOUR BREAST DENSITY, HAS BEEN SENT TO YOUR REFERRING PHYSICIAN’S OFFICE, AND YOU SHOULD CONTACT YOUR PHYSICIAN IF YOU HAVE ANY QUESTIONS OR CONCERNS ABOUT THIS REPORT.”
Tissue Breast Density has long been reported by PRA as it cannot be predicted based on physical exam, is unrelated to breast size or consistency, may lower the sensitivity of mammography, and because studies suggest it may elevate a woman’s lifetime risk of developing breast cancer.
Determination of tissue density along the spectrum from predominantly fatty tissue (less than 25% glandular tissue) to scattered fibroglandular tissue (25-50%) to heterogeneous (50-75%) and extremely dense tissue (over 75%) is somewhat subjective with arbitrary divisions made based on visual inspection by the radiologist at the time of interpretation. The density of the tissue also fluctuates from year to year but tends to decline with age. As most women have either scattered fibroglandular tissue or heterogeneously dense tissue they may get a letter one year stating they have dense tissue but not get a similar letter the following year (and visa versa).
Elevated tissue density is more common in younger women, is elevated during breast feeding, and is elevated in women using hormone replacement therapy. Statistically this amounts to 60% of women under 50, 40% of women in their 50s and 25% of women in their 60s.
The relative risk of having heterogenous to extremely dense tissue is estimated by some studies in the order of 1.8 to 6 fold (most studies 4-5 fold) relative risk relative to having predominantly fatty tissue to scattered fibroglandular densities. New legislation regarding breast density is intended mainly for women who have extremely dense tissue as these women will likely benefit the most from this knowledge and consideration of additional testing. It is important to remind these women that there are multiple other factors that result in relative risk increases (see tables below), and there is currently little convincing data to suggest a woman can do anything to lower her tissue density. As the lifetime risk of a woman developing breast cancer is already very high (approximately one in eight women), unless a woman has other risk factors (see tables below), she likely will not qualify with the insurance providers for additional testing based on tissue density alone.
Table 1 Relative risk >4.0
- Increasing age
- Known genetic risk factors
- Two or more first degree relatives with premenopausal breast cancer
- Radiation therapy to chest between 10 and 30 years of age
- Personal history invasive breast cancer or ductal carcinoma in-situ (DCIS)
- History of biopsy showing atypical ductal hyperplasia or lobular neoplasia
- High breast density
Table 2 Relative risk 1.1-2.0
- Early menarche or Late menopause
- Late first pregnancy or Nulliparity
- Never breastfed
- Hormone replacement therapy
- Obesity (postmenopausal)
- Personal history endometrial, ovarian or colon cancer
- Alcohol consumption
- Physical inactivity
- History of biopsy showing hyperplasia without atypia
Patient concerns about tissue density will likely be driven by the wording required under VA law; specifically, the statement in layman’s terms that dense tissue can “hide cancer” may scare women regarding the utility of mammography. Studies do suggest a lowered sensitivity of mammography, for example: Kerlikowske et al. reported results of 27,281 screening mammograms and found the sensitivity to cancer was 98.4% in women 50 years old or older with fatty breasts and 83.7% in women with dense breasts. AJR May 2003 vol. 180 no. 5 1225-1228. It is important to emphasize however, that mammography is still the best test for early detection. Detection of cancer is based far less on the density of the cancer relative to the surrounding tissue, and more so on factors such as architectural distortion, asymmetry, change, calcifications, etc. that a well positioned, well compressed, motion free study can provide. So while sensitivity for the earliest cancers may be decreased, the study is far from “worthless”.
Patient advocacy groups that supported this legislation such as http://areyoudense.org/ state that “every other” cancer is “missed” in women with dense tissue. This number appears to come from studies comparing screening ultrasound to screening mammography, for example Berg, W et al. JAMA. 2008;299(18):2151-2163 http://jama.ama-assn.org/content/299/18/2151.short. These numbers are somewhat misleading in that in actual practice we do not make the decision based on the screening mammogram as in a trial… a screen detected area of concern often results in a diagnostic workup that includes sonography. This very same study is also the basis for why screening ultrasound is not supported or recommended because it results in an extremely high false positive rate for biopsies. Ultrasound screening results in a high rate of short term follow-up studies as well and because it is time consuming and user dependent is very difficult to follow findings from year to year. More automated 3D screening ultrasound devices are actively being researched, but unfortunately this is not a resource available for standard practice.
In Summary, patients will be receiving a letter stating density and be asked to discuss this with the referring physician per new VA legislation. We therefore recommend several practical steps to address patient concerns and help both them and you work together with us to optimize detection in women who receive this letter.
1) Please emphasize there is a normal spectrum of tissue density and that dense tissue is not in and of itself abnormal and may fluctuate from year to year but tends to decline with age.
2) Dense tissue may lower the sensitivity of mammography but it is still the best test we have. Studies show detection is improved with digital (as opposed to film screen) technique (currently offered at most facilities, exception Eastern Shore where it will soon be available). Annual mammography improves detection including in women with dense tissue. The death rate from breast cancer in the United States, which had remained virtually unchanged for more than 50 years, began a reversal around 1989 in direct correlation with an increase in the number of screening mammograms. This steady rate of decline has continued for the last 10 years, with the largest decrease occurring among younger women. Recent data suggests that mammograms may even be more effective than previously thought, reducing breast cancer mortality by more than 30-60 percent.
3) As elevated tissue density is a risk factor, consider formal risk assessment with a genetic counselor or utilize risk assessment tools such as the Gail model http://www.cancer.gov/bcrisktool/. If a woman has a calculated lifetime risk exceeding 20% she may qualify for additional testing such as breast MRI (unusual in the absence of strong family history with more than 2 first degree relatives, known genetic mutation, history of early chest radiation therapy, or a combination of personal history with other risk factors which does include tissue density). Please counsel women that the downside to additional testing is the higher false positive rate (higher chance she may get a biopsy with the final result being benign).
4) Encourage monthly self breast examination and annual physician examination. Order directed sonography for any areas of concern or change on examination. Please provide both a description of location (quadrant, clock position, etc.) and a diagram.
5) Finally, if patients continue to be frustrated or scared, encourage them to contact their representatives that passed this legislation to go a step further than requiring “scary” letters… if they want to improve detection they need to require insurers to support additional testing when it is actually indicated and supported by good medical research. Ultrasound Screening is not currently supported by the literature or by insurance providers. Breast MRI and occasionally breast BSGI are routinely denied coverage by insurance providers even when indicated and supported by the literature.
Other resources for Clinicians:
Susan G. Komen practical resource for breast density (especially the box at the bottom of the page): http://ww5.komen.org/Content.aspx?id=19327353285
NCI fact sheet
Mammography Saves Lives Campaign
http://www.pedrad.org/associations/5364/ig/Download PRA Information on Breast Density for Clinicians
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