Dense Breast Information

Valley Radiology Statement and Information Regarding the Implementation of the California Breast Density Law

Dear patients and referring colleagues:

California law requires that women with dense breast be notified after undergoing screening mammography. VRC will notify women through the existing lay letter. Increased breast parenchymal density lowers the sensitivity of mammography and it may also increase a woman's overall breast cancer risk, although the extent of this effect is controversial.

Due to the limitations of mammography in the setting of dense breasts there has been considerable research activity with other imaging technologies to supplement mammographic screening. One of these technologies is breast sonography. The most comprehensive study on this topic to date is the American College of Radiology Imaging Network (ACRIN) 6666 study which involved 42,838 examinations at six centers in the United States on high risk women. This study showed an increase of 3.5 cancers detected by Ultrasound for every 1000 women as compared to mammography. Overwhelming majority (94%) of the tumors were invasive cancers and 84% were node negative. However, the study also demonstrated significant increase of false positives compared with mammography (Positive Predictive Value of 8.9% for US vs. 23% for mammography) that result in unnecessary biopsies and follow up examination recommendations with commensurate increase in costs. In summary, although it has not been established that women will benefit from incorporation of sonography into routine breast cancer screening, there may be an appropriate subpopulation of women for whom supplemental screening may be warranted.

Another imaging technology, Breast MRI, is considered the gold standard for screening women at high risk (>20% life time risk) for developing breast cancer. In fact, it is important to keep in mind that the combination mammography and Breast MRI consistently outperforms the combination of mammography and whole breast ultrasound for high risk women independent of breast density. A nine series study summarized by Berg involving 4,485 high risk women showed a 93% sensitivity for mammography and Breast MRI versus 52% for mammography and whole breast Ultrasound. It is for these reasons that the American Cancer Society recommends annual mammography and MRI screening for this subpopulation of women. The disadvantages of breast MRI include increased false positives, high cost and equipment availability.

At VRC, we believe the most prudent approach to the issue of increased breast density is to incorporate this information into a women's overall risk status to include other risk factors, such genetic predisposition, family and personal history of breast cancer. This comprehensive approach to risk assessment can then be used to tailor the appropriate use of the available supplemental imaging technologies to mammography for the various subpopulation of women. Such an approach should result in optimal outcomes while keeping costs as low as reasonably possible.

We plan to use the following matrix to help guide the appropriate imaging based on a woman's breast density and other risk factors:

MANAGEMENT GUIDELINES

High Risk (>20% life time risk) with or without dense breasts: mammography with Breast MRI and genetic counseling. This also applies to women with personal history of breast cancer.
Intermediate risk (10-20% life time risk) with dense breasts: mammography with consideration of breast MRI or whole breast US.
Intermediate risk with non-dense breasts: mammography with consideration of breast MRI (not currently covered by insurance).
Average risk with dense breasts: mammography with consideration of whole breast ultrasound.
Average risk with non-dense breasts: mammography.

HIGH RISK ASSESSMENT

VRC will use the Breast Cancer Risk Assessment Tool- an interactive tool designed by the National Cancer Institute to calculate a woman's life time risk. This can be accessed at www.cancer.gov/bcrisktool/

In conclusion, at VRC we are passionate about what we do, particularly in the area of breast health. We strongly support evidence based medical decision making. We will keep you informed as additional research data becomes available with regard to the best imaging choices on the issue of breast density. We will also update you on the latest imaging technology for breast imaging. Finally, we will keep you informed as we continue to develop our community based breast cancer high risk screening program which will require the collective efforts of all of us in our community.

SPECIAL NOTES:

Screening Mammography: Please don't forget that annual mammographic screening beginning at the age of 40 has been scientifically proven to significantly decrease cancer mortality (20-40%) and this screening regiment is formally endorsed by the American Cancer Society (ACS) and the AmericanCollege of Obstetrics and Gynecology (ACOG).

The American Cancer Society recommends Breast MRI screening examinations for high risk women and pre-operative MRI of the breasts to evaluate the extent of disease for women with biopsy proven breast cancer.

KEY POINTS

Starting April 1, 2013, California law requires that patients are informed if they have "dense breast tissue" on screening mammography, and if so, that they may want to discuss their "screening options" with their primary physician.
Approximately 50% of women undergoing screening mammography are classified as having either "heterogeneously dense" or "extremely dense" breasts. For all of these women, the patient letter will inform them that they have "dense breast tissue."
Only 10% of all women have "extremely dense" breast tissue, which is associated with a relative risk of breast cancer of approximately 2 compared with average breast density. 40% of women have "heterogeneously dense" breast tissue, which is associated with a relative risk of approximately 1.2. Therefore, breast density is not a major cancer risk factor.
The sensitivity of mammography is reduced as background breast tissue density increases. When mammography is the only screening test performed, sensitivity decreases by 10% to 20% for women with "dense breasts".
The recommendations for screening mammography are exactly the same for women with dense breasts as for the rest of the population. Mammography is the only screening modality that has undergone randomized controlled trials demonstrating a reduction in breast cancer mortality. There is no recommendation that it be replaced with another test in any subset of the population.
For patients who are interested in additional screening options, a breast cancer risk assessment may be appropriate. It is a good starting point in the discussion of whether supplemental tests will be beneficial and what tests, if any, to orde
The other breast imaging "screening options" include screening MRI, ultrasound and tomosynthesis ("3D mammography"). Screening breast MRI has been shown to substantially increase the rate of cancer detection. It is recommended in patients who are at very high risk (>20% lifetime risk) based on American Cancer Society guidelines. For patients at "intermediate risk," such as those with a personal history of breast cancer or a prior biopsy diagnosis of atypia (equivalent to a 15% to 20% lifetime risk), a patient-centered shared decision-making approach is recommended.
Screening breast ultrasound is not offered at many centers and may entail an out of pocket charge to patients. Small studies have shown a modest increase in cancer detection, but also a high rate of false positives resulting in benign biopsies. The choice to have this test should be made on an individual basis after a discussion of these risks, benefits, and costs.
Breast tomosynthesis ("3D mammography") is being offered in addition to screening mammography in some centers. Thus far, we have preliminary encouraging data on the performance of tomosynthesis in women with dense tissue.

Key Points from www.densebreast.info

Links

Frequently Asked Questions About Breast Density

www.ACRIN.org

The American College of Radiology - Breast Density Brochure

American Cancer Society

Mammography Saves Lives

Breast Cancer Risk Assessment Tool

Radiology Info

Bibliography
Recent Articles from the Conneticut experience using screening Breast Ultrasound for Dense Breasts.

Radiology 2012;265:59-69
Radiology 2012;265:9-11 (commentary by Dr. Orsi)

Starting April 1, 2013, California law requires that patients are informed if they have "dense breast tissue" on screening mammography, and if so, that they may want to discuss their "screening options" with their primary physician.

Approximately 50% of women undergoing screening mammography are classified as having either "heterogeneously dense" or "extremely dense" breasts. For all of these women, the patient letter will inform them that they have "dense breast tissue."

The sensitivity of mammography is reduced as background breast tissue density increases. When mammography is the only screening test performed, sensitivity decreases by 10% to 20% for women with "dense breasts".

For patients who are interested in additional screening options, a breast cancer risk assessment may be appropriate. It is a good starting point in the discussion of whether supplemental tests will be beneficial and what tests, if any, to orde

Breast tomosynthesis ("3D mammography") is being offered in addition to screening mammography in some centers. Thus far, we have preliminary encouraging data on the performance of tomosynthesis in women with dense tissue.

Key Points from www.densebreast.info