By Bonnie Rush
October 2013—October is National Breast Cancer Awareness Month. As imaging providers, we all desire to offer our patients the advantages of early detection: less suffering, costs, and deaths. Encouragingly, a recent study has validated mammography as life saving. 71% of the 609 deaths in the study were unscreened and, more importantly, 50% were over 50 years.1 So we can wave the banner of early detection through mammography for all women – even the younger ones. Or can we?
Fifty percent is not an encouraging number for about 40% of our screening population – those with dense breast tissue. Having greater than 50% dense tissue (referred to as heterogeneously or extremely dense tissue) puts a woman at a higher risk for developing breast cancer. It also means an increased risk for false negative mammograms with later stage invasive and node positive cancer detection.
Bear with me as I share the compelling stats of this cause célèbre.
An often referenced 2007 study found that 78% of mammographically occult (hidden) lesions in were in women with more than 50% dense tissue. Women of any age with more than 75% density were at 4.7 times greater risk of an interval finding (seen within one year of a normal mammogram) than those with less than 10% density. Despite the encouraging recent news I mentioned earlier, 26% of these hidden cancers were in those under 56 years of age.2 These are worrisome numbers. Although some of the cancers grow rapidly and may not have been diagnostic on the previous mammogram, the fact is that most were just plain not seen – the dreaded false negative mammogram.
This lack of ability to detect breast cancer is often referred to as the masking effect. It impacts mammographic sensitivity inversely – as breast density goes up, sensitivity goes down. What can be seen 80% of the time in the almost entirely fatty breast can only be seen 30% of the time in the extremely dense breast.3 For example, a 3 mm lesion can be seen 95% of the time for those with mainly fatty tissue, but a lesion of 20 mm – about 3 times larger – can only be seen 50% of the time for those with the highest density.4 Even with technological advances such as digital breast tomosynthesis, if the tumor has the same x-ray attenuation factor as the dense tissue then one cannot “see” the tumor. It’s like trying to find a snowball in a snow bank.
These women also have a higher risk for developing breast cancer. A Spanish screening study of over 70,000 women concluded that mammographic density is an important risk factor for all types of breast cancer and strongly increases the risk of developing an interval tumor.5 Well known organizations such as the Center for Disease Control, American Cancer Society, and Susan G. Komen state that it’s a higher risk than having a first degree relative with breast cancer and also greater or equal to having two second degree relatives with breast cancer.6Aggregate data from 42 studies determined an average risk of 1.79 for those with the lowest density vs. 4.64 for the highest concluding that “in well conducted studies” breast density is one of the strongest risk factors for breast cancer. 7 The 10 year recurrence risk is four times more for those with the highest density vs. the lowest (5% vs 21%).8
If our credo is “first, do no harm” is it enough to continue to simply state that mammography is not perfect? Only the patient’s doctor gets to know her level of density and thus how it may impact her. If we do not share this information with the patient, aren’t we potentially doing harm? Without notification, women will not know to seek advice or to inquire about additional imaging after a “good news” gram. They believe in the imaging results – or at least they want to.
On April 3, 2013, AHRA’s Board of Directors, under the leadership of 2012-2013 President, Carlos Vasquez, CRA, FAHRA, endorsed the efforts of Nancy Cappello, PhD, founder of Are You Dense Advocacy, Inc. to notify women and advance the cause of early detection. During my co-presentation with Dr. Cappello at the 2013 AHRA Annual Meeting, she shared her experience of the shock of being diagnosed with Stage IIIC cancer with 13 metastasized lymph nodes just two months after believing in her “happy”gram (negative report). Dr. Cappello and a core of dedicated women with similar stories are fighting for mandated breast density notification. The efforts of Are You Dense? Inc. have driven notification laws in over a dozen states, and they hope to see mandated notification for all women. 9 In a recent Huffington Post article, Dr. Cappello provided an update on the most recent efforts: “Connecticut Congresswoman Rosa DeLauro is poised to reintroduce a federal density reporting bill and we are working with the FDA for revisions to the MQSA regulations to include density reporting in the patient’s mammography results.” 10 They are making headway, but it is a tiring battle – they could use our support.
We must not fail this significant percentage of our screening population. Even if we are not in a state with a mandate yet, we must inform patients with greater than 50% density that: breast density is one of the risk factors for developing breast cancer; cancers in dense breasts can be more difficult to detect on screening; alternative screening modalities such as breast ultrasound and MRI can find cancers missed on mammography, and they should discuss this issue with their physician.
If this cause is also a cause célèbre for you, I encourage you to review more information at www.areyoudense.org and go to www.areyoudenseadvocacy.org. Find your state, and if notification is not yet passed, sign up to let your voice for notification be heard.
References:
1Webb ML, Cady B, Michaelson JS, et al. A failure analysis of invasive breast cancer. Most deaths from disease occur in women not regularly screened. Cancer. Published online: September 9, 2013. DOI: 10.1002/cncr.28199
2Murphy IG, Dillon MF, Doherty AO, et al. Analysis of patients with false negative mammography and symptomatic breast carcinoma. J Surg Oncol 2007; 96:457–463
3Checka CM, Chun JE, Schnabel FR, Lee J, Toth H. The relationship of mammographic density and age: implications for breast cancer screening. AJR Am J Roentgenol. 2012 Mar;198(3):W292-5. doi: 10.2214/AJR.10.6049.
4Digital 3D Breast Tomosynthesis and its emerging role in breast cancer diagnosis – presentation by Jörg Barkhausen, European Congress of Radiology 2011
5Pollan et al., Mammographic density and risk of breast cancer according to tumor characteristics and mode of detection: a Spanish population-based case-control study. Breast Cancer Research 2013, 15:R9
6Breast Density and Risk for Breast Cancer – Center for Disease Control, American Cancer Society, and Komen Foundation – published online
7McCormack, V, Silva, I, Breast Density and Parenchymal Patterns as Markers of Breast Cancer Risk: A Meta-analysis, Cancer Epidemiological Biomarkers & Prevention June 2006 15; 1159: 42
8Mammographic Density and Risk of Breast Cancer: New Findings Presented at the AACR 101st Annual Meeting 2010, published online – www.aacr.org/home/public–media/aacr-press-releases.aspx?d=1964
9A Dozen State Density Laws: Is Your State One Of Them? www.areyoudense.org/worxcms_published/news_page189.shtml
10Huffington Healthy Living Blog – Being Less Dense About Breast Cancer Screening Posted: 09/13/2013 by David Katz, M.D., Director, Yale Prevention Research Center www.huffingtonpost.com/david-katz-md/breast-cancer-screening_b_3922681.html
