Despite research arguments raised at the annual Society of Breast Imaging (SBI) meeting in April, mammography screening guidelines have been in a state of controversy and confusion brought about by a superficial analysis by the U.S. Preventative Services Task Force (USPSTF) and an in-depth, research-based assessment by the American Cancer Society (ACS). All have agreed that mammography saves the most lives when screening begins at age 40.
But factoring in the so-called "harms" of mammography screening, such as false-positive findings and unnecessary biopsies, as well as unmentioned societal costs, the USPSTF recommends rationed screening. The ACS advocates for a more personalized choice to accessible screening beginning at age 40, but also states that women with average risk may begin screening at age 45. The SBI still strongly advocates for annual mammography screening beginning at age 40, even without any known family history, as research demonstrates: risk of breast cancer in a 40-year-old is one in 69; one out of six breast cancers occur in women aged 40-49; and, there is an increased risk of breast cancer based on breast tissue density, regardless of family history1-6 – which can only be determined by a mammogram.
Now, it’s more important than ever, that we need to reduce false-positives to tip the balance clearly in favor of accessible, effective screening mammography. We believe giving women and their physicians access to prior mammograms is crucial to reducing false positives, the callbacks they precipitate along with the concomitant costs to patients, providers, and payers. By reducing the "risks" of mammography screening by simply providing more comparison imaging data, the "benefits" of screening support existing guidelines to begin annual screening at age 40. But if these new rationed screening protocols are adopted – against the advice of experienced breast doctors and researchers – the stakes for women having access to prior mammograms are raised even higher.
What May Happen
After 2017 (unless current Senate proposal is approved for 2019 extension), The Centers for Medicare and Medicaid Services (CMS) will follow mammography screening guidelines recommended by the USPSTF. This means women will have limited access to insurance-covered mammograms and face the risk of later detected breast cancers. Screening-detected breast cancers are usually curable 96%-99% of the time, requiring less invasive and toxic therapies that prolong and improve life years.7-8
There is no doubt that screening guidelines may be most effectively tailored for known high-risk patients, or even reduced somewhat for very low-risk patients (elderly, non-hormonally stimulated breasts composed of fat tissue density with limited glandular activity). But what about the fact that women with no known family history or other defined predisposing risk factors account for 78% of breast cancer diagnoses?
Since women are different – some are risk-averse, others carefree and skeptical of medicine – each may discuss with their physician the best route for them. Women looking for an excuse to delay mammograms may be happy to delay screening until age 45, but the majority of women desiring affordable access to mammography are concerned, and with good reason.
What Women Can Do, Now
Meanwhile, it’s important that women do all they can to provide their physicians with prior comparison mammograms that improve the accuracy of their exam interpretations. With increased availability of prior exams, quality of patient care, and outcomes are improved.
The value of mammography is highly dependent on interpretation of the study with comparison to prior images. Unlike other types of medical imaging, mammography relies heavily on comparisons with prior mammograms to determine what is normal or an early sign of breast cancer. Because breast tissue is unique to each individual, archived images provide a benchmark for evaluating changes in tissue composition and assist in the early detection of cancer. When there is a perceived abnormality, the patient is “recalled” for additional imaging of a finding on screening that 95% of the time is not cancer, therefore a “false-positive” result. This average recall rate for mammography screening in the United States is approximately 10% (9.7%, range 6%-13%),9 whereas in some European countries that provide access to all prior mammograms through a national network, the recall rate is consistently between 1%-3%10,11 (in part also influenced by differences in medico-legal risk).
If we can connect women with their prior mammograms at the point of screening, numerous studies show there will be significant benefits: Additional recall exams will be reduced by 40% to 60%;12-19 breast cancers will be detected 25% earlier,20 with lower rates of nodal disease.20 We need to provide electronic access to prior mammograms now, especially important as policy pushes for starting mammograms for women later. If not, many more women will be diagnosed with later-stage cancers, undergo more invasive and life-altering treatments, and suffer shortened, less-comfortable lives.
1. Kerlikowske K, Zhu W, Tosteson AN, et al. Identifying women with dense breasts at high risk for interval cancer: a cohort study. Ann Intern Med. 2015;162:673–681.
2. American Cancer Society. Breast Cancer Facts & Figures 2013-2014. Atlanta: American Cancer Society, Inc. 2013. Accessed online http://www.cancer.org/acs/groups/content/@editorial/documents/document/acspc-039989.pdf.
3. Bertrand KA, Tamimi RM, Scott CG, et al. Mammographic density and risk of breast cancer by age and tumor characteristics. Breast Cancer Res. 2013:15:R104.
4. Boyd NF, Guo H, Martin LJ, et al. Mammographic density and the risk and detection of breast cancer. N Engl J Med. 2007. 356:227-236.
5. Tamimi RM, Byrne C, Colditz GA, Hankinson SE. Endogenous hormone levels, mammographic density, and subsequent risk of breast cancer in postmenopausal women. J Natl Cancer Inst. 2007;99:1178-1187.
6. Giger ML, Inciardi MF, Edwards A, Papaioannou J, Drukker K, Jiang Y, Brem R, Brown JB. Automated Breast Ultrasound in Breast Cancer Screening of Women With Dense Breasts: Reader Study of Mammography-Negative and Mammography-Positive Cancers. American Journal of Roentgenology. 2016;206:1341-1350.
7. Saadatmand S, Bretveld R, Siesling S, Tilanus-Linthorst M. Influence of tumour stage at breast cancer detection on survival in modern times: population based study in 173 797 patients. BMJ. 2015;351:4901.
8. Howlader N, Noone AM, Krapcho M, et al. (eds.) SEER Cancer Statistics Review, 1975-2012, Table 4.13. National Cancer Institute. http://seer.cancer.gov/csr/1975_2012/, 2015.
9. Rosenberg RD, Yankaskas BC, Abraham LA, Sickles EA, Lehman CD, Geller BM, Carney PA, Kerlikowske K, Buist DSM, Weaver DL, Barlow WE, Ballard-Barbash R. Performance Benchmarks for Screening Mammography. Radiology. 2006; 241:55-66.
10. Fracheboud J, de Gelder R, Otto SJ, et al. National evaluation of breast cancer screening in the Netherlands 1990-2007. Rotterdam, the Netherlands: andelijk Evaluatie Team voor bevolkingsonderzoek naar Borstkanker; 2009.
11. Smith-Bindman R, Chu PW, Miglioretti DL, Sickles EA, Blanks R, Ballard-Barbash R, Bobo JK, Lee NC, Wallis MG, Patnick J, Kerlikowske K. Comparison of Screening Mammography in the United States and the United Kingdom. JAMA. 2003;290:2129-2137.
12. Yankaskas BC, May RC, Matuszewski J, Bowling JM, Jarman MP, Schroeder BF. Effect of Observing Change from Comparison Mammograms on Performance of Screening Mammography in a Large Community-based Population. Radiology 2011;261:762-770.
13. Roelofs AA, Karssemeijer N, Wedekind N, et al. Importance of comparison of current and prior mammograms in breast cancer screening. Radiology. 2007;242:70-77.
14. Thurfjell MG, Vitak B, Azevedo E, Svane G, Thurfjell E. Effects on sensitivity and specificity of mammography screening with or without comparison of old mammograms. Acta Radiol 2000;41:52-56.
15. Sickles EA. Successful methods to reduce false positive mammography interpretations. Radiol Clin North Am. 2000;38:693–700; and Radiol Clin North Am 48 (2010) 859-578.
16. Kleit AN, Ruiz JF. False Positive Mammograms and Detection Controlled Estimation. Health Serv Res. 2003;38:1207–1228.
17. National Cancer Institute: Breast Cancer Surveillance Consortium. Performance Measures for 1,960,150 Screening Mammography Examinations from 2002 to 2006 by Time (Months) Since Previous Mammography --- based on BCSC data as of 2009, www.breastscreening.cancer.gov, 12/14/09.
18. Ryerson AB, Venard VB, Major AC. National Breast and Cervical Cancer Early Detection Program: 1991-2002 National Report. Centers for Disease Control and Prevention, http://www.cdc.gov/cancer/nbccedp/Reports/NationalReport/index.htm.
19. NHS Breast Screening Programme: Annual Review 2012. U.K. National Health Service Breast Screening Web site www.cancerscreening.nhs.uk/breastscreen.
20. Burnside E, Sickles E, Sohlich R, Dee K. The differential value of comparison with previous examinations in diagnostic versus screening mammography. American Journal of Roentgenology. 2002;179:1173-1177.