Breast Cancer Screening
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Methods
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Mammography
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Digital BreastTomosynthesis
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Guidelines
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Preventive Services Task Force (USPSTF)Guidelines
Screening for women aged 40-49 is not supported
Biennial (versus annual) screening supported forwomen aged 50-74.
Kopans, 2010. Radiol Clin N Am. 48: 843-57.
•Age 40 was chosen in part because the breast tissue of womenyounger than 40 is more susceptible to radiation damage.
•Age 50 was chosen as a surrogate for menopause.
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Bleyer and Welch, 2012. NEJM. 367;21: 1998-2005.
Deaths from breast cancer in women over age 40 have decreased 28% over thelast 30 years. “This reduction I mortality is probably due to some combination ofthe effects of screening mammography and better treatment” (treatmentaccounting for as little as 35% of the reduction to as much as 72%; the highernumber is closer to reality.)
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Bleyer and Welch, 2012. NEJM. 367;21: 1998-2005.
“Only 8 of 122were destined toprogress toadvanced disease.”
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Bleyer and Welch, 2012. NEJM. 367;21: 1998-2005.
“Despite substantial increases in the number of cases of early-stage breastcancer detected, screening mammography has only marginally reduced the rateat which women present with advanced cancer. Although it is not certain whichwomen have been affected, the imbalance suggests that there is substantial overdiagnosis, accounting for nearly a third of all newly diagnosed breast cancers,and that screening is having, at best, only a small affect on the rate of deathfrom breast cancer.”
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What are the “harms” in over-diagnosing?
Are we over-diagnosing?
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•Although randomized clinical trials are difficult to do, several studies support the notionthat the decline in death rate from breast cancer since 1990 is predominantly a result ofmammography (not treatment).
•There is no data that screening of high-risk patients has any positive impact on livessaved.
•“The task force admitted that their approach would result in unnecessary deaths thatcould be prevented by screening, but the guidelines would reduce the false-positivestudies, which they decided was more important than saving lives.”
•USPSTF recommendations were determined using computer modeling that focused onthe “number of women needed to be screened to save one life.” (a surrogate for cost?)
•40-49: 1900
•50-59: 1300
•60-74: 300
Kopans, 2010. Radiol Clin N Am. 48: 843-57.
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Kopans, 2010. Radiol Clin N Am. 48: 843-57.