Women age 50 to 74 with an average risk for breast cancer and no symptoms — including women with increased breast density — should undergo screening with mammography every other year, according to a new evidence-based guidance statement issued by The American College of Physicians (ACP) and published in Annals of Internal Medicine. The statement does not apply to women with prior abnormal screening results or to higher-risk populations, such as women with a genetic mutation or a personal history of breast cancer.
ACP concluded that the potential harms of screening for breast cancer before age 50 years outweigh the benefits. These harms include receiving false-positive test results, overdiagnosis, and undergoing unnecessary biopsy or surgery.
The guidance statement is based on a review of selected guidelines from around the world for breast cancer screening and the evidence associated with them. All national guidelines published in English between January 1, 2013 and November 15, 2017 in the National Guideline Clearinghouse or Guidelines International Network library, as well as guidelines commonly used in clinical practice, were included in the review.
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Guidance Statement 1
In average-risk women aged 40 to 49, clinicians should discuss whether to screen for breast cancer with mammography before age 50. This discussion should address the potential benefits and harms of screening, as well as the patient’s preference.
Overdiagnosis rates vary among age groups but are higher in women age 30 to 39, as are rates for receiving a false-positive test result and unnecessary biopsy. The absolute risk reduction in breast cancer mortality is lower in women age 40 to 49 than in older women.
Guidance Statement 2
In average-risk women age 50 to 74, clinicians should offer screening for breast cancer with biennial mammography.
The ACP found little to no difference in breast cancer mortality for screening every year vs screening every other year. Of note, women screened annually received a recommendation for an unnecessary biopsy after a false-positive result more often compared with women who were screened biennially (7.0% vs 4.8%).
Guidance Statement 3
In average-risk women age ≥75 or in women with a life expectancy ≤10 years, clinicians should discontinue screening for breast cancer.
The ACP concluded that the decision to stop screening should incorporate the risk for cancer death, competing risk for other causes or death, the time lag between mammography and reduction in breast cancer mortality, the tradeoffs between benefits and harms, and the patient’s values and preferences. Most guidelines suggest discontinuing screening when, on the basis of advanced age or comorbid conditions, a women is unlikely to have a life expectancy long enough to benefit from screening.
Guidance Statement 4
In average-risk women of all ages, clinicians should not use clinical breast examination (CBE) to screen for breast cancer.
No guideline recommends screening with CBE if mammography is available, and evidence is lacking for a mortality benefit of CBE alone or in combination with mammography. CBE can result in overdiagnosis and false-positive results.
“Beginning at age 40, average-risk women without symptoms should discuss with their physician the benefits, harms, and their personal preferences of breast cancer screening with mammography before the age of 50,” stated ACP President Ana María López, MD, in a press release from the organization. “The evidence shows that the best balance of benefits and harms for these women, which represents the great majority of women, is to undergo breast cancer screening with mammography every other year between the ages of 50 and 74.”
References
- Qaseem A, Lin JS, Mustafa RA; for the Clinical Guidelines Committee of the American College of Physicians. Screening for breast cancer in average-risk women: a guidance statement from the American College of Physicians [published online April 8, 2019]. Ann Intern Med. doi:10.7326/M18-2147
- ACP issues guidance statement for breast cancer screening of average-risk women with no symptoms [news release]. Philadelphia, PA: American College of Physicians; April 9, 2019.
