Mammography Guidelines for Average-Risk Women

SUMMARY:

Professional organizations continue to release evidence based guidance on mammography, with ACP the latest to provide updated recommendations. While required frequency and starting age may differ, they all emphasize shared decision making with patients, which entails counseling about uncertainty, risk/benefit and related patient values.

BENEFITS OF MAMMOGRAPHY

Appears to decrease breast cancer mortality by 15 to 20%
- Studies demonstrate varying magnitude
- ACS (RCT data): Relative risk 0.80 to 0.82
- Recent data from the Canadian National Breast Screening Study did not show decrease when comparing mammography to controls, perhaps due to more recent improvements in treatments but does not take into account advances in imaging
May increase life expectancy (ACS systematic review) but could not quantitate

HARMS OF MAMMOGRAPHY

False Positives (additional images and benign biopsies)

USPSTF review
- Collaborative modeling data: Screening biennially from ages 40 to 74 years would result in 1376 false-positive results per 1000 women screened over a lifetime of screening
ACS review of the same data
- Increased risk of false positive with dense breasts among women 40 to 49
- Callbacks minimized if prior films available

Anxiety and Distress

May persist even if follow-up is normal
Financial concerns as patient may be responsible for paying for additional tests

Discomfort

USPSTF review identified mammography as being a painful procedure
Follow-up procedures may also result in pain

Overdiagnosis and Overtreatment

Overdiagnosis is defined as detecting a cancer that would have remained indolent and not become apparent without screening
Overtreatment is defined as treatment for an overdiagnosed cancer
Difficult to discern actual number of overdiagnosed cancers
◦ Collaborative modeling data (USPSTF): Screening biennially from ages 40 to 74 years would lead to 14 overdiagnosed cases of breast cancer per 1000 persons screened over the lifetime of screening with a very wide range of estimates (4 to 37 cases) across model
Other organizations such as ACS make the point that certain assumptions may not be verifiable in addition to bias in methodology and design

Diversity, Equity Inclusion Considerations

USPSTF cites that Black women are 40% more likely to die from breast cancer than Caucasian women with more aggressive cancers at younger ages
Urgently calling for more research to see if different screening methods are needed for Black women
ACR updated guidelines to include transgender patients stating “Annual screening at age 40 is recommended for transfeminine (male-to-female) patients who have used hormones for ≥5 years, as well as for transmasculine (female-to-male) patients who have not had mastectomy”

PROFESSIONAL GUIDELINES:

ACOG

Start Age
- Recommend at age 40
Screening Interval
- Every 1 or 2 years (shared decision making)
Stop Age
- Age 75
- > 75 shared decision making including overall health and longevity

USPSTF

Start Age
- Recommend at 40 years
Screening Interval: Every 2 years until 74 years
Stop Age
- ≥ 75 years: Insufficient evidence to recommend for/against

ACS

Start Age
- Recommend at age 45 years | Consider 40 years if patient desires

Screening Interval
- 45 to 50 years: annual
- ≥55 years: Every 2 years or can choose annual
Stop Age
- Continue if good health and life expectancy >10 years

ACR

Start Age
- Recommend at 40 years
Screening Interval: Annual
Stop Age
- “Screening should continue past age 74 without an upper age limit, unless severe comorbidities limit life expectancy or ability to accept treatment.”

ACP

Start Age
- Recommended at 50 years
- 40 to 49 years: Discuss risks vs benefits and patient preference (“potential harms outweigh the benefits for most women” in this age bracket )
Screening Interval: Every 2 years
Stop Age
- Screening not recommended for women ≥75
- Life expectancy ≤10 years

NCCN

Start Age
- Recommend at 40 years
Screening Interval: Annual
Stop Age
- Upper age limit not yet established
Consider comorbidities that may impact life expectancy (≤10 years)

American Society of Breast Surgeons

Start Age
- Non-dense breasts (A and B density): 3D preferred modality | Age 40 | No need for supplemental imaging
- Dense breasts (C and D density): 3D preferred modality | Age 40 | Consider supplemental imaging
Screening Interval
- Annual
Stop Age
- When life expectancy is <10 years

ADDITIONAL KEY POINTS:

Clinical Breast Examination (CBE)
- ACOG & NCCN: Offer every 1 to 3 years for women 25 to 39 years and annually for ≥ 40 years
- USPSTF & AAFP: Insufficient evidence to recommend for or against
- ACS, ACP & Canadian Task Force on Preventative Healthcare: Not recommended
- WHO: CBE may be of benefit for women age 50 to 69 years with poor access to healthcare resources
Most professional organizations find insufficient evidence to recommend adjunctive screening using breast ultrasonography, MRI, Digital Breast Tomosynthesis, or other method in the setting of a normal mammogram and no other risk factors