Breast Cancer Screening!


Breast cancer is the most common cause of cancer in women, of which the most common types are invasive ductal carcinoma (54% relative incidence overall) and ductal carcinoma in situ (23%). 

Incidence is going up while mortality has plateaued. Incidence is highest among white women and black women, while mortality is highest among black women. 


Multiple risk factors to consider!

  • Most women can be categorized based on history alone; for others, risk prediction models are available for use if needed.
  • Many women who have a family history of breast cancer are still average risk

Average risk: 12.5% lifetime risk (1 in 8).

Moderate Risk: ~15-20% lifetime risk. 

  • Includes most women who have a family history of breast cancer in a first-degree relative but do not have a known genetic syndrome

High Risk: >20% lifetime risk. 

  • Includes confirmed or suspected genetic mutation known to increase the risk of breast cancer (eg BRCA1 or BRCA2, PTEN, TP53), a history of chest radiation, or having a personal history of breast cancer

Risk assessment tools: National Cancer Institute or the Breast Cancer Surveillance Consortium (BCSC) Risk Calculator.

    • You need to know breast density to use the BCSC calculator


Mammography is the gold standard (evidence 1B).

  • This is the only imaging technique that has been shown to decrease mortality (21% reduction overall, but varies by age–8% in 40s, 14% in 50s, 33% in 60s) 
  • But even in the best circumstances, mammography may miss up to 20% of underlying breast cancers!


Average risk: Depends on the society making the recommendation.

  • The ACS recommends yearly from age 45 to 54 and every other year starting at age 55. 
  • The USPSTF recommends mammography every other year from 50-75.

Moderate risk: Similar to average risk patients, but may start earlier if a first-degree relative had premenopausal breast cancer

  • Supplemental screening (with either MRI or US) in addition to mammography.

High risk: More complicated.

  • Beginning at age 18yo, self breast exams performed periodically 
  • Beginning at age 25yo clinical breast examination should be performed every 6-12 months 
  • MRI for breast cancer screening is recommended annually beginning at age 25yo, or earlier depending on the earliest age of breast cancer in the family 
  • Mammography (consider 3D) in addition to MRI beginning at age 30yo or be individualized if the earliest age of onset in the family is under age 25yo. 

Transgender patients: Studies are lacking, but there is guidance available!


In short, start by discussing the patient’s age, individual risk, and current guidelines for that age bracket. After that, ask about the patient’s preferences. 

Remember that mammograms are not perfect tests!

Additional resources: 

*Blog post based on Med-Peds Forum talk by Ruth Cadet, PGY1

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