Screening for breast cancer

This section covers the following topics:

• Types of breast screening
• Breast screening guidelines for high risk women
• Breast screening guidelines for high risk men
• Breast screening guidelines for average risk women

Types of breast screening

Screening for breast cancer uses tests to try to catch cancer in its early stages, when it is most treatable. The earlier that cancer is found, the better a person’s chance of surviving it. The most common types of breast screening include:

• breast exams
• mammograms
• 3D mammograms (tomosynthesis)
• ultrasound
• magnetic resonance imaging (MRI)

Breast exams

Breast exams involve feeling the breast tissue for lumps or other changes that might be cancer.

• During a clinical breast exam (CBE) the doctor or nurse carefully feels the entire breast to find lumps or other abnormal changes.
• A breast self exam (BSE) involves a person checking their own breasts on a monthly basis to look for abnormalities. BSE is no longer recommended for women by some organizations, but others continue to recommend BSE since many cancers are initially found this way. Experts recommend training high risk men to perform BSE.  
• Breast awareness is a term that highlights the importance of people reporting any changes or abnormalities in their breasts to their doctors. 

Mammograms 

Mammograms use xrays to look at the breast tissue. Mammograms, like other xrays, expose people to a small amount of radiation. They are considered safe for most women, however experts recommend that women who may be sensitive to radiation should avoid mammograms and use breast MRIs instead. This group includes women under the age of 30 and women with certain inherited mutations, such as TP53. 

Mammography is the most commonly used screening tool to detect breast cancer. Mammograms find cancers in women of all ages, however, mammograms are less effective for women with dense breast tissue. For these women, ultrasound may find cancers that were not seen with mammograms.

3D mammograms

Breast tomosynthesis, also known as 3-D mammography, uses xrays to take a series of images that give a layer-by-layer, 3-dimensional picture of the breast. Because of this, 3D mammograms may find cancers earlier than traditional mammograms. They are also less likely to give a "false positive" result, when a person is called back for an abnormality that turns out to be cancer. The radiation exposure  from tomosynthesis is small, and does not increase the risk for breast cancer.

Ultrasound

Ultrasound uses sound waves to image the breast. Ultrasound may be used to find cancers in women with dense breasts, which can hide cancer on a mammogram. Ultrasound is painless, ses no radiation and is widely available. Ultrasound is less sensitive than breast MRI and therefore is not usually used for screening high risk women who already receive yearly MRIs.  

Breast MRI

Breast Magnetic Resonance Imaging (MRI) is an imaging method that uses magnetic fields rather than xrays to produce a detailed picture of the breasts. MRI is sensitive and may pick up an abnormality not seen by other imaging tools. For this reason, MRI is recommended for women at high risk for breast cancer. There is also a greater chance for MRI to find changes that need a biopsy, but end up being benign (not cancer). These are known as "false positive" results. 

MRI exams that look for cancer require the injection of a contrast agent called gadolinium. The contrast helps doctors spot breast abnormalities more easily. There is some concern that with repeated use during yearly breast screenings, gadolinium could build up in the brain. Researchers are studying whether this buildup is harmful to some people. At the moment, most experts have concluded that the benefit of using contrast agents for breast MRIs in high risk women outweighs the small risks that might be caused by repeated exposure to contrast agents.  

Breast screening guidelines

Experts have different recommendations for screening based on a person's risk for breast cancer. Breast cancer screening guidelines are different for people at high risk and average risk. 

Screening for high risk women

The National Comprehensive Cancer Network (NCCN), is an organization of cancer experts that creates guidelines on cancer care and updates them yearly. They create separate guidelines for women at increased risk for breast cancer due to inherited mutations or other risk factors. Screening guidelines for high risk women usually includes a combination of breast exams, 3D mammograms and breast MRIs, often beginning at age 25. You can find information on screening guidelines for specific gene mutations linked to breast cancer here. 

Screening for high risk men

NCCN recommends the following screening for men with an inherited mutation linked to breast cancer. Individual recommendations may vary by gene mutation. 

• ages 35 and older:
  • training in breast self exam
  • clinical breast exam every year

Screening for average risk women

Several organizations publish different breast screening guidelines for average-risk women. Not all of these guidelines are the same, which can lead to confusion. The National Comprehensive Cancer Network recommends the following:

• ages 25-39: 
  • practice breast awareness
  • clinical breast exam every 1-3 years
  • risk assessment, including questions about family and personal medical history should be done during clinical exam to find high risk women who may need additional screening
• ages 40 and older
  • practice breast awareness
  • yearly clinical breast exam
  • risk assessment, including questions about family and personal medical history should be done during clinical exam to find high risk women who may need additional screening
  • yearly mammogram - consider 3D mammograms if available. 

The American Cancer Society has slightly different guidelines. they recommend:

• ages 40 - 44 
  • talk with doctor about the benefits and risks of yearly mammograms
• 45 to 54 
  • yearly mammogram
• 55 and older
  • mammogram yearly or every other year based on their priorities and preferences 
  • Screening should continue as long as a woman is in good health and is expected to live at least 10 more years.

When an abnormality is found

If a breast lump is felt on exam, doctors will usually order diagnostic testing to see if the lump is cancer. This may include mammogram, MRI, ultrasound (a test that uses sound waves to look more closely at breast tissue) and a biopsy. Abnormalities found on mammogram or MRI may require additional imaging or a biopsy.