High-Risk Breast Screening

High-Risk screening refers to the screening of individuals who are determined to have a higher level of risk of getting breast cancer. 

How “high risk” is determined

A patient may be considered high risk if they have either one factor that greatly increases risk, or several factors that together greatly increase risk. The risk factors include:

1. Known genetic mutation carrier where mutation is associated with a high lifetime risk of breast cancer (e.g. BRCA1, BRCA2, Cowden’s Syndrome). The recommendation of a genetics service will also be accepted in the event that a single mutation has not, or cannot, be identified, but the woman is considered by the genetics service to be at high risk. 
2. Someone who has declined genetic testing and who is the first-degree relative of a known mutation carrier (e.g. BRCA 1, BRCA2). 
3. High lifetime risk (>25%) as established, and documented, by a standard risk model (e.g. IBIS, BOADICEA).
4. History of having received radiation as cancer treatment to the chest area (therapeutic thoracic radiotherapy) before age 30. Screening is not indicated until eight years after the end of radiotherapy or age 30, whichever date is later.

Eligibility for high-risk radiological screening

High risk individuals are eligible for radiological screening if they:

• are asymptomatic
• have no personal history of breast cancer 
• have not undergone prophylactic bilateral mastectomy
• are 30 to 74 years old
• fall into one or more of the risk groups above

Screening protocol

Individuals who are considered to be at high risk of breast cancer will be screened as follows:

• Screening includes both mammography and breast MRI.
• The screening interval is one year.
• The screening event begins with a mammogram.
• MRI is performed within one month of mammography.
• Screening continues with both mammography and MRI until age 69, and with mammography alone until age 74.
• Individuals who are in good health at age 75 may continue to be screened with mammography but will not be automatically reminded by the NSBSP.

Note: Individuals are ineligible for screening while pregnant or lactating. Regular screening should resume six months following childbirth or the end of lactation, whichever is later.

Referral to high-risk screening

Individuals cannot self-refer for high-risk screening—a referral must be made by a primary health care provider with clear documentation of patient eligibility. 

MRI contraindications

A contraindication is any reason for a person to not receive a particular treatment or procedure. In the case of breast MRIs, possible contraindications may include: 

• Claustrophobia
• Patient size 
• Previous reaction to Gadovist or other gadolinium contrast agent
• Presence of cardiac pacemakers
• Ferromagnetic intracranial aneurysm clips
• Certain neurostimulators
• Certain cochlear implants
• Certain other ferromagnetic implants, devices, foreign bodies, or electronic devices.

Individuals with any of these contraindications will be screened only with mammography.