High Risk Ontario Breast Screening Program FAQs for Genetics Clinics

Genetics clinics provide genetic assessments (i.e., genetic counselling and testing) to women, trans and nonbinary people to determine their eligibility for screening through the High Risk OBSP. This page includes answers to questions that genetics clinics commonly ask.

What are the roles and responsibilities of genetics clinics in assessing people for High Risk Ontario Breast Screening Program (OBSP) eligibility?

Genetics clinics are responsible for completing genetic assessments (i.e., counselling and/or testing) for people who may be eligible for screening through the High Risk OBSP based on their personal and family history (Category B).

For Category B referrals, the High Risk OBSP site will send the High Risk OBSP Requisition Form and any supporting documents to the genetics clinic. Once the genetic assessment is complete, the genetics clinic must return the High Risk OBSP Requisition Form back to the High Risk OBSP site along with the High Risk OBSP Breast Cancer Genetic Assessment Results Form.

Sometimes, genetics clinics will receive referrals directly from primary care providers to assess eligibility of people for screening through the High Risk OBSP. In these cases, genetics clinics must complete and send the High Risk OBSP Requisition Form (if the referring primary care provider did not complete it) as well as the High Risk OBSP Breast Cancer Genetic Assessment Results Form to a High Risk OBSP site.

Genetics clinics are also responsible for communicating genetic assessment results to people and their referring primary care provider.

Are genetics clinics responsible for follow-up after a genetic assessment?

Genetics clinics are only responsible for providing genetic assessments and communicating the results. The genetics clinic will send the results to the person who was assessed, the referring primary care provider and the High Risk Ontario Breast Screening Program (OBSP) site.

Following a genetic assessment, if someone is found to be not eligible for screening through the High Risk OBSP, it is the responsibility of the referring primary care provider to review the person’s results with them and discuss risk appropriate screening options.

Following a genetic assessment, if someone is eligible for screening through the High Risk OBSP, the High Risk OBSP site will enroll them into the program and schedule screening appointments.

Does the High Risk Ontario Breast Screening Program (OBSP) have a list of pathogenic or likely pathogenic gene variants that will make someone eligible for the program?

The most common genes variants for hereditary breast cancer risk are those in the BRCA1 and BRCA2 genes. Other gene variants include TP53 and PALB2.

The High Risk OBSP does not maintain a comprehensive list of pathogenic or likely pathogenic gene variants that would confirm someone’s eligibility for the High Risk OBSP.

Since the body of evidence on breast cancer susceptibility gene variants is continuously evolving, clinical geneticists are better positioned to determine appropriate management of people with these genetic variants. Please consult with your clinic’s geneticist regarding gene variants which may increase a person’s risk of breast cancer.

What information does the High Risk Ontario Breast Screening Program (OBSP) need following a genetic assessment of someone who may be eligible for the program?

Upon completion of a genetic assessment, the genetics clinic must send a completed High Risk OBSP Breast Cancer Genetic Assessment Results Form along with the completed High Risk OBSP Requisition Form, to a High Risk OBSP site.

Where can I access the IBIS and CanRisk risk assessment tools?

The IBIS and CanRisk breast risk assessment tools have been chosen as the standard assessment tools to determine eligibility for the High Risk Ontario Breast Screening Program.

Below are links to the IBIS and CanRisk risk assessment tools:

IBIS (also known as the Tyrer-Cuzick model): no login required
CanRisk: login required

Is there any guidance on using the IBIS and CanRisk risk assessment tools to assess someone’s personal risk of breast cancer?

Please see the links under “Genetic Clinics Resources” in the Screening Resources for Healthcare Providers page.

Why are participants in the High Risk Ontario Breast Screening Program (OBSP) screened with both mammography and breast magnetic resonance imaging (MRI)?

Annual mammography and breast MRI (or screening breast ultrasound if breast MRI is not medically appropriate) is the recommended standard of care for screening people in the High Risk OBSP because these two tests complement each other.

For people at high risk of breast cancer, screening with mammography alone has limitations. The addition of MRI is better able to find breast cancer (higher sensitivity) but is not as good as mammography in identifying people without breast cancer (lower specificity). As well, the quality of imaging produced by MRI is not affected by breast density.

Therefore, using a combination of mammography and breast MRI to screen participants in the High Risk OBSP helps to address the limitations of each test and identify more breast cancers than using mammography or breast MRI alone.