BRCA and Hereditary Cancer Testing: Who Should Consider It

Maybe your mother had breast cancer young, or an aunt had ovarian cancer. Maybe a relative tested positive for a BRCA change and told the family. Now you wonder whether you should be tested. This guide explains what BRCA genes do, who is usually offered testing, and what the results can mean.

What BRCA genes are

Everyone has two BRCA genes: BRCA1 and BRCA2. They help the body repair damaged DNA. When one of these genes has a harmful change (also called a mutation or pathogenic variant), cells cannot repair DNA as well. This raises the risk of some cancers. [1]

You get one copy of each gene from each parent. A parent with a harmful change has a 1 in 2 chance of passing it to each child, male or female. [1]

How common it is

Harmful BRCA changes are not common. About 1 in 400 people in the general population carry one. In some groups the rate is higher. For example, about 1 in 50 people of Ashkenazi Jewish descent carry a harmful BRCA change. [1]

How much the risk goes up

These numbers come from the National Cancer Institute and describe lifetime risk. [1]

• Breast cancer: about 13 in 100 women in the general population. More than 60 in 100 women with a harmful BRCA1 or BRCA2 change.
• Ovarian cancer: about 1 in 100 women in the general population. About 39 to 58 in 100 with a BRCA1 change, and 13 to 29 in 100 with a BRCA2 change.
• Men with a harmful change have a higher risk of breast cancer, prostate cancer, and pancreatic cancer. Women do too for pancreatic cancer.

These are averages. Your own risk depends on your family history and other factors.

What your doctor looks at

The US recommendation

The US Preventive Services Task Force recommends that primary care clinicians check women for possible hereditary risk if they have: [2]

• A personal or family history of breast, ovarian, fallopian tube, or peritoneal cancer.
• An ancestry linked to BRCA changes, such as Ashkenazi Jewish heritage.

Clinicians use a short family history tool. If the result is positive, you should be offered genetic counseling, and then testing if it is right for you. The Task Force recommends against routine testing for women without these risk factors. [2]

Family history clues

The National Cancer Institute lists factors that make an inherited change more likely: [1]

• A family member with a known harmful BRCA change.
• Breast cancer at age 50 or younger in you or a close relative.
• Ovarian cancer at any age.
• Male breast cancer, pancreatic cancer, or metastatic or high-risk prostate cancer in the family.
• Ashkenazi Jewish heritage.

Testing after a cancer diagnosis

Some people are tested after they get cancer. The result can change treatment. For example, some drugs work best in tumors with BRCA changes. It can also guide surgery choices and testing for relatives.

Canada and the US

In Canada, there is no national guideline from the Canadian Task Force on BRCA testing. Each province runs hereditary cancer or genetics programs with its own rules about who qualifies for publicly paid testing. A referral from your doctor is usually needed. In the US, coverage depends on your insurer, and many plans cover counseling and testing for people who meet the criteria. [2]

Genetic counseling

A genetic counselor reviews your family tree, explains the chance of a harmful change, and helps you decide whether to test. They also explain what each result could mean for you and your family. [1] [2]

Many labs now test a panel of many genes at once, not only BRCA1 and BRCA2. Other genes, such as those linked to Lynch syndrome, can also raise cancer risk. [3]

Possible results

• Positive: a harmful change was found. Your risk is higher.
• Negative: no harmful change was found. If a relative has a known change and you do not, your risk is often close to average.
• Variant of uncertain significance: a change that experts cannot yet classify. Most are later found to be harmless. [3]

What happens after a positive result

Options depend on your age, sex, and plans for a family. They may include: [1]

• Earlier and more frequent breast screening, often with MRI.
• Surgery to remove the ovaries and fallopian tubes after childbearing, which lowers ovarian cancer risk.
• Surgery to remove both breasts, which lowers breast cancer risk.
• Medicines that may lower breast cancer risk.
• Telling relatives, so they can choose testing.

Each option has benefits and trade-offs. Talk with your clinician and genetic counselor.

Questions to ask your clinician

• Does my personal or family history suggest a higher chance of a BRCA change?
• Can you refer me to a genetic counselor or genetics program?
• Should I have a BRCA-only test or a larger gene panel?
• Who pays for the test in my province or with my insurance plan?
• What would a positive, negative, or uncertain result mean for me?
• How would a result change my screening or treatment?
• How should I tell my relatives?

Bottom line

BRCA testing is not for everyone. It is most useful for people with certain personal or family cancer history or ancestry. Genetic counseling helps you decide and understand your result. A positive result is not a cancer diagnosis, but it opens options for earlier screening and risk reduction.

Primary AI can show you the guideline and study sources behind this topic in plain language, so you can bring better questions to your appointment.