Overview

If someone in your family has had breast or ovarian cancer, or some other cancers like pancreatic or prostate cancer, your chances of getting those cancers may be higher. And if you have two or three relatives who have had these cancers, your chances may be even higher.

If you have a family history of these cancers, it may be important to you to find out how high your risk is. By knowing your risk, you can decide whether to do something to lower it. This can include taking medicine or having surgery.

Having a family history means that you have one or more blood relatives with breast or ovarian cancer. They could be:

• Relatives who have died or relatives who are still alive.
• First-degree relatives. (These are parents, sisters, brothers, and children.)
• Second-degree relatives. (These are aunts, uncles, nieces, nephews, and grandparents).
• Third-degree relatives. This includes first cousins.

Some family histories are stronger than others. Here's what determines if your family history is strong:

• How closely related you are to relatives with breast or ovarian cancer, or some other cancers like pancreatic or prostate cancer. Cancer in first-degree relatives increases your risk the most.
• How many of your relatives had or have one of these cancers. The more of these relatives there are, the stronger your family history.
• How young these relatives were when they were diagnosed. Having any relatives who were diagnosed before age 50 adds to your risk.
• Having both breast and ovarian cancer in your family. Having both adds to your risk.
• Having a first-degree relative who had male breast cancer. It's rare. But when this cancer happens in your family, it adds to your risk.
• Having an Ashkenazi Jewish heritage. Breast and ovarian cancer rates are much higher among Ashkenazi Jews. (These are Jews whose ancestors came from Eastern Europe.)

Sometimes a very strong family history is caused by a mutated gene that runs in the family. BRCA1 and BRCA2 are genes that normally help control cell growth. But an inherited change, called a mutation, in one of these genes makes you much more likely to get breast and ovarian cancers.

Finding out about your risk

Finding out how high your risk is can help you make important decisions about your health. Some people decide to take extra steps to prevent breast and ovarian cancer. They may have checkups more often, take anti-cancer medicine, or have surgery to remove the breasts, the ovaries, or both.

The best way to find out about your risk is to talk to your doctor. You'll be asked for as much information about your family history of cancer as you can give. The more you can find out, the better your doctor can help you figure out how strong your family history is.

Your doctor may send you to a genetic counsellor. This person is trained to help people understand their risks for certain diseases.

BRCA gene change

BRCA1 and BRCA2 are genes that normally help control cell growth. But an inherited change, called a mutation, in one of these genes makes you much more likely to get breast, ovarian, and some other cancers. BRCA (say "BRAH-kuh") stands for "BReast CAncer."

BRCA gene changes aren't common. Your doctor may talk to you about testing based on your family medical history or your personal medical history. Your doctor may ask you questions, such as if you have family members who had breast or ovarian cancer, if you were diagnosed with breast cancer before age 50, or if you have an Ashkenazi Jewish heritage.

If you are concerned that you may have a BRCA gene change, talk with your doctor.

In the table below, the figures are only rough estimates from research studies of females. These numbers may not apply to you, but they can give you an idea of how high your risk may be. ^{footnote 1}

Pictures may help you get a better idea of how much a BRCA gene change increases your risk for breast cancer and ovarian cancer.

Genetic testing can show if you have gene changes that increase your risk for breast cancer and ovarian cancer. Before you have genetic testing, you may want to see a genetic counsellor. Counselling will help you decide about genetic testing. Both testing and counselling are often covered by provincial and private health plans. But check with your health plan to find out for sure.