Updated on: Aug 24, 2022

What is Genetic Counselling?

Genetic counselling can help you and your family make decisions about your health care based on your genetics. You might be asked to have genetic testing done so that a Genetic Counsellor can look for changes or risk factors in your DNA. This can give you information about:

Risk of certain types of cancer
What the best type of treatment plan might be for you
Your risk for certain types of cancer that may run in your family
The chances a future pregnancy might have a genetic condition
A diagnosis of a genetic condition

A genetic counsellor will review all of your medical history, family history and genetic tests to help you understand the results.

Visit the Canadian Cancer Society for more information on genetic testing.

What is hereditary cancer?

Hereditary cancer is caused by a change (known as a mutation) in a cancer related gene that is passed down from generation to generation through a family.

A hereditary cancer may have a higher risk in the development of some cancers. Sometimes different cancers may be related in a hereditary pattern (eg. breast/ovary, colon/endometrial).

Are all cancers hereditary?

No, only five to 10 per cent of all cancer are hereditary; 90 to 95 per cent of cancers happen by chance.

Non-hereditary cancers occur for many reasons, including:

Age (our risk increases as we age);
Lifestyle (certain lifestyle habits can increase our risk; high fat/low fibre diet, smoking/use of tobacco products, excessive alcohol, exposing skin to the sun’s rays without protection, being inactive or overweight);
Environment (we may be exposed to harmful substances in our living and working environments, many of which are unknown to us); and
Chance (many cancers happen for unknown reasons, or chance)

What happens at a genetic counselling appointment for hereditary cancer?

After you have completed a family health questionnaire, the genetic counselor will:

Review your personal and family history of cancer;
Assess and explain your personal risk for hereditary cancer;
Give you recommendations for cancer screening;
Review whether you or other family members are eligible for genetic testing;
Discuss the risks, benefits and limitations of genetic testing; and
If you are eligible for genetic testing, the counselor will explain the results and next steps.

Who should receive genetic counselling for hereditary cancer?

People that have:

Many family members with the same or related cancers on one side of the family especially breast/ovarian or colon/uterine(endometrial) as well as other abdominal (organs like colon, rectal, stomach, pancreas, small bowel, ovary kidneys, ureter) cancer;
Many generations affected by cancer on one side of the family (just mother’s side or just father’s side) ;
Cancer at a young age, e.g. breast or colon cancer diagnosed before age 35;
Invasive serous ovarian cancer (a specific type of ovarian cancer);
Breast or ovarian cancer and are of Jewish descent;
A family member who has had more than one kind of cancer;
A family member who has been told they have multiple colon polyps (more than 10) or "polyposis";
Rare cancers, such as male breast cancer; and
A family that has been told that they have a mutation (change) in a gene causing hereditary cancer.

If you think your family history of cancer may be hereditary, ask your doctor (oncologist or primary care physician) for a referral to a genetic counsellor. Before receiving an appointment you will be contacted by phone and will receive a family history questionnaire to collect more information about your family history to help decide if an appointment is needed.

What is genetic testing for hereditary cancer?

Genetic testing for hereditary cancer is the analysis of a blood or tissue sample to determine if there is a genetic cause for cancer in a family.

Some families who are considered high risk for hereditary cancer will be offered genetic testing.

Genetic testing is NOT offered to everyone who receives genetic counselling.

How much does genetic counselling/testing cost?

Genetic counselling appointments are covered by OHIP for individuals who fulfill referral criteria (Ontario Health Insurance Plan).

Genetic testing is also covered by OHIP, but is only available under very specific defined conditions. Your genetic counsellor will tell you if you are eligible for a genetic test.

Does it matter which side of the family the cancer is on?

No. Cancer (or other health problems) on your father’s side or mother’s side are equally important. We inherit our genes from both parents equally, whether we are male or female. We also often share many of the same lifestyle habits and environment with both sides of the family. When you review your family history with your doctor, remember to mention health problems on both sides of your family.

How can I be referred for cancer genetic counseling? Can I make my own referral for cancer genetic counselling?

If you do not have a family doctor or other primary health care provider, you may contact the genetics clinic at 519-749-4370 extension 2832 to discuss your family history and determine if a cancer genetic counselling appointment is right for you.

After review of the referral, certain referrals may be redirected to one of the larger provincial genetics programs.

If you have more questions about a referral please contact the genetics clinic at 519-749-4370 extension 2832.

If you're a referring physician, visit our refer a patient page to obtain a referral form.

What if I am worried about a genetic problem in my family other than cancer?

We only accepts referrals for genetic counselling for individuals with a family history of cancer. If you would like a referral not related to cancer, please contact the regional genetics programs at McMaster University Medical Centre – Hamilton (905-521-5085 / fax 905-521-2651) or medical genetics of Southwestern Ontario at London Health Sciences Centre – London (519-685-8140 / fax 519-685-8214).

How can I learn more about a career in genetic counselling?

If you are interested in a career in genetic counselling or would like to learn more about genetic counselling in general, click on the links below (links open in new window):

Understanding Genetic Risks and Breast Cancer - Grand River Regional Cancer Centre

Transcript for: Understanding Genetic Risks and Breast Cancer - Grand River Regional Cancer Centre

Hi I'm Kathleen Buckley and I'm a genetic counselor at Grand River Hospital's Regional Cancer Centre.

There's been a lot of talk lately about the Jolie Effect. Actress Angelina Jolie recently underwent a double mastectomy. That's because she's a carrier of a DNA change called a mutation in one of the two genes linked to inherited breast cancer.

The genetic counselors at the cancer center have had a lot of calls recently from women asking what they should do. I'd like to give you some facts.

About 10 percent of women with breast cancer have an inherited predisposition. Two genes have been linked to inherited breast cancer. They're called BRCA one and BRCA two.

Angelina Jolie carries a mutation which is like a typo in the BRCA one gene.

About one in every five hundred women have a mutation in BRCA one or BRCA two.

Women who carry one of these mutations are four eight times more likely than other women to have breast cancer in their lifetime.

So how do you know if you're at risk?

It's important to look at breast cancers throughout your family on both your mom's side and your dad's side. Men can also carry these mutations which can be passed on to children.

Speak to your doctor about a genetics referral if you have a family history of multiple women with breast or ovarian cancer, breast cancer before age 50, seros ovarian cancer at any age, breast cancer in a Jewish family, or male breast cancer.

From there, your doctor can refer you to a genetics counselor here at the Cancer Centre. We can speak to you, look at your family history and personal risk factors and in some cases arrange for genetic testing. Not every woman we see will be offered genetic testing, but every woman will receive a personalized risk assessment and screening guidance.

Grand River Hospital also conducts testing for women at higher risk through its MRI unit and at the Waterloo Wellington Breast Centre at Freeport.

Keep in mind while genetics play a part in cancer, there are other factors within your control too. So in general please make sure you eat a healthy diet, exercise, don't smoke, reduce alcohol consumption, practice sun safety, and talk to your doctor about screening exams like pap smears, stool tests and regular mammograms.

Thank you for your time and interest.