Hereditary Cancer Genetics
Everyone has the possibility of developing cancer in their lifetime. Most cancers happen by chance. About 5 to 10% of cancers are due to an inherited predisposition (example: hereditary).
We all have genes that protect us from developing cancer. If you are born with a change (called a mutation) in one of these genes, you have an increased risk of developing certain types of cancer. This is called hereditary cancer. Mutations can be passed down from your parents and passed on to your children.
Generally, an inherited predisposition to cancer may be suspected if one or more of the following are seen:
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Many individuals in a family with the same or related cancers, in several generations.
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Individuals with more than 1 type of cancer or bilateral cancer in paired organs.
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Individuals having cancer at a younger than usual age (example: colon cancer < 50 years of age, breast cancer < 45 years of age).
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Individuals with specific and/or rare cancer pathology (example: breast cancer in an individual assigned male at birth).
Referrals
Individuals with a personal and/or family history suggestive of an inherited predisposition to cancer should be referred for genetic counselling. The Genetic Testing for Hereditary Cancers handout is provided to you when the referral has been submitted.
Refer to the Ontario Health resource for guidance on who should be referred for hereditary cancer assessment.
Preparing for Your Appointment
Our assessment relies on detailed personal and family history information. The more information you can provide us prior to your appointment or have readily available at the time of your appointment, the more accurate and efficient your assessment will be.
In preparation for your appointment, you may be asked to complete the following forms:
If genetic testing results for hereditary cancer are available for one or more of your relatives, please ask your relatives for a copy of their results and forward this information to our clinic prior to your appointment. **This is especially important if your relatives have been identified to carry a harmful change in a hereditary cancer gene (e.g. BRCA1, BRCA2). We need the information from their genetic testing report in order to arrange genetic testing for any relative**
High-Risk Ontario Breast Screening Program (OBSP)
If you have a strong family history of breast cancer, you may be eligible for high-risk breast cancer screening through the OBSP. The high-risk program offers annual breast screening by mammogram and breast MRI to women between the ages of 30 and 69 who have at least a 25% lifetime risk of developing breast cancer. Screening results are sent back to your primary care provider. Follow-up care is arranged through their office.
Go to Cancer Care Ontario's website for more information about who is eligible for assessment for the high-risk OBSP. Ask your primary care provider for a referral to this program if you meet criteria for screening.