Oncogenetics

Your physician has referred you to oncogenetics because he has reason to believe that you are at increased risk of developing one or more types of cancer during your lifetime. This is known as having a genetic predisposition to cancer. Here is a list of risk factors for developing cancer during your lifetime.

  • Cancer at an early age
  • Rare types of cancer (e.g., male breast cancer)
  • Family history of cancer
  • Known family cancer syndrome (predisposition)
  • Ashkenazi Jewish ancestry

A person who is genetically predisposed to cancer will be more closely monitored to prevent or detect cancer, if necessary. A genetic (hereditary) predisposition can be transmitted from parent to child. A predisposition therefore has an impact on both the patient and his family.

Requesting a consultation and procedures

Getting a consultation in oncogenetics

Your attending physician must refer you to oncogenetics

Your attending physician will explain to you why he is referring you to oncogenetics. If your physician has not had the time to do so, the genetics counsellor will explain why a consultation in oncogenetics is desirable for you and your family.

Each consultation request is evaluated

The medical geneticist evaluates every consultation request and assigns each a level of priority. The waiting period for a consultation varies from person to person and according to the urgency of each case.

Your medical record and your family history will be analyzed

A genetics counsellor or a medical geneticist will analyze your medical record and your family history to assess the likelihood that you are genetically predisposed to cancer.

If you are at increased risk of being genetically predisposed to cancer, we will recommend one or more genetic tests. If the tests confirm that you are genetically predisposed, some of your relatives may also be selected for testing.

When it is clear that a person is genetically predisposed to cancer, we can offer adapted cancer screening options and preventive treatments to lower the risk of cancer.

An appointment in oncogenetics is a consultation in medical genetics. Neither you nor your family will be involved in a research project when you consult in oncogenetics.

Before your appointment in oncogenetics

You will be called by a member of the genetics department for an appointment and to fill out a questionnaire. The following information will be requested:

  • The regional origins of your maternal and paternal grandparents
  • The age of those affected when they received their cancer diagnosis
  • The type of cancer (primary site, pathology)
  • The age of your children, brothers, sisters, parents, uncles, aunts, and grandparents
  • The age of your blood relatives at their time of death


We know that it is sometimes difficult to obtain such information; however, the greater its exactitude, the greater the precision of the genetic assessment will be.

You do not need to take anything with you to your consultation except for additional information on your family's cancer history, your medical insurance card, and your hospital card. You may be accompanied by other family members if you wish.

During your consultation

The meeting will last 30 to 45 minutes. The objective is to assess your genetic risk and predisposition to cancer and to explain potential tests to you. This meeting is an opportunity to discuss your concerns about your family history of cancer and your visit in oncogenetics.

During the meeting, we will examine your family tree. We will ask you questions regarding your health and perform a physical examination, if required. In order to provide a better assessment, it is sometimes necessary to obtain further information that is contained in the medical records of your relatives (e.g., type of cancer). If that is the case, the relatives concerned must give their written consent.

If you have an increased genetic risk for cancer, the genetics counsellor and the medical geneticist will recommend genetic testing. The decision whether to take those tests is entirely yours. Using clear examples, the genetics counsellor and the medical geneticist will assist you in making an informed and enlightened decision. Many elements can guide this decision, including:

  • the efficacy of the preventive or cancer-screening methods;
  • anxiety;
  • socio-economic impacts;
  • the possibility of an inconclusive result;
  • the desire to prevent disease among relatives;
  • social and family pressure.

Another concern people have worth mentioning is insurability. Like any other result, the results of genetic tests are kept in the user's medical record. The results can influence the insurability of users whose records are consulted.

You may need time to reflect before taking genetic tests. No matter what decision you make, the medical geneticist will recommend monitoring that is adapted to your needs and that of your relatives.

Taking genetic tests

You will need to sign consent forms. The genetics counsellor will explain their contents to you. Genetic tests may be done on a cancerous tumour kept at the hospital or on a blood sample. Blood samples are usually taken at the screening centre on the day of the consultation.

The waiting period for results is 1 to 4 months. Once a genetic predisposition to cancer is confirmed through genetic testing or if the medical geneticist wishes to see you again, you will be called for a follow-up appointment. The results will be given to you during the consultation.

Genetic tests will attempt to shed light on whether or not you are genetically predisposed to cancer. We seek genetic changes, commonly known as genetic mutations. There are two types of situations.

  • If a mutation in your family is already known, only that specific mutation will be sought.
  • If not, a more in-depth search based on the types of cancer diagnosed in your family will be conducted.

Understanding your results

Negative test result

The interpretation varies on whether the mutation is known or not in your family.

  • The family (hereditary) mutation has not been identified. The result means that the person tested has not inherited the mutation identified in a blood relative. The risk of having cancer is therefore similar to that of the general population.
  • No mutation has been identified through genetic testing. This does not exclude genetic predisposition to cancer by 100%. You may still have a genetic mutation that has not been identified in the tests, either for technical reasons or because some causes of genetic predisposition to cancer have not yet been discovered. Your risk of cancer and the monitoring recommendations will be estimated based on family history.

 

Positive test result

A positive test result means that a genetic mutation has been identified. Targeted screening is recommended according to the risks of developing particular types of cancer associated with the mutation. It is sometimes possible to elect preventive surgery.

Depending on the mode of transmission of the genetic predisposition, the genetics counsellor will inform you about those who are at risk in your family. These persons may take a predictive gene test if they so wish. It is your responsibility, however, to inform them.

The predictive gene test is offered only after a consultation in genetics. A referral from a physician is required.

Receiving a positive result may sometimes lead to shock. The medical geneticist and the genetics counsellor will guide you to the appropriate resources in accordance with your needs.

 

Uncertain result 

A genetic test may occasionally identify a genetic mutation whose clinical significance is uncertain. This means that it is difficult to determine precisely whether or not the genetic mutation has a significant effect on health.

When there is an uncertain result, a follow-up appointment in genetics is held. It may be recommended that other family members be tested to determine whether the genetic mutation has an impact on health. It is also important to contact the genetics department again every 2 to 3 years to keep pace with the progress of scientific knowledge.

Warning | The information contained in these pages is no substitute for an appointment in oncogenetics. This information is intended to help you to plan and to prepare your questions for a future consultation.

These pages have been made possible thanks to the support of the Fonds Brigitte-Perrault of the Fondation du CHUS.

 

 

Contact the Medical Genetics Department

Hôpital Fleurimont
3001 12th avenue North
Sherbrooke (Québec)
Canada J1H 5N4
Phone : 819-820-6828
Fax : 819-564-5217

Other medical genetics departments in Quéeec

Québec

CHU de Québec (CHUQ-CHUL)
Service de génétique médicale 418-525-4444, ext. 47130

 

Hôpital du Saint-Sacrement du CHU de Québec
Centre des maladies du sein Deschênes-Fabia (CMS)
Service d'oncogénétique
418-682-7511, ext. 4621

Montréal

Hôpital général de Montréal (CUSM)
Clinique des cancers héréditaires adultes
514-934-1934, ext. 44067

 

CHUM Montréal Service de médecine génique
514- 890-8104 
web site (French)

 

Jewish General Hospital (JGH)
Cancer Genetics Clinic and General Genetics Clinic
514-340-8222, ext. 3965
Prenatal diagnosis
514-340-8222, ext. 3428
web site

South Shore of Montreal

Hôpital Charles-Lemoyne
Clinique d'oncologie génétique du CICM
450-566-5000, ext. 3563

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