Cancer Genetics at City Hospital Cancer Centre

Inherited genetic mutations play a major role in about 5 to 10 percent of all cancers. Researchers have associated mutations in specific genes with more than 50 hereditary cancer syndromes, which are disorders that may predispose individuals to developing certain cancers.

Genetic tests for hereditary cancer syndromes can tell whether a person from a family that shows signs of such a syndrome has one of these mutations. These tests can also show whether family members without obvious disease have inherited the same mutation as a family member who carries a cancer-associated mutation.

Many experts recommend that genetic testing for cancer risk be considered when someone has a personal or family history that suggests an inherited cancer risk condition, as long as the test results can be adequately interpreted (that is, they can clearly tell whether a specific genetic change is present or absent) and when the results provide information that will help guide a person’s future medical care.

The primary goal of cancer genetic counselling is to identify individuals and families at increased risk of cancer for the purpose of promoting awareness, early detection, and cancer prevention.  There are many known genes that can cause inherited forms of cancer in certain families including hereditary breast and ovarian cancer, hereditary colon cancer and others.  Identification of these inherited cancer syndromes allows for targeting at-risk individuals for the most appropriate medical management.

In some families, a pattern of cancer is obvious, while in others it may be difficult to detect a pattern due to small family size, incomplete family history, or inability to document diagnoses.

Patients with the following should be referred to a cancer genetic clinic:

1. • Cancer diagnosed at an unusually young age (e.g. breast or colon cancer before age 50)
   • Triple negative breast cancer
   • Multiple close family members with the same type of cancer or related cancers (e.g. breast and ovarian cancer, colon and uterine cancer)
   • Two or more primary cancer diagnoses in the same individual (e.g. breast cancer in both breasts, breast and ovarian cancer)
   • Rare cancers or unusual tumors (e.g. medullary thyroid cancer, retinoblastoma, hepatoblastoma, male breast cancer, adrenal cortical carcinoma, pheochromocytoma and paraganglioma)
   • Presence of other features associated with an inherited cancer syndrome (e.g. multiple colon polyps)
     
     

Other patients who may benefit from a referral to a cancer genetic counsellor include: 

1. • Members of a family with a known hereditary cancer syndrome
   • Individuals considering genetic testing for cancer risk
   • Individuals with questions about cancer risk in family members
   • Individuals with heightened risk based on family history or known gene mutation who have questions about cancer screening, prevention or treatment
   • Individuals who have had genetic testing for cancer risk and would like a more detailed discussion of their test results
   • Individuals with extreme cancer anxiety, even in the absence of heightened risk

Screening for potential genetic predisposition prior to referral

We have developed a simple screening questionnaire which the patient can complete with their primary healthcare provider to assess if they are likely to have an increased genetic predisposition to cancer, and would benefit from a referral to the genetics clinic.

Family History Questionnaire for Cancer Risk Assessment

A genetic counsellor can help identify who is at risk for an inherited cancer syndrome and discuss screening and prevention options for those individuals.

A genetic counsellor also facilitates the genetic testing process by identifying the most informative family member to test, assessing the most appropriate genetic test(s) for patients and their families, interpreting the results, and helping patients and their physicians apply the results to medical management decisions.

Genetic counsellors help families with inherited cancer risk deal with many of the personal aspects of having an inherited condition in the family, such as decisions about screening and prophylactic surgeries, discussion of these issues with at-risk family members, and the emotional adjustment to a gene mutation associated with increased cancer risk.  They can also facilitate referrals to long-term resources such as appropriate healthcare providers for ongoing surveillance and management, community agencies, support groups, and other families with the same condition.

During an appointment, the genetic counsellor will typically:

a. Collect a detailed cancer-focused personal and family medical history

b. Assess the patient's risk of developing cancer-based on the collected information

c. Determine whether or not the history is suggestive of an inherited cancer syndrome

d. Provide patient education and answer questions about cancer risks, the option of genetic testing, and the risks, benefits, and limitations of genetic testing

e. Review medical management options with or without genetic testing

f.  If desired, coordinate genetic testing and provide results and test interpretation to the patient and referring provider.

g. Provide psychosocial support to patients and families, and facilitate communication between patients and their families regarding risk information and recommendations

After the visit, the cancer genetic counsellor will communicate back to primary care and referring physicians so that risk assessment information can be incorporated into ongoing management

For health care providers working with cancer patients, it is becoming standard practice to ask about the family history of cancer or refer for cancer risk counselling. The American Society of Clinical Oncology (ASCO) has issued a statement (J Clin Oncol 2006; 24(31):5091-5097) indicating that it is the responsibility of the clinical oncologist to ascertain families at risk for inherited forms of cancer. The National Accreditation Program for Breast Centers (NAPBC) includes cancer risk assessment, genetic counselling, and genetic testing services in its standards (https://www.facs.org/quality-programs/napbc/standards).

Other professional societies with published guidelines recommending cancer risk assessment include:

a. American College of Obstetrics and Gynecology (Obstet Gynecol, 113:957-66)

b. United States Preventive Services Task Force (Ann Intern Med 2005;143(5):362-79)

c. Society of Gynecologic Oncology (Gynecol Oncol 2007;107(2):159-62)

d. National Comprehensive Cancer Network

American Gastroenterological Association (Gastroenterology 2001;121(1):195-7)