Hereditary Cancer Syndrome
A type of inherited disorder in which there is a higher-than-normal risk of certain types of cancer. Hereditary cancer syndromes are caused by mutations (changes) in certain genes passed from parents to children. In a hereditary cancer syndrome, certain patterns of cancer may be seen within families. These patterns include having several close family members (such as a mother, daughter, and sister) with the same type of cancer, developing cancer at an early age, or having two or more types of cancer develop in the same person. Examples of hereditary cancer syndromes are hereditary breast and ovarian cancer syndrome, Li-Fraumeni syndrome, Cowden syndrome, and Lynch syndrome. Also called family cancer syndrome and inherited cancer syndrome.
An individual who inherits a cancer susceptibility variant always get cancer?
No. Even if a cancer susceptibility variant is present in a family, it does not necessarily mean that everyone who inherits the variant will develop cancer. Several factors influence whether a given person with the variant will actually develop cancer. One is the penetrance of the variant. When not all people who carry a variant go on to develop the disease associated with that variant, it is said to have incomplete or reduced penetrance. Hereditary cancer syndromes can also vary in their expressivity—that is, people who inherit the variant may vary in the extent to which they show signs and symptoms of the syndrome, including the development of associated cancers. Lifestyle factors and environmental risks can also influence disease expression.
What are the genetic tests available for cancer risk assessment?
More than 50 hereditary cancer syndromes have been described; see the PDQ Cancer Genetics Overview for a list of familial cancer susceptibility syndromes. Most of these are caused by harmful variants that are inherited in an autosomal dominant fashion—that is, a single altered copy of the gene inherited from one parent is enough to increase a person’s chance of developing cancer. For most of these syndromes, genetic tests for harmful variants are available. Tests are also available for several inherited genetic variants that are not associated with named syndromes but have been found to increase cancer risk. Examples include inherited variants in PALB2 (associated with increased risks of breast and pancreatic cancers), CHEK2 (breast and colorectal cancers), BRIP1 (ovarian cancer), and RAD51C and RAD51D (ovarian cancer).
Who should consider genetic testing for cancer risk?
People who are concerned about whether their family history puts them at risk for cancer should consult with a genetic counsellor. The features of a person’s personal or family medical history that, particularly in combination, may suggest a hereditary cancer syndrome include:
- Cancer was diagnosed at an unusually young age
- Several different types of cancer occurred in the same person
- Cancer in both organs in a set of paired organs, such as both kidneys or both breasts
- Several first-degree relatives (the parents, siblings, or children of an individual) have the same type of cancer (for example, a mother, daughter, and sisters with breast cancer); family members with breast or ovarian cancer; family members with colon cancer and endometrial cancer
- Unusual cases of a specific cancer type (for example, breast cancer in a man)
- The presence of birth defects that are known to be associated with inherited cancer syndromes, such as certain noncancerous (benign) skin growths and skeletal abnormalities associated with neurofibromatosis type 1.
- Being a member of a racial or ethnic group that is known to have an increased risk of having a certain inherited cancer susceptibility syndrome and having one or more of the above features as well
- Several family members with cancer
- If a person is concerned that they may have an inherited cancer susceptibility syndrome in their family, it is generally recommended that, when possible, a family member with cancer have genetic counselling and testing first, to identify with more certainty if the cancer in the family is due to an inherited genetic variant. Genetic testing is often more informative if it can begin in a family member with a previous or current cancer diagnosis than in someone who has never had cancer.
- If a person in the family has already been found to have an inherited cancer susceptibility syndrome, then any family members who could have inherited the variant should consider genetic testing, even if they have not (yet) had a cancer. Knowing about their risks may help them to prevent a future cancer.
What is the role of genetic counselling in genetic testing for
a hereditary cancer syndrome?
Genetic counselling is generally recommended before any genetic testing for a hereditary cancer syndrome and may also be performed after the test, especially if a positive result is found and a person needs to learn more about the hereditary cancer predisposition syndrome they have been found to have. This counselling should be performed by a trained genetic counsellor or other health care professional who is experienced in cancer genetics. Genetic counselling usually covers many aspects of the testing process, including:
- A hereditary cancer risk assessment based on an individual’s personal and family medical history
- Explanation of the specific test(s) that might be used and the technical accuracy of the test(s) and their interpretation
- Discussion of:
- The appropriateness of genetic testing and potential harms and benefits of testing
- The medical implications of positive, negative, and uncertain test results
- The possibility that a test result might not be informative (that is, it might find a variant whose effect on cancer risk is not known)
- The psychological risks and benefits of genetic test results
- The risk of passing a variant to children
- The impact of testing for the family
- The best test to perform
Genetic counselling may also include discussing recommendations for preventive care and screening with the patient, referring the patient to support groups and other information resources, and providing emotional support to the person receiving the results.
Learning about these issues is a key part of the informed consent process for genetic testing. Written informed consent is usually obtained before a genetic test is ordered. People give their consent by signing a form saying that they have been told about, and understand, the purpose of the test, its medical implications, its risks and benefits, possible alternatives to the test, and their privacy rights.
Unlike most other medical tests, genetic tests can reveal information not only about the person being tested but also about that person’s relatives. Family relationships can be affected when one member of a family discloses genetic test results that may have implications for other family members. Family members may have different opinions about how useful it is to learn whether they have a disease-related genetic variant. Health discussions may get complicated when some family members know their genetic status while other family members do not want to know. A conversation with genetics professionals may help family members better understand the complicated choices they may face.
Role of truGeny
Genetic Testing is the future of medical treatment. And truGeny is a thorough Genetic Counselling and Testing services platform.
Genetic counsellors from truGeny are certified and will help you in understanding the risk of you inheriting any a genetic cancer risk, by understanding your health and family history. They will further guide you whether you require Genetic Testing. Post the testing process, the experts guide you through your report helping you plan your course of action.
Genetic Counselling and Testing will build a stronger and healthier tomorrow. We believe with your support we can help in bringing the change. Let us join hands together. Let us choose to be healthy, be strong.
Book your appointment now! Visit www.trugeny.com