Anyone who has or has had relatives in their family who suffered from a diagnosis of cancer should consider genetic testing.

The features of a person’s personal or family medical history that, particularly in combination, may suggest what is known as “hereditary cancer syndrome and it may 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 counseling 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 cancer. Knowing about their risks may help them to prevent future cancer.

Those at risk for hereditary cancer syndrome should consider genetic counseling.

Genetic counseling may 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 counseling should be performed by a trained genetic counselor or other health care professional who is experienced in cancer genetics. Genetic counseling usually covers many aspects of the testing process, including:

• A hereditary cancer risk assessment based on an individual’s personal and family medical history
• 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
• Explanation of the specific test(s) that might be used and the technical accuracy of the test(s) and their interpretation

Genetic counseling 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.

Health insurance typically covers genetic counseling and many genetic tests, if they are considered medically necessary. A person considering genetic testing should discuss costs and health insurance coverage with their doctor and insurance company before being tested.