Can Cancer be Hereditary?

While the majority of cancer is sporadic and occurs by chance, approximately 5-10% is hereditary and occurs because an individual was born with a harmful change in a gene that increased their risk to develop cancer. In general, it is estimated that approximately 5-10% of breast cancer, 5% of colorectal cancer, and up to 25% of ovarian cancer may be due to a mutation in the gene associated with hereditary cancer. Other types of cancer may also be hereditary.

Hereditary Cancers
Hereditary cancers are caused by pathogenic variants (harmful changes) in certain genes passed from one generation to the next. These pathogenic variants are usually inherited from a parent and can significantly increase the risk for one or more cancers.

Sporadic Cancers
Sporadic cancers are caused by a random event and are not passed from one generation to the next within a family. Sporadic cancers occur more frequently as we get older due to environmental and lifestyle exposures such as diet, weight, exercise, smoking, and alcohol use among others.

Is Hereditary Cancer Testing Appropriate for You?

A healthcare provider can use your medical and family histories to better understand if you are at risk for hereditary cancer. You may benefit from genetic testing if you have a personal or family history of any of the following:

• Cancer at a young age (under the age of 50)
• Rare cancers at any age (such as male breast cancer, and ovarian cancer)
• More than one type of cancer in the same individual (also referred to as multiple primary cancers)
• 10 or more colon polyps
• A known genetic alteration in the family
• Multiple cases of cancer on one side of the family spanning multiple generations
• An individual of Ashkenazi Jewish descent with breast, ovarian, or pancreatic at any age

How Genetic Testing Works

• Genetic counseling is recommended prior to genetic testing to understand the benefits and limitations of testing.
• Whenever possible, it is recommended that genetic testing begins with someone in the family who has had cancer.
• Genetic testing analyzes genes associated with hereditary cancer for pathogenic variants (harmful changes) that cause an increased risk of cancer.
• The genetic test is done using a blood or a buccal (cheek cells) specimen.
• It will take approximately 1-3 weeks to receive results, depending on the test ordered.
• Your healthcare provider or genetic counselor will share the results with you and discuss the possible implications for you and your family.

If I Already Have Cancer, Do I Need Genetic Testing?

In many cases, patients with cancer who test positive are at increased risk to develop second cancer. Therefore, knowing your genetic status may direct the treatment of a current cancer diagnosis and help reduce the risk for or improve early detection of future cancer and/or tumors.

What are the Possible Results of My Genetics Test?

There are four possible outcomes of genetic testing: positive (pathogenic variant), likely pathogenic variant, negative, and variant of uncertain significance (VUS). It is important to remember that a positive test result does not mean you have cancer or will develop cancer, instead it means that you may be at higher risk for developing certain types of cancer. Your healthcare provider can use gene-specific information to determine the most appropriate medical management plan to detect cancer early or reduce your risk of cancer. This may include increased cancer screening, medication, and/or surgery.