Collecting Your Family’s Cancer History

Aprobado por la Junta Editorial de Cancer.Net, 11/2022

Sharing your family health history with your health care team is important. This is especially true if you or a family member have been diagnosed with cancer.

People may be more likely to be diagnosed with cancer if someone else in their family also had cancer. It is one of many risk factors for developing cancer.

What is hereditary cancer?

"Hereditary cancer" is a phrase to describe cancer that develops in people with a specific genetic mutation, also called a pathogenic variant or change. This pathogenic variant is passed down from one generation to the next in families. People with specific pathogenic mutations are more likely to develop a hereditary cancer than people without it. It may also be called "familial cancer" or you may say that cancer "runs in the family."

Not all cancers are hereditary. In fact, most cancers are the result of genetic mutations that are not passed down in families but instead are from ones that happen during a person's life, called acquired mutations. Cancer in your family may be a hereditary cancer if:

  • There are multiple relatives with cancer on the same side of the family, especially if they were diagnosed at a younger age.

  • A single person in the family has multiple tumors, especially in the same body part.

If you think a hereditary cancer runs in your family, talk with your doctor. They can help you understand genetic counseling and whether to have genetic tests to predict your personal risk of developing cancer.

What do genetic tests for hereditary cancer find?

Hereditary cancer genetic tests analyze genes, chromosomes, or proteins using a blood sample or tissue sample, such as cells collected from the inside of your cheek.

A hereditary cancer genetic test can:

  • Help predict the risk that you will get specific types of cancer in the future

  • Help in the treatment of cancer if you have already been diagnosed

There are many tests available for many different diseases, including breast, ovarian, colon, thyroid, and other cancers. Learn more about genetic testing.

How does your family’s history of cancer affect you?

Information from your family’s history of cancer can help a doctor to determine:

  • If you or others in your family may benefit from genetic counseling, which helps you understand how genes and cancer run in families before having testing, how genes affect your family's health, and describes the benefits, risks, and limitations of genetic testing

  • If you or others in your family may benefit from genetic testing

  • If you need more intensive follow-up care than people with non-hereditary cancer, even if you do not need genetic testing

Details about your family's cancer history

Your doctor will want information on the cancer history of your first-degree biological relatives (parents, children, and full siblings) and second-degree relatives (grandparents, aunts, uncles, nieces, nephews, grandchildren, and half siblings).

For each relative who has had cancer, collect as much of this information as possible:

  • Any type of cancer(s) they have had

  • Age when diagnosed with cancer

  • The person's relationship to you, such as is this a relative on your mother's side (called maternal relatives) or father's side (paternal relatives)

  • Ethnicity. People of some ethnicities, such as those with Ashkenazi Jewish ancestry, are at greater risk for genes that increase the risk of certain cancers.

  • Results of any previous cancer-related genetic testing

Keep in mind that it might be difficult for some of your family members to discuss their health with you. Remember that health is often a sensitive topic for many people, or it may trigger difficult memories. You may want to send your questions to them ahead of time and emphasize that even a little information is helpful. Some people may prefer to discuss this in person, while others will prefer to communicate the information through email or text.

When to share your family’s history of cancer with your doctor

If you've been diagnosed with cancer, provide your family history of cancer to your doctor before you begin treatment, if possible. It is also important to let your doctor know of any new information you gather or changes to your family history over time.

Sometimes, medical advances may change how your doctor evaluates your family history. It is a good idea to review your family history after your first phase of cancer treatment, during your post-treatment summary, and as part of your post-treatment survivorship care over the long term.

How to collect and share your family’s history of cancer

One way to gather information is to use ASCO’s Family Cancer History questionnaire. Fill it out as best you can. Then, bring it to your next doctor’s appointment and ask to discuss it.

You can also send the completed questionnaire to your close relatives so they have the information to share with their doctors. But know that some relatives may not want or value this information in the same way you do.

Questions to ask your health care team

You probably have many questions if your family has a history of cancer. Consider asking the following questions of your health care team:

  • Does my family history put me at risk for other cancers?

  • What is the purpose of genetic testing?

  • Do you advise that I have genetic counseling and/or genetic testing?

  • Can you recommend a genetic counselor or a way to find one?

  • Will information from genetic testing change my cancer treatment plan?

  • Is genetic counseling and genetic testing covered by my insurance plan? What would I need to pay out of pocket?

  • Is my genetic information protected?

  • Are any of my family members at risk for specific cancers in the future?

  • Does someone who inherits a genetic mutation always develop cancer?

  • What information should I share with family members that could be relevant to their future health?

  • Do you have any suggestions for helping me communicate this information to my family members?

Related Resources

Sharing Genetic Test Results with Your Family

Hereditary Cancer-Related Syndromes

More Information

National Cancer Institute (NCI): Genetic Testing for Hereditary Cancer Syndromes

Centers for Disease Control and Prevention: Family Health History and Cancer

Genetic Alliance: Family Health History

U.S. Department of Health and Human Services: Surgeon General’s Family Health History Initiative

Medline Plus: What is Genetic Testing