Collecting Your Cancer Family History

Approved by the Cancer.Net Editorial Board, 02/2016

Sharing your family health history with your doctor is important. This is especially true if you have been diagnosed with cancer. This article talks about why finding out about a possible family history of cancer is useful and how to do it.

What is hereditary cancer?

Hereditary cancer means that a person was born with a genetic mutation, or change, that makes this person more likely than usual to get cancer. This genetic mutation could have come from either the mother or father or both. Hereditary cancer may also be called familial cancer or cancer in the family.

Approximately 5% to 10% of all cancers are hereditary. This is a small percentage of cancers, so how can you tell whether a cancer runs in the family? Some clues include:

  • Having multiple relatives with cancer on the same side of the family, especially if they were diagnosed at a younger age; or

  • Having a single person in the family with multiple tumors, especially in the same organ.

Genetic testing for hereditary cancer

Hereditary cancer is found through genetic testing. This is the analysis of genes, chromosomes, or proteins. Testing can:

  • Help predict the risk that someone will get a disease.

  • Identify “carriers” of a disease; these are people who do not have the disease but have a copy of the disease gene.

  • Diagnose a disease.

  • Find out the likely course of a disease.

Genetic testing is done by taking a sample of blood or tissue that contains genetic material, such as the cells inside a person’s cheek. More than 900 genetic tests are available for many different diseases, including breast, ovarian, colon, thyroid, and other cancers. Learn more about genetic testing.

What your cancer family history can show

Information from your cancer family history can help doctor to determine whether:

  • You or others in your family may benefit from genetic counseling. This is specialized counseling that explains the risks of an inherited cancer and the benefits, risks and limitations of genetic testing.

  • You or others in your family may benefit from genetic testing.

  • You require more intensive follow-up care than patients with non-hereditary cancer, even if you do not need genetic testing.

Information to collect

Your doctor will want information on the cancer history of your first-degree 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:

  • Type of cancer(s)

  • Age at diagnosis

  • Lineage, meaning is it on the mother’s side (maternal) or on the father’s side (paternal)

  • Ethnicity (some ethnicities, such as the Ashkenazi Jewish population, are at greater risk for 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. You may want to send your questions ahead of time and emphasize that even a little information is helpful. Try to find a time to talk that is free of distractions.

When to share your cancer family history with your doctor

Provide your cancer family history to your doctor soon after your diagnosis and 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. Sometimes, medical advances may change how your doctor evaluates your history. Good opportunities to review your cancer family history are after your first phase of treatment, during your post-treatment summary, and as part of your post-treatment survivorship appointment.

How to collect and share your cancer family history

One way to gather information is to use ASCO’s Cancer Family History questionnaire. After you complete the form to the best of your ability, bring it with you to your next doctor’s appointment and ask to discuss it. You should also send the form to your close relatives so they have the information to share with their doctors. Although, be aware that a few relatives may not want or value this information in this same way you do.

Questions to ask your doctor

If, after reviewing your cancer family history, your doctor suspects that you may have a hereditary cancer, you should understand what this means and what next steps are available. Consider asking the following questions of your health care team:

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

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

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

  • What is the purpose of genetic testing?

  • Will information from genetic testing change your treatment plan for me?

  • Is genetic counseling and testing covered by my insurance plan?

  • Is my genetic information protected?

  • Which of my family members are at risk?

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

  • What information do I need to share with family members?

  • Do you have any suggestions for helping me communicate this information?

More Information

What to Expect When Meeting with a Genetic Counselor

Sharing Genetic Test Results with Your Family

Hereditary Cancer-Related Syndromes

Additional Resources

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

Centers for Disease Control and Prevention: Family Health History

Genetic Alliance: Family Health History

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

Locating Cancer Genetics Specialists

National Society of Genetic Counselors: Find a Genetic Counselor

NCI: Cancer Genetics Services Directory

American College of Medical Genetics: Clinical Services Search Engine

American Board of Medical Genetics: Search for a Certified Geneticist

American Board of Genetic Counseling: Find a Counselor