Collecting Your Family’s Cancer History

Approved by the Cancer.Net Editorial Board, 10/2018

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

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 person’s mother or father or both. Hereditary cancer may also be called familial cancer or cancer in the family.

Approximately 5% to 20% of all cancers are hereditary. This is a relatively 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

  • 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 a person’s 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 family’s history of cancer can show

 Information from your family’s history of cancer can help a 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 need more intensive follow-up care than people 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 (people of some ethnicities, such as those with Ashkenazi Jewish ancestry, 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 family’s history of cancer with your doctor

Provide your 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. It is a good idea to review your family history 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 family’s history of cancer

One way to gather information is to use ASCO’s Family Cancer 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 health care team

If, after reviewing your family’s history of cancer, 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?

  • What is the purpose of genetic testing?

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

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

  • 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?

Related Resources

More Information

Locating Cancer Genetics Specialists