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If cancer has affected someone in your family, genetic testing may sound like a way to get a definitive answer about your own future. It can provide useful information—but it cannot predict with certainty whether you will develop cancer.
Hereditary cancer-risk testing looks for inherited gene changes that may increase the chance of certain cancers over a lifetime. It can help explain a family pattern and support more informed conversations about screening and care planning. A genetic test result is one part of a bigger picture that also includes family history, personal health, age, and guidance from a licensed clinician.
This article explains what genetic testing can reveal about cancer risk, what different results may mean, and when a conversation with a genetic counselor may be helpful.
Hereditary cancer-risk testing examines the DNA you were born with to identify inherited gene changes linked to certain cancer risks. These changes can be passed from a parent to a child.
The National Cancer Institute estimates that inherited genetic changes cause about 5% to 10% of all cancers. Most cancers are not caused by a single inherited change; they develop through a combination of factors over time. Source: NCI.
A hereditary cancer-risk panel can assess several genes at once. The exact genes tested vary by panel and should be selected based on personal and family history with guidance from a qualified professional.
No. A hereditary cancer risk genetic test cannot tell you with certainty whether you will or will not develop cancer.
A positive result means the test identified a harmful inherited gene change associated with an increased risk for one or more cancers. It does not mean cancer is inevitable. Risk can vary by gene, family history, age, sex, and other factors.
A negative result means the test did not identify the specific inherited changes it was designed to detect. It does not eliminate cancer risk. Your clinician may still recommend screening based on your personal and family history.
Some results are classified as a variant of uncertain significance, or VUS. This means there is not enough evidence to know whether a specific change affects cancer risk. A VUS should not be treated as a confirmed harmful mutation. Source: NCI.
A positive hereditary cancer-risk result can provide a clearer starting point for discussions with your physician or genetic counselor. Depending on the gene and your individual situation, those discussions may include:
• Whether screening should begin earlier or occur more often
• Whether relatives may want to consider genetic counseling or testing
• Which cancer types may be relevant to your family history
• What monitoring or care-planning conversations may be appropriate
For example, inherited changes in BRCA1 and BRCA2 can be associated with breast, ovarian, pancreatic, and prostate cancer risk. But the meaning of a result is specific to the gene and to the person receiving it. Source: CDC.
Genetic testing is most useful when it is connected to a complete family history. Record which relatives have had cancer, the type of cancer, their age at diagnosis, and whether relatives are on your mother’s or father’s side.
Some family patterns may make a hereditary cancer-risk conversation more relevant:
• Multiple relatives with the same or related cancers
• Cancer diagnosed at a younger-than-expected age
• A family member with more than one primary cancer
• Breast, ovarian, pancreatic, prostate, colorectal, or endometrial cancer appearing in the same family
• A known inherited cancer-related gene change in a relative
A genetic counselor can help decide whether testing may be informative and whether it is best to test a relative who has had cancer first. In many families, that person’s result provides the clearest information for other relatives.
Each of these tests has a different purpose.
Hereditary cancer-risk testing examines DNA you were born with to identify inherited genetic changes that may affect your risk for certain cancers. Because these changes can be passed through families, the results may also provide information that is relevant to your biological relatives.
Tumor genomic testing examines DNA changes within an existing tumor. It can help an oncology team understand tumor biology and support treatment discussions after a cancer diagnosis.
One does not replace the other. If you have been diagnosed with cancer, your care team can explain whether tumor testing, hereditary testing, or both may be relevant.
Genetic counseling can be useful before or after testing. A genetic counselor can review your family history, explain the limits of testing, help choose an appropriate panel, and interpret results in context.
Consider asking about genetic counseling if you have:
• A known inherited cancer-related gene change in the family
• Multiple close relatives with cancer
• A family pattern involving related cancers
• Cancer diagnosed at a younger age in one or more relatives
• Questions about whether a test result could be relevant to children, siblings, or parents
For a broader explanation of multi-gene testing, read Kadance’s guide to inherited cancer-risk panels. If prostate cancer runs in your family, our guide to genetic testing for prostate cancer may also help.
Start with the family information you have. You do not need a perfect family tree to begin a conversation with your physician.
Consider asking:
• Does my personal or family history suggest inherited cancer risk?
• Would genetic counseling help determine whether testing is appropriate?
• Is there a relative who has already had testing, or who may be the most informative person to test first?
• If a harmful inherited change is found, what screening conversations should I have with my care team?
The goal of genetic testing is not to predict the future with certainty. It is to give you and your care team more information for decisions that fit your individual circumstances.
No. A negative result means the test did not identify a harmful inherited change in the genes it examined. It does not eliminate cancer risk or replace screening recommendations based on family history and other risk factors.
Not necessarily. If a parent has a BRCA gene mutation, each child has a 50% chance of inheriting it. Source: CDC, https://www.cdc.gov/breast-ovarian-cancer-hereditary/causes/index.html
No. Genetic results should be reviewed with a licensed clinician or genetic counselor, who can explain what they mean in the context of your health and family history.
For individuals and families who want a more complete view of inherited cancer risk, Kadance Complete offers complete precision health: hereditary cancer risk, cancer care, and recovery support.
Members receive access to hereditary cancer risk testing and licensed genetic counseling, designed to help them understand results and discuss appropriate next steps with their physician.