Chances are someone you know has battled cancer, and maybe even that someone is you. Although navigating a cancer diagnosis is different for each case, patients and families may have similar questions. It’s natural to wonder, “what causes cancer?” or “why did they develop cancer?” If you have had cancer yourself, maybe you’re wondering whether your relatives are at greater risk to also develop the same type of cancer.
The unfortunate truth is that cancer diagnoses are relatively common. Approximately 1 in 3 people will receive the diagnosis in their lifetime. While all cancers are considered “genetic,” not all are hereditary, or in other words, caused by a genetic change that can be passed down through families. The vast majority of cancers are “sporadic,” meaning they are caused by genetic changes a person acquires throughout their lifetime from exposures, lifestyle factors, or simply during the normal aging process. These acquired genetic changes have the chance to be missed during a cell’s “spell-checking” process and can go on to result in a tumor. As mentioned above, age is a significant risk factor. This is why cancer is more common in individuals later in life. A person with a sporadic cancer may not have any relatives with cancer.
While most cases of cancer are sporadic, some are caused by what is called “inherited” changes, which can lead to hereditary cancers. Hereditary cancers are caused by an inherited genetic change that a person is born with, increasing their chance to develop cancer throughout their lifetime. Hereditary cancers are believed to account for about 5% to 10% of all cancer diagnoses. These genetic changes occur in specialized genes that play an important role in protecting our bodies from developing cancer. When a genetic change or “mutation” is present, the gene may no longer work correctly. If not working correctly, these important genes cannot protect a person from developing cancer. These genetic changes run in families and are passed from generation to generation. They are referred to as “hereditary cancer predisposition syndromes.”
One of the most common cancer syndromes is called hereditary breast and ovarian cancer syndrome (HBOC).
What Does It Mean to Have HBOC?
HBOC is a condition that significantly increases a person’s chance to develop specific cancers throughout their lifetime. Each person with HBOC will be impacted differently, based on the individual’s organ systems they were born with and/or currently have present.
Breast cancer is the most common associated HBOC cancer. Individuals assigned as females at birth with HBOC have up to an 85% lifetime risk of developing breast cancer. However, the risk for breast cancer for everyone with HBOC varies depending on their breast/chest tissue regardless of their sex at birth. In addition, there is an increased risk of cancer in the ovaries, pancreas, prostate, and skin tissue. Due to these risks, people with HBOC are recommended to follow the National Comprehensive Cancer Network (NCCN) guidelines for specific management and screenings.
A general NCCN recommendation for HBOC includes beginning cancer screenings earlier and more frequently. The overall goal is to catch cancer at an early stage for the best possible treatment options and outcomes, if a cancer were to develop. Also, NCCN recommends considering preventive surgeries, such as removing breast/chest tissue and ovaries, to greatly reduce the chance to develop those cancers.
Remember: Just because there is an increased chance for cancer to develop does not mean it will.
Just because you meet with a genetic counselor for an appointment, it does not mean you have to get genetic testing. Genetic testing is always optional
How Does Someone Get HBOC?
Approximately 1 in 400 to 1 in 800 people in the general population have a diagnosis of HBOC. It is due to genetic changes in the BRCA1 or the BRCA2 gene. These genetic changes are typically inherited from a biological parent.
For genes like BRCA1 and BRCA2, 2 copies of the gene are inherited and present at birth. One copy comes from the egg (maternal), and 1 copy comes from the sperm (paternal). A diagnosis of HBOC is made when a person is found to have 1 of the copies of a BRCA gene not working.
For example, imagine the BRCA1 gene as a bodyguard. When people are born with 2 bodyguards working, there is a strong defense system against cancer. However, some people are born with only 1 bodyguard. As you can guess, 1 bodyguard isn’t as strong as having both working to their fullest potential. If the remaining bodyguard stops working and there isn’t a backup bodyguard to defend, a tumor can form. But…sometimes a single bodyguard is strong enough to defend alone for an entire lifetime and prevent cancer from forming.
Not only does HBOC impact the person who is initially diagnosed, but it could have implications for relatives. If someone is diagnosed with HBOC, their biological children, siblings, and parents (first-degree relatives) each have a 50% chance of having the same genetic change. It is like flipping a coin, and unfortunately, we cannot control how we pass this information down. Other distant relatives, such as grandparents and cousins, could have the same genetic change as well and be at risk.
What Are the Signs of HBOC in a Family?
The biggest indicator of HBOC…family history. The following signs are potential indicators for HBOC:
- Early onset of breast cancer (younger than 50 years)
- Ovarian cancer (any age)
- Pancreatic cancer (any age)
- Multiple generations of relatives with breast, ovarian, pancreatic, and/or prostate cancer
- More than 1 cancer diagnosis in a single individual (cancers listed above)
- Ashkenazi Jewish ancestry.
In some ancestral backgrounds, there can be an increased frequency of specific genetic risk factors. For instance, HBOC is more prevalent in those with Ashkenazi Jewish ancestry. It is estimated that about 1 in 40 people of Ashkenazi Jewish descent will have a genetic change in the BRCA1 or BRCA2 gene. However, it is important to note that any person of any ancestral background can have these genetic changes. Our current knowledge of these changes, in large part, is due to biases in scientific research.
What Is the Impact to Families?
Getting a diagnosis like HBOC is never easy, and every person processes information differently. A wide range of emotions can be present at the time of diagnosis, including sadness, anger, anxiety, fear, guilt, neutrality, control, relief, and many more. Some may feel empowered and in control for knowing ways to lower their cancer risks. Others may feel constant anxiety of the unknown and if they are going to develop cancer.
There is never a right or wrong way to feel when getting a diagnosis.
Not only can a diagnosis cause internal emotions in a person, it can also impact family dynamics. One of the most challenging parts can be sharing results, as well as supporting the decision of each relative. When sharing this information, it is common for a relative to say they are not interested in genetic testing because they do not want to know if they are at risk. Independent decisions can often spark tension among family members when there are conflicting views on learning individual risks. It can be a delicate balance between supporting the relative’s autonomy while facing internal emotions regarding their decision.
How Can I Learn More If I Have HBOC?
To learn more about your risks, you can discuss this information with you doctor and consider meeting with a genetic counselor. Genetic counselors are specialized healthcare providers who are experts in inherited conditions such as HBOC. Genetic counselors provide support and education about the risks of inherited conditions based on your personal and family history. Additionally, they can discuss the option of genetic testing with you.
Genetic testing can be completed from a blood, saliva, or cheek swab (buccal) sample. Typically, this test will include genes related to multiple types of cancer conditions that increase the risk for cancer. A genetic counselor can navigate the genetic testing process with you. They can discuss with you the risks, benefits, and limitations of testing, and answer common questions such as test cost, insurance implications, privacy concerns, and much more.
Important: Genetic counseling does not equal genetic testing.
Just because you meet with a genetic counselor for an appointment, it does not mean you have to get genetic testing. Genetic testing is always optional, and the genetic counselor will discuss with you about your goals and what you want out of the session. Even if someone would decide not to proceed with genetic testing, there are recommendations and next steps a genetic counselor can discuss with you.
Listed below are resources from which you can learn more about HBOC or other cancer predisposition syndromes.
- Additional information about cancer genetic testing and considerations: Cancer.Net
- What to Expect When Meeting With a Genetic Counselor: Cancer.Net.
- Find a genetic counselor in your area: National Society of Genetic Counselors.
- The National Comprehensive Cancer Network patient resources:
- Other cancer predisposition syndromes: American Cancer Society.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines). Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic. Version 3.2023. https://www.nccn.org/professionals/physician_gls/pdf/genetics_bop.pdf. Accessed April 30, 2023.
About the Authors
Josie Baker, MS, LGC; Jordan Brown, MA, MS, LGC; and Julia Cooper, MS, LGC, are cancer genetic counselors and assistant professors in the College of Medicine at The Ohio State University Comprehensive Cancer Center.