Almost 1 in every 8 men will be diagnosed with prostate cancer at some point in his life. But what does it mean for cancer to be hereditary?
Content authored by: Ann Faulkner, Licensed Genetic Counselor, Thompson Cancer Survival Center
Cancer develops when cells go haywire; the cells are growing and dividing out of control, causing tumors to form. Changes, called mutations, to the cell’s instruction manual are what make the cell lose control, causing tumors to grow.
Each cell in the human body has sets of instructions called genes. Our DNA is what spells out these instructions. Some genes are meant to tell our bodies what our eye color or hair color should be, while other genes have jobs that help protect us from cancer.
When there are mistakes in the instructions that help protect us from cancer, our cells can’t do their job as well. Most of the time, these mutations happen randomly as we age. They could be caused by our diet, harmful exposures, or just getting older. Between 5 and 10% of cancers are hereditary, meaning a person was born with one of these mutations in a gene that is meant to protect them from cancer. With one of their sets of instructions not working, these people rely on their backup copy and this makes them more likely to develop cancer over their lifetime.
Since genetic information is passed on to the next generation, these “typos” or errors in the instruction manual can be passed from parent to child. Identifying these mutations in families gives people tools to make more informed decisions about their health.
When might a cancer be hereditary?
When a family has a genetic change increasing their risk of cancer, there are often patterns that give us a hint that there might be a hereditary cancer risk, such as:
- Multiple family members or multiple generations of family members who have been diagnosed with cancer, making it look like cancer “runs in the family.” Most commonly, these are breast, colon, and prostate cancer.
- Rare or uncommon types of cancer.
- Family members diagnosed at young ages, especially those younger than 50.
- One person in the family has been diagnosed with more than one type of cancer.
- Bilateral cancers, or cancers affecting both of a pair of organs, such as both breasts.
- Cancer affecting the sex that is not usually affected, such as breast cancer in men.
- Families of certain ethnic backgrounds, like Ashkenazi Jewish ancestry, may also be more likely to have these mutations.
When should you have genetic testing?
The National Comprehensive Cancer Network, or NCCN for short, provides recommendations to patients for when they should consider genetic testing for a personal or family history of prostate cancer. NCCN recommends genetic testing for those with a diagnosis of prostate cancer and any of the following:
- A Gleason score of 8 or higher or a PSA of 20 or higher. These may also be called high-risk prostate cancer.
- Prostate cancer that is metastatic or regional, meaning it has spread to parts of the body outside of the prostate.
- Ashkenazi Jewish ancestry.
- A blood relative that has a known genetic mutation predisposing them to cancer
- A brother, father, or other family members diagnosed with prostate cancer younger than 60 or who passed away due to prostate cancer.
- More than 3 instances of cancer on the same side of the family, especially if they were diagnosed under 50 years old. Types of cancers to consider include breast, colon, ovarian, pancreatic, or any rare types of cancer.
What does the genetic testing process look like?
Genetic testing often begins with a conversation with a genetic counselor. The genetic counselor collects information about personal and family history to provide a personalized risk assessment. This conversation with a genetic counselor gives the patient a chance to ask questions before undergoing testing. The genetic counselor then helps facilitate the testing process.
A sample is collected for testing, most commonly blood or saliva, and sent to a lab for analysis. The lab evaluates multiple genes that are associated with an increased risk of cancer when they have mutations. For prostate cancer specifically, some of these genes may include BRCA1/2, MLH1, MSH2, MSH6, and others.
The lab reports their findings back to the genetic counselor who then reports the results to the patient. If a mutation was found, also known as a positive result, the genetic counselor discusses it with the patient, providing resources and information about the gene. They may also provide information about recommendations for future medical management and offer testing to family members.
*Learn more by reading: Genetic Counseling versus Genetic Testing
Why should I get genetic testing or talk to a genetic counselor?
Whether or not to get genetic testing done is always up to the patient. Genetic testing can be used as a tool to provide more information to the patient and their family.
Many patients pursue genetic testing to find out more information for themselves or change their medical management. For example, some genes associated with prostate cancer may also increase an individual’s risk of developing colon cancer. Identifying this through genetic testing can help a patient plan for the future and take steps to prevent cancer or catch it early, such as more frequent cancer screenings like colonoscopies. It may also inform their treatment.
Some patients are interested in genetic testing for the information it can provide for other members of the family. If a mutation is discovered in a patient, blood relatives also have a chance of having the same mutation. Knowing which family members have the same mutation can help identify who in the family may need more frequent cancer screenings.
At its core, genetic testing is a tool to give patients information and empower them to make informed decisions about their health. The goal is to provide the patient and their family steps to take that can prevent cancer or detect it in its most treatable stages.
National Comprehensive Cancer Network https://www.nccn.org/home/about
Association of Directors of Anatomic and Surgical Pathology. (March 8, 2017). Understanding your pathology report: Prostate cancer. American Cancer Society. https://www.cancer.org/treatment/understanding-your-diagnosis/tests/understanding-your-pathology-report/prostate-pathology/prostate-cancer-pathology.html
The Victor Center for Jewish Genetic Diseases. (2018 – 2021). Judaism: Ashkenazi Jewish Genetic Diseases. Jewish Virtual Library. https://www.jewishvirtuallibrary.org/ashkenazi-jewish-genetic-diseases
Terry, Alora. (June 23, 2021). Genetic Counseling versus Genetic Testing. Thompson Cancer Survival Center Blog. https://www.thompsoncancer.com/genetic-testing-versus-genetic-counseling-whats-the-difference/