What to Know About Cancer-Related Genetic Counseling

What to Know About Cancer-Related Genetic Counseling

Reviewed by Jasper Clinical Board

Last updated 5/24/21

Sometimes, the risk of cancer is passed down through families, much like hair color or height. If your doctor thinks you’ve inherited this susceptibility to cancer, they may recommend a genetic test to gather more information, followed by a meeting to discuss your results. This process is called genetic counseling, and it’s an important part of the cancer journey for many people. Here’s what you should know about it.

What is genetic counseling?

The role genes and family genetics play in your health can be a difficult and confusing topic with big health implications. It can bring up challenging emotions, along with plenty of questions. That’s why there is a whole branch of healthcare dedicated to genetic counseling, with specialized professionals trained to guide you through it. 
A genetic counselor will help determine whether genetic testing is an option for you—and if so, what information testing may provide. They’ll help you consider the pros and cons of getting tested and arrange the actual tests. Typically, they’ll also give you the test results, help you make sense of them, and figure out your next steps. (For example, you might want to share test results or information about inherited genetic risks with family members.) Your genetic counselor can help you navigate these issues and connect you with other resources for ongoing support. 
During your first appointment, the genetic counselor will usually gather information about your family medical history. Any information you can bring with you about cancers in your family will be helpful, including ages of relatives when they were diagnosed, what type of cancer they had, their health outcomes, and dates of birth / death. Your counselor will use this information along with your medical records to understand whether you’re a good candidate for genetic testing.

Cancer & genes: What’s the connection?

Cancer is caused by a genetic change (a mutation) that affects how your body’s cells behave, grow, and divide. These DNA mutations can happen naturally as people age—the result of random errors during cell division. They can also happen when DNA is damaged by exposure to harmful substances like cigarette smoke, pollution, alcohol, industrial chemicals, etc. These are called “acquired genetic mutations.” 
So why does this happen to some people and not others? It depends on two things: Your genes (which you inherit from your parents and cannot control) and your environment (where you live, the kind of work you do, your diet, exercise, stress levels, etc.). A cancer isn’t always the result of one or the other—a genetic propensity to develop cancer is often switched on by your environment. On the flip side, it’s also worth noting that sometimes several members of a family will have the same type of cancer not because it’s inherited (often called a “germline mutation”) but instead because everyone in the family was exposed to the same environmental triggers (to further complicate things, in some cases there might also be a genetic component, but an undetectable one). 
For most kinds of cancer, a higher susceptibility doesn’t seem to be passed down through families. But for some types—including breast, ovary, colon, and pancreas cancer—inherited genetic variants do put people at a higher risk. Genetic counseling tells you if you’ve inherited these risks, and how steep they are.
Here’s the full list of hereditary cancers and cancer genes:
Breast cancer in women: ATM, BARD1, BRCA1, BRCA2, BRIP1*, CHEK2,  CDH1, NF1, NBN, PALB2, PTEN, RAD51C*, RAD51D*, STK11, TP53
Breast cancer in men: BRCA1, BRCA2, CHEK2, PALB2
Colorectal cancer: EPCAM, MLH1, MSH2, MSH6, PMS2, CHEK2, PTEN, STK11, TP53, MUTYH  
Endometrial cancer: EPCAM, MLH1, MSH2, MSH6, PMS2, PTEN, STK11
Fallopian tube, ovarian, primary peritoneal cancer: ATM*, BRCA1, BRCA2, BRIP1, EPCAM, MLH1,  MSH2,  MSH6, NBN*, PALB2, RAD51C, RAD51D, STK11**
Gastric cancer: CDH1, STK11, EPCAM, MLH1,  MSH2, MSH6, PMS2*
Melanoma: BAP1 (especially uveal melanoma), BRCA2 CDK4, CDKN2A, PTEN, TP53
Pancreatic cancer: ATM, BRCA1, BRCA2, CDKN2A, EPCAM*, MLH1,  MSH2*, MSH6,* PALB2, STK11, TP53
Prostate cancer: ATM, BRCA1, BRCA2, CHEK2, EPCAM*, MLH1*, MSH2*, MSH6*, PALB2, PMS2*
* More research is needed to confirm this link
** Most ovarian tumors in people with this mutation are benign.

Why get genetic testing?

It’s important to understand the limits of genetic testing. If you have cancer, testing does not give you a single cause or explanation. It also won’t give a conclusive yes-or-no answer about your future cancer risks. Even so, learning about your genetics can be very helpful! Here are the major benefits of genetic testing and counseling:
  • It can inform important health decisions. If a genetic test shows you’ve inherited a high risk of cancer, you can then take preventive measures to protect your health. This could mean getting regular screenings, changing your lifestyle to reduce other risk factors, and even getting surgery. (For instance, some people with a high genetic risk of breast cancer opt for a prophylactic (preventive) mastectomy.)
  • It can help family members make health choices. Your genetic counselor can help you understand the possible health implications for your blood relatives if your test results show a familial genetic vulnerability to cancer. Should this be so, you might want to share your test results with them. They may want to get tested, too, or get early screenings and other preventive care.
  • It can factor into your life plans. Learning that you have a higher risk of cancer may impact how you spend your time right now (like when you choose to retire). Knowing that a heightened risk level may be passed down to your biological children could affect your family planning decisions, as well.
  • It can help doctors optimize your cancer treatment. Some newer cancer treatment techniques rely on the specific genetic profile of your cancer and fine-tune an approach to match it. These “targeted therapies” are possible only for certain cancers and involve DNA sequencing of tumor cells. (Note that this kind of genetic testing is different from a hereditary cancer risk analysis.)

Potential downsides of genetic testing

As we said above, learning about your inherited genetic risk for cancer can be genuinely empowering, giving you an important perspective to inform your (and your family’s) decisions. At the same time, this kind of information can be a heavy emotional burden to carry. And in many cases genetic testing will not lead to any changes in your treatment. 
You might feel the information will cause you to change your life plans in ways you don’t like, or cause you and your family members too much worry and anxiety. Sometimes test results can be ambiguous, and this can be stressful, too. If testing won’t provide you with any information that will change your treatment or guide future behavior, the emotional impact of getting upsetting or unclear news might not be worth it. 
Having covered all of this, it’s important to stress that should you decide to go through with testing, the 2008 Genetic Information Non-Discrimination Act (GINA) prevents helath insurance companies, employers, and others from changing their behavior toward you based on information about your genetic tests.
A genetic counselor will understand these concerns and will approach them nonjudgmentally. They are there to help you weigh the pros and cons of genetic testing and make an informed decision that’s right for you.

Who should consider genetic testing?

Doctors and genetic counselors typically recommend genetic testing in these situations:
  • You or your family members were diagnosed with cancer at an unusually young age.
  • You or a family member have more than one type of cancer. 
  • You have cancer in a pair of organs, such as both breasts, lungs, or kidneys.
  • Several of your close blood relatives or many people on one side of your family have cancer.
  • You have blood relatives with colon, breast, ovarian, or endometrial cancer.
  • You have a rare cancer type.
  • You or your blood relatives have other symptoms known to accompany inherited genetic variants that increase cancer risk.
  • You’re a member of an ethnic group known to have heightened hereditary risk. People with Ashkenazi (Eastern European) Jewish heritage have higher levels of certain genes known to increase cancer risk, especially breast cancer.

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