Colorectal cancer, commonly shortened to colon cancer, is one of the common sorts of cancer. About 1 in 20 people will develop colon cancer during their life – someone with a median risk has roughly a 5% likelihood of developing colorectal cancer.
We’re commonly asked, “Is colon cancer hereditary?” It may be: A portion of colorectal cancer cases are attributable to genetic mutations which can be passed between parents and youngsters. Individuals who carry an inherited mutation that’s related to colon cancer have the next risk of developing the disease.
Knowing if you have an inherited risk of colon cancer may give you a greater understanding of your personal risks and screening needs. There are various services available that provide genetic screenings for colon cancer, including help from genetic counselors and community health research studies like myGenetics.
Below, we’ll help you understand the fundamental causes of colorectal cancer and the way to determine your personal risk of developing hereditary colorectal cancer.
There are three fundamental causes of colorectal cancer
The causes of colorectal cancer may be broken down into three fundamental categories: sporadic colon cancer, familial colon cancer and hereditary colon cancer.
Sporadic colon cancer
Probably the most common cause is sporadic colon cancer – this affects between 50-60% of individuals diagnosed with colon cancer. Because of this the cancer happens by likelihood. Individuals who develop sporadic colorectal cancer are sometimes the primary of their families to be diagnosed with colon cancer.
Familial colorectal cancer
Familial colon cancer refers to a family where there are multiple individuals who have a history of colon cancer, but no known hereditary cause is found. It represents 20-40% of colon cancer cases. If a couple of first-degree member of the family – a parent, sibling or child – has been diagnosed with colorectal cancer, your risk of developing the condition doubles.
Individuals with a family history of colon cancer should get earlier and more frequent colon cancer screenings than someone with a median risk – often every five years with an affected first-degree relative. Learn more about colon cancer screening guidelines.
Hereditary colon cancer
Hereditary colon cancer makes up the smallest portion of diagnosed colon cancer, accounting for 4-6% of colon cancer cases. Any such colon cancer is caused when parents pass on a genetic mutation that may increase risk for colorectal cancer of their children.
Although a family history of colorectal cancer may indicate that you’re in danger for carrying a genetic mutation that predisposes you to colon cancer, the one way to know needless to say is to have a comprehensive hereditary cancer risk genetic test from a genetic counselor. There are several various kinds of genetic conditions which can be linked to colon cancer, including but not limited Lynch syndrome and Familial Adenomatous Polyposis (FAP).
Colon cancer can run in families
Research shows that 1 in 3 individuals who develop colon cancer have a member of the family who also has the disease. It’s not at all times clear why colon cancer might run in a family. It could be attributable to a mixture of multiple low-risk genetic aspects and environmental or lifestyle aspects.
It also doesn’t mean you’ll develop colon cancer simply because there are people in your loved ones who’ve been diagnosed with the condition. Nonetheless, a family history of colorectal cancer does increase your personal risk of colon cancer between 5% and 15%.
How to know if you have a family history of colon cancer
Having a family history of colorectal cancer means someone in your loved ones has been diagnosed with the disease. Colon cancer is taken into account a part of your loved ones history if you have one immediate member of the family or at the very least two prolonged members of the family who’ve had the condition.
Those with an instantaneous member of the family like a parent, sibling or child are considered to be at the next risk of developing colon cancer. Colon cancer screening guidelines recommend starting screening colonoscopies at 40 years old or 10 years sooner than when your first-degree member of the family was diagnosed – whichever comes first.
Colorectal cancer diagnoses in your clan also affect your risk
Your clan, sometimes called second-degree relatives, includes grandparents, uncles, aunts, cousins, nieces and nephews. If two or more of those relatives have been diagnosed with colon cancer, you could also be at the next risk of developing the disease.
While colon cancer screening guidelines don’t have specific recommendations for individuals with second-degree relatives with colon cancer, consider speaking together with your primary care provider if you have any concerns. In some cases, genetic testing could also be really helpful within the setting of multiple affected prolonged relatives. Genetic counseling may help individuals determine if genetic testing is true for them.
Varieties of hereditary colon cancer
There isn’t one colorectal cancer gene that causes the disease – as an alternative, there are several different genes which have been linked to colon cancer. Scientists are repeatedly researching the causes of colon cancer, and it’s possible that other genetic syndromes can be identified in the long run.
Probably the most common genetic syndromes that we know are linked to hereditary colon cancer are Lynch syndrome and familial adenomatous polyposis (FAP).
Lynch syndrome
Lynch syndrome (previously called hereditary non-polyposis colorectal cancer, or HNPCC), is essentially the most common explanation for hereditary colon cancer. Lynch syndrome results from an inherited mutation in considered one of five genes: MLH1, MSH2, MSH6, PMS2 or EPCAM. These genes help protect the body from certain cancers, but Lynch syndrome prevents them from working properly.
Lynch syndrome causes up to 3-5% of all colorectal cancer cases. It’s also linked to an increased risk of several other sorts of cancer, including colorectal, endometrial, gastric, ovarian, pancreatic, urothelial, brain, biliary tract and small intestine cancers. There are different screening intervals for every of those cancers, and risk-reducing surgeries for a few of these cancers may additionally be really helpful.
Lynch syndrome increases your risk of developing colon cancer
Someone with Lynch syndrome has a lifetime risk of developing colorectal cancer – the danger being between 15% and 61%. Lynch syndrome also increases the likelihood of developing colon cancer before age 50.
It’s essential to keep in mind that not everyone with Lynch syndrome will develop cancer. Nonetheless, those with the disorder should follow different screening recommendations than individuals with a median risk.
Lynch syndrome can affect anyone
Lynch syndrome occurs in roughly 1 in 279 people in america. Most individuals with Lynch syndrome inherit the genetic mutation from their parents. It’s also possible for genetic mutations to randomly occur, though that is rare.
Familial adenomatous polyposis
Familial adenomatous polyposis (FAP) is attributable to an inherited mutation within the APC gene and causes polyps to form in your colon and rectum. Polyps are growths of additional tissue that may turn cancerous if left untreated. Individuals with FAP often develop colorectal cancer by age 40.
Those with FAP have almost a 100% risk of developing colon cancer if the polyps will not be removed. It also increases the danger of developing several various kinds of cancer, including cancer of the small intestine, stomach cancer and pancreatic cancer. Lower than 1% of colon cancer is attributable to familial adenomatous polyposis.
If you have a family history of FAP or a private history of 20 or more colon polyps, or if you are concerned about your personal risk of this genetic mutation, talk to your primary care provider.
Causes of familial adenomatous polyposis
Usually, FAP occurs in individuals with a family history of the condition, and the inherited APC mutation is passed from parent to child. Nonetheless, up to 30% of individuals with familial adenomatous polyposis haven’t any family history of the condition.
Other sorts of hereditary colorectal cancer
Genetic researchers are working to understand all of the genetic causes of hereditary colon cancer. Other less common causes of hereditary colorectal cancer include:
- Attenuated familial adenomatous polyposis (AFAP)
- Peutz-Jegher’s syndrome (PJS)
- MUTYH-associated polyposis (MAP)
- Juvenile polyposis syndrome (JPS)
- Hereditary polyposis
- Cowden syndrome
How to know if you have a risk of hereditary colon cancer
Everyone has a risk of colon cancer, but that risk is highest in individuals who have genetic mutations that cause hereditary colon cancer.
Genetic syndromes, like Lynch syndrome, often go undiagnosed. Many individuals don’t realize they’ve a risk of hereditary colon cancer or other genetic mutations until they’re diagnosed with colorectal cancer.
The one way to know if you’re prone to developing hereditary colon cancer is to get colon cancer genetic testing. Genetic testing can cover all known colon cancer-related genes; nevertheless, there are still situations when genetic testing is unable to discover a causative mutation for those with a private or family history of the disease.
Who should consider colon cancer genetic testing?
Genetic testing for colon cancer risk is obtainable to anyone. Nonetheless, the style of genetic testing you should consider is predicated in your personal and family history. Genetic screening for a subset of colon cancer genes related to Lynch syndrome is obtainable through the myGenetics community health research study and is obtainable for gratis to you.
More comprehensive testing (often referred to as diagnostic or clinical testing) can also be available and needs to be considered if:
- You have got a private history of colon cancer
- You have got a private history of 20+ colon polyps
- You have got a private history of a Lynch syndrome-related cancer before age 50
- Several members of your loved ones have had cancers related to Lynch syndrome
- Certainly one of your members of the family has been diagnosed with Lynch syndrome
Genetic testing is the one way to diagnose hereditary colorectal cancer syndromes
The one way to know if you have a genetic mutation that causes colon cancer is to have genetic testing. Providing a small blood or saliva sample may help give you an image of your personal health risk.
Understanding your risk of developing colorectal cancer may help you manage your long-term health. Those with a risk of hereditary colon cancer may profit from lifestyle changes and specific colon cancer screening guidelines.
Genetic testing for hereditary colon cancer
If you think you would profit from genetic testing for Lynch syndrome or other genetic conditions, you have two options: genetic counselors and genetic testing health studies. Each can provide colon cancer genetic testing services.
Genetic counselors
Genetic counselors can analyze your loved ones medical history, coordinate clinical genetic testing and counsel you in your genetic health risks. They’ll offer robust screenings and talk with you about what your results mean for you and your loved ones. If needed, genetic counselors may also guide you toward additional care you might need to manage your health risks.
So as to meet with a genetic counselor, you typically need a referral from one other doctor. Insurance coverage for genetic counseling services vary depending in your insurance plan.
Genetic health testing studies
Genetic testing for Lynch syndrome and other genetic health conditions is usually available through DNA health studies and screening programs. Our large-scale community health research study, myGenetics, is considered one of the primary of its kind in Minnesota. It’s a voluntary study available to all HealthPartners and Park Nicollet patients over the age of 18.
Genetic screening through myGenetics is obtainable for gratis to you and provides details about three specific hereditary conditions: Lynch syndrome, hereditary breast and ovarian cancer, and a hereditary type of high cholesterol called familial hypercholesterolemia. Information on regional ancestry and traits (like caffeine sensitivity) are also available to participants of the study.
Of note, myGenetics only screens for Lynch syndrome and never the less common genetic causes of colon cancer. If you have a private or family history of colon cancer, you also needs to consider speaking together with your primary care provider to discuss a referral to a genetic counselor. They may help determine if clinical genetic testing could be appropriate.
Learn more about genetic testing with myGenetics DNA health screening