Is colon cancer hereditary? Family history and genetic risk

Colon cancer is cancer of the colon or large intestine. This type of cancer is also referred to as colorectal cancer.

according to American Cancer SocietyColon cancer is currently the third leading cause of cancer death in the United States. Many factors contribute to colon cancer. Genetics is just one risk factor.

Below, we’ll dive into the percentage of colon cancer linked to genetics. Next, we’ll examine other risk factors, screening guidelines, and prevention tips.

Colon cancer can certainly run in families. according to National Cancer Institute (NCI)Older research has found that up to 30% of colon cancer diagnoses are linked to familial risks.

The National Cancer Institute also notes that people who have a first-degree relative with colon cancer have a double risk of developing this cancer. People with more than one first-degree relative are at four times the risk.

First-degree relatives are:

Familial risks can include inherited genetic changes that increase the risk of colon cancer. Inherited means that these changes were passed on to you from your parents.

However, in people with a family history of colon cancer, only about 5% to 10% of the cases are directly related to genetic changes. As such, it is possible that some colon cancers may develop from other genetic changes that have not yet been extensively tested.

In fact, a Study 2021 361 people diagnosed with colon cancer found that 15.5% of them had genetic changes that increase their risk of developing this cancer. Of these changes, 25% are not found using current criteria for genetic testing for colon cancer.

Let’s take a closer look at some of the genes known to be involved in increasing the risk of colon cancer.


APC It encodes a tumor suppressor protein. Normally, tumor suppressors prevent cells from growing out of control. When certain changes occur in tumor suppressor genes, this function is impaired.

When certain genetic changes occur in APCIn the colon, cells can grow out of control, causing hundreds of polyps to form. This greatly increases the risk of colon cancer.

Some inherited genetic syndromes can increase the risk of colon cancer and are caused by changes in APC. here they are:


Likes APCAnd the STK11 It also encodes a tumor suppressor gene. When certain genetic changes occur in this gene, they lead to an inherited genetic syndrome called Peutz-Jeghers syndrome.

People with Peutz-Jeghers syndrome can have more polyps in the colon, which increases the risk of colon cancer. They also have an increased risk of developing many other types of cancer, such as breast and pancreatic cancer.

DNA repair enzymes

A cell must copy its DNA before it can divide. Sometimes, errors occur naturally during this process. Proteins called DNA repair enzymes can help detect and fix these errors, preventing changes that could lead to cancer.

Certain changes in the genes that encode DNA repair enzymes can increase the risk of colon cancer. Inherited genetic syndromes associated with these changes include Lynch syndrome and MUTYH-associated polyposis.

At this time, we do not know the exact cause of colon cancer. In general, cancer occurs when cells undergo genetic changes that cause them to grow and divide out of control. It usually takes many of these changes to lead to cancer.

As mentioned earlier, you can inherit some genetic changes from your parents. In addition, other genetic changes can occur over the course of your life. These are called acquired genetic changes.

While acquired genetic changes can occur due to random errors that occur during cell growth and division, they can also be caused by medical or lifestyle factors.

The outlook for people with colon cancer improves when it is caught early. For this reason, regular examination is very important.

The American Cancer Society Colon cancer screening guidelines recommend that people with an average risk of developing cancer have regular screenings at age 45 and continuing until age 75.

Several test options can be used for screening. These include stool-based and imaging tests, such as:

These guidelines are for people who have an average risk of colon cancer. People who are considered to be at high risk of colon cancer may need to start screening at a younger age or need to be screened more frequently.

It is important to have a conversation with your doctor about when to start colon cancer screening if any of the following apply:

  • You have a strong family history of colon cancer
  • You have been diagnosed with an inherited genetic syndrome that increases your risk of colon cancer
  • You have a history of certain types of polyps or colon cancer
  • I received a diagnosis of inflammatory bowel disease
  • You have had radiation to your abdomen or pelvis as part of your cancer treatment

Anyone can develop colon cancer. However, there are some steps you can take in your daily life to help reduce your risk:

  • Get regular checkups: Regular colon cancer screenings are important for everyone, especially for those at higher risk. Talk to your doctor about when and how often you should have the exam.
  • Adjust your diet: Focus on eating a balanced diet while reducing or avoiding red or processed meat. Additionally, if you drink alcohol, try to drink in moderation or not at all.
  • stay active: Physical inactivity increases the risk of colon cancer. Try to do moderate to vigorous exercise most days of the week.
  • Control your weight: Overweight and obesity increase the risk of colon cancer. Talk to your doctor about sustainable ways to manage and maintain a moderate weight.
  • Quit Smoking: Smoking increases the risk of colon cancer and many other health conditions. If you smoke, work with your doctor to create a plan to quit smoking.

A family history of colon cancer increases the risk of developing this cancer. In fact, having one relative with colon cancer can double your risk of developing it. Shared genetics and environmental factors can contribute to familial colon cancer risk.

But there are steps you can take to manage your risk of colon cancer and improve your future condition if you do develop colon cancer.

The outlook for people with colon cancer is better when it is caught early. If you have a family history of this cancer, you may need to start colon cancer screening early or get screened more often. Be sure to talk to your doctor about when and how often the examination will take place.

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