Is Colon Cancer Hereditary?

Colon cancer is the second-highest cause of cancer-related deaths in both men and women in the United States. According to the latest data from the American Cancer Society, more than 50,000¹ deaths will be attributed to colon cancer this year.

Hereditary cancer syndromes are conditions caused by genetic mutations that can be handed on from parent to child, increasing the child's likelihood of getting cancer. If one of your parents or any other first-degree relative has been diagnosed with colon cancer, you may have inherited that characteristic as well.

Is colon cancer genetic?

All cancers, particularly colon and rectal cancers - collectively known as colorectal cancer (CRC) - have genetic characteristics that may increase one's risk of getting them. The cancer gene is passed from parent to child in hereditary colorectal cancer; therefore, some families will be more affected than others.

Colorectal cancer is classified into three main categories, two of which include a genetic component. The percentages for each type are shown below:

• 50-70% are sporadic².

• 25-35% of instances are familial³.

• 5-10% of occurrences are inherited/hereditary⁴.

I. Sporadic colon cancer

The most prevalent form is sporadic colorectal cancer, which mainly affects people over the age of 50. It has no apparent familial pattern and no hereditary gene mutation. This kind of colorectal cancer affects around one in every 23 Americans⁵.

Close relatives should be informed if a person is the first in their family to be diagnosed with colorectal cancer. Screenings should begin at a younger age for people with a family history of the disease since most cancers are sporadic, which means that they begin with healthy genetics and then acquire gene mutations over time.

II. Familial colon cancer

Family members may have similar habits in terms of what they eat and drink, their levels of physical activity, and their interaction with their environment. Some of these habits can increase the likelihood of developing colon cancer. Colon cancer is known as familial when several family members have cancer.

There is cause for concern if a family has more than one member with colorectal cancer, especially if it is diagnosed before they reach the age of 50. When a first-degree relative has it, the risk for family members will double⁶.

III. Hereditary colon cancers

An inherited genetic variant causes hereditary colon cancer. Family history information enables your doctor to assess your risk of colorectal cancer and formulate the best plan for prevention and treatment.

Knowing whether or not your cancer is hereditary is important because it will help you understand the underlying cause of your disease. Your doctor will also advise you whether you are at risk of developing other forms of cancer. Finally, it will help you know whether other family members are at risk of developing cancer.

Inherited gene mutations cause a relatively small percentage of colon cancers. Many of these DNA alterations and their consequences on cell development are now well understood.

Lynch syndrome

Lynch syndrome is the most prevalent⁷ genetic condition related to colon cancer. If you are diagnosed with Lynch syndrome, you are much more likely to acquire various forms of cancer and require more regular screening and monitoring.

Familial Adenomatous Polyposis (FAP)

Familial Adenomatous Polyposis is the second most common⁸ kind of hereditary colorectal cancer. FAP affects one in every 10,000 people. It is characterized by the formation of up to thousands of polyps (adenomas) in the colon, typically at a young age. If left untreated, the chance of getting colon cancer is 100%.

Attenuated familial adenomatous polyposis (AFAP) is a more minor type of FAP, although it still increases colorectal cancer risk compared to the general population.

FAP and AFAP are both linked to the APC gene (adenomatous polyposis coli). The APC gene is a tumor suppressor gene; it typically helps control your cell growth. If you have inherited mutations in the APC gene, this "stopper" on cell growth is removed, resulting in hundreds of polyps in the colon.

MUTYH-Associated Polyposis (MAP)

Mutations in the MUTYH gene cause MAP. Because MAP has a recessive inheritance pattern, parents and children of people with the condition are typically unaffected.

Is colon cancer preventable?

Gene mutations are the root cause of all colon cancers. Because new mutations accumulate as we age, the risk grows with age, which is why most colon cancers develop after the age of 50. Also, specific hereditary mutations might cause colon cancer to develop at an earlier age.

So, what options do you have? You may lower your risk of colon cancer by:

1. Maintaining a healthy weight

Obesity raises the risk of colorectal cancer in both men and women, although the relationship appears to be greater in males. Maintaining a healthy weight may help reduce your risk.

2. Consuming a healthy diet

Diet changes are being studied to see whether they might lower the prevalence of colorectal cancer. To minimize the risk of other chronic diseases, such as coronary artery disease and diabetes, medical professionals recommend a diet low in animal fats and high in fruits, vegetables, and whole grains. This diet may help lower the risk of colorectal cancer.

Limiting your consumption of red and processed meats and increasing your vegetables, fruits, and whole grains may help decrease your risk.

3. Exercising regularly

Regular, moderate exercise, such as walking, reduces your risk of colon cancer. However, intense activity appears to be most effective.

4. Reducing alcohol consumption

Several studies have linked increasing alcohol use to an increased risk of colon cancer⁹, particularly in men. While it is recommended not to drink alcohol, people who do should limit themselves to one drink per day for women and two drinks per day for men.

5. Taking aspirin

Researchers are investigating the impact of several medications and supplements¹⁰ in the prevention of colon cancer. Many studies have indicated that people who often use aspirin or other NSAIDs, such as ibuprofen (Motrin, Advil) and naproxen (Aleve), had a reduced risk of colon cancer and polyps.

However, aspirin and other NSAIDs can have serious side effects that may exceed the advantages of these medications for the general population. As a result, the American Cancer Society does not recommend taking NSAIDs simply to decrease your risk of colorectal cancer if you are at average risk.

According to the US Preventive Services Task Force¹¹, taking low-dose aspirin can help prevent cardiovascular disease and colorectal cancer in certain individuals, depending on age and risk factors.

6. Avoiding smoking

Long-term smoking has been related to an increased risk of colorectal cancer and other cancers and health issues. Quitting smoking may reduce your chance of getting colorectal cancer.

7. Having genetic screening for colon cancer

The practice of checking for cancer or precancer in people who have no signs of the disease is screening. One of the most effective methods for avoiding colorectal cancer is regular colorectal cancer screening.

It generally takes ten to 15 years for colon cancer to develop from when the first cells grow into polyps. Most polyps may be detected and treated with frequent screening before they develop into cancer. Screening can also detect colon cancer early when it is small and simpler to cure.

When should colon cancer screening begin?

Screening guidelines for persons who have an inherited gene mutation differ from those for those who are at average risk of getting colon cancer. Although there is no established method of entirely preventing colorectal cancer, you may be able to reduce your risk.

Genetic counseling can help you and your family decide if you are at a higher risk of developing cancer and provide prevention, early detection, and treatment choices.

Family members who are examined and proven to be free of genetic mutation may be eligible to be screened at the same age and rate as the general population.

What is involved in colon cancer screening?

Colorectal cancer is detected with a variety of tests. Although a colonoscopy is the most common procedure, there are alternatives.

The Fecal Immunochemical Test (FIT)

This test is simple to do at home by collecting feces in tubes. The test looks for blood in the feces that can’t usually be seen, and any blood found will be analyzed at a lab.

Colonoscopy

Colonoscopy is the most effective method for detecting colorectal polyps and cancer. 

A colonoscopy is an outpatient procedure where a physician views the rectum and whole colon through a long, flexible scope (called a colonoscope). Polyps can be removed and screened for malignancy during the operation.

A colonoscopy is regarded as a risk-free procedure. Before the procedure, the colon must be cleaned out with a laxative ("bowel preparation"). The patient is generally given a sedative for this treatment and will need help getting home when the sedation has worn off.

Fecal DNA test

This test detects genetic mutations and blood products in the feces. DNA, or genetic material, is found in every cell of the body, including the cells that line the colon. Every day, normal colon cells and their genetic material are excreted with the feces. When a colon cancer or a big polyp forms, defects (or mutations) arise in the cells' genetic makeup. Laboratory examination of the feces can reveal specific mutations present in the polyp or tumor.

The lowdown

Fortunately, you may avoid most colon cancers by changing your lifestyle and removing precancerous polyps through screening. Colonoscopy is the gold standard for detecting polyps and the only test that allows them to be removed.

Colonoscopy and polyp removal can lower your risk of colon cancer by an extra 70-90%¹² regardless of risk grouping.

Learn more about colon cancer prevention and discover ways to reduce your risk.