Could My Genetics Be What Causes Colon Cancer?

Colorectal cancer can affect the colon, rectum or both. According to the World Health Organization, it’s the third most common cancer across the globe.

What causes colon cancer? Your genetics or a family history of colorectal cancer may play a role among many other factors.

“Hereditary cancers can develop if you inherit a gene mutation that causes colorectal cancer,” says Kathryn Jones, FNP-BC, AOCNP, a board-certified advanced oncology nurse practitioner at Beaufort Memorial Oncology Specialists. “You might have a family history because of that inherited condition or mutation. However, family members may also share habits that increase the risk of colorectal cancer. So, you can still have a family history of the disease without having an inherited genetic condition or mutation.”

Read More: Colon Cancer Symptoms: How to Recognize a Potential Problem

Colon Cancer Causes Starting in Your Genetics

The majority of cancers, including colon cancers, are not related to hereditary genetic mutations, but rather to small changes that lead to abnormal, out-of-control cell growth.

For the small group of people who carry genetic mutations, their genes put them at higher risk for abnormal cell growth leading to malignancy.

Additional factors that elevate malignancy risk are chronic health conditions and environmental exposures. As we consider colon, endometrial and gastrointestinal tract cancers, the two most common types of hereditary syndromes evaluated by genetic testing are lynch syndrome and familial adenomatous polyposis.

Two inherited conditions that increase the risk of developing colorectal cancer are:

• Lynch syndrome — Also known as hereditary non-polyposis colorectal cancer, Lynch syndrome prevents proteins from repairing damaged DNA. Research published by the American College of Medical Genetics and Genomics states that this condition is responsible for 2–3% of all colorectal cancers. If you have Lynch syndrome, your likelihood of developing colorectal cancer is approximately 80%, according to research published by the National Institutes of Health. You’re also at higher risk for endometrial cancer and other cancers.
• Familial adenomatous polyposis (FAP) — With FAP, polyps develop in the large intestine (colon), often early in life. It causes fewer cases of colorectal cancer, but when polyp growth starts in the teen years and isn’t treated, you have a 100% chance of the polyps turning into colorectal cancer, according to the American Cancer Society. FAP may also raise your risk of developing other cancers.

How to Learn if Your Genetics Could Cause Colon Cancer

If you have a family history of colorectal cancer, you’re at increased risk for the disease. Discuss your risks with your healthcare provider to determine if you should undergo genetic testing.

If you have three or more family members with colon, gastrointestinal tract or endometrial cancer diagnosed over age 50, or two or more family members diagnosed under age 50, you may be appropriate for genetic testing.

With a simple blood draw, genetic testing can help uncover Lynch syndrome, FAP and other inherited gene mutations. These tests aim to provide helpful information about your risk of developing colorectal cancer.

Based on the results, your healthcare provider may recommend one of the following:

• Carry on — If you don’t have an inherited mutation that increases your risk, you may be able to continue a normal screening schedule.
• Screening changes — If you test positive for a genetic mutation, starting screening tests at an earlier age or with greater frequency can help detect colon cancer as early as possible.
• Testing loved ones — Your close blood relatives may want to find out if they, too, are at increased risk for colon cancer due to their genetics. Additional testing can help them find out.

Read More: Genetic Testing for Cancer: Do You Need It?

What Else Causes Colon Cancer

Genetics is only one cause of colon cancer. Several other factors also increase your risk. You can manage some, while others are out of your control.

Those you can do something about include the following:

• Drinking — Avoid drinking alcohol excessively. Limit yourself to no more than one (women) or two (men) drinks a day.
• Eating — Red meat and processed meats put you at a higher risk of colorectal cancer. In particular, eating processed meats such as deli and cured meats is associated with elevated colon cancer risk. So do ultra-processed foods, so eat less of these foods and more fruits, vegetables and whole grains.
• Obesity — Obtaining and maintaining a healthy weight isn’t easy, but weight loss helps reduce your risk for colon cancer.
• Sitting around — Living a sedentary lifestyle puts you at risk for all sorts of diseases, including cancer.
• Smoking — Yes, smoking makes you more likely to get colorectal cancer, yet another reason to begin your journey to smoking cessation.

Risk factors you can’t change for colorectal cancer include:

• A history of ovarian or colorectal cancer
• Being 50 years old or older
• Being Black or of Ashkenazi Jewish descent
• Having an inflammatory bowel disease (Crohn’s disease or ulcerative colitis) or Type 2 diabetes

Read More: Early Signs of Colorectal Cancer: What Adults Under 50 Should Know

Whatever Causes It, Detect Colon Cancer Early

No matter what causes colon or rectal cancer, the disease is highly treatable. Colonoscopy empowers your care team to detect and remove polyps before they have the chance to develop into cancer.

“Regardless of your genetic makeup, a colonoscopy is the most effective way to screen for colon cancer,” Jones says. “These screenings allow us to find and remove colon cancer early, before it has spread.”

Here’s when you should add colonoscopy screening into your cancer care routine.

• Average risk — If you don’t have risk factors, undergo your first colonoscopy at age 45. The test should be repeated every 10 years.
• Increased risk — If you have a family history of colorectal cancer or genetic risk factors, you may need screening earlier or more often. Talk with your healthcare provider to determine the best schedule for you.

Other screenings are available, including at-home options. These must be repeated more frequently than a colonoscopy. If these tests uncover something suspicious, a colonoscopy provides a definitive diagnosis.

Spotlight on What Causes Colon Cancer

The list of what causes colon cancer includes genetics, but there are other causes as well. Regardless of the cause, early detection and treatment are crucial.

1. Inherited conditions that may result in colorectal cancer include familial adenomatous polyposis and Lynch syndrome.
2. Your risk also increases if you smoke, have inflammatory bowel disease or have other risk factors, such as obesity or a personal history of ovarian cancer.
3. Regular colon cancer screening allows you to detect and treat colorectal cancer in its earliest stages.

Talk with your primary care provider to discuss your risks and schedule a screening. Don’t have a provider? Find one at Beaufort Memorial accepting new patients.