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Who is at risk for colon cancer?

Medically reviewed by Neka Miller, PhD on June 15, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.


What risk factors make it more likely that someone will develop colon cancer? That’s what you’ll discover here—so read on to better understand who is at risk for colon cancer, when to take a colon cancer screening test, and more. Let’s start by taking a closer look at what colon cancer is in the first place.

Colon cancer: an overview

Colon cancer develops in the large intestine, also called the colon—the final part of your digestive tract (which begins at the mouth). You might also hear it referred to as colorectal cancer, which describes cancer that affects the colon and the rectum (which makes up the last part of the large intestine).


Related: Signs of colon cancer in women


Adenocarcinomas are the most common form of colorectal cancer. These develop in the cells (epithelial cells) that line the large intestine and typically start as a growth of tissue called a polyp (polyps are often removed during colonoscopies to prevent cancer development).

Other less common types of colorectal cancer include lymphomas, gastrointestinal stromal tumors, sarcomas, and carcinoid tumors.

Colon cancer risk factors

Who is at risk for colon cancer? Here are some top risk factors to note.

Age

The risk of colon cancer increases with age. Most people who are diagnosed (over 90% in fact) are age 50+. That’s why public health organizations like the U.S. Preventive Services Task Force (USPSTF) recommends routine, annual colon cancer screening for women and men who are age 50+ and who have an otherwise average risk. To easily screen for colon cancer from the comfort of home, consider the Everlywell FIT Colon Cancer Screening Test.

Physical activity levels and obesity

Low levels of physical activity and obesity are two related risk factors for colon cancer. More frequent and/or intense physical activity is linked with a lower risk. On the other hand, obesity—which can result in part from a lack of physical activity—is connected with a greater likelihood of colon cancer.

Diet

Diet is a lifestyle factor that affects colon cancer risk. A diet that’s high in red meats (think beef, pork, lamb, and liver) and processed meats—like certain lunch meats and hot dogs—raises one’s risk for colon cancer. What’s more, cooking meats at high temperatures—like frying, broiling, or grilling—creates chemical byproducts that may also increase colon cancer risk. Colon cancer risk may also be associated with a diet that’s low in fiber, fruits, and vegetables.

Alcohol and cigarette smoking

Cigarette smoking is a well-known cause of lung cancer, but it also puts you at an increased risk for other cancers as well—including colon cancer. Colon cancer risk has also been linked to moderate to heavy alcohol consumption.

Inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn’s disease, is another factor that puts you at a higher risk for colon cancer. With IBD, the colon is inflamed over a long period of time. If left untreated, you can develop dysplasia, which makes the cells that line the colon appear abnormal. Although these aren’t true cancer cells, they can become cancerous over time. For this reason, people who have IBD may need routine colon cancer screening at a younger age than people at average risk—and on a more frequent basis. If you have IBD, ask your healthcare provider what screening frequency is right for you.

Type 2 diabetes

Those with type 2 diabetes may have an increased risk of colorectal cancer. Type 2 diabetes and colon cancer share similar risk factors, like physical activity levels and obesity. However, even after taking into account these overlapping risk factors, those with type 2 diabetes still have an increased risk of developing colon cancer.

Race

In the United States, black communities face the highest risk of colon cancer compared to other racial groups. Barriers to equal access to screening and care (such as insurance coverage or lack thereof) play key roles in this disparity.

Family history

If you have a family history of colon cancer and a blood relative who has been diagnosed, you’re more likely to develop the disease yourself. Your risk increases if more than one family member has had colon cancer.

Genetics

About 5% of individuals who develop colon cancer have inherited gene mutations that cause family cancer syndromes. The most common syndromes that are passed down through genetics and are linked to colon cancer are Lynch syndrome and familial adenomatous polyposis.

Lynch syndrome, also known as hereditary non-polyposis colon cancer or HNPCC, is the most common hereditary colon cancer syndrome. It accounts for between 2–4% of all colorectal cancers. Depending on which gene is affected, the average risk for those with this syndrome might be as high as 80%.

Familial adenomatous polyposis, or FAP for short, accounts for about 1% of colon cancers. It’s caused by a gene that you inherit from your mother or father. There are three different types of FAP; the most common one causes hundreds or thousands of polyps to form on the colon or rectum. As early as age 20, cancer may develop from one or more of these polyps.

When considering genetic syndromes and who is at risk for colon cancer, there are other inherited (but rare) conditions that may increase one’s risk. These include Peutz-Jeghers syndrome (PJS) and MYH-associated polyposis (MAP).

Colon cancer symptoms

According to Mayo Clinic, the following are symptoms and early signs of bowel cancer.

  • A persistent change in bowel habits, including diarrhea or constipation or a change in the consistency of your stool
  • Rectal bleeding or blood in your stool
  • Persistent abdominal discomfort, such as cramps, gas, or pain
  • A feeling that your bowel doesn't empty completely
  • Weakness or fatigue
  • Unexplained weight loss

It’s important to note that when it comes to colon cancer, many people experience no symptoms at all in the early stages. When they do appear, symptoms can vary based on the cancer’s size and specific location in the large intestine.

Colon cancer screening

Colorectal cancer typically develops from precancerous polyps in the colon or rectum and if these are found through screening, they can be removed before cancer develops.

The U.S. Preventive Services Task Force recommends annual colon cancer screening for women and men who are in the 50-75 age range. Several different screening methods exist, including fecal occult blood tests, colonoscopy, flexible sigmoidoscopy, and CT colonography (virtual colonoscopy).

If you may be at a higher risk for colorectal cancer, talk with your healthcare provider about screening options. If you are age 50+ and would like to screen for colon cancer from the comfort of home, try our at-home colon cancer screening test.


References

1. Colon cancer. Mayo Clinic. URL. Accessed June 15, 2020.

2. Basic Information About Colorectal Cancer. Centers for Disease Control and Prevention. URL. Accessed June 15, 2020.

3. What Is Colorectal Cancer? American Cancer Society. URL. Accessed June 15, 2020.

4. What Are the Risk Factors for Colorectal Cancer? Centers for Disease Control and Prevention. URL. Accessed June 15, 2020.

5. Haggar FA, Boushey RP. Colorectal cancer epidemiology: incidence, mortality, survival, and risk factors. Clin Colon Rectal Surg. 2009;22(4):191-197. doi:10.1055/s-0029-1242458

6. Alshareef SH, Alsobaie NA, Aldeheshi SA, Alturki ST, Zevallos JC, Barengo NC. Association between Race and Cancer-Related Mortality among Patients with Colorectal Cancer in the United States: A Retrospective Cohort Study. Int J Environ Res Public Health. 2019;16(2):240. doi:10.3390/ijerph16020240

7. Tawk R, Abner A, Ashford A, Brown CP. Differences in Colorectal Cancer Outcomes by Race and Insurance. Int J Environ Res Public Health. 2015;13(1):ijerph13010048. doi:10.3390/ijerph13010048

8. Jasperson KW, Tuohy TM, Neklason DW, Burt RW. Hereditary and familial colon cancer. Gastroenterology. 2010;138(6):2044-2058. doi:10.1053/j.gastro.2010.01.054

9. What Should I Know About Screening? Centers for Disease Control and Prevention. URL. Accessed June 15, 2020.

10. Hamzehzadeh L, Yousefi M, Ghaffari SH. Colorectal Cancer Screening: A Comprehensive Review to Recent Non-Invasive Methods. Int J Hematol Oncol Stem Cell Res. 2017;11(3):250-261.