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What is colon cancer?

Medically reviewed on February 22, 2022 by Jordan Stachel, M.S., RDN, CPT. 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.

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Colon cancer, also referred to as colorectal cancer, is cancer that develops within the lining of the colon. It’s one of the most common types of cancers seen in men and women in the United States [1].

While common, colon cancer is also increasingly preventable, thanks to effective screening protocols, early cancer treatment options, and at-home colon cancer screening tests. If you’re ready to start taking your health into your own hands, you’ve come to the right place.

Below, we’ll break down the symptoms of colon cancer, risk factors, and current colorectal cancer screening recommendations. We’ll also provide some proactive measures to reduce the risk of colon cancer.


How does colon cancer develop?

Colon cancer occurs when cells within the colon begin to multiply uncontrollably. These abnormal cells usually begin as small, precancerous polyps. A colon polyp impacts between 20% and 30% of the U.S. adult population [2]. While most colorectal polyps are harmless, some may become cancerous over time.

Colon polyps rarely have any noticeable symptoms, so you may not detect them until your first colorectal cancer screening [3]. By removing these colorectal polyps before they become cancerous, colon cancer can be successfully prevented.

If a colon polyp has already become cancerous, however, colon cancer treatment such as surgery, chemotherapy, or a combination of both is an option.

What are the symptoms of colon cancer?

Colon cancer doesn’t always have noticeable symptoms. However, the most common symptoms associated with this disease are:

  • A change in bowel movement
  • Narrow, pencil-thin stools
  • Blood in stools
  • Frequent abdominal pain or bloating
  • An ongoing sense of incomplete bowel evacuation
  • Weakness, tiredness, and fatigue
  • Nausea or vomiting
  • Significant, unexplained weight loss

If you experience any of these symptoms, you should inform your healthcare provider right away.

What are the risk factors for colon cancer?

While the cause of colon cancer is still unknown, some risk factors that have been identified are [4]:

Age – Colon cancer can develop at any age, but older adults are a greater risk factor. 90 percent of colon cancer cases occur in people over the age of 50.

Race – African Americans currently experience the highest prevalence of colon cancer in the United States. If you’re African American, you could be 20 percent more likely to develop colon cancer than people of other racial backgrounds [5].

History of colon polyps – If you’ve had colon polyps or colon cancer in the past, you may be at greater risk for developing colon cancer in the future [6].

Family history of colon cancer – There is a greater propensity to develop colon cancer if other people in your family have too, especially first-degree relatives.

Abdominal radiation – If you’ve ever had radiation therapy around the abdomen, it may increase the risk of developing colon cancer in the future.

Having certain genetic mutations – Some genetic mutations are associated with a notably higher risk of colon cancer. Around 5 percent of people who develop colon cancer have one of these genetic mutations. The most common ones are hereditary nonpolyposis colorectal cancer (also known as Lynch syndrome) and familial adenomatous polyposis (FAP). Genetic counseling can help to determine if there are these inherited mutations.

Inflammatory bowel disease – Chronic intestinal inflammation can increase colon cancer risk. It’s associated with conditions such as ulcerative colitis and Crohn's disease [7].

Obesity and type 2 diabetes – If you are overweight, obese, or have type 2 diabetes, there may be at greater risk of developing colon cancer. These conditions can also worsen the prognosis if colon cancer develops.

Smoking, drinking, and inactivity – Smoking cigarettes, heavy alcohol consumption, and leading a sedentary lifestyle can all increase the risk of developing colon cancer, as well as increasing the risk for a slew of other health problems.

A diet that’s low in fiber and high in saturated/trans fats – Lastly, diet plays a notable role in colon health and subsequent cancer risk. The standard American diet tends to be low in fiber and high in saturated/trans fats. Unfortunately, this type of diet may be associated with an increased risk of colon cancer.

As you can see, some colon cancer risk factors are hereditary, while others are within your control. By taking proactive steps to lead a healthier lifestyle, you may be able to lower your risk of developing this disease.

How to screen for colon cancer

Colon cancer screening can help your healthcare provider identify polyps within the colon before they turn cancerous.

It is recommended to have regular colon cancer screenings from ages 45 to 75 [8]. However, your healthcare provider may advise that screening start sooner if colon cancer runs in your family or if you have a notable risk factor.

Here are the most common types of colon cancer screening tests [9]:

Stool tests – One way to screen for colon cancer is to look for blood in the stool using a fecal occult blood test (FOBT) or a fecal immunochemical test (FIT). These tests only require a small sample of stool. You can complete them from home and send the samples to a lab for examination. These tests should be done once a year.

Stool DNA test – Another common stool test is a FIT-DNA test. It combines the FIT stool test with one that can detect altered DNA in the stool. Altered DNA may indicate the presence of cancerous cells. This test requires a sample of a full bowel movement. It should be done once every three years.

Flexible sigmoidoscopy – A flexible sigmoidoscopy is a procedure in which a healthcare provider visually examines the rectum and lower colon using a lighted, flexible tube with a camera at the end. During this procedure, a healthcare provider can look for polyps and potential cancer cells. This test should be done every five years.

Colonoscopy – A colonoscopy allows a healthcare provider to examine the entire colon. If they see any polyps or cancers, they can remove them during the procedure. Colonoscopies are often administered when other colon cancer screening tests uncover abnormalities. Colonoscopies should also be done as a part of a regular screening every 10 years.

Computed tomography (CT) colonography – A CT colonography constructs images that map out the entire colon. These images can give a healthcare provider a better look at the colon. If there are any colon polyps or tumors, a CT colonography can show their shape, size, and location in greater detail.

How to diagnose colon cancer

If any concerns arise during colon cancer screening, a healthcare provider can perform a variety of diagnostic tests to determine if there is colon cancer.

Some of these diagnostic tests include:

  • Colonoscopies with biopsies
  • Colon tumor biomarker testing
  • Blood tests
  • CT or CAT scans
  • Magnetic resonance imaging (MRIs)
  • Ultrasounds
  • Positron emission tomography (PET) scans

The specific tests a healthcare provider will use to diagnose colon cancer will depend on symptoms, age, health, family history, and medical history.

Colon cancer prognosis

The overall survival rate for colon cancer five years post-treatment is 63 percent [10]. However, the prognosis of a colon cancer diagnosis largely depends on the cancer’s staging when it’s first discovered.

Here are the five-year survival rates for colon cancer discovered in the following stages:

  • 91% – Localized (the cancer is contained within the lining of the colon)
  • 72% – Regional (the cancer has spread to the surrounding area or lymph node)
  • 14% – Distant (the cancer has spread to distant parts of the body)

As you can see, catching colon cancer early on can make a significant difference in its prognosis. That’s why colon cancer screening is so important.

How to prevent colon cancer

Colon cancer takes the lives of tens of thousands of Americans each year [11]. By proactively screening for colon cancer, you can reduce your risk of dying from colon cancer.

In addition to attending regular colon cancer screenings, you can reduce your risk by [12]:

  • Maintaining a healthy weight
  • Increasing physical activity
  • Eating a diet that’s high in fruits, vegetables, and whole grains
  • Limiting consumption of red meat and processed meat
  • Reducing or eliminating alcohol consumption
  • Quitting smoking

If you have ever questioned how to keep your colon healthy, many of these healthy habits can help lower the risk for colon cancer, other types of cancers, or chronic diseases such as obesity, type 2 diabetes, and more.

Track your colon health at home with Everlywell

Want to monitor colon health from the comfort of your own home? By taking an at-home Colon Cancer Test from Everlywell, you can. Our FIT Colon Cancer Screening Kit is available to anyone over the age of 45. It can help you get ahead of colon cancer by detecting any traces of blood that may be in the stool. Best of all, it's non-invasive and easy to use.

Like all our tests, our FIT Colon Cancer Test kit gets sent to a CLIA-certified laboratory that adheres to the highest standards. If test results come back positive for blood, you can discuss them with one of our independent healthcare providers who are committed to helping you find the best steps forward.

Proactive screening is the key to colon cancer prevention. Take ownership over your health and order one of our at-Home colon cancer screening kits today.

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1. Key Statistics for Colorectal Cancer. American Cancer Society. URL. Accessed February 22, 2022.

2. They found colon polyps: Now what? Harvard Health. Harvard Health. URL. Accessed February 22, 2022.

3. Colon polyps - Symptoms and causes. Mayo Clinic. URL. Accessed February 22, 2022.

4. Colorectal Cancer. Harvard Health. URL. Accessed February 22, 2022.

5. Colorectal Cancer Rates Higher in African Americans, Rising in Younger People. American Cancer Society. URL. Accessed February 22, 2022.

6. Colon polyps - Symptoms and causes. Mayo Clinic. URL. Accessed February 22, 2022.

7. Inflammatory bowel disease (IBD) - Symptoms and causes. Mayo Clinic. URL. Accessed February 22, 2022.

8. What Should I Know About Screening for Colorectal Cancer? Centers for Disease Control and Prevention. URL. Accessed February 22, 2022.

9. Colorectal Cancer Screening Tests. Centers for Disease Control and Prevention. URL. Accessed February 22, 2022.

10. Rectal Cancer: What Is It, Signs, Stages & Treatment. Cleveland Clinic. URL. Accessed February 22, 2022.

11. QuickStats: Death Rates* from Colorectal Cancer,† by Age Group — United States, 1999–2019. MMWR Morbidity and Mortality Weekly Report. 2021;70(35):1233.

12. What Can I Do to Reduce My Risk of Colorectal Cancer? Centers for Disease Control and Prevention. URL. Accessed February 22, 2022.

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