Understanding risks for colon cancer

Colon cancer, or colorectal cancer, is one of the most common forms of cancer diagnosed in the United States but also one of the most preventable and treatable. Treatment is most successful when started as early as possible, so knowing your risk factors, colon cancer symptoms and screening options could save your life. 

What is colon cancer?

Colon cancer begins when cells in your large intestine (colon) or rectum grow out of control. It typically develops slowly, starting as a non-cancerous (benign) colon polyp, which is an irregular growth in the bowel tissue. Identifying colorectal cancer symptoms and removing polyps early are key to detection and treatment.

What are common risk factors for colorectal cancer?

At times, your chance of developing colorectal cancer can’t be controlled, but sometimes making changes to some of your habits can help.

Risk factors you cannot change

• Age. The risk of getting colorectal cancer increases as you age.
• Family history. If direct family members have had colon polyps, colorectal cancer or genetic colon cancer syndromes (for example, Lynch syndrome), you’re more likely to develop colon cancer.
• Medical History. Patients with a history of inflammatory bowel disease (such as ulcerative colitis and Crohn’s Disease) are at increased risk of developing colorectal cancer.
• Gender. Men have a slightly higher risk of developing colorectal cancer than women. Recently however, the difference in risk between genders has narrowed significantly. 

Risk factors for colon cancer you can control

• Weight. Maintaining a healthy weight or losing weight can lower your risk of colorectal cancer. 
• Diet. A diet heavy in red or processed meat can increase your risk. Eating foods low in fat and high in fiber and eating plenty of fruits and vegetables can lower your risk. 
• Exercise. An active lifestyle can lower your risk of developing colon cancer. 
• Habits. Drinking alcohol in excess or smoking can contribute to your risk of colon and other cancers. 

Who has the highest risk of colon cancer?

The biggest risk factor for colorectal cancer is a family history. This includes diagnosis in directly related individuals such as biological parent, sibling(s) or child(ren). Your risk increases even more if multiple family members have developed colorectal cancer or if those family members were diagnosed before the age of 50.Still, in the United States, more than half of all colorectal cancers are diagnosed in people who have unhealthy habits including poor diet, lack of physical activity, excessive alcohol use and/or smoking. 

Ways to lower your risk of colon cancer

There are a few steps you can take to lower your risk of colorectal cancer.

• Get regular screening tests. A colonoscopy can help catch pre-cancerous growths. Stool test kits can help catch hidden blood or cancer-related DNA in your stool.
• Modify your diet. Improve your colon and gut health with a diet low in fat and high in fiber. Eat plenty of fruits, vegetables and whole grains.
• Make lifestyle changes. Make healthy choices, especially at a young age, to improve your overall health and decrease your risk of developing colorectal cancer. Get regular exercise and maintain a healthy weight. Drinking alcohol, using tobacco, being overweight and not getting enough exercise can increase your risk of colorectal cancer.
• Know your family history. When possible, find out if your parents or siblings have had polyps or colorectal cancer.

Why are more younger adults getting colon cancer?

A 2023 study from the American Cancer Society showed diagnoses of colorectal cancer in adults younger than 55 increased from 11 percent (1 in 10) in 1995 to 20 percent (1 in 5) in 2019.

While studies are confirming more younger adults are getting colon cancer, experts aren't sure why. Some National Cancer Institute studies point to external factors, such as unhealthy diets containing processed meats, inactivity due to frequent sitting, or altered gut bacteria from chemicals we eat, drink and breathe, which have become more common. This reinforces that certain lifestyle factors to reduce the risk of colon cancer are under your control, such a healthy diet and increased activity levels. 

Other experts say young adults may put off getting early symptoms evaluated, increasing the likelihood that colon cancer isn’t caught until the stage is more severe and more challenging to treat. The American College of Surgeons says the most common signs of colon cancer in younger patients are blood in the stool, abdominal pain, anemia and altered bowel habits, which is why it’s important to pay attention to signs and talk to your doctor. 

Still, some researchers say they are unable to determine why seemingly healthy young patients without any risk factors are being diagnosed with the disease.

Colorectal cancer symptoms

Signs of colon cancer can vary, including some or all the following symptoms:

• change in bowel habits, including the frequency, size, color and shape, or constipation or diarrhea lasting more than a month
• rectal bleeding or signs of blood in your stool
• consistent pain during bowel movements or a feeling that your bowel does not empty completely
• stomach discomfort (bloating, fullness, cramps, gas or abdominal pain) or unexplained weight loss

It’s important to talk to your provider, because colorectal cancer symptoms can also be signs of other problems such as ulcers, an inflamed colon or hemorrhoids.

Ways to get screened for colon cancer

Screening typically starts at age 45, but if you have certain risk factors, your provider may suggest you start screening earlier for colon cancer. Because treatment for colon cancer is more successful when it’s caught early, it’s important to talk to your provider about when to begin your screenings. There are a few options for colon cancer screening:

Colonoscopy: This is often considered “the gold standard” for detecting and diagnosing colorectal cancers. While you’re under sedation at a hospital or surgery center, a gastroenterologist or general surgeon inserts a thin flexible tube with a tiny camera into your rectum and through your entire colon. This screening should be repeated every 10 years. 

Stool test (iFOBT): This is an at-home screening test that detects hidden blood in the stool. This test should be completed annually.

FIT-DNA: This is a screening test that detects abnormal DNA or blood in the stool. This test should be completed every three years.