Your colon cancer screening guide

Let’s start with the good news: When colorectal cancer is diagnosed early, it’s highly survivable. In fact, there are more than 1.5 million colorectal cancer survivors in the United States today.

(Note: The term “colorectal cancer” refers to both colon cancer and rectal cancer, with colon cancer being the more widespread of the two.)

In recent years, there’s been a push to get more people screened for it. Plus, medical technology is better than ever, and more treatment options are available as well. In fact, the number of deaths caused by colon cancer has been dropping for several decades.

That said, colon cancer isn’t something to be taken lightly. It’s still one of the leading causes of cancer deaths in the United States, and more people under the age of 50 are being diagnosed with colon cancer than ever before.

Here’s what you need to know about detecting this common cancer, as well as the lifestyle habits to help keep you and your colon healthy.  

When should I start screening for colorectal cancer?

Because cases are showing up earlier than age 50, the American Cancer Society (ACS) and the U.S. Preventive Services Task Force both recommend that colorectal cancer screenings begin at age 45.

Those with a higher risk for colon cancer may need to start screenings sooner. Common reasons for increased risk include:

• Colorectal cancer or adenomatous polyps (growths in the lining of the rectum or colon)
• Crohn’s disease
• Family or personal history
• Ulcerative colitis

The types of screening tests

There are two main types of screening tests: stool-based and visual. The first type is noninvasive. Your stool will simply be checked for signs of cancer. Visual exams such as a colonoscopy look at the structure of your colon or rectum for cancer.    

Both types have their pros and cons, including differences in how often they need to be performed. And some might be a better fit for you than others. For example, if you are in a higher-risk group, your doctor may recommend a full colonoscopy for screening, while those with average risk may be able to use the noninvasive stool tests.  

Keep in mind: If results for tests other than a colonoscopy come back positive, a full colonoscopy is still recommended to confirm, or rule out, those findings. Talk to your doctor about which test is right for you and when it should be performed.  

Here’s a rundown of your colorectal cancer screening options:   

Visual tests

• Colonoscopy: This exam is the most common and most thorough type of screening. It usually requires pre-screening prep using laxatives to empty the bowels before the test. During the test, you’ll be given anesthesia. Then a small, flexible tube with a camera at the end (called a scope) is inserted into the colon via the rectum to examine the full length of the colon. The pros of this gold-standard screening are that suspicious-looking growths can be removed and biopsied during the test. 

  Recommended frequency by the ACS: Every 10 years

• Flexible sigmoidoscopy: This screening uses a flexible, narrow tube with a camera attached to the end and visualizes the lower part of the colon (not the entire colon, as a colonoscopy does). 

  Recommended frequency by the ACS: Every five years

• Computed tomographic colonography (virtual colonoscopy): A CT scan analyzes your abdominal organs, as opposed to a physical scope being inserted. (Note: Pre-procedure prep is still needed ahead of this screening.) 

  Recommended frequency by the ACS: Every five years

Stool-based tests

• Fecal occult blood test (FOBT) and fecal immunochemical test (FIT): FOBT and FIT are noninvasive screenings that test for blood in the stool, which can be a sign of polyps or cancer. The tests require no prep, but some foods or drugs can affect the results of the FOBT, so discuss dietary restrictions with your doctor. You’ll collect a bowel movement and send it back to the lab in supplied packaging. If the screening finds blood in the stool, you will be offered more tests, such as a colonoscopy, to determine the cause of the bleeding.

  Recommended frequency by the ACS: Every year

• Stool DNA test (also known as a multitargeted stool DNA test, or mt-sDNA): A noninvasive test that looks for altered DNA and/or blood in the stool. Just like the FOBT and FIT tests, no prep is required. If any abnormalities are found, a colonoscopy is recommended.  

  Recommended frequency by the ACS: Every three years

The best ways to prevent colon cancer

Take these actions to lower your risk of colon cancer, according to the ACS:

• Make movement a part of your day. Aim for 30 minutes or more of moderate exercise each day. This will help you maintain a healthy weight, which prevents many diseases, including cancer. 
• Fill your plate with nourishing foods. Focus on a healthy eating pattern that includes nutrient-rich foods like vegetables, beans, fruits, and whole grains. Try to limit red and processed meats, sugar-sweetened beverages, and highly processed foods like packaged cookies and cakes.    
• Don't smoke. Smoking raises the risk of numerous cancers as well as heart disease, stroke, and emphysema. It should be avoided entirely. If you need help quitting, talk to your doctor.  
• Limit alcohol. Drinking alcohol increases your cancer risk. If you choose to drink, limit yourself to no more than one drink per day if you’re a woman and two drinks per day if you’re a man.    

At your next doctor's appointment, ask your doctor about your risk level, whether you are due for a screening, and which type of test is right for you.