Colon Cancer Screening for Younger Adults

Colon cancer usually occurs in people older than 50, so the U.S. Preventive Services Task Force’s recommendation is that colon cancer screening should begin when someone turns 45. However, in recent years the number of colorectal cancer cases has been increasing in adults under age 50. Colorectal cancer is now the leading cause of cancer deaths for younger adults.

Why is this happening? The exact causes are unknown, but possible explanations include:

• Diets high in processed foods and low in fiber.
• Increasing rates of obesity and more sedentary lifestyles.
• Changes in the gut microbiome—the bacteria that live in our digestive tract. Research indicates younger people with colon cancer have less bacterial diversity.
• Overuse of antibiotics, which can alter or wipe out gut bacterial strains.
• Exposure to microplastics. Younger people have been exposed to microplastics since birth.

While the reasons for the growing number of colorectal cancer cases among people under 50 remain a mystery, how to prevent colorectal cancer is not a secret. Getting screened is essential for detecting colorectal cancer early, when it can be successfully treated.

Colorectal Cancer Screening

Colonoscopy is considered the best method for colorectal cancer screening, as it allows a physician to visually inspect the rectum and colon. Any precancerous growths, called polyps, can be removed during the colonoscopy, which helps prevent colorectal cancer from occurring. Check out our blog on what really happens during a colonoscopy.

Other less-invasive screening methods are available, including tests you can do at home. These involve collecting a stool sample and sending it to a lab.

• Stool DNA/RNA tests look for microscopic traces of blood in the stool, along with DNA or RNA markers shed by precancerous polyps or cancer cells. This type of screening is done every three years.
• Fecal immunochemical tests use antibodies to look for blood in the stool. This screening is done annually.
• Guaiac-based fecal occult blood tests use a chemical reaction to detect blood in the stool. This type of screening is annual, but it requires strict dietary and medication restrictions in advance of the test.

A blood-based screening has also been approved by the Food and Drug Administration. A sample of blood is analyzed for DNA that indicates mutations or patterns linked to colorectal cancer. However, the test is considered less sensitive for detecting polyps (only about 13% are detected) than the other types of screenings available.

These non-invasive screenings are for people at average risk for colorectal cancer and who have no symptoms of bowel problems and no family history of colorectal cancer. They are not recommended for people who have an increased or high risk. For those people, a colonoscopy is the screening method of choice.

If a blood test or an in-home stool test is positive, a colonoscopy will likely be recommended to visually inspect for polyps and remove any that are found.

To determine which colorectal cancer screening method is right for you, talk with your health care provider.

Should You Get Screened?

As we said at the beginning of the article, periodic colorectal cancer screening is recommended for everyone at average risk beginning at age 45. Previously, the recommendation was that screening commence at age 50, but it was lowered to 45 a few years ago because of the increase in colorectal cancer among younger adults.

If you are younger than 45, should you get screened early? For people at average risk, the answer is no. One of the reasons to avoid early screening if you are at average risk is the possibility of a false positive and undergoing an unnecessary procedure. Check out our blog article about false positives.

If you have an increased or high risk, on the other hand, early colorectal cancer screening may be recommended. Things that can put you at increased or high risk include:

• Family history of colorectal cancer or polyps
• Inflammatory bowel disease like Crohn’s disease or ulcerative colitis 
• Genetic syndromes such as Lynch syndrome or Familial Adenomatous Polyposis (FAP) 
• Prior radiation therapy of the abdomen or pelvic area for cancer treatment

If you are under age 45 and have one or more increased risk factors for colorectal cancer, talk with your health care provider about whether you should begin screening early.

Warning Symptoms

Routine screenings for colorectal cancer are done when people have no symptoms of the disease. It is a preventive measure to find the disease when it’s in an early stage, before symptoms appear.

If you are having warning symptoms of colorectal cancer—at any age—you should see your health care provider immediately. The warning signs include:

• Blood in the stool, either bright red or dark
• Persistent change in bowel habits such as diarrhea or constipation
• Unexplained weight loss
• Ongoing abdominal pain, cramps, or bloating
• Feeling like the bowel has not completely emptied, even after going
• Consistent narrowing of the stool

Get Checked Out

Colorectal cancer is the second-deadliest cancer in the U.S. for men and women combined, with more than 55,000 Americans dying from it each year. Only lung cancer is deadlier.

If you are experiencing symptoms that may be related to colorectal cancer, be sure to get checked out by your health care provider as soon as possible.

If you don’t have symptoms, talk with your health care provider about establishing a colorectal cancer screening schedule and then stick with it. Colorectal cancer is highly treatable and can be completely cured—especially if it is found early. Regular colorectal cancer screening is the key to preventing this serious disease.