You know colorectal cancer screenings are important and can be lifesaving, but you dread getting a colonoscopy.
“When it comes to colonoscopies, patients are often concerned about discomfort, cost, prep and potential complications,” says Dr. Johann Hsu, an oncologist at Atrium Health Levine Cancer. “Many also feel that they are healthy and don’t necessarily need a screening.”
However, even if you feel healthy, colorectal cancer screenings are essential. They can detect cancer and precancerous polyps in their earliest, most treatable stages.
“Colon cancer is the third most common cancer in men and women,” says Hsu. “Finding it early improves survival.”
The good news is there are now less-invasive colorectal cancer screenings on the market; but how effective are they?
Colorectal screening test options
There are a few types of colorectal screening tests available:
- Visual (structural) tests, where a doctor looks at your colon and rectum using special imaging tests or a scope. Visual tests include colonoscopy, CT colonography and sigmoidoscopy.
- Blood-based tests, where a sample of your blood is sent to a laboratory for testing to check for signs of colorectal cancer or precancerous polyps.
- Stool-based tests, which are usually done at home. These tests screen stool (feces) for signs of colorectal cancer or polyps.
There are pros and cons to each type of colorectal cancer screening.
Pros and cons of colonoscopy for colorectal cancer screening
During a colonoscopy, while you are completely sedated, a long, flexible tube called a colonoscope is inserted into the rectum to look for colorectal cancer, precancerous polyps and swollen or irritated tissue.
Pros:
- Can examine the entire colon.
- Allows for immediate biopsy and removal of polyps and abnormal tissue.
- Done every 10 years.
- Can help detect other diseases.
Cons:
- Requires full bowel prep.
- Sedation is required.
- Small risk of infection, bleeding and bowel tears.
Pros and cons of CT colonography for colorectal cancer screening
CT colonography is a computed tomography (CT) scan of the rectum and colon to look for abnormal areas. During the screening, a small catheter is placed in the rectum to fill the colon with air for better imaging results.
Pros:
- Takes about 15 minutes.
- Generally safe.
- Can examine the entire colon.
- No sedation is required.
- Done every five years.
Cons:
- Can miss small polyps.
- Polyps cannot be removed during the procedure.
- Requires full bowel prep.
- Possibility of false-positive results.
- Colonoscopy is needed if you have abnormal results.
Pros and cons of sigmoidoscopy for colorectal cancer screening
Sigmoidoscopy is similar to a colonoscopy, but it only examines the anus, rectum and lower portion of the colon.
Pros:
- Avoids the need for sedation.
- Decreased bowel perforation rates.
- Only takes about 10 to 20 minutes.
Cons:
- Only evaluates the lower portion of the colon.
- Not a commonly used screening test in the United States.
- May require bowel prep.
- Small risk of bowel tearing, bleeding or infection.
- Possible discomfort.
- Colonoscopy is needed if you have abnormal results.
Pros and cons of blood-based tests for colorectal cancer screening
There are currently two blood-based tests approved by the FDA: Epi proColon and Shield.
Pros:
- Does not require bowel prep.
- No need to adjust your medications or diet before the test.
- No risk to the colon.
Cons:
- Can miss polyps and cancers.
- Insurance coverage can vary.
- Colonoscopy is needed if you have abnormal results.
Pros and cons of stool-based tests for colorectal cancer screening
Stool-based tests include the fecal immunochemical test (FIT), guaiac-based fecal occult blood test (gFOBT)and stool DNA test. Both FIT and gFOBT look for hidden blood in the stool. A stool DNA test looks for hidden blood in the stool and abnormal sections of DNA related to polyps or cancer cells.
Pros:
- No direct risk to the colon.
- No bowel prep.
- Sampling can be done at home.
Cons:
- Can miss polyps and some cancers.
- Can have false-positive results.
- Stool DNA tests must be done every three years.
- FIT and gFOBT tests must be done every year.
- Colonoscopy is needed if you have abnormal results.
“Multitarget stool DNA test (Cologuard) has a sensitivity of 92% in detecting colorectal cancer. However, the sensitivity of the test for detecting advanced precancerous lesions is only 43%. This is why I still recommend colonoscopy as the test of choice,” says Dr. Jessica Sang, a gastroenterologist at Atrium Health.
When should you get a colorectal cancer screening?
Your colorectal cancer screening recommendations are based on your personal risk factors. Hsu says if you answer “no” to the following questions, you have an average risk of colorectal cancer. If you answer “yes” to any of these questions, you are considered high-risk:
- Have you ever had colorectal cancer or a precancerous polyp?
- Do you have any biological family members who have had colorectal cancer or a documented advanced polyp?
- Do you have biological family members with any known genetic syndromes that cause colorectal cancer, including familial adenomatous polyposis (FAP), Lynch syndrome, juvenile polyposis syndrome, Peutz-Jeghers syndrome or MUTYH-associated polyposis?
- Do you have inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease?
- Did you receive abdominal radiation for childhood cancer?
Average risk: If you have an average risk of colorectal cancer, you should begin regular screenings at age 45. If you are in good health, you should continue screenings through age 75. If you’re between ages 76 and 85, your screening frequency will be determined based on your personal preferences, life expectancy, overall health and prior screenings. After age 85, colorectal cancer screenings are no longer recommended.
High risk: If you have a high risk of colorectal cancer, you will likely need to begin colorectal cancer screenings before age 45. Talk to your healthcare provider to determine when you should begin screenings.
The American College of Gastroenterology recommends a colonoscopy every 10 years or a fecal immunochemical test (FIT) annually as the primary screening methods. “The other tests should only be an alternative if the patient is not willing to undergo these as the first step,” Sang says.
“The important message we want to convey to our patients is that screening is essential,” Hsu says. “A less invasive option is better than no screening, but the colonoscopy remains our best tool in detecting colorectal cancers.”
Use our risk assessment tool and more about colorectal cancer screenings at Atrium Health.
