Key Takeaways
The American Cancer Society updated its colorectal cancer screening guidelines to include a broader range of screening options, featuring additional at-home stool tests and, for the first time, a blood-based test
New screening tools like the updated Cologuard test, ColoSense and the Shield blood test aim to make colorectal screenings easier to access for all eligible Americans.
Individuals with an average risk for colorectal cancer should consult their doctor about beginning screening at the age of 45.
Colorectal cancer is the leading cause of cancer deaths in people under the age of 50 in the United States, and the second-leading cause of cancer deaths overall.
The American Cancer Society updated its colorectal cancer screening guidelines. The new guidelines reaffirm some of the nonprofit organization’s previous criteria, while updates include additional at-home screening options that aim to make screenings easier to access as colorectal cancer mortality rates per year have continued to increase.
What Are the Changes in the New Colon Cancer Screening Guidelines?
Three new colon cancer screening options have been added as viable options:
An updated version of Cologuard, an at-home stool test that checks for cancer-specific DNA mutations and blood in feces
ColoSense, an at-home stool test that screens for cancer-specific RNA markers and blood in feces
The Shield blood test, the first blood test to be added to the screening guidelines, detects cancer DNA in a person’s blood if it has been shed by a tumor.
Changes to the screening guidelines by the ACS reflect the critical nature of early detection by working to offer more accessible screening options in hopes of preventing the disease or catching it in the early stages.
Of those eligible for recommended colon cancer screenings, 1 out of 3 Americans, more than 22 million people, have never been tested.
“We need to increase our emphasis on colorectal cancer as a highly preventable disease as much as a treatable one,” Robert Smith, senior vice president of Early Cancer Detection Science for the ACS and senior author of the report, said in a statement.
New At-Home Stool Tests and Colon Cancer Blood Tests Explained
Here is how the three new test options stack up in the guidelines:
Crucial clinical nuance
The ACS guidelines strictly emphasize that any abnormal or positive result from a stool-based or blood-based test must be followed up with a diagnostic colonoscopy – ideally within six months – to ensure any polyps or early-stage cancers are caught and removed.
Other colon cancer screening guidelines have remained unchanged as their effectiveness has proven effective in early detection.
Visual Screening vs. Stool Tests: Choosing Your Colon Cancer Screening Options
There are the types of screenings and options with specific timelines for each.
Visual screening
Colonoscopy: A colonoscopy is both the most common and most recommended form of screening. To prepare for the procedure, you are prescribed a bowel prep the day before in the form of liquid, pills or both, to clear out stool and debris from your colon and rectum so that your doctor can view it clearly during the procedure.
During the procedure, usually performed by a gastroenterologist or a colorectal surgeon, you are sedated while the doctor inserts a colonoscope, a long catheter with a camera, into your anus so that they can examine the inner lining of your colon and rectum for polyps or abnormalities. Any polyps found are typically removed and biopsied. If the doctor finds nothing abnormal, and you aren’t considered high-risk, you typically won’t need to have another colonoscopy for 10 years. However, if anything of concern is found, the doctor may suggest you return for your next colonoscopy sooner.
CT colonography: This is a virtual colonoscopy, where you are awake and a tube is inserted into the anus to inflate the bowel with gas for better visualization while a computerized tomography scanner, or CT scanner, takes pictures of your colon and rectum. You still need to undergo a bowel prep, similar to a colonoscopy. It’s recommended for every five years.
Sigmoidoscopy: A sigmoidoscopy uses a sigmoidoscope, a flexible tube with a small camera at the end similar to a colonoscope, inserted in the anus to examine the rectum and the lower part of the colon. The camera allows the doctor to see any abnormalities and potentially remove them.
However, it doesn’t allow the doctor to examine your entire colon. You will still undergo a bowel prep, most likely using an enema, prior to the procedure. Most people aren’t sedated for the procedure but it can be discussed with your doctor. It’s recommended for every five years.
Stool-based tests
Fecal immunochemical test (FIT): A FIT test detects hidden blood in your stool and is recommended once every year.
FIT-DNA test: A FIT-DNA test detects both blood and DNA mutations in your stool and is recommended once every year.
Multi-targeted stool DNA (mt-sDNA) test: Cologuard, the brand name version of this test, checks for cancer-specific DNA mutations and blood in feces. It is recommended for every three years.
Multi-targeted stool RNA (mt-sRNA) test: ColoSense, the brand name for this test, screens for cancer-specific RNA markers and blood in feces. It is recommended for every three years.
Blood test
The Shield blood test: This blood detects cancer DNA from tumors in your blood. However, blood-based tests are a last resort and are only recommended if you refuse to get any other version of screening, as they have a much lower sensitivity in detecting advanced precancerous lesions and stage I cancers compared to the recommended stool-based tests.
Abnormal or positive results
If you receive a positive result for any of the stool-based or blood-based tests, you need to schedule a follow-up colonoscopy to thoroughly screen for any abnormalities.
Colon Cancer Screening Age: Who Needs Testing and When?
Determining who should be screened for colorectal cancer, and when, comes down to your age, your cancer risk and what type of screening you use.
Those with a higher risk of cancer may be advised to be screened earlier and more frequently. Similarly, different types of colorectal screenings have different timelines for how often they should be performed.
“Given rising rates of colorectal cancer in younger adults, timely screening is especially important,” says Dr. Paul Limburg, the chief screening medical officer for Abbott Cancer Diagnostics. “The disease is highly treatable when found early, which is why following recommended screening guidance remains so important.”
These are the ACS’s general guidelines:
People with an average risk of colorectal cancer can begin screening at the age of 45. and should continue to receive screenings through the age 75 (if their life expectancy is greater than 10 years).
People who have an increased or high risk of colorectal cancer should begin screening before the age of 45, receive more screenings than someone with an average risk, and should have specific screening tests (to be discussed and determined with their doctor).
People between the ages of 76 and 85 should decide whether or not they will get screened based on their screening history, their health, their life expectancy and their personal preference.
People over the age of 85 can stop colorectal cancer screenings.
“People 45-49 years make up 50% of diagnoses under 50,” Dr. Ahmedin Jemal, senior vice president of Surveillance, Prevention and Health Services research for the ACS said in a statement, “so increased screening uptake will prevent disease as well as death.”
How to Know Which Screening Option Is Right for You
A colonoscopy remains the gold standard for the prevention and early detection of colorectal cancer. However, access to a colonoscopy, certain medical conditions or an unwillingness to undergo the bowel prep can all prevent someone from using this form of screening.
You should consult with your doctor to find out which is right for you.
Early detection remains critical in increasing a person’s chances of survival. When discovered in the early stages, colorectal cancer has a five-year survival rate of more than 90% in the United States. What’s most important is that when you are advised and eligible for screening, that you do get checked in one of these advised forms.