Colon cancer is one of the most preventable cancers when precancerous polyps are found and removed before they have a chance to develop into cancer. Screening can also find colorectal cancer at an earlier stage, when treatment may be more effective.
There are several ways to screen for colorectal cancer. Some tests examine the colon directly, while others look for signs of cancer or precancerous changes in a stool or blood sample. Each approach has advantages and limitations.
As a gastroenterologist, I recommend colonoscopy because it allows me to examine the colon directly and remove precancerous polyps during the same procedure. However, understanding the available screening options can help you have an informed conversation with your healthcare provider about the appropriate test for you.
When Should Colon Cancer Screening Begin?
For adults at average risk of colorectal cancer, the American Cancer Society recommends regular screening beginning at age 45. People at increased risk may need to begin screening earlier or follow a different screening schedule.
Your risk may be affected by factors such as a personal or family history of colorectal cancer or certain polyps, inflammatory bowel disease, or an inherited condition associated with colorectal cancer.
Screening recommendations generally apply to people who do not have symptoms. If you are experiencing rectal bleeding, blood in your stool, an unexplained change in bowel habits, persistent abdominal symptoms, or other concerning digestive symptoms, talk with your healthcare provider rather than waiting for routine screening.
What Are the Main Colon Cancer Screening Options?
Several recommended colorectal cancer screening strategies are available, including tests that examine the colon and rectum directly and stool-based tests that look for blood or other markers associated with colorectal cancer.
For most people deciding how to be screened, colonoscopy and at-home stool tests are among the options they are most likely to encounter.
Colonoscopy
A colonoscopy allows a gastroenterologist to examine the inside of the entire colon and rectum using a thin, flexible instrument with a camera. Unlike other screening tests, colonoscopy can both detect and remove precancerous polyps during the same procedure.
For an average-risk person with a normal examination, screening colonoscopy is generally performed every 10 years. Colonoscopy requires bowel preparation beforehand and typically involves sedation.
If you would like more information about the procedure itself, visit our page about colonoscopy with Dr. Sameer Islam.
Fecal Immunochemical Test (FIT)
The fecal immunochemical test, commonly called FIT, is an at-home stool test that looks for hidden blood in the stool. It does not require bowel preparation or sedation.
FIT is generally performed every year. Because it does not allow a physician to directly examine the colon, an abnormal FIT result needs to be followed by a colonoscopy.
Multitarget Stool DNA Testing
Multitarget stool DNA testing looks for certain DNA changes associated with colorectal cancer as well as blood in the stool. Cologuard is a well-known example of this type of screening test.
The test can be completed at home and does not require bowel preparation or sedation. For some self-pay patients, the upfront cost may also be lower than a colonoscopy.
One important limitation is that an abnormal stool DNA test still needs to be followed by a colonoscopy. The American College of Gastroenterology notes that a positive stool-based screening test requires follow-up colonoscopy. This means someone who starts with Cologuard may ultimately need to complete and pay for both tests.
For these reasons, I generally recommend starting with colonoscopy when it is an appropriate screening option for the individual
Other Screening Options
Other recognized colorectal cancer screening options include highly sensitive guaiac-based fecal occult blood testing, CT colonography, flexible sigmoidoscopy, and newer stool RNA tests. Blood-based screening tests are also available, although current American Cancer Society guidelines do not consider them a preferred screening option.
The appropriate screening method depends on factors including your colorectal cancer risk, medical history, previous screening, and your ability and willingness to complete the recommended test at the appropriate interval.
Comparing Colon Cancer Screening Tests
| Screening Method | Done at Home? | Bowel Prep? | Typical Screening Interval* | Can Remove Polyps? |
|---|---|---|---|---|
| Colonoscopy | No | Yes | Every 10 years | Yes |
| FIT | Yes | No | Every year | No |
| Multitarget stool DNA | Yes | No | Every 3 years | No |
*These are general screening intervals for average-risk adults with normal results. Individual recommendations may differ based on personal risk factors, previous findings, and other medical considerations. An abnormal non-colonoscopy screening test requires follow-up with a colonoscopy.
Why I Recommend Colonoscopy for Colon Cancer Screening
I recommend colonoscopy as the gold standard for colon cancer screening because it allows me to examine the entire colon directly and remove precancerous polyps during the same procedure.
This is an important distinction between colonoscopy and tests that look indirectly for signs of colorectal cancer. If an at-home screening test produces an abnormal result, a colonoscopy is still needed to examine the colon and determine what caused the abnormal finding.
That doesn’t mean other screening tests have no role. For someone who is unwilling or unable to complete a colonoscopy, another recommended screening method is preferable to remaining unscreened. The important thing is to discuss your individual risk and screening options with your healthcare provider and complete screening at the recommended intervals.
Colon Cancer Screening FAQs
At what age should I get screened for colon cancer?
Adults at average risk should begin regular colorectal cancer screening at age 45. People with certain risk factors may need to begin earlier or follow a different screening schedule.
Is Cologuard the same as a colonoscopy?
No. Cologuard is an at-home stool test that looks for DNA changes and blood associated with colorectal cancer. A colonoscopy allows a gastroenterologist to directly examine the colon and remove polyps. An abnormal Cologuard result needs to be followed by a colonoscopy.
How often do I need colon cancer screening?
The interval depends on the screening method and your individual risk. For average-risk adults with normal results, FIT is generally performed every year, multitarget stool DNA testing every three years, and colonoscopy every 10 years.
What happens if an at-home colon cancer screening test is positive?
An abnormal result from a stool-based screening test does not by itself mean you have colorectal cancer. A colonoscopy is needed to examine the colon and determine the reason for the abnormal result.
Do I still need colon cancer screening if I don’t have symptoms?
Yes. Screening is specifically intended to look for colorectal cancer or precancerous changes before symptoms develop. Average-risk adults should begin regular screening at age 45 even when they feel well.
Considering a Colonoscopy in Lubbock?
Dr. Sameer Islam recommends colonoscopy as the gold standard for colorectal cancer screening because it allows precancerous polyps to be identified and removed during the same exam.
Need to schedule a colonoscopy in Lubbock? Learn more about colonoscopy with Dr. Sameer Islam, including his colonoscopy quality indicators, insurance coverage, self-pay options, preparation, and what to expect from your procedure.
