When & How Should I Be Screened For Colon Cancer?
September 30, 2025
Colon cancer, also known as colorectal cancer, is the third most common cancer in the United States, but it's also one of the most preventable.
Regular colon cancer screening is key to catching the disease early, when treatment is most effective. Learn why colon cancer screening is important, when you should be screened for colon cancer, and the ways you can have colon cancer screening.
Key Takeaways: Colon Cancer Screenings
- Staying up-to-date on your colon cancer screening schedule helps any cancer be found early while tumors are still small. Your health history and the types of screening you have impacts how often you need to be screened.
- Colonoscopies are the preferred way to check for colon cancer, but other options such as at-home tests and blood tests are now available.
- If your at-home stool test warns of a possible colon cancer, a diagnostic colonoscopy is the next step.
Why Is Colon Cancer Screening Important?
Colon cancer is the third most common cancer diagnosed in both men and women each year in the United States. Staying up-to-date on your colon cancer screening schedule is the single best way to ensure that you are cancer-free or that, if cancer is present, it is detected early while tumors are still small. Colorectal cancer often has no outward symptoms. So, even if you feel fine and believe your risk of colon and rectal cancer is small, you should still get screened.
When colon cancer is a stage 0 or stage I cancer, it drastically improves your survival rate.
What is stage 0 colon cancer?
Stage 0 colon cancer means that the cancer has not spread beyond the colon's inner lining.
What is stage I colon cancer?
Stage I colon cancer refers to tumors that have spread deeper into the colon wall but have not spread beyond the colon itself.
Most patients with colon cancer detected in stage 0 or stage I recover fully after surgery to remove the tumor - often with no chemotherapy or radiation required. Learn more about cancer stages.
When Should I Be Screened For Colon Cancer?
The American Cancer Society's colon cancer screening guidelines say the recommended age for your first colonoscopy or other routine colon cancer screenings is age 45. (That’s if you are not at a higher risk of colon cancer.)
After a normal colonoscopy or colon cancer screening test result, many patients at average risk for colorectal cancer won’t need to be screened again for 5-10 years, continuing until the age of 75.
Other colon cancer screening tests, because they are less comprehensive, are recommended on a more frequent basis than if you were getting a colonoscopy.
The American Cancer Society recommends:
- CT colonography (virtual colonoscopy) every 5 years
- Sigmoidoscopy every 5 years
- Stool-based tests as often as once a year
Colon cancer screening guidelines if you have higher risk
If you are at higher risk for colorectal cancer, such as if a family member had colon cancer, your doctor may recommend that you begin colon cancer screening earlier than age 45 and do so more often than every 5-10 years.
"For patients who at high-risk for colorectal cancer, at-home tests cannot be substituted - no exceptions," said John Underwood, MD, medical oncologist at Franciscan Health Indianapolis. "High-risk patients include those with a personal or family history of colorectal cancer, those with a personal history of inflammatory bowel disease (Chron’s disease or ulcerative colitis), or certain genetic syndrome with a known increased risk, such as Lynch syndrome or familial adenomatous polyposis. Patients with worrisome symptoms, such as unexplained weight loss, changes in bowel habits, or rectal bleeding may not be candidates, either. And when in doubt, talk to your primary care provider for guidance."
“If you have a personal history of, for instance, certain inflammatory bowel disease like Crohn’s or ulcerative colitis, or if you have a family history of colon cancer or polyps, or there’s a few different genetic conditions out there…you wouldn’t bother with a Cologuard or any other test out there,” adds Narayan Prabhakar, MD, a Dyer, Ind., family medicine doctor with Franciscan Physician Network. "You would go right to a colonoscopy in those situations."
What Increases My Risk For Colorectal Cancer?
The American Cancer Society says people are considered at higher risk of colorectal cancer if they have these risk factors:
Colorectal cancer risk factors you can change
- Being overweight or obese
- Having a diet higher in red meat
- Being a smoker
- Using alcohol
- Not being physically active
Learn how diet and exercise can help improve your colon cancer risk.
Colorectal cancer risk factors you can't change
- A family history of colorectal cancer
- Previous colorectal cancer
- History of polyps
- Inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease
- Familial adenomatous polyposis (FAP)
- Lynch syndrome (hereditary non-polyposis colon cancer or HNPCC)
- A personal history of getting radiation to the abdomen (belly) or pelvic area to treat a prior cancer
- Your race. Colorectal cancer is more common in Native American and Black Americans, according to the American Cancer Society.
What Are The Screening Options For Colon Cancer?
Colon cancer screening test options include:
Colonoscopies
A colonoscopy is a short procedure allows the doctor to look inside the entire rectum and colon while a patient is under anesthesia. Colonoscopies are considered "the gold standard" for screening people who are at average risk for colon cancer.
"A screening colonoscopy is considered the gold standard for colorectal prevention due to having the highest detection rate of small tumors and polyps," said Dipen C. Maun, MD, a surgeon with Franciscan Physician Network Indiana and Colon and Rectal Specialists.
Colonoscopies are medical procedures that are done under anesthesia and offer the best chance of detecting early colon or rectal cancer. During a colonoscopy, patients are sedated. Then, a doctor uses a flexible, lighted tube called a colonoscope to examine the rectum and colon.
If you are having a colonoscopy, doctors will remove any noticeable polyps to reduce your future risk of developing colorectal cancer.
"This is an important but underappreciated benefit of colonoscopy," said Ben Tsai, MD, a colorectal surgeon with Franciscan Physician Network Indiana Colon & Rectal Specialists in Indianapolis. "With colonoscopy, we are able to completely remove polyps or biopsy suspicious lesions."
Polyps, while relatively common, may later become cancerous if not removed.
Other visual exams
Procedures such as flexible sigmoidoscopy allow doctors to directly view the colon and rectum for abnormalities. A flexible sigmoidoscopy is like a colonoscopy in that your doctor uses a flexible, lighted tube (sigmoidoscope) to see the lower part of your colon. You will still have to do bowel prep similar to that of a colonoscopy and may need a follow-up exam with a colonoscopy to view the entire colon.
A virtual colonoscopy, or CT colonography, uses a CT scan and X-rays to show abnormal areas, like polyps or cancer. It does not require you to be sedated but still requires the bowel prep like a colonoscopy.
Stool tests for colon cancer screening
If you are still leery of having a colonoscopy, there are less invasive options for colon cancer screening. For example, at-home stool sample tests check for blood and altered DNA in your stool, which are associated with the possibility of cancer or pre-cancer, but they are less effective at finding tumors or polyps.
"Colonoscopy is the gold standard and the preferred cancer screening test among oncologists," said Dr. Underwood. "However, for individuals without a personal or family history of colorectal cancer who are unable or unwilling to undergo a colonoscopy, at-home tests are a reasonable alternative, and I’ve seen many patients for whom a positive at-home test successfully led to the detection of colon or rectal cancer."
Stool tests are non-invasive at-home tests that detect hidden blood in stool. With each type of test, a patient provides a stool sample which is sent to a lab for review. There may be specific instructions of things to avoid eating or medication to stop prior to the test, so be sure to review all instructions carefully. Results are provided to your primary care physician in about two weeks.
There are three main types of at-home tests to screen for colon cancer:
- Fecal DNA Test: A fecal DNA test is the newest type of at-home colon cancer screening, and looks for abnormal DNA as well as blood in your stool sample.
- Fecal Immunochemical Test (FIT): A FIT test looks for blood in your stool.
- Fecal Occult Blood Test (FOBT): A fecal occult blood test also looks for the presence of blood in your stool using a substance galled guaiac.
Because at-home stool-based tests are easier to complete, many patients opt for this method since some type of colorectal cancer screening is preferred to none at all. Current estimates suggest that only 70 percent of eligible patients get a colon cancer screening of any kind.
Challenges that may lead to someone delaying a colonoscopy include work schedules, having no driver to bring you home after an appointment, potential out-of-pocket expenses for colonoscopy prep and more.
Limitations of stool-based tests
At-home stool-based tests are limited in their ability to detect polyps. While stool tests can detect colon cancer, they are generally less sensitive than colonoscopy for detecting precancerous polyps. This means they might miss some polyps that could potentially develop into cancer.
These tests also not differentiate between cancer and benign polyps. This can result in a positive stool test that creates unnecessary worry. Some of these positive test patients will have completely normal colonoscopy exams; some will have polyps that are easily removed with colonoscopy; and a small fraction will have cancer.
- Positive At-Home Stool Test: A positive at-home stool test means that DNA and/or hemoglobin (blood) biomarkers that may be associated with colorectal cancer were found in the stool. Note that not all at-home tests check for both DNA and blood in the stool. If the stool-based test turns out positive, the next step for the patient is to have a colonoscopy to rule out cancer.
- Negative At-Home Stool Test: A negative at-home stool test means that the home test did not detect significant levels of DNA and/or hemoglobin biomarkers in the stool that are associated with colorectal cancer.
At-home colon cancer screening tests are needed more often
At-home fecal immunochemical tests (FIT) and fecal occult blood tests (FOBT) are yearly tests, while the recommendation of fecal DNA testing varies from yearly to every three years. Any positive test results shown on these at-home stool tests require immediate follow-up with colonoscopy for further diagnosis. Colonoscopy, on the other hand, is suggested every 10 years or as recommended by your physician based on risk factors and findings.
If a stool test returns a positive result, a colonoscopy is required to confirm the finding, ensure it is not a false positive and potentially remove any polyps or cancerous tissue.
Blood tests for colon cancer screening
In 2024, the FDA approved a blood test for colon cancer. The main issue with blood tests is that, unlike colonoscopies, they often miss precancerous growths on the colon, and at a rate lower than the most advanced fecal tests. Check with your insurance plan about coverage of blood tests for colorectal cancer screening.
Does Insurance Cover Colon Cancer Screenings?
Commercial insurance and Medicare provide coverage for screening colonoscopies and at-home tests, but patients must choose one or the other (not both, unless an at-home test results in a positive stool sample). Commercial insurance and Medicare also recently began providing coverage at no cost for follow-up colonoscopies after a positive at-home stool test. Be sure to check with your insurance provider prior to any testing to confirm your coverage.
What matters most is that all patients undergo age-appropriate colon cancer screening of some type and adhere to routine surveillance depending on their specific circumstances.
What If My At-Home Test Indicates I Need More Testing?
If your at-home stool test warns of a possible colon cancer, a diagnostic colonoscopy is the next step. Unfortunately, only about half of people who undergo a stool test to screen for colon cancer follow up with a colonoscopy when that test warns of a possible cancer, according to a new study in JAMA Network Open.
"If you have a positive stool-based test, you're at roughly 10 times higher risk of having colon cancer, so that it makes it very urgent that you would go in," said study-co-author Jeff Mohl, director of research and analytics for the American Medical Group Association.
Detection and removal of precancerous polyps can significantly reduce the incidence of the cancer and deaths caused by it.
Understanding The Power Of Early Detection
According to the American Cancer Society, only 20% of adults under the age of 50 are up-to-date on their colon cancer screening. That matters because colon cancer is increasing in people under 50 years of age.
Rochelle Bowman expected to receive a clean bill of health when she went in for her first colonoscopy at age 51. After all, the mother of two grown children felt well, exercised regularly, and had no concerning symptoms.
However, during Rochelle's colonoscopy, doctors at Franciscan discovered she had stage I colon cancer. "They found a tumor that was a foot long," she said. "I feel very lucky to have found it before it spread."
Rochelle's cancer had not spread beyond her colon. Doctors were able to remove the tumor during a two-and-a-half-hour surgery.
For those putting off getting a colonoscopy, Rochelle's advice is simple: Don't.
"Everyone should get screened," she said. "It's an easy, minimally invasive procedure that everyone over 45 should be doing."
Talk with your provider to discuss the best colon cancer screening strategy for your healthcare needs. But above all, don't wait. If you haven't had a colon cancer screening and you're over age 45, make an appointment today.
“The earlier you can catch it, the better,” said Dr. Prabhakar. “With any cancer for that matter. And that's the key."
