Colorectal Cancer Screening at 45: Colonoscopy vs. Stool Tests Explained

If you're 45 or older and haven't been screened for colorectal cancer, this post is for you. And if you've been putting it off because you dread the colonoscopy, you may be glad to hear that it's not your only option.

As a surgical oncologist, I've operated on many patients whose cancers could have been prevented or caught much earlier with a simple screening test. Colorectal cancer is one of the few cancers we can stop before it starts.

Screening finds precancerous growths called polyps, which can be removed before they ever turn into cancer.

Why the Age Dropped from 50 to 45

For years, screening started at 50. In 2021, the U.S. Preventive Services Task Force lowered the recommended starting age to 45. The reason is sobering: colorectal cancer is rising in younger adults. It's now one of the leading causes of cancer death in people under 50.

Most insurance plans, including Medicare, now cover screening starting at 45. That means cost shouldn't be the barrier it once was.

Your Screening Options

The best screening test is the one you'll actually complete. Here's how the main options compare.

Colonoscopy (every 10 years if normal)A doctor uses a thin, flexible camera to examine your entire colon while you're sedated. Its big advantage is that it both finds and removes polyps in the same procedure. The downsides are the bowel prep the day before, the need for a ride home, and taking a day off.

FIT test (every year)The fecal immunochemical test checks a small stool sample for hidden blood. You do it at home, there's no prep, and it's inexpensive. The trade-off is that you have to repeat it every year.

Stool DNA test, such as Cologuard (every 1 to 3 years)This at-home test looks for both hidden blood and abnormal DNA from cancer or polyps. It's more sensitive than FIT but also more likely to give a false positive.

CT colonography (every 5 years)Sometimes called a "virtual colonoscopy," this uses a CT scan to image the colon. It still requires bowel prep, and any polyps found need a regular colonoscopy to remove.

Blood-based testsNewer FDA-approved blood tests are now available for average-risk adults. They're convenient, but they're less effective at finding precancerous polyps than a colonoscopy or stool tests. Talk with your doctor about whether one is right for you.

The One Thing You Must Know About At-Home Tests

A positive at-home test is not the finish line. It requires a follow-up colonoscopy.

This is where too many people fall through the cracks. A positive stool test doesn't mean you have cancer, but it does mean something needs a closer look.

Skipping the follow-up colonoscopy cancels out the benefit of screening. Under current federal rules, most insurance plans must cover that follow-up colonoscopy as part of screening, so check with your plan.

Who Should Start Earlier

The age-45 guideline is for people at average risk. You may need to start earlier, or be screened more often, if you have:

• A parent, sibling, or child with colorectal cancer or advanced polyps

• A personal history of polyps or colorectal cancer

• Inflammatory bowel disease, such as Crohn's disease or ulcerative colitis

• A known inherited condition, such as Lynch syndrome

If any of these apply to you, talk with your doctor about a personalized screening plan.

Screening and Health Equity

Black Americans are about 20% more likely to be diagnosed with colorectal cancer and about 40% more likely to die from it than most other groups. Much of that gap comes from differences in access to screening and timely follow-up care, not biology. [read more in our Disparities series]

Closing the screening gap is one of the most powerful tools we have for saving lives in underserved communities.

Don't Wait If You Have Symptoms

Screening is for people without symptoms. If you have rectal bleeding, blood in your stool, a lasting change in bowel habits, unexplained weight loss, or ongoing abdominal pain, don't wait for your screening age. See a doctor now, at any age.

Frequently Asked Questions

Is Cologuard as good as a colonoscopy?

Cologuard is a good option for average-risk adults, but colonoscopy is more accurate and can remove polyps during the same procedure. A positive Cologuard result always needs a follow-up colonoscopy.

Does colon cancer screening start at 45 or 50?For average-risk adults, screening starts at 45.

How often do I need a colonoscopy?

If your results are normal and you're at average risk, every 10 years. Your doctor may recommend a shorter interval if polyps are found.

When can I stop screening?

Most people continue through age 75. Between 76 and 85, the decision depends on your health and screening history, so talk with your doctor.

Take the Next Step with EDDIE Colon

Not sure which test is right for you, or what your results mean? EDDIE Colon, your AI-powered colorectal cancer copilot, can answer your questions in plain language, 24/7. Download it free on the App Store today.

This article is for educational purposes only and is not a substitute for professional medical advice. Talk with your healthcare provider about the screening plan that's right for you.