Prevention · 6 min read
Colorectal cancer screening at 45: your options, explained
The best screening test is the one that actually gets done. Here is how to choose yours.
Written and medically reviewed by Dr. Savita Srivastava, MD, board-certified gastroenterologist · Last updated · Sources · Editorial policy
Colorectal cancer (cancer of the colon or rectum) is one of the most preventable cancers. Most colorectal cancers start as small growths called polyps that take years to change. Screening can find and remove polyps before they become cancer, and it can find cancer early, when it is easier to treat. Yet many people who are due for screening have never had it.
Why the starting age moved to 45
For many years, screening for people at average risk began at 50. That changed in 2021, when the US Preventive Services Task Force (USPSTF) recommended starting at 45 1. The American College of Gastroenterology 2 and the US Multi-Society Task Force on Colorectal Cancer 3 made the same recommendation.
The main reason is that colorectal cancer has been rising in younger adults. American Cancer Society data show that the share of cases in people under 55 has grown over recent decades, and these cancers are more often found at a later stage 4. Starting screening earlier is a way to catch more of these cancers, and the polyps that lead to them, in time.
Your screening options
There is more than one good way to screen. The USPSTF lists several options 1:
| Test | What it involves | How often (if normal) |
|---|---|---|
| Colonoscopy | A flexible camera looks at the whole colon. Polyps can be removed during the same test. Needs bowel prep and sedation. | Every 10 years |
| FIT (fecal immunochemical test) | A home stool test that checks for hidden blood. No prep or diet changes. | Every year |
| Stool DNA-FIT | A home stool test that looks for blood and DNA changes. | Every 1 to 3 years |
| CT colonography | A special CT scan of the colon. Needs bowel prep. | Every 5 years |
| Flexible sigmoidoscopy | A camera looks at the lower part of the colon. | Every 5 years (or every 10 years with yearly FIT) |
The ACG names colonoscopy and FIT as the main first-choice tests for most people at average risk 2.
A positive stool test is not the end of screening. It is the start of a colonoscopy.
How to choose
Each option has trade-offs. Colonoscopy is the most complete test and lets the doctor remove polyps right away, but it needs a bowel prep, sedation, a driver, and usually a day off. Stool tests are done at home and are easy to repeat, but they must be done on schedule, and they are less likely to find polyps before they bleed.
The key point: a positive stool test or abnormal CT scan needs a follow-up colonoscopy to complete the screening 1 2. Skipping that step leaves the job half done. If you choose a home test, plan for that possibility.
Who may need to start earlier?
The age-45 advice is for people at average risk. You may need to start sooner, or be screened more often, if you have:
- a parent, sibling or child with colorectal cancer or advanced polyps
- a known inherited syndrome, such as Lynch syndrome
- inflammatory bowel disease (Crohn's disease or ulcerative colitis)
- a personal history of colorectal cancer or certain polyps
- a history of radiation to the abdomen or pelvis
Talk with your doctor about your family history. The details, such as how old a relative was when diagnosed, change the plan.
Common worries, honestly answered
"I feel fine." That is exactly when screening is meant to happen. Early polyps and cancers usually cause no symptoms.
"I'm dreading the prep." Bowel preps have improved, and split-dose regimens (half the evening before, half the morning of) are often easier to tolerate. Your care team will give you clear instructions.
"Will insurance cover it?" Coverage for screening has expanded in recent years, including for follow-up colonoscopy after a positive stool test in many plans, but rules vary. Check with your insurer and the practice before your test.
The bottom line
If you are 45 or older and at average risk, it is time to talk about colorectal cancer screening. Colonoscopy and FIT are both good choices. The best test is one you will actually complete, along with any follow-up it needs.
Sources & references
- US Preventive Services Task Force; Davidson KW, Barry MJ, Mangione CM, et al. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2021;325(19):1965-1977. View source
- Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK. ACG Clinical Guidelines: Colorectal Cancer Screening 2021. Am J Gastroenterol. 2021;116(3):458-479. View source
- Patel SG, May FP, Anderson JC, et al. Updates on age to start and stop colorectal cancer screening: recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2022;162(1):285-299. View source
- Siegel RL, Wagle NS, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2023. CA Cancer J Clin. 2023;73(3):233-254. View source
Keep reading
Nutrition · 6 min
Fiber and your gut microbiome: what the science actually says
Your gut microbes eat what you eat. Fiber is their main course, and the evidence for eating more of it is some of the strongest in nutrition science.
Microbiome · 6 min
Probiotics: what the evidence says, and what it doesn't
Probiotics fill whole aisles. The guidelines written by gastroenterologists are far more cautious than the labels.
Conditions · 7 min
Irritable bowel syndrome (IBS): the basics, in plain language
IBS is common, real and treatable. It is also a diagnosis that should be made carefully, not by guesswork.