At 45, a new item quietly joins the list of things you're supposed to do: colorectal cancer screening. For many women, the word colonoscopy is where that conversation stalls, whether it's the prep, the time off work or plain dread.
What many people don't realize is that colonoscopy is one of several recommended options. A test you actually complete, on schedule and with follow-up when needed, beats a perfect test you keep postponing. Here's how the main choices compare.
Why 45, and who this applies to
In its 2021 update, the US Preventive Services Task Force recommended screening for adults aged 45 to 49, in addition to its long-standing recommendation for ages 50 to 75. It noted that colorectal cancer incidence in adults aged 40 to 49 rose by almost 15% between 2000-2002 and 2014-2016 (US Preventive Services Task Force, 2021). In 2023, an estimated 19,550 people younger than 50 were expected to be diagnosed in the US (Siegel et al., 2023).
These recommendations are for adults at average risk who don't have symptoms. That means no personal history of colorectal cancer, advanced polyps or inflammatory bowel disease, and no known inherited syndrome such as Lynch syndrome (US Preventive Services Task Force, 2021). If you have a strong family history, your doctor may suggest starting earlier. If you have symptoms such as bleeding or anemia, you need a diagnostic evaluation, not a screening test.
The options, side by side
These are the main tests in the 2021 USPSTF recommendation, with the intervals it lists (US Preventive Services Task Force, 2021):
Colonoscopy, every 10 years. A doctor examines the entire colon and can remove polyps during the same procedure. It requires a full bowel prep, sedation and a ride home.
Fecal immunochemical test (FIT), every year. You collect a small stool sample at home and mail it in, with no prep or diet changes. In a meta-analysis of 19 studies, FIT had a pooled sensitivity of 79% and specificity of 94% for colorectal cancer (Lee et al., 2014).
Stool DNA-FIT, every 1 to 3 years. A home test that looks for both blood and DNA changes in stool. In a study of 9,989 people, it detected 92.3% of cancers compared with 73.8% for FIT, but it produced more false positives, with specificity of 86.6% versus 94.9% (Imperiale et al., 2014).
CT colonography, every 5 years. A CT scan of the colon that needs bowel prep but not sedation.
Flexible sigmoidoscopy, every 5 years, or every 10 years combined with a yearly FIT. It examines only the lower part of the colon.
Where blood tests fit
Blood-based screening tests are newer, and their appeal is obvious: nothing more than a routine blood draw. In a study of 7,861 average-risk adults, one cell-free DNA blood test detected 83.1% of the colorectal cancers found on colonoscopy. But it detected only 13.2% of advanced precancerous lesions, the growths screening aims to find and remove before they become cancer (Chung et al., 2024).
That's an important trade-off. A blood test may appeal if you would otherwise skip screening altogether, but it misses most of the precancerous growths that colonoscopy is designed to catch. If you're considering one, ask your doctor how it compares with the options above for you.
The trade-offs that matter in real life
Finding cancer vs. preventing it. Colonoscopy can find and remove precancerous polyps in one step. Stool tests are better at detecting cancer than advanced precancerous lesions: in the stool DNA study, sensitivity for those lesions was 42.4% with stool DNA and 23.8% with FIT (Imperiale et al., 2014).
Effort now vs. effort later. Colonoscopy means one demanding day every 10 years. FIT is easy, but only works if you really do it every year.
A positive home test is a first step. An abnormal stool or blood test needs a follow-up colonoscopy to complete the screening. Skipping that step leaves the job half done.
Cost and coverage. Ask your insurance plan what's covered, including the follow-up colonoscopy after a positive home test.
How to choose
Confirm your risk level. If you're unsure about your family history, ask relatives about colorectal cancer and polyps.
Mention any symptoms, even mild ones. Symptoms change the plan.
Be honest about follow-through. Would you rather do one prep day per decade, or a home kit every year or every few years?
Ask what your practice offers and how results and follow-up are handled.
Put the next due date in your calendar before you leave the appointment.
Sources
US Preventive Services Task Force, Davidson KW, Barry MJ, et al. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2021;325(19):1965-1977. PMID 34003218
Siegel RL, Wagle NS, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2023. CA Cancer J Clin. 2023;73(3):233-254. PMID 36856579
Lee JK, Liles EG, Bent S, Levin TR, Corley DA. Accuracy of fecal immunochemical tests for colorectal cancer: systematic review and meta-analysis. Ann Intern Med. 2014;160(3):171. PMID 24658694
Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med. 2014;370(14):1287-97. PMID 24645800
Chung DC, Gray DM 2nd, Singh H, et al. A cell-free DNA blood-based test for colorectal cancer screening. N Engl J Med. 2024;390(11):973-983. PMID 38477985
This article is for general information and isn't medical advice. Talk to your healthcare provider about which screening test fits you, especially if you have symptoms or a family history of colorectal cancer.
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