Colorectal Screening Starts at 45 Now, Not 50

A great many men are carrying a number in their heads that is five years out of date, and in this particular case those five years are the ones where the disease has been growing fastest.

Why did colorectal screening move to 45?

Screening ages are not arbitrary and they do not move often. This one moved because the disease moved.

Between 2000–2002 and 2014–2016, the incidence of colorectal adenocarcinoma in adults aged 40 to 49 increased by almost 15%. That is a substantial shift in a cancer that had been steadily declining in older adults: precisely because screening was working there.

Why early-onset colorectal cancer is rising is not settled. Diet, obesity, sedentary behaviour and the gut microbiome are all under investigation, and none of them has been established as the driver. What was settled enough to act on was the trend itself.

Modelling by the Cancer Intervention and Surveillance Modeling Network estimated that starting at 45 rather than 50 yields 22 to 27 additional life-years gained per 1,000 adults screened. On that basis the Task Force issued a Grade B for ages 45 to 49, meaning high certainty of moderate net benefit, and meaning most US insurance plans must cover it without cost-sharing.

What are the screening options?

This is the part most people do not know. Colonoscopy is the best-known strategy, not the only recommended one. The Task Force lists six:

Which screening test should you choose?

The genuine differences are these.

Colonoscopy is both a test and a treatment. It is the only option where a polyp found is a polyp removed in the same session. Everything else, if positive, leads to a colonoscopy anyway. It requires bowel preparation, sedation and a day off, and it carries a small risk of bleeding or perforation.

Stool tests require nothing of you but a sample. No prep, no sedation, no time off, done at home. The trade-offs are that they must be repeated annually (or every one to three years for the DNA version), and a positive result means a colonoscopy follows.

CT colonography sits in between. Bowel prep, no sedation, and findings still route to colonoscopy. Access varies considerably by region.

The evidence does not establish one strategy as clearly superior in practice, and there is a reason for that. Adherence matters enormously. An annual stool test that you actually complete beats a ten-yearly colonoscopy that you keep postponing, and the second scenario is extremely common. The best screening test is a real one you will do, not a theoretically superior one you avoid.

This is worth being honest with yourself about. If the reason you have not booked is the prep, or the sedation, or taking a day off, then the stool test is not a lesser option. It is the option that gets you screened.

What if you have symptoms?

Screening applies to people without symptoms. That is what the word means.

If you have rectal bleeding, a persistent change in bowel habit, unexplained weight loss, unexplained iron deficiency anaemia, or abdominal pain that will not settle, that is not a screening conversation. It is a diagnostic one, it does not wait for your next birthday, and it does not matter that you are only 38.

Rectal bleeding gets attributed to haemorrhoids by patients and sometimes by clinicians. Haemorrhoids are common and usually the answer. “Usually” is doing real work in that sentence, and the determination is not one to make yourself.

Who should start earlier than 45?

The age of 45 applies to average risk. Earlier and more frequent screening is generally advised for:

• A first-degree relative with colorectal cancer or advanced polyps, particularly diagnosed young
• Inflammatory bowel disease, Crohn’s or ulcerative colitis
• A known inherited syndrome such as Lynch syndrome or familial adenomatous polyposis
• Previous abdominal or pelvic radiation

If any of those apply, the schedule is set by a specialist rather than by a general recommendation.

What should you actually do?

If you are 45 or older and have never been screened, you are overdue by definition. Ask which options your provider offers, and say explicitly that you are willing to consider a stool-based test if colonoscopy is the barrier.

If you are under 45 with a family history, raise it now rather than waiting.

And if you have symptoms, ignore everything above and get seen.

Colorectal screening sits alongside the rest of the evidence-graded list, and unlike PSA screening, this one is not a close call. The benefit is established, the grade is A from 50, and the only real decision is which method.

This article is for information only and is not medical advice. It cannot account for your individual circumstances. Talk to a doctor about your own situation, particularly before starting or stopping any prescription medication.