Colorectal Cancer Is Showing Up Younger. Screening Hasn't Caught Up.

For most of the last century, colorectal cancer was thought of as a disease of older age. That picture is changing, and it is changing faster than most people realize.

According to the American Cancer Society's Colorectal Cancer Statistics, 2026, the number of cases in adults aged 20 to 49 has been rising by about 3% every year. Over the same period, cases in adults 65 and older have been falling by roughly 2.5% a year, in large part because that group gets screened regularly. The result is a widening divide between generations. Colorectal cancer is now the leading cause of cancer death in adults under 50, and nearly half of all new cases, about 45%, now occur in people younger than 65.

If that surprises you, you are not alone. The idea that colon cancer is something to worry about only later in life is deeply held, by patients and sometimes by clinicians too. And that belief, however reasonable it once was, is part of the problem.

Why it can be harder when it comes early

When colorectal cancer appears in someone younger, it is more often found at a later stage. The 2026 data show that the rise in early-onset cases is driven mostly by advanced-stage diagnoses, the kind that are harder to treat and more dangerous.

Part of the reason is human and understandable. When a healthy 42-year-old notices a change, a little bleeding, some discomfort, a shift in their usual rhythm, cancer is rarely the first explanation anyone reaches for. The symptoms get attributed to something more common and less frightening. Weeks or months can pass before anyone thinks to look closer.

This matters enormously, because colorectal cancer is one of the most treatable cancers there is when it is caught early. Found at a localized stage, the odds are strongly in the patient's favor. Found late, everything gets harder. The window between those two outcomes is often the difference between a routine intervention and a life-altering one.

The guidelines already moved

The medical community saw this trend coming and acted on it. In 2021, the U.S. Preventive Services Task Force lowered the recommended age to begin screening from 50 to 45 for adults at average risk.

It was the right call, and it was not made lightly. It followed years of rising incidence in younger adults and careful modeling of the benefits and tradeoffs. The message was clear: a whole group of people who had never been told to think about screening now needed to start five years earlier than the previous guidance suggested.

On paper, the system responded exactly as it should have. The guidance caught up with the disease.

The screening, though, didn't follow

Here is the difficult part. Changing a recommendation is not the same as changing what actually happens in people's lives.

As of the most recent CDC data, only about 37% of adults aged 45 to 49 are up to date on colorectal cancer screening. In the established 50 to 75 age group, that figure is more than 73%. In other words, two out of every three people in the newest eligible group have not been screened.

Sit with that for a moment. This is the age band where the disease is growing fastest. It is also the age band least likely to have been screened. The guideline moved. The behavior didn't.

The obvious question is why. And the answer is not what most people assume.

It is not that the test doesn't work

Colonoscopy is remarkably effective. It is the only screening tool that can both find and remove precancerous growths in a single visit, which means it does not just catch cancer early, it can prevent it from developing at all. Almost everyone who works in this field agrees on its value. Most patients, when asked, understand it too.

So the barrier is not awareness. People know screening saves lives. The barrier is not access in most cases either, since more than 15 million colonoscopies are performed in this country every year. When a test is proven, recommended, and available, and a large share of eligible people still put it off, the honest explanation is usually the one nobody likes to say out loud.

It is the experience.

For colonoscopy, the part patients dread is not the procedure. They are asleep for that. It is the preparation the night before: the daylong fast, the large volume of liquid laxative, the disruption, the discomfort, the uncertainty about whether it even worked. We have written before about why so many people avoid colonoscopy, and the pattern is consistent across decades of research. When people describe the worst part of the experience, they almost always describe the prep.

For a 46-year-old who feels perfectly healthy, who has no family history, who has never been told before now to think about this, the prep is often enough friction to justify waiting. And waiting, for a disease that is quietly becoming more common in exactly this group, is the one thing the data tells us not to do.

Where Zera fits

Zera Medical exists because of this gap. The company was founded on a straightforward belief: the biggest obstacle standing between millions of people and a lifesaving screening is not medical or technological. It is the experience of getting ready for it.

That belief shapes everything the company does. Screening only saves lives when people actually go, and people are far more likely to go when the process treats them with comfort, clarity, and dignity. The team at Zera believes the preparation step deserves the same care and seriousness that the rest of modern medicine already brings to the procedure itself.

The disease is showing up younger. The guidelines have already adjusted. The remaining work is to make screening something people are willing to follow through on, not something they quietly postpone. That is the work worth doing, and it is the work Zera is committed to.

If you are 45 or older, or you have a reason to be screened sooner, talk to your doctor. It is a conversation worth having, and it is very much worth having early.

This post is part of an ongoing series from Zera Medical on the colorectal cancer screening gap and the preparation experience that shapes it. Zera Medical is developing ZeraFlow™, a clinic-based bowel preparation system. ZeraFlow™ has not been cleared by the FDA and is not available for commercial use or sale in the United States. This device is currently under FDA review and is not available in all markets.