Something shifted in the colorectal cancer data around 2013. Deaths in older Americans kept falling, a decades-long success story of colonoscopy programmes and improved treatment, but among people under 50 the numbers started moving the other way. Not dramatically at first, just a nudge upward, easy to explain away. Then a trend.
By 2026, colorectal cancer had become the leading cause of cancer death for men under 50 in the United States, and the second for women in the same age bracket. Roughly 55,000 people will die of it this year. The disease, for all its treatability when caught early, is still very much with us.
The American Cancer Society has responded this week with updated screening guidelines, adding new tests to the menu and drawing a clear line around which of those tests are actually worth using. The picture that emerges is more complicated than the headlines suggest.
What’s driving the rise in younger adults remains, frustratingly, not well understood. Obesity, dietary changes, gut microbiome disruption: these are the favoured suspects, but none quite accounts for the scale of the shift. What researchers do understand is that disease caught early is very different from disease caught late. Five-year survival rates above 90% for early-stage colorectal cancer drop sharply once it has spread beyond the colon wall. The window matters enormously, which is why the American Cancer Society lowered the recommended screening age from 50 to 45 back in 2018. Getting more people through that window, at the right moment, is the whole game.
The problem is uptake. Currently, something like one in three adults eligible for colorectal cancer screening hasn’t been tested as recommended. Among the 45-to-49 age group, the newly included cohort, the gap is twice as bad. More than 20 million Americans who should be screened simply aren’t, and the reasons are roughly what you’d expect: inconvenience, cost, access, and the visceral unpleasantness of the available tests.
A Test for Every Threshold of Willingness
This is where the pragmatism running through the new guidelines becomes interesting. The expert panel, led by Andrew Wolf at the University of Virginia, arrived at a conclusion that sounds almost self-evident but carries real weight as a clinical principle: “The most effective screening test is the one that the patient completes.” The colonoscopy remains the gold standard, a visual examination of the full colon every 10 years that can both detect and remove precancerous polyps in a single procedure. But colonoscopies require bowel prep, sedation, and time off work. A lot of eligible people won’t do it. So the updated guidelines expand the alternatives.
Two new stool-based tests have been added to the preferred category. One is a next-generation version of the stool DNA test (sold as Cologuard), updated to improve sensitivity over its predecessor. The other is genuinely new: a stool RNA test called ColoSense, which looks for different molecular markers in a sample sent through the post. Both are recommended every three years. Both showed high sensitivity for detecting colorectal cancer and moderate sensitivity for advanced precancerous lesions, the growths most likely to turn malignant. They join existing annual stool tests and visual options already on the list. “The new guidance adds a stool RNA test and an updated stool DNA test to the menu of preferred options,” said Wolf, “which currently include colonoscopy and stool tests that detect tiny amounts of blood, among other options.” The idea is a menu broad enough that almost anyone can find something they’ll actually do.
The Blood Test Problem
Then there are the blood tests, and this is where the guidelines get more pointed. A blood draw every three years to screen for cancer sounds, on its face, enormously appealing; a patient survey found 53% of respondents would prefer it to a stool test or colonoscopy. The test, sold as Shield, detects tumour DNA circulating in the bloodstream. It is approved and available. It is also, by the panel’s reckoning, markedly inferior to the alternatives.
Wolf put it plainly: “Although the idea of a blood test for colorectal cancer sounds very attractive, they aren’t yet as good as the other tests at detecting precancerous growths and early-stage cancer, so we don’t believe they are as effective as a screening test.” The data bear this out: blood tests showed lower sensitivity for both advanced precancerous lesions and stage 1 cancers than the stool-based options. This matters because the point of screening is not only to catch cancer that has already formed but to intercept the precancerous polyps before they get there. A test that misses those more often is, in a meaningful sense, less of a prevention tool and more of an early-detection tool. The distinction has consequences for how many deaths screening can actually prevent.
The panel’s solution is pragmatic rather than prohibitive. Blood-based tests are not pulled from the guidelines, but demoted. They are now an option only for people who decline the preferred stool tests and visual exams. “While colorectal screening blood tests may not be as effective as other options,” Wolf said, “they are certainly better than not screening.” The condition attached matters: patients who opt for a blood test need to understand that a positive result still means a colonoscopy, and a negative result offers somewhat weaker reassurance than a stool-based test would provide.
Who Actually Gets Screened
The equity dimension is something the ACS is being direct about. “Expanding screening options only matters if people can actually access them,” said Lisa Lacasse, president of the ACS’s advocacy affiliate ACS CAN. Coverage gaps mean that a guideline recommending a new at-home test is effectively meaningless to someone without insurance that covers it, and underserved populations are precisely where the screening gap is widest and outcomes tend to be worst.
The numbers Wolf keeps returning to are sobering in their simplicity. Almost a third of adults are not up to date with colorectal cancer screening; among 45-to-49-year-olds, it’s roughly two thirds. The new guidelines are, in some ways, an attempt to meet people where they are rather than where medicine would prefer them to be. At-home stool tests that can be mailed off are genuinely accessible in a way that a procedure requiring a hospital visit is not. Whether accessibility alone shifts behaviour at population scale is a different question, one these guidelines cannot answer by themselves.
Perhaps the most striking thing Wolf says is also the most straightforward. Colorectal cancer “is a disease you don’t have to die from,” he notes, and there is a screening test available to suit nearly every preference and circumstance. The gap between what is possible and what is actually happening in clinics and living rooms across the country is, at its core, a gap between knowledge and action. Extending the menu may help. Closing the gap will almost certainly require something more.
https://doi.org/10.3322/caac.70083
Frequently Asked Questions
Why are blood tests for colorectal cancer not recommended even though they sound easier?
The appeal is real, but the performance data is the issue. Blood-based tests showed lower sensitivity for detecting both early-stage cancers and, crucially, the advanced precancerous growths that screening is designed to catch before they become malignant. Stool-based tests are better at finding the problem early enough to prevent it, which is a meaningfully different goal than detecting cancer that has already formed. Blood tests remain in the guidelines as a fallback for people who decline everything else.
Is colorectal cancer really rising in younger people, and why?
The trend is real and has been building since around 2013. Colorectal cancer is now the leading cause of cancer death for men under 50 in the United States and the second for women in that age group. The causes are not fully understood, though researchers point to obesity, dietary patterns, and possible gut microbiome changes as likely contributors. The uncertainty is part of why the American Cancer Society lowered the recommended screening age from 50 to 45 in 2018.
What happens if an at-home stool test comes back positive?
A positive result on any stool-based or blood-based test requires a follow-up colonoscopy, ideally within six months. The at-home tests are a first filter, not a diagnosis. A colonoscopy can visually confirm whether cancer or precancerous polyps are present and, in many cases, remove them in the same procedure. This two-step design is intentional: the cheaper, easier test flags who needs the more thorough exam.
Who should consider getting screened before age 45?
People with a family history of colorectal cancer, inflammatory bowel disease, or hereditary syndromes like Lynch syndrome may need to start screening considerably earlier, sometimes in their teens. Those who previously had certain polyps removed, or who received abdominal radiation for earlier cancers, are also in a higher-risk group. A conversation with a doctor about individual risk factors is the right starting point for anyone uncertain about their situation.
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