UNITED STATES — Colorectal cancer rates in the United States are rising in nearly all adult age groups, not only among younger adults, according to a new analysis reported by Reuters on 30 October 2026 — the first overall increase in more than two decades, and a finding that complicates a long-standing public-health success story.
For years, medical groups have warned about a troubling rise in colorectal cancers among younger adults. The new analysis, based on data from the United States National Cancer Institute, extends that concern across the age spectrum: after falling for more than 20 years, the overall incidence rate turned upward again in 2023. Researchers say the pattern cannot be explained by screening alone, pointing instead to risk factors that are not yet fully understood.
The findings arrive alongside a second strand of research reported the same day: tumors in younger patients appear biologically different from those in older patients, with features that may help explain why the disease is often more aggressive at younger ages. Together, the two studies sharpen both the scale of the problem and the scientific questions that remain.
Illustration: A doctor discussing colorectal cancer screening with an adult patient in a modern clinic. This is an AI-generated illustration, not a real photograph.
What Happened
Reuters reported on 30 October 2026 that a new analysis of National Cancer Institute data found colorectal cancer incidence fell from 55.2 cases per 100,000 people in 2000 to 36.7 per 100,000 in 2022, then rose to 38.3 per 100,000 in 2023. The researchers, led by Caitlin Murphy of the University of Chicago, described it as the first increase in the overall rate in more than 20 years.
The rise was not confined to one age band. Among adults aged 20 to 49, incidence increased by 3 percent a year between 2013 and 2022, according to data from the American Cancer Society cited in the report. By 2026, colorectal cancer had become the leading cause of cancer deaths in that younger age group, the American Cancer Society data showed.
The sharpest increase in the new analysis was seen in adults aged 45 to 49, where incidence rose by 12.76 percent a year from 2019 to 2023. The researchers linked that jump in part to expanded screening: the United States lowered the recommended starting age for colorectal cancer screening to 45 from 50, so more cancers in that group are now being found. Murphy said that pattern shows screening working as intended. "That means that screening is doing as we intend it to do. It's catching cancer earlier," she said in a statement reported by Reuters.
But the researchers cautioned that screening increases do not explain the rise across all ages or in other age groups. That gap, they said, suggests unknown risk factors — including possibly environmental factors — may be offsetting the gains made by screening.
Background
Colorectal cancer begins in the colon or rectum, and screening can both detect it early and prevent some cases by finding and removing precancerous growths. That dual benefit is why decades of screening were credited with driving incidence down: fewer cancers developed, and those that did were often caught sooner.
The younger-adult trend has nevertheless been moving in the opposite direction for years, prompting guidelines to be revised downward and awareness campaigns aimed at people in their forties and younger. Symptoms such as persistent changes in bowel habits, blood in the stool, abdominal pain or unexplained weight loss are often urged to be checked promptly rather than dismissed because of age — a message that has become a staple of cancer-awareness efforts.
The new analysis adds a further layer. If incidence is rising even among older adults, where screening is well established, then something beyond detection is at work. Researchers have previously explored a range of possible contributors to the younger-adult rise, including diet, obesity, sedentary lifestyles, antibiotic use, gut-microbiome changes and environmental exposures, but no single explanation has been established. The latest findings do not settle that debate; they widen it.
Illustration: Scientists examining tumor samples in a research laboratory. This is an AI-generated illustration, not a real photograph.
Why It Matters
First, the reversal matters because it breaks a two-decade trend. Public-health progress against colorectal cancer has long been held up as an example of screening working at population scale. An overall uptick, even a modest one in a single year, raises the question of whether that progress is stalling or whether 2023 marks the start of a new direction. Researchers will need several more years of data to tell whether the rise persists, but the signal itself is enough to prompt closer surveillance.
Second, the age pattern matters for prevention. A rise concentrated only in younger adults would point mainly at generational exposures. A rise across nearly all ages up to 70 points to broader forces that could affect the whole population, and it strengthens the case for keeping screening uptake high among older adults as well as expanding it among younger ones.
Third, the biology matters for treatment. A separate team analysed 189 tumors from adults of all ages, looking for factors that changed gradually with age, and reported its findings in Nature Medicine. Among tumors of the most common colorectal cancer subtype, younger patients' tumors had significantly more connective and supporting cells than cancer cells — a feature linked to chemotherapy resistance in several types of solid cancer. Younger patients also showed higher activity of long non-coding RNAs, molecules that regulate genes without making proteins, many of which are described as "dark" RNAs whose functions remain largely unknown. The researchers also saw gene activity suggesting stronger signalling between cells that can help cancer cells move and invade nearby tissue.
"While we're still at the beginning of understanding what these differences mean, our work gives researchers a new direction to pursue in tackling this urgent problem in human disease," study co-author Ana Anderson of Harvard Medical School said in a statement reported by Reuters.
For patients and families, the practical message remains unchanged: screening recommendations exist for a reason, and symptoms should not be ignored at any age. This article is general health information only, not medical advice; anyone concerned about symptoms or about when to be screened should speak with their own clinician.
What Happens Next
Researchers will watch the next annual data releases closely to see whether the 2023 increase is sustained, grows, or proves to be a one-year fluctuation. If the rise continues, health agencies may face pressure to re-examine screening intervals, outreach to under-screened groups, and research funding into the environmental and lifestyle factors the authors flagged.
The tumor-biology findings are also likely to feed further studies. If the connective-tissue and RNA patterns seen in younger patients' tumors are confirmed in larger samples, they could eventually inform how aggressively different patients are treated or which therapies are prioritised — though researchers stress that work is at an early stage and no new treatment follows directly from these results.
Separately, Reuters also reported encouraging survival data the same day for some patients with advanced kidney cancer: in a midstage trial, 51 patients with clear cell renal carcinoma that had spread received an alternating combination of two targeted drugs, Votrient and Avastin, and survived for a median of 63.2 months, with median progression-free survival of 24.8 months, according to results reported in The Lancet Oncology. In favorable-risk patients, median overall survival reached 76.9 months. The study leader, Dr. Saby George of the Roswell Park Comprehensive Cancer Center, said the benefit was comparable to or better than contemporary immunotherapy combinations, with a lower cost — a point that could matter in low-resource settings where checkpoint inhibitors such as Keytruda and Opdivo cannot be used by patients with autoimmune diseases or are prohibitively expensive.
Illustration: Adults of different ages outdoors in a city park, highlighting health awareness. This is an AI-generated illustration, not a real photograph.
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FAQ
What did the new analysis find?
It found that colorectal cancer incidence in the United States fell from 55.2 per 100,000 in 2000 to 36.7 in 2022, then rose to 38.3 in 2023 — the first overall increase in more than 20 years, based on National Cancer Institute data.
Is the rise limited to younger adults?
No. While medical groups have long warned about rising rates among younger adults, the new analysis found the increase extends to nearly all age groups up to age 70.
Why did rates rise fastest among 45- to 49-year-olds?
That group saw a 12.76 percent annual increase from 2019 to 2023, which researchers linked in part to more screening after the recommended starting age was lowered to 45 from 50, so more cancers are being detected.
Does screening explain the overall rise?
No, according to the researchers. Screening increases do not explain the rise in incidence overall or in other age groups, suggesting unknown risk factors, including possibly environmental ones, may be at work.
What did the tumor study find about younger patients?
Younger patients' tumors of the most common subtype had more connective and supporting cells than cancer cells, higher activity of long non-coding RNAs, and gene activity suggesting stronger cell-to-cell signalling that can help cancer spread — findings reported in Nature Medicine that may help explain more aggressive disease at younger ages.
Sources
Reuters, "Rise in US colon cancer rates not limited to young adults, analysis finds", 30 October 2026 (National Cancer Institute data; American Cancer Society data; University of Chicago researcher Caitlin Murphy; NEJM Evidence screening analysis; Nature Medicine tumor study with Harvard Medical School co-author Ana Anderson; The Lancet Oncology kidney-cancer trial data).
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