Colorectal cancer has overtaken every other cancer as the leading cause of cancer death among Americans under the age of 50, according to a major new report released by the American Cancer Society. 

The report, published in March 2026 in the journal CA: A Cancer Journal for Clinicians, paints a troubling picture of a disease that is retreating among the old but advancing steadily among the young.

The American Cancer Society releases this comprehensive study on colorectal cancer once every three years. This year’s edition is based on incidence data collected up to 2022 and mortality figures updated through 2023, making it the most current and detailed snapshot available of how the disease is behaving across the country.

The headline finding is stark. While colorectal cancer death rates have continued to fall among people aged 65 and above, thanks largely to widespread screening through colonoscopy, the opposite is happening in younger age groups. 

Deaths have been rising by about 1% every year among adults under 50 since 2004. More worryingly, for the first time, death rates have also started climbing among people between the ages of 50 and 64, a group that was previously seeing steady improvement.

“The risk of dying from colorectal cancer is climbing in younger generations of men and women.” That is how the report’s lead author summed up the findings, adding that the trend points to a real increase in disease risk caused either by something people are doing differently or by some other exposure that has not yet been identified.

“There will be an estimated 158,850 new cases of CRC in the United States in 2026, including 108,860 colon tumors and 49,990 rectal tumors. Nearly one half (45%) of new diagnoses are currently in individuals younger than 65 years, up from 27% in 1995. In addition, an estimated 55,230 individuals will die from CRC in 2026, nearly one third of whom will be younger than 65 years,” the report estimated.

Scientists working on the report describe this pattern as a “birth cohort effect.” 

In simple terms, this means that a person’s risk of developing colorectal cancer appears to be linked more closely to the decade in which they were born than to their current age. 

According to the data, every generation born in the United States after roughly 1950 carries a higher risk of the disease than the generation before it. As these birth cohorts grow older, the report warns, the overall burden of colorectal cancer will keep rising like a wave moving through time.

What makes this trend particularly puzzling is that many of the usual explanations do not fully hold up. 

“Likely contributors include established risk factors (Table 5), such as obesity, physical inactivity, and reduced dietary quality, as well as yet unknown etiologic factors. Inflammatory bowel disease is associated with increased CRC risk, and pediatric onset may be increasing, but population‐based incidence is unknown because inflammatory bowel disease is not a reportable condition. Established risk factors based on disease associations in older cohorts do not appear to fully explain contemporary disease patterns,” the study mentioned.

“For example, obesity and physical inactivity are more strongly associated with tumors in the colon than in the rectum, but the increasing trend is driven by rectal cancer. Much of the ongoing research focuses on the gut biome and inflammation associated with contemporary exposures, such as ultraprocessed foods, microplastics, and antibiotics,” it added.

The report also highlighted a worrying pattern in how the disease shows up in younger patients. Three out of every four people diagnosed with colorectal cancer before the age of 50 already have advanced disease by the time they are diagnosed. Younger patients are also more likely to experience delays before getting a proper diagnosis, often because their symptoms, such as rectal bleeding, stomach pain or unexplained anaemia, are mistaken for less serious conditions like piles or irritable bowel syndrome.

The study also reported that, “Despite later stage diagnosis, individuals younger than 50 years have similar or higher 5‐year relative survival than older patients, with the largest gap for distant‐stage disease (23% vs. 17% in those aged 50–64 years and 10% in individuals aged 65 years and older). Factors that contribute to higher survival include fewer comorbidities, more physical activity after treatment, and more aggressive treatment, including more extensive surgery, multiagent systemic therapy, and adjuvant or neoadjuvant therapies.”

The findings have reignited calls to improve awareness about colorectal cancer symptoms among both doctors and the general public, and to encourage more people between the ages of 45 and 49 to get screened. In the United States, the recommended age to begin screening was lowered from 50 to 45 in 2018, but the report finds that uptake among this age group remains low, at just 37%.

The report’s authors have called for urgent research into what exactly is driving this trend. Until scientists can pinpoint the cause, they say the priority must be catching the disease early, since colorectal cancer remains highly treatable when detected in its initial stages. For now, doctors are urging younger adults not to ignore persistent digestive symptoms and to speak to a physician if something feels wrong, rather than assuming they are too young to be at risk.

Doctors say India must watch the trend, but not panic yet

As the American Cancer Society’s 2026 report raises questions about rising colorectal cancer among younger adults, doctors in India say the findings deserve attention, even though the study is based on American data.

Dr Darshan Patil, consultant in surgical oncology at Aster CMI Hospital, Bangalore, said the exact cause remains unclear, but the pattern is hard to ignore. “The American Cancer Society report shows a clear age-related divide. Colorectal cancer incidence is falling in adults aged 65 and above, while it is increasing in younger adults.” 

He explained that older adults have benefited from wider screening, while younger people have historically skipped tests, “allowing cancers to remain undetected until later stages.”

On the “birth cohort effect,” he said it suggests people born around the same period may share exposures that shape cancer risk later in life. “This does not mean that birth year itself causes cancer. Rather, it is a clue that certain exposures may have become more common or occurred earlier in life.”

Since obesity and poor diet do not fully explain the rise, he said researchers are examining wider possibilities, “including changes in the gut microbiome, antibiotic exposure, early life diet and environmental chemicals, metabolic health, inflammation and other lifestyle or environmental exposures,” though these remain unproven.

He urged young adults not to dismiss symptoms like rectal bleeding, unexplained anaemia or persistent abdominal pain, noting these are “easily mistaken for piles, irritable bowel syndrome, acidity, infections or dietary problems.”

He was cautious about lowering the screening age further, saying the bigger priority is ensuring eligible people actually get screened.

Regarding India, he said, “We should not directly apply US screening recommendations to the Indian population without stronger Indian population-based evidence,” citing fragmented yet concerning data from South Indian studies on early-onset cases.

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