Colorectal cancer – cancer of the colon or rectum – is now the leading cause of cancer death in people under the age of 50 in the United States, a new study shows.
Colorectal cancer incidence and mortality have increased in people under 50 each year since 2013 and 2004, respectively, according to research published March 2 by American Cancer Society (ACS). This increase in early diagnoses is driven by advanced stage disease. (Intestinal cancer is also known as bowel cancer.)
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The incidence also increases among adults aged 50 to 64, and the disease is diagnosed at more advanced stages. This is believed to be linked to the correspondingly increased mortality in this age group, the authors wrote in the study.
The trend in people under 65 stands in marked contrast to the declining rates of new bowel cancer cases and deaths in adults aged 65 and over. Because most cases are in people 65 and older, this declining trend masks an opposite pattern among the younger cohorts, the authors wrote in the study.
A disturbing trend
Colorectal cancer is second leading cause of cancer deaths globally and mainly affects people over the age of 65. But colorectal cancer “can no longer be called an old person’s disease,” Jemal said in a statement. Actually, a 2025 analysis revealed that colon cancer cases simultaneously increased in people under 50 and either stabilized or declined in 50- to 74-year-olds in 14 countries, including the United States, Canada, Australia and England.
But in the new study, the researchers pooled data on the number of new cases of colon cancer from 1998 to 2022 along with the number of deaths from colon cancer from 1930 to 2023, while zooming in on slightly different age cohorts. The data were obtained from the National Cancer Institute and the Centers for Disease Control and Prevention (CDC).
By narrowing down the age groups examined, the team found that the increase not only occurs in people under 50, but also in people up to 65. “The increase in colon cancer is not just in young people, per se,” the study authors told Live Science.
This phenomenon is called the “birth cohort effect”, which means that when an individual was born is more closely related to disease risk than when they were diagnosed. This confirms “a real increase in disease due to something we do or other exposure,” Siegel said in a statement.
However, it remains unclear what causes this trend, the authors wrote in the study.
“Long-established risk factors for colon cancer were identified based on cancers in older adults who were exposed to different risk factors than those in more recent generations,” Siegel, Sandeep Wagle and Jemal told LiveScience. For example, for all ages combined, almost 14% of colon and rectal cancer is due to smokingbut people under 50 are less likely than older adults to have smoked, they said.
Since the second half of the 20th century, individuals have been exposed to new environmental factors that can increase the risk of cancer, such as e.g. microplastics and ultra-processed foodthey said. Research has also previously found colorectal cancer is associated with high exposure to antibiotics and processed meat.
Colon cancer screening saves lives
The team estimated that there will be 158,850 new cases of bowel cancer in 2026. Of these, 47,600 will be in 50- to 64-year-olds and 24,640 will be in those under 50. Over 55,000 people of all ages are estimated to die from the disease this year. Of these, 7% will be among those under 50 and 24% will be among people aged 50 to 64.
Since most people under the age of 50 are diagnosed with an advanced stage of the disease, which is more difficult to treat, earlier diagnosis is critical, Siegel, Sandeep Wagle and Jemal told LiveScience.
“Earlier diagnosis can also be achieved by increasing awareness of symptoms of colon cancer such as blood in the stool, abdominal pain, diarrhea or fatigue, which can often be mistaken for other health problems,” they said. “Earlier attention to symptoms can help shift diagnoses towards earlier, more treatable cancer”
Screening also allows for earlier detection and removal of precancerous lesions of the intestine; which accounts for 79% of averted deaths from colon cancer. Current ACS guidelines The state’s average risk individuals — those without a personal or family history of the disease — should begin screening for colorectal cancer starting at age 45. Medicare covers various screening tests from this age, including a stool DNA test and colonoscopy. There are no specific ACS guidelines for high-risk individuals, but they may require earlier and more frequent screening.
However, the researchers found that only 37% of 45- to 49-year-olds are up-to-date with colon cancer screening. With half of deaths in people under 50 occurring in 45- to 49-year-olds, this means many colon cancer deaths in this cohort are preventable, Siegel, Sandeep Wagle and Jemal said.
This article is for informational purposes only and is not intended to provide medical advice.
Siegel, RL, Wagle, NS, Star, J., Kratzer, TB, Smith, RA, & Jemal, A. (2026). Colorectal cancer statistics, 2026. CA: A cancer journal for clinicians76(2), e70067. https://doi.org/10.3322/caac.70067
