Rising Colorectal Cancer Rates in Younger Adults Raise Concerns

Colorectal cancer – cancer of the large intestine or rectum – is now the leading cause of cancer deaths in people under 50 in the U.S., according to new research. Incidence and mortality rates have been increasing in this age group since 2013 and 2004, respectively . This rise is largely driven by diagnoses at more advanced stages.

A Concerning Trend

Researchers Rebecca Siegel, Nikita Sandeep Wagle, and Dr. Ahmedin Jemal of the American Cancer Society (ACS) emphasized the seriousness of the trend, stating, “Colorectal cancer is the only common cancer [in people] under 50 with rising mortality.”

While colorectal cancer traditionally affects those over 65, the increasing incidence in younger adults is a significant shift. A 2025 analysis showed rising cases in individuals under 50 alongside stabilization or decline in those aged 50 to 74 across 14 countries, including the U.S., Canada, Australia, and England.

The “Birth Cohort Effect”

The researchers found that the increase in colorectal cancer isn’t limited to young adults but extends to those up to age 65. This phenomenon, known as the “birth cohort effect,” suggests that the year a person was born is more closely linked to their disease risk than their age at diagnosis. This indicates a real increase in disease potentially linked to environmental or lifestyle factors.

Unclear Causes, Potential Factors

The exact cause of this rising trend remains unclear. While established risk factors exist, they don’t fully explain the increase in younger adults. For example, smoking is a risk factor for colorectal cancer but younger individuals are less likely to have a history of smoking.

Potential contributing factors being investigated include exposure to new environmental factors like microplastics and ultraprocessed foods, as well as high antibiotic exposure and processed meat consumption.

Statistics and Projections for 2026

The ACS estimates 158,850 new cases of bowel cancer will be diagnosed in 2026. Of these:

• 47,600 will be in adults aged 50 to 64
• 24,640 will be in those under 50

Over 55,000 deaths from the disease are projected this year, with 7% occurring in those under 50 and 24% in those aged 50 to 64.

The Importance of Screening

Early diagnosis is crucial, especially as most people under 50 are diagnosed with advanced-stage disease. Screening can detect precancerous lesions, preventing cancer development and improving treatment outcomes. Screening accounts for 79% of averted colorectal cancer deaths.

Current ACS guidelines recommend that individuals at average risk – those without a personal or family history of the disease – initiate colorectal cancer screening at age 45. Medicare covers various screening tests, including stool DNA tests and colonoscopies, from this age.

However, screening rates remain low, with only 37% of 45- to 49-year-olds up-to-date with recommended screenings. Increasing screening rates could prevent many deaths in this age group, as half of deaths in people under 50 occur in those aged 45 to 49.

Recognizing Symptoms

Increased awareness of colorectal cancer symptoms is also vital. Symptoms can include blood in stool, abdominal pain, diarrhea, or fatigue, which are often mistaken for other health issues. Prompt attention to these symptoms can lead to earlier diagnosis and more treatable cancer.

The American Cancer Society National Colorectal Cancer Roundtable (ACS NCCRT) is dedicated to reducing the incidence and mortality from colorectal cancer through coordinated leadership, strategic planning, and advocacy.