Why Are Almost 50% of Cases Occurring Earlier?

• The American Cancer Society reports that the incidence of colorectal cancer cases in U.S. adults ages 20 to 49 has been rising about 3% per year.
• Experts say there may be a number of factors for this increase, including unhealthy diets, sedentary lifestyles, and the impact of microplastics on the human body.
• They recommend that most adults start colorectal cancer screenings at age 45.

A new report from the American Cancer Society (ACS) highlights what’s being described as an alarming increase in colorectal cancer cases in young adults.

In their findings, published in CA: A Cancer Journal for Clinicians, officials at the ACS report that the overall incidence of colorectal cancer in adults in the United States decreased by nearly 1% annually between 2013 and 2022.

The decline was mostly driven by a 2.5% annual decrease in colorectal cancer cases among U.S. adults ages 65 years and older.

However, the report found that colorectal cancer cases have increased by 0.4% annually in U.S. adults ages 50 to 64.

More alarming, the authors said, was the 3% annual increase in colorectal cancer cases in U.S. adults ages 20 to 49.

They project that 45% of colorectal cancer diagnoses this year will be in individuals younger than 65, up from 27% in 1995. They predict that one-third of the expected 55,000 colorectal cancer deaths in the United States this year will be in people younger than 65.

The findings also show that rectal cancer cases now represent 32% of all colorectal cancer cases, up from 27% two decades ago.

Nikita Wagle, PhD, a principal scientist in cancer surveillance research at the ACS and second author of the new report, said the trend is a call to action for the medical community.

“Despite decades of progress in the fight against cancer, colorectal cancer death rates are increasing among younger men and women,” Wagle told Healthline. “It is important that we intensify research to uncover the causes as well as take action to prevent these deaths.”

In their report, ACS officials state that colorectal cancer is the third most commonly diagnosed cancer in both males and females in the United States.

They say it’s the second most common cancer-related death in the United States overall. It’s the number one cause of cancer-related death in U.S. adults under 50 years of age.

The ACS estimates there will be 158,850 new cases of colorectal cancer in the United States in 2026, including 108,860 colon tumors and 49,990 rectal tumors.

In its report, the ACS states that more than one-half of colorectal cancer cases are attributable to modifiable risk factors, such as:

Nilesh Vora, MD, a medical oncologist and medical director of the MemorialCare Todd Cancer Institute at Long Beach Medical Center, has witnessed an uptick in colorectal cancer patients and said the numbers didn’t surprise him. Vora wasn’t involved in the report.

“It doesn’t change the concern I already have about this trend,” he told Healthline.

Geoffrey Buckle, MD, a gastrointestinal medical oncologist at the University of California, San Francisco, said the new ACS statistics align with what he and his colleagues have noticed in their practices. Buckle wasn’t involved in the report.

“We are seeing a growing incidence of colorectal cancer that is indeed alarming,” said Buckle. “The statistics reflect what we see in our clinics every day.”

Buckle told Healthline that there are various factors driving the increase in early onset colorectal cancer cases, including:

Some research has indicated that an overabundance of microplastics in the bodies of younger adults may be another factor, Buckle said.

Another theory suggests that toxins produced by the bacteria E. coli, which damage DNA, could be contributing to rising colorectal cancer cases.

Wagle agreed there may be new factors affecting younger adults’ risk of colorectal cancer.

“Since the late 20th century, there have been many newer exposures, such as ultra-processed food and microplastics, that may influence cancer risk, and to which younger generations have had greater cumulative exposure than older adults, who have had a lifetime of cumulative exposures,” she explained.

Vora echoed that there may be some credence to these theories. “Other environmental factors need to be considered,” he said.

The issue came to the forefront in August 2020, when Chadwick Boseman, the star of the film “Black Panther,” died from colon cancer at 43.

In 2024, a study presented at the Digestive Disease Week conference reported that colorectal cancer cases had tripled among U.S. teens from 1999 to 2020.

In October 2025, researchers reported that rectal bleeding is a strong indication of early onset colorectal cancer in adults under 50.

The issue was highlighted again in early February when James Van Der Beek, an actor best-known for his role on the television series “Dawson’s Creek,” died from colon cancer at the age of 48.

The trends prompted the U.S. Preventive Services Task Force to revise its guidelines for colorectal cancer screening. The agency now recommends that these screenings begin at age 45 for most adults.

There are different options for colorectal cancer screening that range from a colonoscopy to at-home stool-based tests.

Buckle said screening is the most important tool in the prevention of colorectal cancer. He added that young adults should be aware of the early warning signs of the disease, such as:

Buckle said that adults in their late 40s and 50s have become increasingly aware of the risk of colorectal cancer and the potential symptoms.

However, he said that adults under 45 aren’t as attuned to the issues. “There is a definitive lack of recognition,” Buckle said.

Buckle noted that younger adults should also be aware of their family history of colorectal cancer.

He recommended regular exercise as well as a diet that avoids ultra-processed foods, sugar, and red meat and includes plenty of fresh vegetables and fruits.

Wagle recommended that younger adults avoid smoking, limit their alcohol use, and maintain a healthy weight.

Vora said it’s important for younger adults to be diligent in monitoring symptoms and getting screened.

“You should get screened on time for colorectal cancer even if you don’t have symptoms,” said Vora. “And if you have symptoms, seek medical care as soon as possible.”