X-ray of person's colon

Why Are So Many Young People Getting Colorectal Cancer?

Plus, how to get ahead of a diagnosis.

In 2020, actor Chadwick Boseman’s death at 43 years old shined a spotlight on a growing issue: colon cancer rates are rising, especially in younger Americans (1, 2). 

“It’s concerning that across the U.S., disease occurring between ages 18 and 49, is on the rise for cancers of the colon and rectum,” says oncologist Misagh Karimi, M.D.

In 2017, a study funded by the American Cancer Society (ACS) revealed that people born around 1990 have twice the risk of developing colon cancer and quadruple the risk of developing rectal cancer compared to those born around 1950 (3). Shortly after, the ACS reduced the recommended screening age for people of average risk. 

In a study published last year, four symptoms were commonly reported in those who were later diagnosed with colorectal cancer: diarrhea, abdominal pain, rectal bleeding, and iron deficiency (anemia) (4). Having just one of these symptoms pop up may be cause for getting a colorectal cancer screening done even earlier. 

Experts haven’t been able to pinpoint an exact reason for the rising rates of colon cancer, but one possible factor is that Americans are getting heavier, Karimi suggests. “About half of our younger patients diagnosed with colon cancer are overweight.” 

Another factor may be exposure to environmental carcinogens, Karimi says. These may include air and water pollutants and endocrine-disrupting chemicals, which can be found in food packaging, pesticides, cosmetics, and other beauty products (5, 6). Other possible causes include poor gut health and a sedentary lifestyle, Karimi notes.

About the Experts

Adam L. Booth, M.D., an assistant professor of pathology and immunology at Washington University School of Medicine in St. Louis who specializes in gastroenterology. 

Misagh Karimi, M.D., a medical oncologist at City of Hope Orange County in California.

Why Is Colorectal Cancer Screening Important? 

Because of the increase in cases among younger adults, in 2021, the U.S. Preventive Task Force lowered its age recommendations for colon cancer screening from age 50 to age 45 (7). 

“Screening for colon cancer is the only true method of preventing colon cancer,” says Adam L. Booth, M.D., an assistant professor of pathology and immunology at Washington University School of Medicine in St. Louis. 

If colon cancer is caught early enough, the odds of living five years post-diagnosis are high (8): If there’s no sign the cancer has spread beyond the colon or rectum, the survival rate is 91 percent.

And there are also proactive ways to decrease your risk of getting colon cancer (9): 

  • Getting regular exercise
  • Eating a fiber-rich, plant-based diet
  • Eating less red meat (beef, pork and lamb) and processed meat (cold cuts, bacon, sausage and hot dogs)
  • Not smoking
  • Limiting alcohol consumption


When Should You Start Screening? 

If you have an average risk of colorectal cancer, you should start screening at age 45 by getting a colonoscopy

Average risk is defined as “any patient that has no family history of colon cancer,” Booth says, “or they don’t have any other risk factors that might put them at a higher risk of developing colon cancer, like inflammatory bowel disease.”

If you’re under 45 but have increased risk because of any of the below, talk to your doctor about getting screened earlier (9):

  • Having a BMI score of 27 and over 
  • Smoking
  • Drinking two or more alcoholic drinks per day
  • Eating a diet heavy in red and processed meats
  • Having a family history of colon cancer
  • Drinking sugary beverages regularly 


If you have a parent or sibling who had colon cancer, experts say you should get tested 10 years before the age they were diagnosed. “So, if you have a mother that was diagnosed with colon cancer at 47, then you would start screening at 37,” Booth says. 

The timetable matters because colon cancer doesn’t always have symptoms. Those that do exist can mimic other conditions so call your physician if you experience any of the following (10):

  • A change in your BMs (either diarrhea or constipation) that lasts for more than a few days
  • Bright red blood from the rectum
  • Blood in the stool
  • Unexplained weight loss
  • Abdominal cramping or pain
1. National Cancer Institute. Study identifies possible warning signs of colorectal cancer in younger adults.
2. Britannica. Chadwick Boseman.
3. Rebecca L. Siegel, et al. (2017). Colorectal Cancer Incidence Patterns in the United States, 1974–2013.
4. Cassandra D L Fritz, et al. (2023). Red-flag signs and symptoms for earlier diagnosis of early-onset colorectal cancer.
5. National Cancer Institute. Why is colorectal cancer rising rapidly among young adults?
6. National Institute of Environmental Health Sciences. Endocrine Disruptors.
7. U.S. Preventive Service Task Force. Colorectal Cancer: Screening.
8. American Cancer Society. Survival rates for colorectal cancer.
9. American Institute for Cancer Research. Colorectal cancer report (2019).
10. American Cancer Society. Do I have colorectal cancer? Signs, symptoms and work-up.