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Outside of skin cancer, colorectal cancer is the third most common cancer diagnosed in men and women in the United States. The American Cancer Society estimates in 2024 about 106,000 Americans will be diagnosed with colon cancer and another 46,000 will be diagnosed with rectal cancer.

Colon and rectal cancers have become the leading causes of cancer death in younger adults. According to a recent study from the American Cancer Society, colorectal cancer is now the leading cause of cancer death in men under 50 and second in women under 50 behind breast cancer.

There are many theories as to why these cancers are on the rise in younger populations. The U.S. Centers for Disease Control and Prevention says lifestyle factors may contribute to an increased risk of disease, including:

  • Lack of regular physical activity
  • A diet low in fruits and vegetables
  • A low-fiber and high-fat diet or a diet high in processed meats
  • Overweight and obesity
  • Alcohol consumption
  • Tobacco use

Dr. Tiago Biachi

Dr. Tiago Biachi, gastrointestinal oncologist

“These cancers take years to develop,” said Dr. Tiago Biachi, a gastrointestinal oncologist at Moffitt Cancer Center. “When we talk about diet being a risk factor, we’re not talking about what you ate last year. If someone who is 40 is being diagnosed with colorectal cancer, you have to look at what their diet was like when they were in their 20s or even younger.”

Biachi adds that it’s never too early to improve your diet. He recommends that parents keep an eye on what their kids are eating to help lower their risk for cancer later in life.

Your risk of getting colorectal cancer also increases as you get older. Other risk factors include:

  • Inflammatory bowel disease such as Crohn’s disease or ulcerative colitis
  • A personal or family history of colorectal cancer or colorectal polyps
  • A genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (Lynch syndrome)

When should you get screened for colorectal cancer?

In 2022, the U.S. Preventive Services Task Force recommended that people of average risk start colorectal cancer screenings at age 45. This includes people with no prior diagnosis of colorectal cancer, no family history or genetic disorders that increase your risk of disease, no history of precancerous polyps and no diagnosis of inflammatory bowel disease.

“When we talk about the screening age of 45, that’s for asymptomatic people,” Biachi said. “If you have symptoms like rectal bleeding, change in bowel habits or sudden unexpected weight loss, you need to talk to your doctor about getting a colonoscopy to determine what the underlying problem is.”

 

In addition to colonoscopy, other recommended screenings include computed tomography colonography and stool-based tests with high sensitivity such as fecal immunochemical tests (FIT) that are widely accessible and would require a colonoscopy follow-up if the test comes back abnormal.

At-home tests like Cologuard, which identifies altered DNA or blood in the stool, were initially approved in 2014 for people between 50 and 75 years old. Now, the test is available for individuals as young as 45 with a prescription from their doctor.

“A screening colonoscopy is the only test that can detect a polyp,” Biachi said. “At-home tests are certainly better than doing nothing, but if you have a positive result, you would still need a colonoscopy to confirm any suspicions. Another benefit of colonoscopy is that you may only need one every 10 years. At-home testing needs to be done much more frequently, even annually.”