Colorectal cancer now deadliest cancer under 50

Colorectal cancer, once considered a disease that primarily affected older adults, is increasingly being diagnosed in younger people.

Jason Bill, MD, an interventional gastroenterologist with OSF HealthCare, says the trend is concerning and highlights the urgent need for awareness, earlier detection and preventive screening.

Not only is it being diagnosed more, a JAMA study released in January reveals colorectal cancer is now the leading cause of cancer-related death in adults 50 and younger. The findings suggest colorectal cancer is the only major cancer that has increased in the last two decades, averaging a 1.1% increase every year since 2005. The American Hospital Association (AHA) reports colorectal cancer ranked fifth in cancer deaths from 1990-1994.

A troubling rise in diagnoses among younger adults

“We are seeing much younger people being diagnosed with colon cancer. Unfortunately, these younger people are being diagnosed at later stages of disease, as well," Dr. Bill says. "There is clearly something going on. A lot of research is happening behind the scenes that's trying to sort out what is causing this."

Dr. Bill says researchers are actively investigating the causes behind the increase in cases. While no single explanation has been confirmed, experts believe multiple factors may be contributing.

“There seems to be a birth cohort effect, meaning those born after a certain time, seem to have an increasing incident of colon cancer diagnosis,” Dr. Bill says. “So, what that leads people to believe, is that there must an environmental trigger to the increased incidence. The most likely culprits include ultra-processed foods and the obesity epidemic. Further research is going into other exposures including microplastics.”

Genetics and inherited conditions can increase risk

Genetics can play a significant role in colorectal cancer risk. One inherited condition, known as Lynch syndrome, increases the likelihood of developing colorectal cancer and other cancers.

Lynch syndrome is caused by inherited mutations in genes responsible for repairing damaged DNA – including MLH1, MSH2, MSH6, PMS2 and EPCAM. When these repair systems don’t function properly, damaged DNA can accumulate, increasing the risk of cancer over time.

“In those who have a family history, be a little more aggressive and more sensitive, mindful of your symptoms. With rectal bleeding in a young person, we need to treat that more aggressively and strongly recommend a colonoscopy,” Dr. Bill says.

Doctors may recommend genetic counseling and testing for individuals with strong personal or family histories of colorectal cancer or related cancers. Identifying inherited risk factors can help patients and providers create personalized screening and prevention plans.

 “No one loves the idea of getting a colonoscopy, but it is the right thing to do. If you have any symptoms you’re concerned about, talk to your primary care provider and they can move you forward to get a colonoscopy. But the best advice is to get screened when it’s appropriate and be mindful of the symptoms,” Dr. Bill adds.

Screening guidelines may miss at-risk younger adults

Colorectal cancer screening guidelines have evolved in recent years. The American Cancer Society recommends routine screening beginning at age 45 for people at average risk.

While research is ongoing, Dr. Bill notes that current guidelines may not fully address this younger population; however, the decrease in the screening from 50 to 45 was an important step.

Colonoscopies don’t just detect cancer – they prevent it

A colonoscopy remains the gold standard for colorectal cancer screening, not only detecting cancer but preventing it, Dr. Bill says.

“It’s a test where we’re able to examine the colon and prevent cancer,” Dr. Bill says. “In those patients who have decided to not get a colonoscopy, any screening is better than nothing. That’s where the mailed stool kits come in handy.”

During a colonoscopy, physicians can identify and remove polyps (abnormal growths) that can develop into cancer if left untreated. These samples can then be analyzed to determine cancer risk.

“In general, we can tell you right then and there what your findings are," Dr. Bill points out.

This immediate feedback provides patients with clarity and allows care teams to quickly determine next steps if needed.

Symptoms and risk factors shouldn’t be ignored

Even for adults under age 45, certain symptoms and medical histories may warrant earlier screening. These include:

• Rectal bleeding
• Anemia (low red blood cells)
• A strong family history of colorectal cancer
• Family history of polyposis syndromes
• Personal history of inflammatory bowel disease, including ulcerative colitis or Crohn’s disease
• Sudden abdominal pain
• Unexplained weight loss

If you're concerned your at-risk for colorectal cancer or are experiencing any of the symptoms above, it's time to speak with your primary care provider and request further screening. 

Lifestyle changes can help lower risk

While some risk factors, such as genetics, cannot be controlled, healthy lifestyle choices can help reduce colorectal cancer risk. Experts recommend:

• Avoiding tobacco use
• Limiting or avoiding alcohol
• Reducing consumption of ultra-processed and processed foods
• Exercising regularly
• Maintaining a healthy weight
• Avoiding prolonged sedentary behavior
• Eating a fiber-rich, balanced diet

These steps support overall digestive health and may reduce cancer risk over time.

Screening saves lives

Colorectal cancer is highly treatable when detected early – and often preventable through routine screening.

If you're concerned, OSF HealthCare offers a colorectal cancer risk assessment that can help you figure out when you should start screening.

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