Why colon cancer may start forming in childhood

Colon cancer is no longer waiting for middle age. New research suggests that colon cancer may start developing in the first 10 years of life — years before symptoms appear and decades before most people think about screenings.

According to the study, adults diagnosed with colon cancer before age 40 are three times more likely to have a special DNA mutation caused by childhood exposure to colibactin, a toxin from some E. coli bacteria. This DNA damage can stay hidden for years before any symptoms appear.

“These findings stand to reshape our understanding of early-onset colon cancer and help explain why we’re seeing the disease in a growing number of younger adults who often have no traditional risk factors,” says Dr. Michael Breen, a hematologist-oncologist at Advocate Health Care.

Colon cancer is typically viewed as a disease that primarily affects older adults. However, alarming new statistics from the American Cancer Society show that colorectal cancer is increasing rapidly among people younger than age 50. From 2019 to 2022, the number of new colon cancer diagnosis in adults aged 45 to 49 rose by 12% each year.

“Further research is needed to confirm and fully understand these findings. But if scientists are right about the link between childhood exposure to colibactin and adult colon cancer, we may need to expand prevention and screening efforts to include people of all ages,” Dr. Breen adds.

Do you need a colon cancer screening?

National screening guidelines recommend beginning colorectal cancer screening at age 45 and earlier for adults with a family history of colon cancer. But in light of the recent rise in early-onset colon cancer, Dr. Breen urges adults in their 20s, 30s and 40s to see their doctor if they notice the following early warning signs:

• Abdominal pain
• Rectal bleeding
• Changes in bowel habits
• Fatigue
• Weakness
• Shortness of breath
• Unexplained weight loss

How to reduce your colon cancer risk

Dr. Bree recommends implementing the following habits to reduce your risk:

• Reduce your exposure to colibactin by practicing safe food handling — no matter your age
• Wash your hands regularly
• Keep kitchen spaces clean
• Maintain good gut health by eating a healthy diet
• Take antibiotics only when needed

Want to learn more about your colorectal cancer risk? Take a free online quiz.