To prevent colorectal cancer, there are several important things you need to know. These points are based on recommendations from major health organizations such as WHO, CDC, and IARC, and supported by strong scientific evidence.

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1. Understand the risk factors

• Age over 50 (risk increases significantly, though the disease is becoming more common in younger people).

• History of colon polyps or chronic inflammatory bowel diseases (ulcerative colitis, Crohn’s disease).

• Family history of colorectal cancer.

• Diet high in red meat and processed meats (sausages, smoked meats).

• Low-fiber diet with few vegetables and fruits.

• Physical inactivity, obesity, large waist circumference.

• Smoking and heavy alcohol consumption.

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2. Warning signs that require medical attention

Colorectal cancer often has no early symptoms, but when present, look for:

• Blood in stool (bright red or black).

• Persistent changes in bowel habits: long-term constipation or diarrhea.

• Narrow or pencil-shaped stools.

• Persistent abdominal pain or bloating.

• Unexplained weight loss.

• Unexplained iron-deficiency anemia.

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3. Regular screening – the most important preventive measure

Screening helps detect polyps (precancerous growths) and remove them before they turn into cancer.

• Colonoscopy:

  • Starting at age 45 for average-risk individuals.

  • Starting at 40 or earlier for those with a family history.

  • Repeat every 5–10 years depending on the findings.

• Fecal occult blood test (FOBT) or FIT:

  • Once a year.

  • Suitable if colonoscopy is not immediately available.

• Flexible sigmoidoscopy or CT colonography may also be used depending on resources.

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4. Lifestyle and diet to reduce risk

• Eat plenty of fiber: vegetables, whole grains, fruits.

• Limit red meat and processed meat.

• Consume foods rich in calcium and vitamin D.

• Reduce alcohol intake and avoid smoking.

• Engage in at least 150 minutes of physical activity per week.

• Maintain a healthy body weight.

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5. Polyps are not cancer — but they must be monitored

About 70–90% of colorectal cancers develop from adenomatous polyps.
Removing polyps during colonoscopy is one of the most effective ways to prevent cancer.

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6. Genetics also plays a role

Around 5–10% of colorectal cancer cases are associated with inherited mutations such as:

• Lynch syndrome

• Familial adenomatous polyposis (FAP)

People with these conditions need earlier and more frequent screening.