Colon cancer occurs when there is an abnormal cell division in the colon. Contrary to the division of normal cells, these cancer cells have acquired certain characteristics that allow them to divide indefinitely and live longer than normal. During the course of the disease, even in the asymptomatic phase, some cancer cells can migrate from their place of origin to form metastases in nearby or distant organs. It is for this reason that screening for colon cancer should be started from age 40 for people at risk and 50 for individuals who are at low or risk. The screening must be done regularly as recommended by the American Cancer Society:
- fecal occult blood testing every year
- flexible sigmoidoscopy every five years
- double-contrast barium enema every five years
- colonoscopy every 10 years
- Virtual colonoscopy (CT colonography) every five years.
The exact cause leading to the uncontrolled development of colon cells is not well known. However, several factors are suspected. Although genetics, sex and age may contribute to the occurrence of colon cancer, environmental factors and lifestyle (including unhealthy diet) are the most common causative major of colon cancer; they are responsible for about 80 to 90% of all colon cancers. Some of lifestyle habits that can cause the development of colon cancer include: alcoholism, smoking, sedentary lifestyle, excessive consumption of red meat and foods containing highly saturated fats and proteins.