An image showing the normal abdominal contents. The brown organ is the liver. The purple one is the spleen. The tubular structure is the large intestine or the colon.
(Image from Sabiston Textbook of Surgery, 18th ed.)
At what age should individuals get screened for colorectal cancer ?All individuals should be screened for colorectal cancer after the age of 50. In some cases, screening can start at an earlier age if there is an increased risk of colorectal cancer.
What are the factors that increase the risk of having colon cancer ?- Increasing age.
- Red meat.
- Low dietary fibre intake.
- Family history of colon cancer.
- Alcohol excess.
- Colorectal polyps.
- Chronic inflammatory bowel diseases.
What are the factors that decrease the risk of having colon cancer ?- Increased fibre intake.
- Fruits and vegetables.
- Calcium consumption.
What are the symptoms of colon cancer ?Symptoms include change in bowel habit, rectal bleeding, tenesmus and symptoms of anemia, unexplained weight loss.
The above symptoms can be caused by other disorders affecting the large intestine and are non-specific to colon cancer.
That's why screening should be started immediately, in high risk individuals, if there is any of the above symptoms. If these symptoms occur in any individual over 35 - 40 years, colon cancer should be excluded.
What are the screening tests for colon cancer ?- Fecal occult blood testing. It is done annually.
- Stool DNA tests.
- Flexible sigmoidoscopy. It is done every 5 years.
- Double-contrast barium enema. It is done every 5 years.
- Colonoscopy every 10 years.
- CT colonography every 5 years.
Although that genetic factors can play an important role in colon cancer, most patients do not have a strong family history.
What does colon cancer look like ?Colon cancer can be: annular, tubular, ulcer or cauliflower in shape.
(From Bailey and Love's, Short Practice of Surgery, 25th edition)