The large intestine also known as the large bowel is an organ which makes up the digestive system.


The large intestine is divided into 3 sections;

  1.  Appendix and Cecum
  2. Colon
  3. Rectum

The colon is divided into 4 sections in the following order:

  1. Ascending Colon
  2. Transverse Colon
  3. Descending Colon
  4. Sigmoid Colon

The colon is responsible for the absorption of the remaining water and electrolytes from the digested food.

The colon is responsible for the formation of feces and for moving the feces to the rectum.

The rectum serves as a temporary storage location for feces before defecation occurs.

Bowel cancer also known as Colorectal cancer begins with abnormal and uncontrolled growth of cells in the colon or the rectum resulting in the formation of abnormal tissue growths which are called polyps.

These polyps are initially noncancerous which means they grow slowly and do not spread to other parts of the body. However overtime, polyps can become cancerous.

If cancer begins in any section of the colon, it can be classified as colon cancer. If cancer begins in the rectum, it can be classified as rectal cancer.

The most common type of bowel cancer is adenocarcinoma which begins in the cells lining the walls of the colon or the rectum.


Patients with bowel cancer might not experience any symptoms in the early stage of the disease. Patients only begin to experience significant and bothersome symptoms once tumors have grown and become large in the colon or the rectum or once the cancer has spread out of the colon or the rectum. Symptoms may vary among patients.

  1. A change in bowel habits : diarrhea, constipation, or feeling that the bowel does not empty completely
  2. Bright red or very dark blood in the stool
  3. Stools that look narrower or thinner than normal
  4. Discomfort in the abdomen, including frequent gas, bloating, fullness, and cramps
  5. Unexplained and unintentional weight loss
  6. Constant tiredness or fatigue









There is no known cause for bowel cancer.


  1. Smokers are more likely to develop bowel cancer than non-smokers.
  2. Obese people are more likely to develop bowel cancer.
  3. People who are physically inactive are more likely to develop bowel cancer than active individuals.
  4. Individuals with moderate to heavy alcohol use are at a higher risk of developing bowel cancer.
  5. The chances of being diagnosed with bowel cancer increases with age.
  6. Individuals with type 2 diabetes are at a higher risk of developing pancreatic cancer.
  7. Having a genetic condition such as Lynch syndrome (hereditary non-polyposis colorectal cancer, or HNPCC) and familial adenomatous polyposis (FAP).
  8. If you have been diagnosed with colorectal polyps or colorectal cancer or inflammatory bowel disease, your risk has been increased.


Guidelines recommend starting routine screening from age 45 years in order to detect for signs of colon cancer or noncancerous colon polyps and even earlier if there is a family history of bowel cancer or Familial adenomatous polyposis or risk factors.

The benefit of screening is that cancer is detected early, managed and increases the chance of successful recovery and outcomes. Speak to your doctor about the most appropriate screening in your circumstance. The following screening techniques are used:

  1. Colonoscopy
  2. Computed tomography (CT or CAT) colonography.
  3. Sigmoidoscopy
  4. Fecal occult blood test (FOBT) and fecal immunochemical test (FIT which is more sensitive and more convenient to carry out)
  5. Stool DNA tests


Chemotherapy, Radiation Therapy, Surgery, Drug Therapy, Targeted therapy and Immunotherapy are all treatment options for bowel cancer. The selection of treatment is made by the doctor based on the type of bowel cancer the patient has, the location of the tumor in the colon and/or rectum, how far the cancer has spread, the speed at which tumors are developing and the overall health of the patient.



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