Colon cancer is the growth of rapidly dividing cells in the large intestine. It is also referred as colorectal cancer. Cancers of colon develop from polyps, the small and non-cancerous growths of tissues. Colon cancer usually begins in glands lining the colon and rectum. Colon cancer initially begins as noncancerous tumours and gradually develops into cancer which spreads to other tissues.
Although colon cancer affects people of all ages, it is common in people aged 60 years and above. Certain factors are that increase the risk of developing colon cancer include alcohol, smoking, high fat intake, family history of colon cancer, presence of polyps, and increased age (>60 years).
In the early stages, people with bowel cancer may not experience pain. However, the following symptoms may indicate colon cancer:
- Blood in stools
- Change in the bowel habits, such as thin stools, diarrhoea, and constipation
- Unexplained weight loss
- Abdominal pain
Colon cancer is diagnosed by symptoms, medical history, and other diagnostic procedures which include:
- Colonoscopy- It is a procedure done to look inside the entire colon. It is performed using an instrument called colonoscope, a flexible tube with a tiny camera attached to one end which is connected to a large screen.
- Sigmoidoscopy- It is a performed to examine the large bowel and the rectum using a sigmoidoscope.
- Barium enema- It is done to assess the abnormalities of the colon. In this procedure barium fluid is administered into the bowel through rectum. X-ray images are then captured to view inside the bowel.
If the colon cancer is confirmed, staging is performed to detect the size, location, and stage of the cancer. Staging is performed using ultrasonography or computed tomography (CT) scan of the abdomen, chest X-rays, magnetic resonance imaging (MRI) scans of the bowel, and complete blood count.
Faecal occult blood test (FOBT) – is a test which determines small amounts of blood in the faeces. However this test does not diagnose colon cancer, hence need to be performed during colonoscopy or sigmoidoscopy.
Treatments depend on the size, location, and stage of the cancer. Colon cancer may be treated using chemotherapy, radiation therapy, and/or surgery.
Chemotherapy and Radiotherapy
Colon cancer can be treated using anti-cancerous medications or radiation depending on the site and severity of cancer. These treatments can be used as alone or in addition to surgery to destroy the remaining cancer cells and to prevent from further spreading.
Colectomy is the most common procedure performed to remove the cancer cells. It is the surgical resection of all or part of the large intestine. It is also called large bowel resection. Colectomy is performed under general anaesthesia by open surgery method or by laparoscopic method. The procedure takes about 1 to 4 hours.