Colon Cancer

What causes colon cancer?

Colon cancer is a disease caused by an interaction of genes and certain lifestyle factors, such as smoking and diet. Genes are part of the DNA present within each cell of the body, and cancer arises when the genes controlling cell growth stop working normally. There are many factors that may increase the risk of developing colo-rectal cancer. To list a few: age over 50 years; obesity and physical inactivity; having a pre-cancerous polyp in the colon; a family history of colon cancer; inflammatory bowel disease; tobacco, smoking and heavy alcohol use; and type II diabetes.

What are the symptoms of colon cancer?

Many people with colon cancer experience no symptoms in the early stages of the disease, and the cancer is detected on routine health checks and screening colonoscopies. Blood that oozes from the tumour into the stool often goes undetected by the naked eye and is many times found only on laboratory examination of the stool for occult blood; the anaemia this causes may lead some people to experience easy fatiguability, lethargy and breathlessness. Many people experience alarming features such as loss of appetite and weight loss, which prompt them to seek evaluation. Some may have symptoms such as abdominal bloating, pain or discomfort along with altered bowel habits like constipation, diarrhoea or bloody stool, and those who present with such obstructive features usually have advanced disease.

How is colon cancer diagnosed?

If your symptoms indicate that you could have colon cancer, your doctor may recommend blood tests, stool examination, colonoscopy, a barium enema x-ray or a computerised tomography (CT) scan to help make a diagnosis. Colonoscopy is an endoscopic procedure for visualisation of the colon, in which a colonoscope — a flexible tube containing a camera chip and channels through which biopsies can be taken — is inserted via the anal canal under direct visual guidance. Colonoscopy allows the growth to be seen directly, its location and extent to be checked, and biopsy samples, which are tiny tissue fragments, to be taken. The biopsies are then evaluated in the laboratory under a microscope to establish the nature of the tumour and whether it carries malignant potential. If you are diagnosed with colon cancer, your doctor will then order tests such as CT, MRI or PET scan to determine the extent, or stage, of the cancer. Staging helps determine what treatments are most appropriate for you.

How is colon cancer treated?

Depending on the stage of the colon cancer, treatment may include surgery, radiation and/or chemotherapy.

What is colonic stenting?

Colonic stents are made of metal and are deployed via a colonoscope under fluoroscopic guidance. They are used for the palliative management of colon cancer, which means relieving obstructive symptoms where surgery is not feasible.

When should you seek medical advice?

Talk with your doctor right away if you notice a change in bowel habits such as constipation or diarrhoea, rectal bleeding, blood in or on the stool, stomach pain or bloating, loss of appetite or weight loss.