Cancer of the large bowel can affect either the colon or the rectum. Combined, it is the second most common cancer in Australia.

Colon cancer affects men and women equally but rectal cancer is slightly more common in men. Bowel cancer becomes more common with age and most patients develop bowel cancer from age 50. People with genetic predisposition to developing bowel cancer often develop cancer under the age of 50 but they make a small minority of people with bowel cancer. People with family history of bowel cancer or polyps have a higher risk of developing bowel cancer. This risk increases with other factors such as number of family members with bowel cancer, ages at diagnosis or multiple cancers in the same individual. Other conditions of the bowel may also increase your risk of bowel cancer such as inflammatory bowel disease.


Symptoms of bowel cancer varies depending on the location of the cancer and the stage at diagnosis. Common symptoms include rectal bleeding, change of bowel habit, abdominal pain, unexplained or unexpected weight loss and anaemia.

Patients with colorectal cancer will require several tests to confirm the diagnosis and assess the stage of disease. These tests may include:

  • colonoscopy – this allows surgeon to locate the exact location of the tumour and take a sample for pathology to confirm the diagnosis
  • CT scan – to check for spread of the tumour. This usually includes a CT of the chest, abdomen and pelvis
  • MRI – patients with rectal cancer may require a MRI to assess the local spread of the tumour and respectability
  • CEA – a tumour marker (blood test) that may be helpful in the detection of cancer recurrence after treatment


Main treatment for colorectal cancer is surgery. This involves removing a segment of the large bowel where the tumour is located as well as the lymph glands surrounding the tumour. Most patients will be able to have their bowel reconnected (anastomosis) although some patients may require a temporary or permanent stoma bag.

Further treatment such as chemotherapy and radiotherapy may be required either before or after the surgery.