Bowel cancer is the second most common cancer in both men and women in Australia and is more common in people over the age of 50.
Bowel cancer, also known as colorectal cancer, develops from the inner lining of the bowel and is usually preceded by growths called polyps, which may become invasive cancer if undetected. Depending on where the cancer begins, bowel cancer may be called colon or rectal cancer.
In 2013, 14,962 new cases of bowel cancer were diagnosed in Australia. The risk of being diagnosed by age 85 is 1 in 10 for men and 1 in 15 for women.
In 2014, there were 4071 deaths caused by bowel cancer in Australia. This represents the second highest number of cancer deaths after lung cancer.
Across all cases, the five-year survival rate for Australians diagnosed with bowel cancer is 69%.
Symptoms of bowel cancer include:
- change in bowel habit with diarrhoea, constipation or the feeling of incomplete emptying
- thin bowel movements
- blood in the stools
- abdominal pain, bloating or cramping
- anal or rectal pain
- a lump in the anus or rectum
- weight loss
- unexplained anaemia.
Some factors that increase your risk of bowel cancer include:
- inherited genetic risk and family history
- inflammatory bowel disease
- high red meat consumption, especially processed meats
- being overweight or obese
- high alcohol consumption
Screening, using a non-invasive test for blood in the faeces that can be done at home, is recommended for all Australians aged 50 to 74. Known as the faecal occult blood test (FOBT), the test is only for low-risk people with no symptoms of bowel cancer. The FOBT is not for people with a family history of bowel cancer. In this case, you may need screening colonoscopies
The National Bowel Cancer Screening Program currently provides the test free for people aged 50, 55, 60, 64, 65, 70, 72 and 74. More aged groups will be added in coming years and by 2020, the test will be available free (once every two years) to all Australians aged 50 to 74.
For further information call 1800 118 868 or visit cancerscreening.gov.au.
A number of tests are used to diagnose bowel cancer. Initially your doctor will give you a physical examination to feel if you have any abdominal swelling.
You may have a blood test to see if there are any signs that you are losing blood in your stools. It can also check your red blood cell count.
The best test for bowel cancer is a colonoscopy, which examines the length of the large bowel. Air is pumped into the colon through a flexible tube that is inserted into the anus. A camera on the end of the tube allows your doctor to look for abnormal tissue that is removed for further examination.
Flexible sigmoidoscopy is used to examine the rectum and left side of the lower colon. Any unusual tissue can be removed for further examination.
CT or MRI scan
CT scans produce three-dimensional pictures of several organs at the same time and can be used to examine the bowel. An MRI scan produces detailed cross-sectional pictures of the body and can show the extent of any tumours.
In a positron emission tomography (PET) scan, a small amount of radioactive glucose is injected into the body. When scanned, cancer cells will appear brighter.
This is a test using soundwaves that echo when something dense is encountered such as a tumour. An abdominal ultrasound is used to see if the cancer has spread to the liver whereas an endorectal ultrasound (ERUS) is done if other tests have shown cancer in the rectum or anus.
Treatment for early bowel cancer
The main treatment for early bowel cancer is surgery. The most common surgery for cancer that begins in the colon is a colectomy. The type of colectomy performed will depend on whether all or part of the colon needs to be removed.
Radiotherapy is often used before surgery for locally advanced rectal cancer and may be used in combination with chemotherapy to reduce the number and size of cancer cells.
Chemotherapy may be recommended after surgery for rectal or colon cancer. This aims to reduce the risk of the cancer returning.
Treatment for advanced bowel cancer
Systemic treatment for advanced bowel cancer uses drugs that move through the bloodstream to reach cancer cells throughout the body. Systemic treatment can include chemotherapy and targeted therapies.
You may be offered surgery to remove small secondary cancers if the cancer has spread to other areas of the body.
Your GP will help set up initial tests and discuss your overall treatment and health. In addition, your treatment team may be made up of a number of specialist staff, such as:
- colorectal surgeon who diagnoses and operates on bowel cancer
- gastroenterologist who specialises in the digestive system
- medical and radiation oncologists who prescribe and coordinate the course of chemotherapy and radiotherapy
- cancer nurses
- other allied health professionals, such as a dietitian, social worker and occupational therapist.
In some cases of bowel cancer, your medical team may talk to you about palliative care. Palliative care aims to improve your quality of life by alleviating symptoms of cancer, without aiming to cure it.
As well as slowing the spread of bowel cancer, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.
An individual’s prognosis depends on the type and stage of cancer, as well as their age and general health at the time of diagnosis.
The risk of bowel cancer can be reduced by not smoking, a healthy diet with plenty of fresh fruit and vegetables, and maintaining a healthy body weight.
Understanding Bowel Cancer, Cancer Council Australia © 2017. Last medical review of this booklet: February 2017.
Australian Institute of Health and Welfare. ACIM (Australian Cancer Incidence and Mortality) Books. Canberra: AIHW.
Australian Institute of Health and Welfare (AIHW) 2017. Cancer in Australia 2017. Cancer series no. 101. Cat. no. CAN 100. Canberra: AIHW