Bowel Cancer

One in 13 Australians will develop bowel cancer in their life, making it one of the highest rates of bowel cancer in the world. In Australia, South Brisbane has the highest rate.

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On this page, we’ll answer the following questions:


What is bowel cancer?

Bowel cancer is a growth that can affect any part of the colon (large intestine) or rectum. It is also known as colorectal cancer, and depending on where the cancer is located, you might hear it referred to as colon cancer or rectal cancer (the rectum is the last 15-20cm of the bowel).

How does bowel cancer develop?

Most bowel cancers start as harmless growths called polyps. These are small bumps in the lining of the bowel.

Some polyps (especially adenomas and sessile serrated polyps) have the potential to grow into a cancerous tumour. However, the vast majority of small polyps can be removed from the bowel during a colonoscopy, removing the risk of that polyp turning into cancer.

What are the symptoms of bowel cancer?

Symptoms of bowel cancer vary. Any of the following symptoms can be indicative of bowel cancer and should be investigated:

  • Bleeding: bright red or dark red / maroon blood in the stool, in the toilet bowel or on wiping. Do not assume bleeding is caused by haemorrhoids; all bleeding requires investigation.
  • A change in bowel habits: a change from your usual pattern of bowel motions, including loose motions / diarrhoea, constipation, difficulty completely emptying or a change in appearance with a narrower shaped stool.
  • Pain: either abdominal pain, or lower pain in the anus / rectum.
  • A noticeable lump or mass in your abdomen.
  • Unexplained weight loss or anaemia (low blood count), causing tiredness.

A colonoscopy is usually recommended to investigate these symptoms.

Most people will have no symptoms at all during the early stages of bowel cancer. This is why screening is so important.

You should never be told you are too young to have bowel cancer.

What is bowel cancer screening?

If you are aged 50 and over, and you don’t have a family or personal history of bowel cancer / polyps and have none of the symptoms mentioned above, it is recommended you undergo bowel cancer screening every one or two years.

Bowel cancer screening is a simple test that looks for tiny amounts of blood in your stool. The screening test, called a faecal immunochemical test, is available through your GP and some pharmacies. It involves placing small amounts of stool / toilet water on a special card and sending it to be analysed for blood.

In Australia, the National Bowel Cancer Screening Program sees everyone in the country aged 50-74 receive a taxpayer funded screening test in the mail every two years.

If the test results do find blood, this does not definitely mean you have bowel cancer, but you will be notified of the result and will need a colonoscopy within 30 days.

What is bowel cancer surveillance?

If you have a family history of bowel cancer / polyps, including known inherited gene mutations, or you’ve had polyps removed during a colonoscopy, you will need extra testing.

This means you’ll need a colonoscopy anywhere from every one to five years, depending on your situation.

How is bowel cancer diagnosed?

If you have any concerning symptoms, or your bowel screening test (see above) is positive, a colonoscopy will be recommended. Bowel cancer can be diagnosed during the colonoscopy, or small biopsies will confirm the finding.

What is a colonoscopy?

A colonoscopy is a thorough examination of the lining of the large bowel (colon and rectum), and allows for procedures such as biopsies and polyp removal.

The procedure involves a long, thin, flexible tube with a video camera at the tip, being passed through the rectum and large bowel.

What are the risk factors for developing bowel cancer?

In most cases, bowel cancers develop with no underlying, predictable cause.

However like most cancers, the risk of developing bowel cancer increases as you age, with the majority of bowel cancers occurring in people aged over 50 years. Those aged under 50 shouldn’t take that as a sign it’s OK to ignore symptoms – it’s not.  

Along with age, there are other important risk factors to be aware of, although as you’ll see these can’t be changed.

  • A personal history of polyps or bowel cancer, and other types of cancer (e.g. stomach cancer and uterine cancer). Some of these cancers may be caused by a similar cancer-causing gene abnormality.
  • A family history of polyps or cancer. Sometimes people can be tested for inherited bowel cancer genes.
  • Having inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease.

There are other risk factors too, and these can be changed. There is convincing evidence that the risk of bowel cancer can be reduced through diet and lifestyle changes. These risk factors are:

  • Smoking
  • A diet high in red meats, processed meats, fried foods, alcohol
  • A diet low in fibre, vegetable, fruit and whole grain
  • Being overweight / obese or physically inactive

How is bowel cancer treated?

The combination of earlier diagnosis and better treatments have seen a great improvement in survival rates from bowel cancer in Australia over the past 50 years.

If detected early with no spreading of the cancer outside the bowel, patients can often be cured with surgery to remove a short length of bowel that contains the cancer.

Depending on certain aspects of the cancer (such as size, location) and patient factors (for example previous abdominal surgery or other significant health issues) there are multiple surgical options available.

The rectum is the last 15-20cm of the bowel, and cancers located in the rectum can be quite complex and hard to treat. If you have a rectal cancer, you need to be treated by a colorectal surgeon as they have extensive training and experience when it comes to rectal cancer.

Depending on the results of routine investigations (“staging”), up to half of rectal cancers may require radiotherapy and even small amounts of chemotherapy before surgery. At Brisbane Colorectal, we routinely use a cancer multidisciplinary meeting to discuss any complex rectal cancer case where there are a number of treatment options. Different specialists attend including medical oncologists, radiation oncologists, radiologists and surgeons.

As experienced colorectal surgeons we offer a number of surgical treatment options. Each of our patients’ situations are unique and we tailor your treatment to what is best for you.

  • Laparoscopic (keyhole) surgery and robotic surgery, which are minimally invasive.
  • Open surgery including extended resections, often with the assistance of other subspecialists, for large / locally advanced cancers.
  • Transanal full thickness excision of early rectal cancers, including transanal minimally invasive surgery (TAMIS).
  • Total mesorectal excision for rectal cancers, including transanal options (taTME).

If the cancer is within millimetres of the anal canal, or involving the anal canal, patients will sometimes need the complete removal of the anus and rectum to achieve a good cancer result. This can lead to the need for a permanent colostomy.

At Brisbane Colorectal, we take time and care to explain this, and encourage a second opinion so you can be assured that this is the best treatment for you. We also involve our stomal therapists at an early stage to allow patients to come to terms with what a colostomy is, and how it will affect them.

In instances where the cancer has spread outside the bowel (metastatic bowel cancer), surgery is usually combined with other treatment options to kill any remaining cancer cells. Chemotherapy is an important part of this treatment.

What happens after bowel cancer treatment?

The risk of bowel cancer recurring has decreased, thanks to the improvement of surgical techniques in recent years. However, there is still a chance your cancer may return.

The risk of recurrence of bowel cancer is highest in the first five years after your surgery. We therefore follow up with you very closely over this period. This involves a combination of:

  • Clinical review: assessment of symptoms and a thorough examination, every three to six months over the first year, and then often every six to 12 months for five years.
  • Colonoscopy: the first follow-up colonoscopy is usually performed six to 12 months after surgery, and then anywhere from every one to five years, depending on the findings.
  • Investigations: a combination of imaging (e.g. CT scans, PET scans) and tumour marking blood tests such as carcinoembryonic antigen (CEA) at defined intervals.

These websites are trusted sources of further information about bowel cancer:

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