Colonic Polyps

Colonic polyps (also referred to as Bowel polyps) are among the most commonly encountered findings in gastroenterology. They form on the inner lining of the large bowel, known as the colon and rectum, and they are far more prevalent than most people realise. In fact, around half of all Australians will develop a bowel polyp at some point in their lives, yet most will never know it, because polyps rarely cause symptoms.

The relationship between bowel polyps and bowel cancer is the reason early detection matters. While the majority of polyps are harmless and will never cause any problem, a small proportion can slowly change over many years and develop into bowel cancer, one of the most common and preventable cancers in Australia. Understanding what polyps are, how they are found and what happens when they are detected is an important step in protecting your long-term bowel health.

What is a Colonic Polyp?

A colonic (or bowel) polyp is an abnormal fleshy growth that extends from the inner wall of the large bowel. Polyps vary considerably in their type, shape, size, location and number, and each of these characteristics plays a role in how your specialist will manage them.

There are three main types of bowel polyp. Adenomatous polyps, also called adenomas, are the most clinically significant because they have the potential to develop into cancer over time. Sessile serrated lesions, sometimes abbreviated to SSLs, also carry a cancer risk if left untreated. The third type, known as hyperplastic polyps, do not develop into cancer and are generally considered benign. Adenomas and sessile serrated lesions may also occur as part of rare inherited genetic syndromes.

In terms of shape, a polyp described as sessile is flat and only slightly raised above the surrounding bowel lining. A pedunculated polyp, by contrast, has a stalk and resembles a small mushroom. Most polyps are quite small, typically less than one centimetre in diameter, though some can grow to several centimetres in width. Your specialist’s report will document the type, shape, size, location and number of any polyps found during your procedure.

How are Bowel Polyps related to Bowel Cancer?

Bowel cancer is the second most common cause of cancer death in Australia. Each year, almost 15,000 new cases are diagnosed, and around 100 Australians die from bowel cancer every week^#. These are sobering figures, particularly given that bowel cancer is one of the most preventable cancers when detected early.

Most polyps are not cancerous. However, certain types, particularly adenomas and sessile serrated lesions, can progress to bowel cancer through a process that unfolds over many years. At the time of a colonoscopy, it is not possible to determine with certainty which individual polyps carry this potential. For this reason, the standard practice is to remove all polyps wherever it is safe and practical to do so.

Larger polyps and adenomas carry a greater risk of harbouring cancerous change. Detecting and removing them before this change occurs is one of the most effective ways of preventing bowel cancer altogether.

Who is at risk of developing Bowel Polyps?

Bowel polyps often cause no symptoms at all, which is why understanding your personal risk level is so important. Both men and women are affected, and the risk of developing bowel cancer before the age of 75 is approximately one in 19 for men and one in 28 for women in Australia. This places Australia among the countries with the highest rates of bowel cancer in the world.

Certain factors are associated with a higher likelihood of developing bowel polyps or bowel cancer. Age is among the most significant, with risk increasing steadily from 50 years onwards. A personal or family history of bowel polyps or bowel cancer also raises your risk considerably, as does a history of inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis. Lifestyle factors, including smoking and carrying excess weight, are also associated with increased risk. If you fall into one or more of these categories, it is worth discussing your screening options with your doctor.

How are Bowel Polyps detected?

Because bowel polyps rarely produce symptoms, they are most commonly found incidentally during bowel cancer screening or through a colonoscopy requested for another reason. There are two primary ways polyps and early bowel cancer are identified.

Faecal Occult Blood Testing

A Faecal Occult Blood Test, commonly known as an FOBT or poo test, is a simple screening tool that checks for traces of blood in a stool sample. This two-minute test can be performed at home using a kit available from your local pharmacy or GP. It is recommended for all adults over the age of 50 and forms the basis of the Australian Government’s National Bowel Cancer Screening Program. People with a family history of colorectal cancer are advised to perform this test every one to two years.

A positive FOBT result does not mean cancer is present, but it does indicate that further investigation with a colonoscopy is warranted.

Colonoscopy

Colonoscopy is the gold standard examination for detecting bowel polyps. It is the only test that allows the bowel lining to be examined directly and, critically, it enables polyps to be removed at the same time they are found. During a colonoscopy, a long flexible tube with a small camera at its tip is passed gently through the rectum into the colon, allowing the gastroenterologist to inspect the entire bowel lining. You can read more about what to expect from this procedure on our colonoscopy page.

While colonoscopy is the most accurate test available for examining the bowel, it is important to understand that no medical test is perfect. A small proportion of polyps, particularly very small ones, may not be detected during an examination. This is one reason why ongoing surveillance is recommended for people who have previously had polyps.

Polyp removal during colonoscopy

When a polyp is identified during a colonoscopy, the gastroenterologist will generally remove it during the same procedure. This process is called a polypectomy. Removal is performed using a small wire loop that is passed over the polyp and then closed at its base, cutting the growth away from the bowel wall. The removed polyp is sent to a laboratory for pathological analysis to confirm whether it is benign or whether any concerning changes are present.

In most cases, removal of an individual polyp effectively eliminates the cancer risk associated with that specific growth. Rarely, pathology may reveal that cancer is already present within the polyp, and further treatment or surgery may then be needed to ensure the bowel is clear.

Risks associated with polypectomy

Polypectomy is a safe and well-established procedure. Complications are uncommon. There is a very small risk of bleeding at the site where a polyp has been removed, and a smaller risk still of a perforation, which is a small hole forming in the bowel wall. If either of these complications occurs, treatment in hospital may be required. You should seek medical attention promptly if you experience significant bleeding from the bowel or persistent abdominal discomfort following your procedure.

What happens after polyp removal?

The removal of a polyp does not necessarily conclude your monitoring. Having a polyp or bowel cancer in the past places you at a higher risk of developing further polyps in the future. For this reason, your gastroenterologist will advise you on when your next colonoscopy should take place.

The recommended interval between colonoscopies is determined by several factors, including the type, size and number of polyps removed. If your specialist needs to confirm that a polyp was completely removed, or if your procedure was not fully completed on the first occasion, a follow-up colonoscopy may be scheduled sooner. People with a strong family history of bowel cancer, or those with a large number of polyps, may require more frequent surveillance.

Reducing your risk of Bowel Polyps and Bowel Cancer

Alongside regular screening, a healthy lifestyle plays a meaningful role in reducing your bowel cancer risk. Not smoking, maintaining a healthy body weight, staying physically active and eating a nutritious diet are all steps that contribute to your long-term bowel health. Participation in the National Bowel Cancer Screening Program, including using Faecal Occult Blood Tests as recommended, is one of the most effective things you can do.

If you have specific questions about your diet and its relationship to bowel health, speaking with an accredited practising dietitian is a worthwhile step. To find a qualified dietitian in your area, you can use the Find a Dietitian directory on the Dietitians Australia website.

Speak with a Specialist

If you have been told you have bowel polyps, if you are concerned about your bowel cancer risk, or if you have been referred for a colonoscopy, the gastroenterologists at Queensland Gastroenterology are here to support you with experienced, patient-centred care. Early detection and appropriate monitoring are the most important steps you can take to protect your bowel health.

To learn more about colonoscopy at Queensland Gastroenterology or to request a referral, visit our colonoscopy page or contact our Brisbane rooms to make an enquiry.