What is a colonic polyp?

A colonic polyp refers to an abnormal fleshy “growth” in the lining of the colon (large bowel). Most colonic polyps are benign.  However, some polyps may develop into bowel cancer over time – usually five to ten years.   It is thought that removing polyps when little prevents the potential development of bowel/colon cancer.

How are colonic polyps detected?

Colonic polyps can be detected during a colonoscopy procedure. Colonoscopy is the best test for the detection and treatment of polyps because the lining of the colon can be directly visualised, and because the polyp can usually also be removed during the same procedure. 

Are there different types of colonic polyps?

The appearance of colonic polyps during a colonoscopy may vary considerably. Polyps may be “sessile” (flat) or “pedunculated” (with a stalk). The polyp size may also vary.

Colonic polyps can be classified based on their microscopic appearance into adenomatous and non-adenomatous polyps. Adenomatous polyps are of greater concern as they have a greater risk of developing into bowel cancer. It is not always possible to differentiate between these types of polyp on the appearance during colonoscopy alone, and so removal for analysis is recommended.

How common are colonic polyps?

Colonic polyps are common and increase with age.  They occur in approximately 30-50% of adults. 

Why did I develop a colonic polyp?

The exact cause of colonic polyps is not known in most cases, but it is thought to be due a combination of lifestyle and genetic factors.  Lifestyle factors include a high fat diet, low fibre diet, diet high in red meat, obesity and smoking. Genetics are also important, because colonic polyps and bowel cancers can run in families.  There are some genetic diseases (e.g. familial adenomatous polyposis coli) which can cause many colonic polyps to form in early adulthood, and subsequent higher risk of bowel cancer. 

In general, you are at higher risk of having colonic polyps if:

• you are older than 50
• you have had polyps before
• there is a family history of polyps
• there is a family history of bowel cancer

You should talk to your doctor if you fit into any of these categories. 

What are the symptoms of a colonic polyp?

The majority of colonic polyps do not cause any symptoms. Polyps may bleed, although this is not always noticed. Occasionally very large polyps may cause abdominal cramping or discomfort.

What are the chances of a colonic polyp developing into cancer?

The chance of a cancer forming is determined by the type, size and number of polyps found. In general, large adenomatous polyps are associated with the highest risk.

What is the management for a colonic polyp?
The detection and removal of colonic polyps before they develop into bowel cancer is the basis of screening for bowel cancer. The removal of a colonic polyp is referred to as a “polypectomy”.

Do I need any follow up after colonic polypectomy?

People who have adenomatous polyps have a higher rate of forming new polyps over time. Consequently a repeat colonoscopy is recommended. A number of factors determine the time interval for a repeat colonoscopy including: microscopic characteristics of the polyp (histology), number, size, appearance at colonoscopy, adequacy of bowel preparation. 

Do my family members need testing if I have colonic polyps?

In general, all people should undergo bowel cancer screening at age 50. However, earlier screening may be recommended in first degree relatives of people who have been diagnosed with either adenomatous polyps or bowel cancer before the age of 55. Earlier screening may also be recommended if polyps/bowel cancer has been detected in multiple family members.


Where I can obtain more information?

Contact GastroNorth