A polyp is a growth in the lining of the bowel. Polyps are common and are seen during colonoscopy. A polyp can be sessile (no stalk) or pedunculated (on a stalk or stem). Some polyps can turn into cancer if they are left untreated which is why it is important to detect polyps and remove them during colonoscopy.
Do all polyps turn into cancer if left untreated?
There are different types of polyps in the colon and only some of these might turn into cancer if they are not removed. When polyps are removed at colonoscopy, the polyp tissue is sent to the laboratory for testing under the microscope to determine the exact type of polyp removed. The type of polyp removed will indicate your risk of developing cancer and will guide us as to the optimal time for you to have a repeat procedure.
- Hyperplastic polyps – these are common and are usually regarded as harmless as they very rarely develop into cancer
- Adenomatous Polyps – these can develop into cancer over time
- Serrated Polyps – these have an accelerated path to the development of cancer
How do polyps turn into cancer?
The progression of a polyp to cancer is now well understood. A polyp forms and over time, grows larger as it progressively undergoes genetic changes. Eventually over a five to ten year period it may transform into a cancer as it accumulates genetic defects. It is therefore essential to check for polyps and remove them. Early detection can significantly reduce your chance of developing bowel cancer.
What are the symptoms of polyps?
You will be able to return to your normal activities and diet after the testing has finished. The information gathered will be interpreted by Dr Melissa Haines or Dr James Fulforth, who are gastroenterologists with specific training in the interpretation of diagnostic breath test results. Your doctor will inform you of the test results and refer you to a dietician to give you individualized dietary advice.
Please note that there may be a delay of up to a week to obtain results from methane gas testing as the sealed bags of gas are sent to Auckland for analysis.
How do I check if I have polyps?
During a colonoscopy, polyps can be seen through the camera. If a polyp is found it will often be removed there and there. If you have a large polyp removed, a high risk polyp or more than three polyps, then it is recommended that you have a repeat colonoscopy at a shorter interval. If you have someone in your family who has had polyps or bowel cancer then regular colonoscopies are recommended.
By removing polyps we help to prevent bowel cancer!
How are polyps treated?
During the colonoscopy an instrument can be inserted through the colonoscope to obtain a biopsy or remove the polyp for laboratory analysis. There is no sensation inside the colon so when the tissue is removed you will not feel it. Most polyps can be removed safely this way but very large polyps may need to be taken out in a special endoscopy session or surgically.
Do colonic polyps run in the family?
Yes. If you have family members who have polyps or who have had bowel cancer then your chance of developing polyps and cancer is increased. In these circumstances you should consider screening colonoscopies. These are routine scopes, without symptoms, to check for the development of polyps.
When should I start screening colonoscopies?
As a general rule, in the absence of a family history of bowel cancer, it is a good idea to begin screening at around 45-50 years. The screening colonoscopy can then be repeated every 3-5 years, depending on whether or not colonic polyps are found.
Because New Zealand has such a high prevalence of bowel cancer (about 2000 new cases each year), and because it is so easily prevented, New Zealand has just begun a nationwide Bowel Cancer Screening Programme. This publicly funded screening uses a stool specimen to identify risk of asymptomatic people 60 to 74. If the stool test is positive, the person gets invited to have a colonoscopy.