A polyp is a fleshy growth that forms on the lining of the bowel. Some polyps are flat and others are attached to the lining of the bowel by a stalk and look more like a mushroom. The way a polyp is removed depends upon the type of polyp. The procedure of removing a polyp is called a polypectomy.
Most people do not have any symptoms from their polyps and they are detected co-incidentally during an examination of the large bowel (colon). A few patients who may have larger polyps may experience mucus or occasionally some bleeding
There are many different types of polyps and only certain types need to be removed. We remove some polyps (adenomas) as they can sometimes turn cancerous over several years. Removing these polyps greatly reduces your risk of bowel cancer. Other types of polyp (hyperplastic) do not turn cancerous and so don’t require removal.
There are several different techniques we use to help distinguish between different types of polyp: (i) by pushing a button on the camera to change the colour of the picture (ii) to spray the surface of the polyp with special dyes to highlight the surface of the polyp. These dyes are harmless and temporary, and are also commonly used as a food colouring. However you may notice that the dye may temporarily change the colour of your stool (motion) to a blue/green colour after the procedure.
This depends upon the type and size of polyp you have. Small polyps may be removed using biopsy forceps (cupped forceps). Stalked polyps are usually removed using a snare (wire loop) through which a small amount of electrical current is passed (diathermy). Flat polyps are often removed by a procedure called EMR (Endoscopic Mucosal Resection). This is where fluid is injected under the polyp to raise the polyp up on a cushion, to make it easier to see and remove. The snare is then used to capture and remove the polyp. To use the snare we need to place a sticky pad, usually to the top of your leg. This will be removed at the end of the procedure.
The bowel lining does not contain any pain receptors and so removing a polyp should not cause you any discomfort. Sometimes you may feel bloated/ distended during the test due to the gas inserted into the bowel by the camera. If you do experience any pain at any time you should let the nurse or specialist know immediately.
The risks of removing a polyp are small, but it is important that you are aware of them. There is a risk of about 1 in 500 cases of a tear in the lining of the bowel (perforation) during the procedure. In the majority of cases this is identified during the procedure. It can sometimes be dealt with through the camera, using small metal clips, however in some cases an operation may be required to deal with this.
Bleeding can also occur after removing a polyp and occurs in around 1 in 100 – 200 cases. This is usually minor and can be dealt with at the time of the procedure. However in a small number of cases you may notice bleeding after the procedure (passing blood in you motion). If this occurs you should contact the endoscopy unit or if after 17:00pm seek advice from the Accident & Emergency department or you out of hours GP. If this happens if is helpful if you take your copy of the endoscopy report with you so that the specialist knows exactly what procedure you had performed.
The risk of complications does increase slightly with larger polyps. For these cases you may be given a separate information leaflet or be invited to meet up with a specialist in clinic.
Large stalked polyps in particular can contain blood vessels running up through the stalk. To reduce the risk of bleeding after removing the polyp the specialist may place small metal clips across the base of the polyp to reduce its blood supply. These usually fall off after a few weeks to days and will passed naturally in the stool. It is important to tell the specialist if you have an appointment for an MRI scan within the few weeks after your camera test. The doctor may also inject a small amount of a drug called adrenaline into the stalk of the polyp to help reduce the blood supply to the polyp temporarily.
Small polyps can often be removed during a standard procedure. If your bowel contains a large polyp or there are a lot of polyps in your bowel (colon), then the specialist may advise that you have a further procedure at a later date. This can be for a number of reasons: (i) so that we can talk to you in more detail about the procedure and what is involved. The risks associated with removing larger polyps can be higher than for smaller ones. Some larger or complex polyps require referral to a specialist who has a particular interest in this type of polyp, (ii) larger polyps often take longer to remove and so we need to arrange a longer time for the procedure, (iii) so that we can plan the best and safest way to remove the polyp.
After removal, the polyp is sent to a laboratory for analysis. They are looked at under a microscope to give us more information about the type of polyp and whether it has been completely removed. Because the polyps require special preparation to be seen under the microscope, it can sometimes take a month or more before the results are available.
In the majority of cases the results are sent to you GP once available. If the specialist is due to see you in the outpatient department or would like to discuss the results further with you then you will be sent an appointment.
Whether you require any future camera tests will depend upon the type, size and number of polyps in your bowel. The specialist will give you advice either at the time of your procedure or after the biopsy results are available.
We advise that you do not eat red coloured jelly before the test as this can make your bowel look red and can be confused with blood.
You have the option of having a mild sedative and painkiller for your procedure. They are given through a small plastic tube (cannula) inserted into your arm before the procedure. These medications can make you lightly drowsy and relaxed but not unconscious (ie you will not be ‘knocked out’). The reasons for this are that we may need you to change your position during the procedure and the risks of the procedure can increase with larger amounts of sedation.
We routinely give everybody having sedation oxygen through little prongs (nasal cannulae), which sit in your nostrils. Whilst you are sedated, we monitor your oxygen levels and heart rate using a finger probe. Your blood pressure is also recorded intermittently.
It is important to remember that if you are having sedation for your procedure that you advised not to drive for 24 hours afterwards. This is as sedation, similar to alcohol, can impair your judgement and decision-making.