Polypectomy / endoscopic mucosal resection


What is a polypectomy?

A polypectomy is a procedure to remove one or more polyps from the bowel.

What is a polyp?

A polyp is a small growth on the wall of the bowel, which generally protrudes out from the bowel wall. Polyps are common with up to half of all adults having them. There are generally no symptoms associated with having polyps, although they can occasionally bleed and can become cancerous if left in situ, which is why doctors recommend them to be removed.

Polyps are generally only detected when a patient is undergoing an investigative or routine colonoscopy.

What causes polyps?

Polyps are formed due to genetic material within the cells lining the colon changes and becomes abnormal (mutates). Most cell types in the body is programmed to multiply, mature and die in a consistent and times manner. However, certain genetic changes prevent cells from maturing, and the cells do not die. This leads to an accumulation of immature, genetically abnormal cells, which eventually results in the formation of polyps. The mutations may occur as a sporadic event after birth or they may be present from before birth.

What happens during a polypectomy procedure?

If a polyp is under a certain size (generally under 1cm in diameter), it can be removed during the colonoscopy with special instruments on the colonoscope which are used to either cut the polyp off or catch the polyp in a type of noose. If a polyp is too large then a later procedure called an endoscopic mucosal resection (see below) may be needed.

Endoscopic mucosal resection

What is an endoscopic mucosal resection?

Endoscopic mucosal resection (often abbreviated to EMR) is a procedure to remove abnormal lesions, such as polyps, or cancerous tumours from the gastrointestinal tract ('endoscopic' - using an endoscope as opposed to conventional open surgery, 'mucosal' - this is the lining of the oesophagus/stomach/colon, 'resection' means surgical removal).

How is an endoscopic mucosal resection different from an endoscopy?

Like a conventional endoscopy it is performed using an endoscope which is equipped with a slightly different set of surgical instruments than a normal endoscope, and is needed where polyps or lesions are too large (ie larger than 1cm in diameter) to be removed during a standard endoscopy.

EMR is performed to remove these lesions either in the oesophagus, stomach, duodenum or in the colon. If the lesion is in the oesophagus, stomach or duodenum (small intestine) the endoscope is inserted via the mouth of the patient, and where the lesion or polyp is in the colon the endoscope (colonoscope) is inserted via the anus.

What happens during an endoscopic mucosal resection?

Much like a conventional endoscopy, an endoscopic mucosal resection generally does not require a hospital stay.

Once the gastroenterologist has inserted the endoscope and identified the lesion/polyp to be removed, saline solution is injected into the mucosal layer to separate this layer from the underlying muscle layer to allow the lesion/polyp to be removed without damaging the underlying tissue. The lesion/polyp is then removed using instruments on the endoscope.

What are the risks involved in the procedure?

The risks and complications associated with EMR differs based on the location of the lesion and the size of the lesion. Your treating gastroenterologist will discuss these risks in detail with you before the procedure. In some instances, for example where a cancerous tumour has penetrated through the mucosal layer, or where a lesion is in an awkward location or is too large, the EMR procedure may not be possible and conventional surgery may be required. Also, in rare cases where a complication does occur, an EMR may need to be converted to conventional open surgery.

Both preparation for and recommendations for what to look out for after these procedures are listed here.