Colonoscopy & Polyp Removal

Colonoscopy involves passing a thin, flexible camera through the rectum to examine the entire lining of the large bowel and the last part of the small bowel. It is performed as a day procedure under sedation given by a specialist anaesthetist.

The procedure has two essential functions. It identifies abnormalities (including polyps, inflammation, diverticular disease and cancer) and it allows treatment at the same time. Most polyps can be removed during the examination using small instruments passed through the colonoscope, removing the need for further surgery in the majority of cases.

Colonoscopy is widely regarded as the most accurate test of the large bowel because it both visualises the bowel lining directly and provides the opportunity to take tissue samples for pathology.

Colonoscopy is recommended in several common situations: investigation of rectal bleeding, a persistent change in bowel habit, unexplained abdominal pain, iron deficiency anaemia or unexplained weight loss. It is also the recommended follow-up to a positive faecal immunochemical (FIT) screening test.

Surveillance colonoscopy is used to monitor patients with a personal history of polyps or bowel cancer, those with a significant family history, and patients with long-standing inflammatory bowel disease. Intervals between procedures are guided by national surveillance guidelines and the findings of previous examinations.

• Symptoms such as rectal bleeding or change in bowel habit.
• Follow-up of a positive bowel cancer screening test.
• Surveillance after previous polyps or bowel cancer.
• Strong family history of bowel cancer or polyps.
• Iron deficiency anaemia of uncertain cause.
• Long-standing inflammatory bowel disease.

Any rectal bleeding, persistent change in bowel habit, unexplained weight loss or new abdominal pain should be reviewed by a GP and considered for colonoscopy, regardless of screening history. Symptoms are never normal simply because they are common.

While most patients with these symptoms have benign conditions such as haemorrhoids or an anal fissure, colonoscopy is the most reliable way to exclude polyps and cancer.

All patients are reviewed before colonoscopy to discuss the reason for the procedure, relevant medical history, current medications and allergies. Blood thinners, diabetic medications and iron supplements may need to be adjusted, and specific instructions are provided in writing.

The consent process covers the benefits of the procedure, the small but important risks, and what to expect on the day. Patients have the opportunity to ask questions before consenting.

Good bowel preparation is the single most important factor in a safe, accurate colonoscopy. If the bowel is not adequately clear, polyps and other abnormalities can be missed and the procedure may need to be repeated.

Preparation involves a low-residue diet for several days, clear fluids on the day before the procedure, and a prescribed preparation solution taken in two doses, typically the evening before and several hours before admission. Detailed written instructions are provided well in advance.

On the day, you are admitted to the day procedure unit and reviewed by both the surgeon and the anaesthetist. Sedation is given through an intravenous line and the procedure performed in a private theatre. Most patients have no recollection of the examination.

The colonoscope is gently advanced to the start of the large bowel, and the lining carefully inspected as it is withdrawn. Any polyps identified are usually removed during the same procedure, and small tissue samples may be taken from areas of concern for pathology.

Polyps are small growths arising from the bowel lining. Most are benign, but certain types (particularly adenomas and serrated lesions) can develop into bowel cancer over many years. Removing polyps when they are small is one of the most effective ways to prevent colorectal cancer.

Small polyps are typically removed with a wire snare or biopsy forceps. Larger or more complex polyps may require advanced endoscopic techniques and, occasionally, surgical referral. The pathology of every removed polyp is reviewed to guide future surveillance.

After the procedure you rest in the recovery area until the sedation wears off. Recovery time varies according to the procedure, sedation and the individual patient. You can eat and drink lightly before going home with a responsible adult. Sedation can affect judgement and coordination, so you should not drive, sign legal or financial documents, or operate machinery for 24 hours.

Visible findings are discussed with you in recovery, and a written report is sent to your referring doctor. Biopsy and polyp pathology results typically return within one week and are reviewed at follow-up. The timing of any surveillance colonoscopy is confirmed once the pathology results are available.

Colonoscopy is commonly performed and can provide important diagnostic and treatment benefits. It also involves preparation, sedation and procedural risks. Your specialist will discuss the expected benefits, alternatives and relevant risks with you before the procedure.

The most common after-effects are mild abdominal discomfort and bloating from air introduced during the procedure, which usually settle within a few hours. Significant complications are uncommon. Bleeding can occur, particularly after removal of larger polyps, and rarely a small tear in the bowel wall (perforation) may require further treatment. These points are covered in detail at consent so that patients can make a fully informed decision.