If you have visited your GP with symptoms, have a history of bowel cancer in the family or have had an ‘abnormal’ result after a bowel screening, you may have been referred for further investigations.

There are three investigations that your specialist may refer you for.


Rigid Sigmoidoscopy

Your specialist will assess you and may decide to perform a simple rectal examination during the appointment. This is a quick examination which involves the insertion of a gloved finger into the rectum.

The next step is a rigid sigmoidoscopy; a straightforward investigation which involves an endoscope, a thin tube attached to a camera, passed into the back passage. This allows your specialist to look into the rectum and the bottom part of the colon.

Flexible Sigmoidoscopy

Your specialist may book you an appointment for a flexible sigmoidoscopy, (also known as a ‘flexi-sig’ or a bowel scope) which is a straightforward procedure performed in the endoscopy unit. This procedure allows your specialist to see around the bends of the colon. This involves passing a thin, flexible tube into the back passage. Your specialist will be able to see around into the lower part of the bowel, which is where the majority of polyps are found, and where most bowel cancers start. Samples (biopsies) can be taken during this procedure if your doctor sees anything that needs further investigation. Any samples can be sent for examination in a laboratory.

If you are aged 55 years or above, you may qualify for a bowel scope screening programme, funded by the Department of Health in England, for men and women across the country. See bowel scope screening for more information.

How to prepare for a Sigmoidoscopy

Sigmoidoscopies can be performed in clinics as outpatient procedures, safely and comfortably without the need for anaesthetic or sedation. They can be uncomfortable but are not painful. Before the procedure, you will require some kind of bowel preparation, usually an enema (a medicine inserted into the back passage) on the day. This is to ensure that the bowel is clean and clear for the specialist’s optimum visibility.


A colonoscopy is a procedure done to examine the lining of the whole large bowel, to investigate for polyps or any growth that requires further investigation. The procedure involves a long, flexible tube (endoscope) being passed through the back passage. A bright light and tiny camera are attached to the end of the tube, allowing your specialist to get a clear view of the lining of the bowel. Samples (biopsies) or photographs may be taken during this procedure if your doctor sees anything that needs further investigation. Polyps can be removed quickly and simply during this procedure.

How to prepare for a Colonoscopy

A specialist nurse or screening practitioner may want to see you before the procedure to explain what it involves, and to talk you through the pros and cons of having it done. Alternatively, this information can be delivered by post or over the telephone. You will be asked about any medical conditions (e.g. kidney problems, diabetes) to ensure that the bowel preparation and the procedure can both be carried out correctly.

You will need to start the bowel preparation one day before. This involves a combination of a medicine which you will need to drink, and a temporary change of diet. This will ensure that your bowel is empty, which allows your specialist to get the clearest view of your bowels during the procedure.

Putting you at ease

You will be able to talk to your doctor or nurse about any concerns you may have, and to discuss whether or not you can have sedation during the procedure. You should let your doctor or nurse know as soon as you can if you have problems lying flat or curling up on your side. This will allow your specialist to make any alternative arrangements should they be necessary.

During a colonoscopy, a gas is used to inflate the bowel for optimum visibility. After the procedure, this may cause some discomfort in your abdomen or shoulders. This will only last for a short time, and can be relieved by peppermint chewing gum or warm peppermint tea. Massaging your abdomen or walking about can also help to relieve this, as this will aid the gas passing out of your body.

Virtual Colonoscopy

A virtual colonoscopy (also known as a CT colonography) is a procedure which involves using a CT scanner to produce 2D and 3D images of the rectum and the large bowel. This procedure can be used for patients who are not suited to a regular colonoscopy due to other medical reasons.

How to prepare for a virtual colonoscopy
The specialist nurse will talk to you before the procedure about bowel preparation. This Involves taking a drink for two days post meals which tags to the lining of the bowel. You will be asked about any medical conditions (e.g. kidney problems, diabetes) that they should be aware of prior to you beginning the bowel preparation.

Gas will be used to inflate the bowel, via a thin, flexible tube which will be placed in your back passage. CT scans will then be performed with you lying on your back, and then on your front, to allow the doctors to obtain a clear set of images of your bowel.

One disadvantage of this procedure is that if anything ‘abnormal’ should be detected, a regular colonoscopy may need to be performed anyway at a later date, to allow your specialist to take samples (biopsies) or remove polyps.

You may have to visit a specialist hospital for this procedure, as virtual colonoscopies are not currently available at all hospitals nationwide.

Waiting for Test Results

It can be worrying waiting for test results, so be sure to ask your specialist, or your nurse when you can expect to find out the results. Results are usually delivered in person, but you might be asked if you are happy to receive your results over the phone. You should think carefully about this choice, as you might prefer to be with the doctor or nurse in person when they tell you, should you have cancer.

When you receive the results, if you do have bowel cancer, your specialist doctor will discuss with you what happens next.