CHECK-UP: I’m in my late 50s with a strong family history of bowel polyps and cancer. As a precaution, my GP would like me to go for a colonoscopy and some X-rays.
Colonoscopy, barium enemas and X-rays are tests used to screen for cancers and polyps (growths in the lining of the large bowel). Polyps may be non-cancerous (benign) or pre-cancerous (have the potential to develop into cancer).
The goal of screening is to find growths in their early stages, and remove them before cancer has had a chance to develop. Internal examination of the colon and rectum is performed using a colonoscopy.
In this procedure, a thin tube with a bright light at the end is placed in the back passage and moved up into the colon. This allows the doctor to examine the inside of the rectum and colon for abnormalities. If an abnormality is found, it may be removed completely or a portion taken for biopsy. Sedation may be required.
Barium enema and X-ray can also be used to examine the colon. In this test, the colon is filled with barium (a contrast medium) via a tube inserted into the back passage. When the X-ray is taken, the outline of the lining of the colon and any abnormalities may be seen.
I heard it’s possible to have a virtual colonoscopy. Is this less unpleasant than the standard scope?
Computed tomographic colonography (virtual colonoscopy) is a minimally invasive scan.
It is used to produce three-dimensional images that can depict polyps and other lesions in the colon and rectum. Sedation and pain-relievers are not usually needed, so there is no recovery period after the procedure.
While the scan itself is relatively non-invasive, two aspects of the procedure may cause some discomfort. The first is that the colon needs to be thoroughly cleaned prior to the scan. As in regular colonoscopy, this is achieved by using oral preparations to empty the bowel fully in the days before the test. Some find this an unpleasant process.
The second uncomfortable aspect is that, in order for virtual colonoscopy results to be accurate, the colon must be fully distended during the scan.
This is done using air or carbon dioxide to inflate the colon – and it may cause some discomfort. If an abnormality is detected on CT colonography, a regular colonoscopy will be required to perform a biopsy and to treat the problem.
