Bowel cancer diagnosis
If you see a doctor and have symptoms that suggest you might have bowel cancer, the doctor will want to find out for sure. The first step is a direct examination. The doctor puts on plastic gloves and feels up the rectum with a finger (this won't help, of course, if the lump is too far up the bowel to feel). The doctor may also do a test to check for blood in the faeces. You can't always see a small amount of blood even if it is there.
But feeling a lump or finding blood doesn't prove someone has cancer. The next step is to take a look inside. How? There are 3 possibilities: X-rays, sigmoidoscopy and colonoscopy.
X-rays
The bowel won't normally show on an X-ray. So a chemical that will show — barium sulphate — is put into the bowel through a tube into the anus. The chemical coats the inside of the bowel, creating an outline that will show up on an X-ray photo, and the doctor can see if there's anything unusual. This is called a barium enema.
The barium sulphate is one of the safest ways to spot cancer. It's passed out when you next go to the toilet.
Sigmoidoscopy or colonoscopy
A short hollow tube (a sigmoidoscope) is put into the lower part of the bowel through the anus. It has a tiny light with or without a small camera on the end, and the doctor can take a look through it. Most cancers are near enough to the anus to be seen this way. Alternatively, during a colonoscopy, a longer, flexible, hollow tube is used to do the same thing. This reaches further and can spot problems more deeply inside. A sedative is given before the colonoscopy to help you relax while this is going on.
Biopsy
If the tests show there's something unusual in the bowel, the best way of finding out for sure whether it's cancer or some other problem, or something harmless, is to look at a bit of it under a microscope. This is called a biopsy. To get the sample doctors need, a small clump of cells can be pinched off while the sigmoidoscopy or colonoscopy is being done, using a thing like tweezers that goes up the hollow tube. This causes no pain.
For further information and advice, call the Cancer Helpline on 13 11 20
Last Reviewed: 03 January 2002
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