fWhen a patient is seen at hospital with a suspected bowel cancer, a number of steps will be taken to make the diagnosis and plan the treatment. Firstly the doctor will take the medical history and carry out a physical examination. This will usually include a rectal examination: to do this the doctor places a gloved finger in the back passage and gently feels for lumps or swellings. This may be a little uncomfortable but should not be painful. It is likely the doctor will also want to look inside the colon and rectum. This can be done using examinations known as proctoscopy, sigmoidoscopy and colonoscopy. These tests allow the doctor to get a detailed view of the rectum and colon.
Proctoscopy and sigmoidoscopy allow the doctor to look at the rectum and the lower part of the colon. The examinations are usually performed as an out-patient at the hospital. The patient lies on their side and a thin tube is gently passed into the back passage. A proctoscope is a short tube that just goes into the rectum, a sigmoidoscope is longer and so can look further up into the bowel. With the help of a fibre optic light on the inside of the tube the doctor can see any abnormal areas. If necessary a small sample of the bowel lining can be taken for examination under the microscope (this is called a biopsy).
Depending on the results of these examinations your doctor may advise a colonoscopy. This allows the doctor to look at the whole length of the colon and rectum. The examination is usually performed in an Endoscopy unit at the hospital and takes about an hour. Laxatives are given the day before the test to empty the bowel so that a clear picture can be seen. Usually a mild sedative is given to help the patient relax during the examination. A flexible tube is then gently passed into the back passage. This tube, called a colonoscope, is made up of flexible fibres and uses a light and a fibre-optic camera to see the whole length of the large bowel (colon and rectum) and also the lower part of the small bowel. During the test photographs of the bowel and samples of the bowel lining (biopsies) can be taken. The procedure should not be painful but can be uncomfortable.
Another test that is sometimes used is a barium enema. This is a special x-ray of the large bowel. Once again the patient usually takes a laxative the day before the test. For the enema itself, a mixture of barium (which shows up on the x-ray) and air is passed through a tube into the back passage. The doctor can then watch the passage of the barium through the bowel on an x-ray screen and any abnormal areas can be seen.
Other tests are ultrasound, CT and MRI scans. An ultrasound scan uses sound waves to build up a picture of the inside of the body. A CT scan (or CAT scan) is a specialised type of x-ray where a number of pictures are taken from different angles and fed into a computer which shows detailed pictures of the inside of the body. An MRI scan (or Magnetic Resonance Imaging) is similar to a CT scan but uses magnetism instead of x-rays to build up a cross-sectional picture of the body.
Although all these tests are available, usually only a few of them will be needed to make a complete assessment for any one patient. A biopsy is necessary to confirm the diagnosis of cancer. Usually either colonoscopy or the combination of sigmoidoscopy and a barium enema will give sufficient information on the location of the cancer in the bowel. For a few patients when these tests do not give sufficient information about the position or size of the cancer then CT or MRI scans may be needed. Ultrasound, CT or MRI scans are also used to look at the liver to check for any signs of spread of the cancer from the bowel.
This means that the tests your father had were the right ones and further tests would only have been needed if the results from the colonoscopy or the ultrasound are unclear.