Diagnostic Tests

Colonoscopy

A colonoscopy is a type of endoscopy, which is a diagnostic test that uses a small, thin tube with a camera on one end to look inside the body. A colonoscopy is used to examine the lining of your large bowel to check for polyps or cancer. During the procedure, a long, thin, flexible tube with a light at one end is gently inserted into your back passage. This allows the doctor to see inside the bowel and examine the bowel lining. Photographs or biopsies can be taken if there are any areas of concern and simple polyps can be removed (a procedure called a polypectomy). Speak to your doctor if you are concerned about the procedure. You may be able to have a sedative or, in some cases, be given a general anaesthetic so you will be asleep throughout.

Flexible Sigmoidoscopy

A flexible sigmoidoscopy is a type of endoscopy that examines the rectum and lower part of the bowel (the sigmoid colon), which is where the majority of polyps and bowel cancers begin. You will normally need an enema to clear the bowel beforehand so the doctor can see the bowel lining clearly.

CT Scans

A CT (computerised tomography) scan uses a series of X-ray images taken from different angles to produce a cross-section of the soft tissues, blood vessels and bones inside your body. They can provide a more detailed view than X-rays alone. A CT colonography (also called a virtual colonoscopy) uses CT scans to create a 3D image of the large bowel and rectum. This type of scan is normally used for patients who may not be suitable for a regular colonoscopy. During the procedure you will lie on your back while gas is gently pumped into the bowel via a thin flexible tube inserted into your back passage. This inflates the bowel so the doctor can obtain a clear scan. A CT colonography can detect shape changes within the bowel but can’t be used to take samples or remove polyps.

MRI Scans

An MRI (magnetic resonance imaging) scan produces more detailed pictures than a CT scan and is normally used if you have been diagnosed with bowel cancer. Using strong magnets and radio waves, it builds up a detailed picture of the inside of your bowel and can show the doctor the extent of the cancer and whether it can be removed using surgery alone or whether you will need to undergo radiotherapy beforehand. During the procedure you may be given an injection of dye into your arm. This helps to provide clearer images of the inside of your body. Some people can find the scanner a little claustrophobic and the noise it makes is quite loud. You will be given headphones or earphones and will be able to talk to the radiographer on an intercom throughout. The scan can take 30-45 minutes. Talk to your doctor if you are concerned and you may be given a sedative to help you relax.

PET-CT Scans

You will sometimes be given a PET (positron emission tomography) and CT scan simultaneously if the results of your other scans aren’t clear, or if the doctor suspects your bowel cancer may have returned after treatment or if the cancer has spread to your liver or lungs. By combining the PET scan with the CT scan, the doctor will be able to see more detailed pictures of your body than just using a CT scan alone. You will need to avoid food for six hours before the scan. You will be given an injection of a mildly radioactive drug and asked to wait for 30 minutes while it spreads throughout your body. The scan will take around half an hour.

Ultrasound

You may be given an ultrasound scan if you have rectal cancer or if the doctor believes the cancer may have spread. Ultrasound scans use soundwaves to build up a clear picture of the inside of the body. They can reveal the location and extent of the cancer. During the scan you will lie on your back while the sonographer gently moves the ultrasound probe over your skin. If you have rectal cancer, you will need to lie on your side while the probe is gently inserted into your back passage. An ultrasound scan normally takes around 10-15 minutes and you can go home immediately.

Blood Tests

Blood tests are used to diagnose bowel cancer as well as checking how well your liver and kidneys are functioning and your overall state of health. The blood will be taken from a vein in your arm or hand. The doctor will analyse the red cells, white cells and platelets in your blood (Full Blood Count test). Tumour markers – usually proteins – may be raised if you have cancer. The presence of tumour markers in your blood can be used to monitor how well your treatment is working or whether the cancer has returned.

Pre-operative Assessments

If you require surgery for bowel cancer, you will be given a pre-operative assessment beforehand to check on your overall health and ensure you are fit enough for the operation. This may entail having blood tests, as well as checking your blood pressure and an ECG to assess your heart function.