If any of the general tests or tests to find cancer in the bowel show you have bowel cancer, more will be done to see if it has spread to other parts of your body. Before you book any test, ask how much it will cost.
Learn more about these other tests:
CEA blood test
You may be tested for carcinoembryonic antigen (CEA), a protein produced by some (not all) bowel cancers. Low levels are normal – but if you have a high level, your doctor may do more tests. Smoking, pregnancy and other factors can also raise CEA levels. If CEA is high, it will be retested after treatment to see if it has returned to normal.
CT scan
A CT (computerised tomography) scan uses x-rays and a computer to create a detailed picture of the inside of the body. CT scans are usually done at a hospital or radiology clinic.
A dye is injected into a vein to make the pictures clearer. It may make you feel hot, have a strange taste in your mouth or feel that you need to urinate (wee or pee), but these sensations won’t last long.
During the scan, you lie still on a table that moves in and out of the machine. Your chest, abdomen and the area between your hip bones (pelvis) will be scanned to see if the cancer has spread to these areas. The scan itself takes 5–10 minutes and is painless.
Learn more about CT scans.
Before having scans, tell the doctor if you have any allergies or have had a reaction to dyes during previous scans. You should also let them know if you have diabetes or kidney disease, are pregnant or breastfeeding, or are claustrophobic (afraid of confined spaces).
MRI scan
An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to create detailed pictures of the inside of your body. MRIs are mostly used only for cancers in the rectum, not cancers higher in the bowel. An MRI may also be used to scan the liver if there was an abnormality seen on a CT scan that needs to be checked.
Before the scan, let your medical team know if you have a pacemaker or any other metallic object in your body. If you do, you may not be able to have an MRI scan as the magnet can interfere with some metallic objects. Newer devices are often safe to go into the scanner.
Before the MRI, you may be injected with a dye to help make the pictures clearer. During the scan, you lie on a table that slides into a large metal tube open at both ends. The noisy, narrow machine makes some people feel anxious or claustrophobic. If you might feel distressed, talk to your medical team beforehand. You may be given medicine to help you relax. You will wear headphones or earplugs. The scan may take 30–90 minutes, depending on the area being scanned.
Learn more about MRI scans.
PET-CT scan
A positron emission tomography (PET) scan combined with a CT scan is a specialised imaging test. The 2 scans provide more detailed and accurate information about the cancer. A PET–CT scan is most commonly used before surgery to help find out where the cancer has spread to in the body. It can also be used after surgery to check if the cancer has come back after treatment.
When you make the appointment for the scan, you will be given instructions to follow about how to prepare for the scan, including what you can eat and drink.
Before the scan, you will be injected with a glucose solution containing a small amount of radioactive material. Cancer cells show up brighter on the scan because they take up more glucose solution than the normal cells do. You will then be asked to sit very quietly or lie down for 30–90 minutes as the glucose spreads through your body. Then you will have the scan itself, which usually takes around 30 minutes.
You will also usually have a CT scan, before or after the PET scan.
Medicare will only cover the cost of a PET–CT scan for bowel cancer in limited circumstances. If this test is recommended, check with your doctor what you will have to pay.
Learn more about PET-CT scans.
Genomic testing
If you are diagnosed with bowel cancer, the tissue removed during surgery will usually have more tests. Called genomic (or molecular) tests, they look for gene changes (mutations) and other features in the cancer cells that may cause them to multiply and grow.
Results can help decide which treatments may or may not work for you. Some targeted therapy drugs only work for people with a RAS gene mutation. Immunotherapy drugs also only work for people with a fault in the gene that helps the cell’s DNA repair itself (called mismatch repair or MMR genes).
For more on this, see Drug therapies.
→ READ MORE: Bowel preparation before tests
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Prof Alexander Heriot, Colorectal Surgeon and Director Cancer Surgery, Peter MacCallum Cancer Centre, Director, Lower GI Tumour Stream, Victorian Comprehensive Cancer Centre, VIC; Dr Cameron Bell, Gastroenterologist, Royal North Shore Hospital, NSW; Graham Borgas, Consumer; Prof Michael Bourke, Director of Gastrointestinal Endoscopy, Westmead Hospital, The University of Sydney, NSW; Laura Carman, 13 11 20 Consultant, Cancer Council Victoria, VIC; Amanda Connolly, Specialist Bowel Care Nurse, Icon Cancer Centre Windsor Gardens, SA; A/Prof Melissa Eastgate, Operations Director, Cancer Care Services, Royal Brisbane and Women’s Hospital, QLD; Anne Marie Lyons, Stomal Therapy Nurse, Concord Repatriation General Hospital and NSW Stoma Ltd, NSW; Lisa Nicholson, Manager Bowel Care Services, Bowel Cancer Australia, NSW; Stefanie Simnadis, Clinical Dietitian, St John of God Subiaco Hospital, WA; Rafi Sharif, Consumer; Dr Kirsten van Gysen, Radiation Oncologist, The Nepean Cancer and Wellness Centre, NSW; Sarah Williams, Clinical Nurse Consultant, Lower GI, Peter MacCallum Cancer Centre, VIC.
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