Tests and Investigations

Tests and investigations used in the diagnosis of bowel cancer

If your doctor suggests that you are referred for further investigations, this does not mean you have bowel cancer.
 
It means that further tests are needed to clarify what is causing your symptoms.
 
If you have several higher-risk symptoms which could be suspected bowel cancer, you should receive an urgent referral and have a colonoscopy within 30 days.
 
About Bowel Cancer-Colonoscopy 
 
If symptoms are not considered higher-risk, you will receive a routine referral.
 
The waiting list for routine referrals varies around Australia.
 
Further investigations will usually take place at a clinic in your local hospital.
 
The specialist will ask you questions about your symptoms (similar to questions asked by your doctor), your general health and other medical conditions you might have.
 
You will sometimes be given the results from investigative tests immediately, or you will be called back to the hospital at a later date to receive the results.
 
If the tests for bowel cancer are negative, you may be diagnosed with another common gastrointestinal condition and given appropriate treatment.
 
If you test positively for bowel cancer, you will meet with a specialist who will put together your treatment plan.
 
The following table outlines the tests and investigations which are used in the diagnosis of bowel cancer, including advantages and disadvantages.
 

Tests and Investigations - Advantages and Disadvantages 

Digital
Rectal Exam (DRE) 
 
Tests_Advantage
Advantages
A digital rectal exam (DRE) may be done as part of a routine physical exam.
 
A digital rectal exam is an exam of the rectum.  
 
A doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual.
 
No cleansing of the colon is necessary.
 
The test is usually quick and painless.
Tests_Disadvantage
Disadvantages
Studies have not shown that screening for bowel cancer using digital rectal exam (DRE) helps decrease the number of deaths from the disease.
 
Study results have shown that there is no evidence to support DRE as a screening method for bowel cancer.
 
The test can detect abnormalities only in the lower part of the rectum.
 
Additional procedures are necessary if the test indicates an abnormality. 

Faecal Occult Blood Test (FOBT)
 
Faecal Immunocehmical Test (FIT) 
Tests_Advantage
Advantages
No cleansing of the colon is necessary.
 
Samples can be collected at home.
 
The cost is low compared with other bowel cancer screening tests.
 
FOBT/FIT does not cause bleeding or tearing/perforation of the lining of the colon.
Tests_DisadvantageDisadvantages
This test does not detect some polyps and cancers.
 
Dietary restrictions and changes, such as avoiding meat, certain vegetables, vitamin C, iron supplements, and aspirin, and increasing fibre consumption, are often recommended for several days before a guaiac FOBT.
 
These restrictions and changes are not required for FIT.
 
Additional procedures, such as colonoscopy, may be necessary if the test indicates an abnormality.
 
False-negative test results can occur
Screening test results may appear to be normal even though colorectal cancer is present.  
 
A person who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.
 
False-positive test results can occur
Screening test results may appear to be abnormal even though no cancer is present.
 
A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests (such as biopsy), which also have risks.
 
A false-positive test result can cause anxiety and lead to more testing, including colonoscopy or barium enema with sigmoidoscopy.

Barium Enema 
Tests_Advantage
Advantages
This test usually allows the doctor to view the rectum and the entire colon.
 
Complications are rare.
 
No sedation is necessary.
Tests_Disadvantage
Disadvantages
The test may not detect some small polyps and cancers.
 
Thorough cleansing of the colon is necessary before the test.
 
False-positive results are possible.
 
The doctor cannot perform a biopsy or remove polyps during the test.
 
Additional procedures are necessary if the test indicates an abnormality.

Sigmoidoscopy 
Tests_Advantage
Advantages
The test is usually quick, with few complications.
 
For most patients, discomfort is minimal.
 
In some cases, the doctor may be able to perform a biopsy (the removal of tissue for examination under a microscope by a pathologist) and remove polyps during the test, if necessary.
 
Less extensive cleansing of the colon is necessary with this test than for a colonoscopy.
Tests_Disadvantage
Disadvantages
This test allows the doctor to view only the rectum and the lower part of the colon.
 
Any polyps in the upper part of the colon will be missed.
 
There is a very small risk of bleeding or tearing/perforation of the lining of the colon.
 
Additional procedures, such as colonoscopy, may be necessary if the test indicates an abnormality.
 
There can be discomfort or pain during sigmoidoscopy.  Tears in the lining of the colon and bleeding also may occur.

Colonoscopy  
Tests_Advantage
Advantages
This test allows the doctor to view the rectum and the entire colon.
 
The doctor can perform a biopsy and remove polyps or other abnormal tissue during the test, if necessary.
Tests_Disadvantage
Disadvantages
This test may not detect all small polyps, non-polypoid lesions, and cancers, but it is one of the most sensitive tests currently available.
 
Thorough cleansing of the colon is necessary before this test.
 
Some form of sedation is used in most cases.
 
Although uncommon, complications such as bleeding and/or tearing/perforation of the lining of the colon can occur.
 
Serious complications from colonoscopy are rare, but can include tears in the lining of the colon, bleeding, and problems with the heart or blood vessels. These complications may occur more often in older patients.

Virtual Colonoscopy  
Tests_Advantage
 Advantages 
This test allows the doctor to view the rectum and the entire colon.
 
This is not an invasive procedure, so there is no risk of bleeding or tearing/perforation of the lining of the colon.
Tests_Disadvantage
Disadvantages
This test may not detect all small polyps, non-polypoid lesions, and cancers.
 
Thorough cleansing of the colon is necessary before the test.
 
If a polyp or non-polypoid lesion 6 to 9 millimetres in size or larger is detected, standard colonoscopy, usually immediately after the virtual procedure, will be recommended to remove the polyp or lesion or perform a biopsy.
 
Virtual colonoscopy often finds problems with organs other than the colon, including the kidneys, chest, liver, ovaries, spleen, and pancreas. Some of these findings lead to more testing. The risks and benefits of this follow-up testing are being studied.

  
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