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Consumer Fact Sheet
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Bowel Cancer Screening and Testing
- Making Individual Choices
This fact sheet provides information on currently available bowel cancer screening and
testing methods. Each procedure has advantages and disadvantages that may differ for
individuals.
Bowel (colorectal) cancer screening and testing decisions should ideally be made after
discussions with a doctor, so an assessment can be made on the type of screening
method that will suit you best. Your family medical history and other health conditions
may mean some bowel cancer screening methods will not be right for you.
Screening and Testing For Bowel Cancer
Many cancers, including bowel cancer, are curable if found early. Most cancers do not
cause any warning signs in their beginning stage, which makes finding cancer early,
very important. Regular bowel cancer screening is used to detect cancers at an early
stage when they are curable and to identify non-cancerous growths known as
adenomas or polyps. Although polyps are not cancers, they may turn into cancer if they
aren't removed.
Testing for bowel cancer is normally carried out after a screening test has given a
positive result; or when signs and symptoms such as passing blood in the stool (poo),
changes in bowel habits (constipation and/or diarrhoea) or abdominal pain are
experienced.
The cure rate for patients who have surgery before bowel cancer has spread is about
90%. However, once bowel cancer has spread to nearby areas only about half of
patients are cured and, if it spreads to any other organs or tissues, cures are much less
likely.
Bowel cancer may occur at any age but the likelihood increases progressively after age
40 and sharply after age 50. It is generally accepted that screening and testing
procedures should be quite safe, and that the benefits should considerably outweigh the
harms.
Bowel Cancer Risk
Some people are more at risk of developing bowel cancer than others. Anything that
increases a person's chance of getting bowel cancer is called a risk factor. Individuals
with one or more of the known risk factors are classified as above average or high risk,
while those without any of the known risk factors are classified as average risk. Some
risk factors for bowel cancer have not been fully identified or are not yet known.
Bowel Cancer Screening and Testing - Making Individual Choices
Known risk factors for bowel cancer include:
Being older than 50 years of age.
Having a parent, brother, sister, or child with bowel cancer or polyps.
Having certain hereditary conditions, such as familial adenomatous polyposis
(FAP) and hereditary nonpolyposis colon cancer (HNPCC also known as Lynch
Syndrome).
Having a personal history of any of the following:
Bowel cancer or non cancerous polyps
Other types of cancer that may spread to the bowel
Inflammatory bowel diseases such as Ulcerative colitis or Crohn's
disease.
If you have one or more of these factors you should discuss the risk with your
doctor.
Around 4% of bowel cancers are passed on in families. In some cases where there is a
family history of bowel cancer, a doctor may suggest commencing screening earlier
and/or more often. Your doctor will discuss your family history with you and may
recommend particular kinds of bowel cancer screening that would best suit you. In
some cases a doctor may suggest genetic testing which will provide an assessment of
your risk for developing bowel cancer. The limitations of genetic testing will be
discussed with you before and after genetic testing.
Bowel Cancer Screening and Testing Options
There is a range of bowel cancer screening tests currently available. The tests differ in
cost and potential risk to the patient. The effectiveness and potential harms of the most
commonly used tests are provided below. Costs and availability are given in the tables
on the last two pages.
Faecal Occult Blood Test (FOBT)
Polyps and bowel cancer often (but not always) produce a tiny amount of blood that you
usually cannot see. You can use a FOBT at home to check for this blood. The
instructions will explain how to take some samples of your stools (poo) on separate
days.
Types of FOBT
Two main types of FOBT are available - guaiac and immunochemical tests.
Immunochemical tests (eg. Detect, also known as Magstream (produced by Bayer)
and Insure produced by Enterix, do not require special dietary or medication restrictions.
This type has been found to be best at detecting bowel cancer Guaiac tests (eg.
Haemoccult, Haemoccult II, Haemoccult Sensa) require that you don’t eat red meat, raw
fruit and vegetables and iron supplements for three days prior to stool sample collection.
Availability of FOBT
Currently, FOBT kits are available through General Practitioners (cost approx $32,
including pathology testing costs) or by participating in small community based
initiatives (such as Rotary Bowelscan). Test kits are also available directly from
The Cancer Council NSW – Consumer Fact Sheet
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Bowel Cancer Screening and Testing - Making Individual Choices
manufacturers for approximately $15 (this does not include cost of pathology testing). It
appears likely that a national bowel cancer screening program using immunochemical
tests will be introduced gradually over the next few years, which may mean the cost of
the tests will be free or reduced. The manufacturers of the two types of
immunochemical tests recommended for use in the national pilot project are:
Bayer Australia Ltd
PO Box 903
875 Pacific Highway
Pymble NSW 2073
Australia
Ph: +61 (0) 2 9391 6000
Fax: +61 (0) 2 9988 3311
Enterix Australia
15/2 Eden Park Drive
Email:
[email protected].
Phone: 9889 5200.
Fax: 9889 5211
How often?
The risk of death from bowel cancer is reduced more with yearly screening than with
2nd yearly screening. It has been found that the risk of death is reduced by around a
third (30%) with yearly screening compared to around a 7th (15%) in people who are
screened every two years.
When introduced, the national bowel cancer screening program will more than likely be
based on 2nd yearly screening for both men and women 50 years or older of average risk
(without a personal or family history of bowel cancer and without symptoms).
Advantages
• Once you and your doctor have agreed that FOBT is a suitable test for you,
FOBT can be performed at home, making it more convenient and cheaper than
other tests (The FOBT is sent to a lab for processing once the specimen has
been collected).
• It has been found that people over the age of 50 who are of average risk (those
without a family history or a previous history of bowel cancer or other bowel
diseases and who have no signs or symptoms of bowel cancer) will have a much
lower chance of dying from bowel cancer if they have a second yearly FOBT.
• Most people find the FOBT easy and convenient.
Disadvantages
• Not all polyps or cancers will bleed, thus a FOBT may produce normal results
even when cancer is present. Therefore if there are other symptoms or risk
factors such as a family history of bowel cancer, you should see your doctor.
• Conditions other than cancer (such as stomach ulcers and haemorrhoids) may
cause bleeding. Therefore, a FOBT may detect blood that is not associated with
bowel cancer and you may have to undergo more tests, which may not have
been necessary. The main harm identified with use of FOBT is anxiety after a
false positive test (when the FOBT detects blood from causes other than cancer)
• Some patients fail to report a positive FOBT test to their doctor.
The Cancer Council NSW – Consumer Fact Sheet
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Bowel Cancer Screening and Testing - Making Individual Choices
Flexible sigmoidoscopy
A flexible sigmoidoscopy involves the use of a lighted tube to examine the lower part of
the bowel. The bowel is inflated with air to make viewing the walls of the bowel easier.
Unlike a colonoscopy that examines the entire bowel, a flexible sigmoidoscopy only
explores the lower third to half of the colon. Around half of all bowel cancers occur in
the lower third of the colon. Several leading medical groups recommend routine
screening with sigmoidoscopy every 4-5 years, along with second yearly FOBT, for both
men and women 50 years or older of average risk (without a personal or family history
of bowel cancer and without symptoms).
Advantages
• A flexible sigmoidoscopy can be more quickly and easily performed and is
generally less expensive than full colonoscopy.
• Potential cancers can be seen and biopsied and/or removed at the time.
Disadvantages
• Patients are usually not sedated for this test so may experience pain or
discomfort — mostly gas-like pains from the air used to inflate the bowel
• As is the case with colonoscopy, the procedure carries with it the small risk of
bowel perforation and infection, though this is less common with sigmoidoscopy
than it is with colonoscopy.
• A flexible sigmoidoscopy cannot detect polyps or cancers that are located deep
within the colon beyond the reach of the sigmoidoscope.
UBarium Enema
A barium enema involves filling the bowel through a thin tube inserted into the anus
with liquid called barium. The barium causes some polyps or cancers to show up in an xray. Like the sigmoidoscopy and colonoscopy, this procedure requires the bowel to be
properly emptied before the test. Patients are normally required to have a liquid diet
before the test and a drink containing a special bowel cleansing solution prior to the
test. The cleansing solution helps patients pass all the contents of the colon, which
makes it easier for the doctor to view the walls via an xray of the colon and detect any
abnormalities.
Advantages
• Barium enema is good at detecting large cancers and large polyps.
• Most of the bowel can be inspected with a barium enema
Disadvantages
• A barium enema doesn't allow the doctor to remove or perform a biopsy on any
detected polyps or masses during the procedure. Instead, it requires a follow-up
colonoscopy.
• A barium enema may miss a substantial proportion of small and medium-size
polyps.
• A barium enema does not always show the lowest part of the bowel, which may
mean that other procedures could also be required.
• Certain people such as those with existing bowel conditions (eg. Crohns disease)
are at greater risk for complications with this procedure such as perforation of
The Cancer Council NSW – Consumer Fact Sheet
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Bowel Cancer Screening and Testing - Making Individual Choices
the bowel, infection or the bowel may narrow and become blocked by the
barium.
Colonoscopy
A colonoscopy is a procedure that examines the entire length of the bowel using a long,
thin, flexible tube that is inserted in the anus. The tube has a light at the end and is
connected to a video monitor to assist the doctor in detecting and removing polyps and
cancers.
While colonoscopy can be used as a screening test (it is often recommended for people
of above average risk), it is more often used to provide a more complete assessment of
the bowel after other tests that screen for bowel cancer (FOBT, sigmoidoscopy, barium
enema) have come back positive.
This procedure requires the bowel to be properly emptied before the test. Patients are
normally required to have a liquid diet before the test and a drink containing a special
bowel cleansing solution prior to the test. The cleansing solution helps patients pass all
the contents of the colon, which makes it easier for the doctor to view the walls of the
colon and detect any abnormalities. The doctor also inflates the bowel slightly (by
pumping air into it via the anus) to make viewing the walls of the colon even easier.
Patients are usually sedated but awake during the procedure, and typically experience
little pain.
Your doctor will usually provide you with a referral to a specialist to have a colonoscopy.
A colonoscopy is most often performed in a hospital or day clinic and requires you to be
away from home or work for around 4 hours. Patients are normally advised not to drive
for 24 hours after a colonoscopy.
Waiting times for a colonoscopy in a public hospital differ depending on where you live.
Information on waiting times and waiting lists for surgical and medical procedures in
NSW public hospitals can be obtained from www.health.nsw.gov.au/waitingtimes/
Advantages
• By providing a more complete bowel examination, colonoscopy is the most
effective test for detecting bowel cancer and large polyps.
• The test allows doctors to see the bowel directly and to remove or take a sample
of any suspicious growths.
Disadvantages
• Colonoscopy may miss up to 15 per cent of growths that are less than 1cm
• Patients may find a colonoscopy inconvenient, uncomfortable or embarrassing.
• A colonoscopy carries a small risk of puncturing the colon, which can lead to
internal bleeding and infection. There is also a very small risk of death with a
colonoscopy.
• A specialist gastroenterologist usually carries out this test. Patients are able to
claim the cost of this procedure under Medicare (covers high risk patients every
two years and those needing follow up tests). Additional costs may include the
The Cancer Council NSW – Consumer Fact Sheet
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Bowel Cancer Screening and Testing - Making Individual Choices
•
cost of the specialist appointment, cost of the bowel preparation, pathology
costs for testing any polyps or biopsies if they are taken and transport costs.
After sedation patients are unfit to drive, so transport will need to be organised.
Virtual Colonoscopy
Virtual colonoscopy has some similarities to a colonoscopy. The day before the
procedure, a preparation is taken orally to help patients completely empty their bowel.
Prior to the procedure, the bowel is inflated with air via a tube inserted in the anus to
make viewing the bowel easier. A computed tomographic (CT) scanner is then used to
take hundreds of pictures of the bowel (from the outside). Using a computer to put the
images together, a radiologist can view the bowel from many different angles. Virtual
Colonoscopy is not commonly used as a routine screening procedure at present
Advantages
• Virtual colonoscopy presents less risk of puncturing the colon than colonoscopy
does.
• Virtual colonoscopy takes around five minutes (excluding preparation time), and
since sedation is usually unnecessary, the patient can leave immediately after
the scanning is completed.
• Virtual colonoscopy doesn’t normally require sedation or painkillers and may be
more acceptable to the elderly, the immobile or for those whom colonoscopy is
not recommended such as persons with heart or lung problems.
Disadvantages
• Virtual colonoscopy detects 60 to 90 percent of medium to large polyps or
cancers but may not detect small polyps or cancers.
• Follow-up colonoscopy is required to confirm findings, perform biopsies or
removal of any detected polyps or masses.
• Currently patients are unable to claim the cost of this procedure under Medicare.
The cost to patients is approximately $350.
• This procedure is currently limited to centres, usually in major metropolitan
areas, with established CT scanners, relevant computer software and specialists
trained in the interpretation of processed images.
Questions for you and your doctor to consider:
•
•
•
•
Am I at risk of bowel cancer?
What bowel screening/testing options are best for
me?
Do I have other illnesses that may have an
influence on the screening/testing procedure I
have?
What is the cost of the screening/testing
procedure?
The Cancer Council NSW – Consumer Fact Sheet
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Bowel Cancer Screening and Testing - Making Individual Choices
Bowel Cancer Screening and Testing Options
Procedure
Faecal Occult
Blood Testing
(FOBT)
Flexible
sigmoidoscopy
Frequency
Risk
Cost
Advantages
Disadvantages
FOBT
detects
between
79% and
37% of
bowel
cancers.
Detection
Routine screening at
least every two years
for both men and
women 50 years or
older of average risk
(without a personal or
family history of
bowel cancer and
without symptoms).
The main harm
identified with use of
FOBT is anxiety after a
false positive test
(when the FOBT
detects blood from
causes other than
cancer)
FOBT kits can be
purchased from
chemists (for between
$15 and $32).
Additional costs may
include any follow up
tests should the FOBT
be positive for blood.
FOBT can be done at
home, making it
more convenient and
cheaper than other
tests.
Not all polyps or cancers will
bleed. Therefore, a FOBT
may produce normal results
even when cancer is present.
Cannot
detect polyps
or cancers
that are
located deep
within the
bowel
beyond the
reach of the
sigmoidosco
pe and may
miss small
cancers or
polyps
Routine screening
with sigmoidoscopy
every 4-5 years, along
with a second yearly
FOBT, for both men
and women 50 years
or older of average
risk (without a
personal or family
history of bowel
cancer and without
symptoms).
The procedure carries
with it the small risk of
bowel perforation and
infection, though it is
less common with
sigmoidoscopy than it
is with colonoscopy.
Patients are able to
claim the cost of this
procedure under
Medicare. Additional
costs may include the
cost of the specialist
appointment, cost of
the bowel preparation,
pathology costs for
testing any polyps or
biopsies if they are
taken.
The Cancer Council NSW – Consumer Fact Sheet
Most people find the
FOBT easy and
convenient.
A flexible
sigmoidoscopy can
be more quickly and
easily performed than
full colonoscopy.
Potential cancers can
be directly visualized
and can be biopsied
(take a sample for
testing) and/or
removed
Conditions other than cancer
(such as stomach ulcers and
haemorrhoids) may cause
bleeding. Therefore, a FOBT
may detect blood that is not
associated with bowel
cancer.
Since they are rarely given an
intravenous sedation for the
procedure, patients are more
likely to experience pain or
discomfort — mostly gas like
pains from the air used to
inflate the bowel
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Bowel Cancer Screening and Testing - Making Individual Choices
Procedure
Detection
Frequency
Risk
Cost
Advantages
Disadvantages
Barium Enema
A barium
enema
detects most
large cancers
and polyps
but may miss
a substantial
proportion of
small and
medium-size
polyps.
Routine screening
every 4-5 years for
both men and women
50 years or older of
average risk (without
a personal or family
history of bowel
cancer and without
symptoms).
Certain people such as
those with existing
bowel conditions (eg.
Chrohns disease) are
at greater risk of the
following
complications with this
procedure: the barium
may perforate the
colon and cause
infection. The bowel
may also narrow and
become blocked.
Patients are able to
claim the cost of this
procedure under
Medicare. Additional
costs may include cost
of the bowel
preparation and travel
costs if required.
Barium enema is
good at detecting
large cancers and
large polyps in
particular areas of the
bowel.
A barium enema doesn't
allow the doctor to remove or
perform a biopsy on any
detected polyps or masses
directly. Instead, it requires a
follow-up colonoscopy.
Colonoscopy
detects most
cancers and
polyps
greater than
1 cm but may
miss up to 15
per cent of
growths that
are less than
1 cm.
Colonoscopy is
usually recommended
as a follow-up
test if any of the other
screening tests are
abnormal.
Colonoscopy is not
normally used as a
routine screening
procedure for people
of average risk for
bowel cancer.
However it is the
screening method of
choice for people at
above average risk.
Screening intervals
from 2 – 10 years may
be required.
A colonoscopy carries
a small risk of
puncturing the colon,
which can lead to
internal bleeding and
infection. There is also
a very small risk of
death with a
colonoscopy.
Patients are able to
claim the cost of this
procedure under
Medicare (covers high
risk patients every two
years and those
needing follow up
tests). Additional costs
may include the cost of
the specialist
appointment, cost of
the bowel preparation,
pathology costs for
testing any polyps or
biopsies if they are
taken and transport
costs.
Potential cancers can
be directly visualised
and can be biopsied
(take a sample for
testing) and/or
removed
Colonoscopy
The Cancer Council NSW – Consumer Fact Sheet
A barium enema does not
always allow an evaluation of
the lowest part of the bowel,
which may mean that a
sigmoidoscopy may also be
required.
Patients may find a
colonoscopy inconvenient,
uncomfortable and
embarrassing.
A colonoscopy is most often
performed in a hospital or day
clinic and requires you to be
away from home or work for
around 4 hours. Patients are
normally advised not to drive
for 24 hours after a
colonoscopy.
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Bowel Cancer Screening and Testing - Making Individual Choices
Virtual
Colonsocopy
Virtual
colonoscopy
detects 60 to
90 percent of
cancers and
polyps that
are medium
to large in
size, may
miss small
polyps and
cancers.
Virtual Colonoscopy is
not commonly used
as a routine screening
procedure at present.
Because it is well
tolerated without
sedation or analgesia
and may be more
acceptable to the
elderly, the immobile,
those with
contraindications for
conventional
colonoscopy and
those with heart or
lung problems.
Virtual colonoscopy
presents less risk of
puncturing the colon
than colonoscopy
does.
The dose of radiation
from a virtual
colonoscopy has been
estimated to be about
equal to that of a
barium enema
Patients are currently
unable to claim the
cost of this procedure
under Medicare (or
private funds in
Australia) at this stage.
The cost to patients is
approximately $350.
Additional costs may
include any follow up
tests should the virtual
colonoscopy find any
abnormalities.
Virtual colonoscopy
takes less than five
minutes, and since
sedation is usually
unnecessary, the
patient can leave
immediately.
Follow-up colonoscopy is
required to confirm findings,
perform biopsies or removal
of any detected polyps or
masses directly.
This procedure is currently
limited to centres, usually in
major metropolitan areas,
with established CT
scanners, relevant computer
software and specialists
trained in the interpretation of
processed images.
This resource is intended for use by the general public and is based on the best
available information at the time of publication. Additional information and advice
on bowel cancer can be obtained by phoning the Cancer Helpline on: 13 11 20 or
by visiting the Cancer Council NSW web site www.cancercouncil.com.au
The Cancer Council NSW – Consumer Fact Sheet
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