1. Bowel cancer screening update GP education event 28 Nov 2017
Dr. Hooi Ee
Gastroenterologist
Sir Charles Gairdner Hospital 1

2. Most common cancers - Australia
AIHW, Cancer in Australia: an overview, 2014

3. Bowel cancer - Australia
Most common cancer affecting both men and women
Risk: M = 1:10 F = 1:15
Second biggest cancer killer in Australia
In 2016:
17,520 estimated cases
4,094 estimated deaths
Incidence may increase with increased risk factors
Increased obesity, unhealthy diet, low exercise
Incidence set to increase
Why?
Living longer
Ageing population
Poor lifestyle choices
Males have higher incidence and mortality from bowel cancer.
Why? Worse diet; more alcohol; less physical activity.

4. Age is a major risk factor
AIHW, Bowel cancer , 2016

5. Slow rate of development
Polyps are quite common in the colon, especially as you age.
There are different types of polyps – one is type is the adenoma. Adenomas can potentially change and become cancerous but as it is hard to tell the difference between these and other polyps it is important that polyps are removed
Less than 5% of all adenomas turn into bowel cancer.
5 – 15 year sequence

6. Signs & Symptoms Early bowel cancer has no symptoms
If present, can include:
Rectal bleeding
Symptoms of anaemia
Change in bowel habit (diarrhoea more important)
Abdominal pain
Rectal bleeding is a common symptom in the general population and affects up to 15% of all adults
Prevalence of rectal bleeding in a 6 month period ranges from 4.4% and 16%
Although most cases of rectal bleeding are due to self limiting local anorectal conditions, it may also be the only sign of colorectal neoplasia

7. Earlier diagnosis = better prognosis

8. Bowel cancer screening
Why screen?
Early detection of bowel cancer greatly improves prognosis
Better use of limited resources
Repeat screening at regular intervals is necessary
Screening ≠ diagnosis
Assists in determining who might best benefit from the definitive (and more invasive and expensive) diagnostic procedure
Short term expense for long term gain 8

9. What is cancer screening?
Population screening is:
Systematic application
of a
Suitable screening test
to identify
Individuals at risk of a condition
to warrant
Intervention
Participants have no symptoms

10. Bowel cancer is ideal for screening
Common serious disease No symptoms during early phases Removing precursors can prevent cancer Earlier detection improves survival Widespread screening saves lives

11. Updated NHMRC Guidelines 2017 (i)
Consensus-based recommendations:
Resources should be invested in increasing participation in the existing NBCSP target age group of 50–74
In 45–49 y.o. who request screening, GPs could offer an iFOBT every 2 years until NBCSP invitation at age 50
_for_colorectal_cancer
_recommendations

12. Updated NHMRC Guidelines 2017 (ii)
Practice points
Encouragement by GPs and practice staff substantially boosts participation in screening
GPs have a critical role in managing the interface between screening and personalised care:
Advising on appropriateness of NBCSP participation, balancing life expectancy, comorbidities
GPs should advise those at average or slightly above average risk that iFOBT is the preferred screening.
GPs should discourage inappropriate use of colonoscopy

14. National Bowel Cancer Screening Program
iFOBT kits in 2017:
50, 54, 55, 58, 60, 64, 68, 70, 72, 74
2-yearly screening for everyone aged by 2019
Names and addresses are automatically obtained from the Medicare Registry and Department of Veterans Affairs Registry

15. iFOBT kit
The FOBT is performed at home, placed into a reply-paid envelope and sent to a pathology laboratory for analysis
Participants with a positive result will need to undergo further diagnostic tests, usually a colonoscopy

16. Faecal Occult Blood Test (iFOBT)
Sensitivity (with disease and positive test):
83% for cancer
regular testing increases sensitivity
Positive predictive value
5% for cancer, 20% for advanced adenoma, 25% for precancerous growth called a non-advanced adenoma
iFOBT(+) is X more likely to have bowel cancer than iFOBT (-)
The test itself cannot confirm cancer and further investigations must be undertaken.
The iFOBT is the best performing screening tool available for population screening for bowel cancer with numerous RCT studies confirming this. The test effectively identifies those for whom colonoscopy is necessary and prevents an unnecessary invasive procedure for those with a negative result.
~52% of people with a positive FOBT will have some type of neoplastic lesion (adenoma or cancer).(2)  The remainder usually have a noncancerous condition such as haemorrhoids. So a lot of positive cases will NOT be a diagnosis of bowel cancer or adenoma.
A negative result does not mean that you will not develop bowel cancer in the future. Hence the need for 2 yearly testing because your risk continues to increase with age.
Appleyard, 2011

17. Summary of NBCSP Pathway
Invitation and kit sent
Participant performs test
-ve result
+ve result
GP submits form
Repeat test in 2 years
Assessment colonoscopy (if needed)
Participant treated (if needed)
Pre-invitation letter
Those who have a clear colonoscopy will return to 2-yearly FOBT screening
Colonoscopy clear –
test repeated in 4 yrs

18. NBCSP GP Assessment form

19. Good Economic Sense ACPS Stage Cost to treat1 1 $30,890 2 $47,354 3
$74,225 4
$61,423
Pignone et al 2011
Ananda et al 2010

20. Summary of NBCSP performance Cancers being detected earlier
Participation rate – all
Participation rate – male
Participation rate – female
39%
37%
41%
Positive FOBT 7%
Presence of cancer
3-4%
Cancers being detected earlier

21. Summary
Bowel cancer is a very common cancer Mainly a disease of middle and older age Early diagnosis improves outcome Screening should be encouraged, especially NBCSP Inappropriate (low yield) colonoscopy should be avoided