Bangkok, Thailand

1
Bangkok, Thailand
Title Colorectal cancer screening, an Asian
perspective Speaker Dr Taya Kitiyakara
Department of Gastroenterology
Faculty of Medicine Ramathibodi Hospital,
Mahidol University Time 0900 (TH)
CanalAVIST Medical Forum 19 September 2008
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Bangkok, Thailand
Dr Taya Kitiyakara graduated from St Marys
Hospital, Imperial College, London 1996 after
attending Cambridge University for BA in Medical
sciences. He was at Kings college Hospital,
London for his Senior House Officer (residency)
Medical rotation up to 2000. He trained in
Gastroenterology in Oxford, 2000-2007, with one
year of liver transplantation at the Royal Prince
Alfred Hospital, Sydney, Australia in 2004. He
has recently started as consultant
Gastroenterologist at Ramathibodi Hospital,
Mahidol University, Bangkok, Thailand.


CanalAVIST Medical Forum 19 September 2008
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Colorectal cancer screening, an Asian perspective

• Dr Taya Kitiyakara
• Dept of gastroenterology
• Faculty of medicine
• Ramathibodi hospital
• Mahidol University

4
Content

• Incidence
• Investigations/ screening tests
• Implementation/ strategies
• Improvements

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Incidence
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Incidence of colorectal cancer is high

• Second leading cause of cancer death in the West.
• Estimated 49,960 deaths in USA, 2008

Jemal et al Cancer J Clin 2008
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Incidence of colorectal cancer in Asia
Sung et al Lancet 2005
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Increasing incidence of colorectal cancer in Asia

• Increasing incidence of colorectal cancer in Asia
• Westernisation of diet and lifestyle
• Increasing life expectancy

J Ferlay et al 2004 KS Chia et al 1995 L Yang et
al 2004
H Sriplung et al 2006
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Increasing mortality from colorectal cancer in
Asia
Mortality rates men

• Decreasing mortality in western world
• Increasing mortality in Asia

Mortality rates women
Sung et al Lancet 2005
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Screening is appropriate colorectal cancer

• Natural history
• Early detection
• Treatment available and acceptable
• Change in outcome

R Rerknimitr et al 2006
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Evidence for efficacy of screening
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EFFICACY OF SCREENING- colonoscopy

• Colonoscopy used in all other screening
  modalities to remove polyps and confirm CRC

Gupta et al 2005
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Asia Pacific consensus recommendations
GUT 2008
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Investigations and screening tests
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Understanding screening

• National screening
• Individual screening
• High risk vs. average risk screening
• asymptomatic

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Tests available for screening

• Stool tests
• Faecal occult blood (guaiac based)
• Faecal occult blood (immunobased)
• Stool DNA testing
• Imaging tests
• Barium tests
• CT colonography
• Endoscopy tests
• Flexible sigmoidoscopy
• Colonoscopy

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Understanding tests

• Tests for (mainly) early cancer
• Stool tests
• Tests for polyps and cancer
• Colonoscopy,
• CT colonography,
• DCBE

Joint Guideline , US Multi-society task force on
colorectal cancer 2008
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Stool tests FOB tests

• FOBT sensitivity variable depending on type (high
  with Hemoccult SENSA)
• Higher sensitivity lower specificity
• Requires annual/biennial testing
• Further colonoscopy needed if positive
• Acceptable test to initiate screening

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FOB in screening studies
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Immunochemical FOB may be better in Asia

• Cost-effectiveness Cost of tests false
  positive test
• Dietary manipulation is thought difficult in many
  Asian countries

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Understanding sensitivity

• Per Test sensitivity
• (screening) programme sensitivity for test
• Repeated chance of detecting lesion
• May be better at detecting rapidly growing cancer
  compared to an infrequent test

Ransohoff Gastroenterology 2005
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Imaging- double contrast barium enema

• No RCT/ major trials showing reduction in CRC
  mortality
• Interval not determined
• Decreasing use
• Labour intensive
• Training issues
• Radiation
• Superceded by CT colonography

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CT colonography
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Imaging tests- CT colonography

• CT colonography not in Asia Pacific
  recommendations.
• Increasing use/availability
• More acceptable than colonoscopy
• Extra-luminal imaging
• Costly
• Radiation
• Flat/ depressed lesions difficult to image

• Criteria needed for best sensitivity
• Excellent bowel prep
• Fecal tagging
• Cutting edge equipment
• Analysis of both 2D and 3D images
• Experience of radiologist

Castells Gastroenterology 2008
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CT colonography- detection rate
Iannaccone et al 2005

• Sensitivity of CT colonography compared to 2
  colonoscopies.
• 2nd colonoscopy aware of all lesions detected
  from CT and initial colonoscopy
• Minimised known miss rate- true sensitivity of CT
  results

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Endoscopic tests
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Flexible sigmoidoscopy

• Decreasing numbers performed in USA
• incomplete test
• Miss proximal lesions
• False sense of reassurance
• Benefit of cost-effectiveness vs thoroughness may
  be lost to screenee
• Legal implications?
• Quality of procedure very variable in studies.

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Colonoscopy- advantages

• Complete test
• 10 yr interval
• Expected 90-70 reduction in CRC mortality

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Colonoscopy- disadvantages

• Expensive
• Time and labour intensive
• May be least acceptable of screening tests
• Recognised complications
• Miss rates and interval cancers

Ransohoff Gastroenterology 2005
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Miss rates in back-to-back studies
Van Rijn et al Am J Gastro 2006
Heresbach et al Endoscopy 2008
Iannaccone et al Radiology 2005
Kaltenbach et al Gut 2008
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Quality control requirements for screening

• Bowel prep
• Training/experience
• Complete insertion rate
• Withdrawal time/technique and polyp detection
  rate
• Proper consent
• Complete polyp removal
• Timely detection and appropriate management of
  complications
• Follow-up protocol

Joint Guideline , US Multi-society task force on
colorectal cancer 2008
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Implementation
?


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FOB may be most cost-effective screening test in
Asia

• Chinese study, Markov model, comparing gFOB, FS,
  and colonoscopy (population age 50-80yrs)
• Colonoscopy used if initial test positive
• Colonoscopic screening reduced CRC the most
  (54.1)
• FOB is most cost-effective (then colonoscopy
  ,then FS) US 6222 /life year saved
• FOB remains most cost-effective with different
  compliance to screening, but not if sensitivity
  is 30-60, and specificity is 20-50

Tsoi et al APT 2008
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Large variability in compliance in
AsiaPopulation screening studies
Saito 2006 Yang et al 2006 Li et al 2003 Weller
et al 2007 Denis et al 2007
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Compliance, understanding and barriers to
screening

• Public knowledge of CRC is poor
• Lack of time, financial constraints
• Lack of physicians recommendation
• Lower knowledge about cancer and screening tests
  less likely to screen
• Tests embarrassing
• No health insurance
• Ostrich strategy
• Popular support from press and public figures

Sung et al 2008
Ransohoff et al 2005
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Resource available?

• 400 endoscopy units in Thailand
• (if FOB Japanese rates from Saito 2006 used )
• 126,405 colonoscopies needed
• 316 additional colonoscopies/ unit
• Not counting further surveillance colonoscopies
  needed

National database 2007 Department of Provincial
Administration Ministry of Interior Thailand
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Targeted/ stratification screening

• Selective screening for high risk patients?
• Increased risk for those with FH of CRC
• Relaxed FH screening guideline may be of
  benefit
• RISK SCORING for deciding initial test
• Using age/ sex/ FH or distal findings
• Reducing number of colonoscopy required by 40
• Detecting 89-92 of CRCs

Johns et al Am J Gastro 2001
Subramanian et al Colorectal Dis 2008
Lin et al Gastroenterology 2006 Imperiale et al
Ann Intern Med 2003
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Preparation for screening in UK Fitness to scope

• Capacity evaluation
• Audits
• Complete caecal intubation rate (national)
• Improving endoscopy list efficiency
• Global rating score
• Driving test
• National endoscopy training centres
• JAG accreditation
• Funding incentives

Nnoaham et al Gut 2008
Bowles et al Gut 2004 Ball et al BMJ 2004
Pickard et al Colorectal dis 2006
www.grs.nhs.uk
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Improvements
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New technologies too new

• New endoscopic equipment
• High definition/ Digital chromoendoscopy eg. NBI
  (Olympus), i-scan (Pentax)
• confocal microendoscopy
• Capsule endoscopy (colonic setting)
• Fecal DNA

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Flat/ depressed lesion detection

• Recognised in Japan for many years
• Recently accepted in the west
• Difficult to detect
• Higher proportion of high-grade dysplasia/
  carcinoma
• May be one factor for interval cancers

Muto et al Dis Colon Rectum 1985
Rembacken et al Lancet 2000
Kudo et al World J Surg 2000 Soetikno et al JAMA
2008
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Improvement in already available techniques

• Endoscopic
• Patient education
• Physician education- referral/ follow-up
• General satisfaction

East et al APT 2008
Sung et al Am J Gastro 2008
Turner et al J Gen Intern Med 2003
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Endoscopy Units should strive for quality
assurance

• Audit cycles
• Local rates eg. for cecal intubation, polyp
  detection, interval cancers, complications
• Appropriate indication and intervals for
  procedures according to guidelines (improving
  cost-effectiveness)
• Training in detecting flat polyps
• Consenting
• Training trainers/trainees

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National programmes should adapt to the country

• Resource
• Geography
• Patient acceptance/education
• Healthcare system and infrastructure
• Funding of screening

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More research needed

• Evidence to base national programme and Policies
• Uptake of each screening modality?
• Barriers to screening in each country?
• Dietary restrictions for FOB possible?
• Possibility of mixed strategies or targeted
  screening?
• Pilot studies.
• Increase in number of colonoscopist/ pathologist/
  surgeons needed?

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Summary

• Incidence of colorectal cancer in Asia in rising
• Screening reduces mortality from CRC
• Screening tests available include FOB, CT
  colonography, colonoscopy
• Per-test sensitivity vs per- programme
  sensitivity (which require infrastructure to
  ensure repeat testing)

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Summary

• Education, reduction in barriers, encouragement
  by physicians needed
• Quality assurance is needed for colonoscopy and
  CT colonography
• Resource may be a limitation
• Stratification or mixed strategies may be more
  cost-effective
• Pilot studies in screening general population
  likely to be needed- up-take/ capacity/
  cost-effectiveness for each country

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Bangkok, Thailand
End of Presentation by Dr Taya Kitiyakara
CanalAVIST Medical Forum 19 September 2008