Report of the Colorectal Cancer Screening Advisory Group

161 Pages·2006·0.79 MB·English

Report of the Colorectal Cancer Screening Advisory
Group
Published in November 2006 by the
Ministry of Health
PO Box 5013, Wellington, New Zealand

ISBN: 0-478-30099-9 (Internet)

This document is available on the Ministry of Health Website:
www.moh.govt.nz
FOREWORD

Colorectal cancer (cancers of the colon and rectum) is an important cause of
morbidity and mortality in New Zealand. Each year approximately 2500 people
develop colorectal cancer (CRC) and 1100 people die of the disease (Cancer
Registrations and Deaths 2002, NZHIS 2006). These figures give New Zealand,
along with Australia, one of the highest incidence rates of CRC in the world and,
compared with other OECD countries, the highest death rate for colon cancer
(Minister of Health, 2003).

Recent years have seen increasing interest in the potential of screening (the testing
of people without symptoms to identify possible disease) to reduce the burden of
colorectal cancer in New Zealand. This potential was highlighted in the late 1990s
when a reduction in CRC mortality was demonstrated with faecal occult blood testing
(FOBT) in two randomised controlled trials in Nottingham, England and Funen,
Denmark.

In 1997, in response to these trial results, a working party was established by the
National Health Committee to make recommendations on the advisability of
introducing a publicly funded screening programme based on FOBT screening.

Having considered all available evidence and assessing its implications for New
Zealand, the 1997 working party made the following recommendations (National
Health Committee 1998).

1. Given the modest potential benefit, the considerable commitment of health sector
resources and the small but real potential for harm, population-based screening for
colorectal cancer with faecal occult blood tests is not recommended in New Zealand.

2. Population-based screening for colorectal cancer with other modalities, such as
flexible sigmoidoscopy, colonoscopy or double-contract barium enema, is also not
recommended as there is not yet evidence from randomised controlled trials that
screening with any of these modalities reduces colorectal cancer mortality.

3. These decisions should be reviewed as evidence of benefit from new faecal occult
blood tests and other screening modalities becomes available.

4. Colorectal cancer is recognised as an important cause of morbidity and mortality
and it is recommended that New Zealand participate in international research in this
area.

5. Wider consultation and further consideration should be undertaken to develop
appropriate advice on surveillance recommendations for groups identified to be at
increased risk of colorectal cancer (Working Party on Screening for Colorectal
Cancer 1998).

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In the intervening years, Guidelines on Surveillance and Management of Groups at
Increased Risk of Colorectal Cancer (New Zealand Guidelines Group 2004) have
been developed by a subcommittee of the original working party under the auspices
of the New Zealand Guidelines Group. However, as documented in the report that
follows, capacity constraints restrict the ability of large centre public hospitals to
provide surveillance colonoscopy as recommended by the guidelines.

While no further randomised controlled trial evidence in relation to CRC screening by
any modality has been published since 1998, recent evaluation reports of the
colorectal cancer screening pilots in both the United Kingdom and Australia have
stimulated renewed interest in the potential of screening using FOBT to reduce
mortality from CRC. The availability of long-term follow-up data in relation to the
Nottingham and Funen trials also provides an opportunity to review the advice of the
initial working party.

Consequently in early 2005 the National Screening Unit (NSU) appointed a
Colorectal Cancer Screening Advisory Group. The role of this advisory group is to
provide the NSU with independent strategic advice and recommendations on
population screening for CRC in New Zealand. The advice provided by the group
does not necessarily reflect the views of the National Screening Unit.

This report provides the advisory group’s advice and recommendations on screening
and other issues in relation to colorectal cancer. It should be considered within the
broader context of a range of activities offering potential improvement in the control
of colorectal cancer in New Zealand.
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CONTENTS

Foreword...................................................................................................................2
List of abbreviations................................................................................................6
Membership of the Colorectal Cancer Screening Advisory Group......................7
EXECUTIVE SUMMARY ...........................................................................................8
RECOMMENDATIONS............................................................................................11
A. Screening options.............................................................................................11
B. Optimising diagnosis and treatment of colorectal cancer in New Zealand .......12
C. Improving outcomes from CRC for Maori........................................................14
D. Ongoing programme of research into the control of colorectal cancer in New
Zealand and factors driving inequalities................................................................14
E. Review of recommendations............................................................................14
Introduction............................................................................................................17
Improving the control of colorectal cancer in New Zealand..................................17
Screening for colorectal cancer............................................................................17
Initial advice on screening for colorectal cancer in New Zealand .........................18
Surveillance recommendations for groups at increased risk.................................18
Review of New Zealand decision on population screening for CRC.....................19
Establishment of the Colorectal Cancer Screening Advisory Group.....................20
Advisory Group’s process for determining advice.................................................21
1. Is CRC a suitable candidate for screening? ....................................................23
Epidemiology of colorectal cancer in New Zealand..............................................23
Incidence and Mortality for Māori..........................................................................26
Colorectal cancer screening and Māori................................................................27
2. Is there a suitable CRC screening test available?...........................................30
Faecal occult blood tests......................................................................................30
Flexible sigmoidoscopy as first-line screening......................................................34
Colonoscopy as first-line screening......................................................................36
Other potential modalities.....................................................................................39
3. Is there an effective and accessible treatment for CRC detected at an early
stage?......................................................................................................................41
Surgery.................................................................................................................41
Radiation and chemotherapy................................................................................41
Treatment outcomes for Māori..............................................................................43
4. Is there high quality evidence for the effectiveness of a CRC screening
programme?...........................................................................................................45
Evidence for the effectiveness of guaiac faecal occult blood testing....................45
Evidence for the effectiveness of immunochemical FOBT....................................48
Evidence for the effectiveness of flexible sigmoidoscopy.....................................50
Evidence for the effectiveness of colonoscopy.....................................................51
5. Does the potential benefit of CRC screening outweigh the potential harm?53
Physical harm.......................................................................................................53
Psychological harm...............................................................................................54
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6. Could the health care system fully support a CRC screening programme? 56
Identification of eligible population........................................................................56
Providing information and inviting participation.....................................................57
Screening test volumes........................................................................................58
Management and treatment of disease................................................................67
Programme co-ordination, monitoring and evaluation..........................................71
7. What are the social and ethical issues in relation to CRC screening?..........73
Information and consent.......................................................................................73
Acceptability and participation..............................................................................75
Impact of a screening programme........................................................................78
Cultural issues for Māori.......................................................................................79
Inequalities ...........................................................................................................80
8. What is the balance between the costs and the benefits of a CRC screening
programme?...........................................................................................................81
Cost-effectiveness................................................................................................81
Costs of a screening programme in New Zealand................................................84
An assessment of total costs and total benefits....................................................88
Conclusions............................................................................................................91
Implications of CRC screening test options for New Zealand...............................96
Appendix 1: Randomised Control Trials............................................................101
Appendix 2: Physical Harms Associated with CRC Screening........................109
Appendix 3: Role of General Practitioners in UK and Australian Colorectal
Cancer Screening Pilots......................................................................................114
Appendix 4: A Survey of Colonoscopy Capacity In New Zealand...................119
Appendix 5: Computed Tomography Colonography (CTC) Independent Report
NZ branch of the Royal Australian and New Zealand College of Radiologists
...............................................................................................................................140
Appendix 6: Proposed Feasibility Study of Colorectal Cancer Screening with
Immunochemical Faecal Occult Blood Testing in New Zealand......................144
Appendix 7: List of External Contributors.........................................................148
References............................................................................................................149

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LIST OF ABBREVIATIONS

CAD computer aided polyp detection system
CRC colorectal cancer
CT colonography computed tomographic colonography
DHB District Health Board
FOBT faecal occult blood testing
FOBTg guaiac faecal occult blood testing
FOBTi immunochemical faecal occult blood testing
FS flexible sigmoidoscopy
FSA first specialist assessment
GP general practitioner
KPI key performance indicator
NHC National Health Committee
NHMRC National Health and Medical Research Council
NSU National Screening Unit
NZHTA New Zealand Health Technology Assessment
PHO Primary Health Organisation
QALYs quality adjusted years of life saved
RCT randomised controlled trial
VC virtual colonoscopy

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MEMBERSHIP OF THE COLORECTAL CANCER SCREENING
ADVISORY GROUP

Susan Parry (Chair) – Gastroenterologist, Middlemore Hospital, Auckland.
Ian Bissett – Colorectal Surgeon, Faculty of Medicine and Health Sciences,
University of Auckland.
Ashley Bloomfield, Public Health Physician, Chief Advisor Public Health, Public
Health Directorate, Ministry of Health.
Vinton Chadwick – Gastroenterologist, Wakefield Hospital, Wellington.
Chris Cunningham – Director of Health Research, School of Maori Studies, Massey
University.
Michael Findlay – NSAC representative, Oncologist, Faculty of Medicine and Health
Sciences, University of Auckland.
Terri Green – Health Economist, University of Canterbury.
Barbara Greer – Consumer representative, Rata te Awhina Trust, Hokitika.
John McMenamin - New Zealand College of General Practitioners representative
Betsy Marshall – Policy Advisor, Cancer Screening and Cancer Control, Cancer
Society of New Zealand.
Ann Richardson – Epidemiologist, Christchurch School of Medicine.
Greg Robertson – General Surgeon, Association General Surgeons, Christchurch.
Judi Strid – Consumer representative, Office of the Health and Disability
Commissioner, Auckland.
Tai Sopoaga (for first part of process) – NSAC representative and Senior Lecturer
Pacific Health, University of Otago.
Clinton Teague – Pathologist, Medical Laboratory, Wellington.

NSU Secretariat

Carolyn Shaw, Public Health Registrar
Linda Berkett, Senior Policy Advisor

Final Editor Eileen Reid, Scribes Editing Service, Christchurch

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EXECUTIVE SUMMARY

This report follows the report of the Working Party on Screening for Colorectal
Cancer in 1998, which did not recommend population screening with faecal occult
blood tests because of “the modest potential benefit, the commitment of health
sector resources and the small but real potential for harm” (National Health
Committee 1998). The 1998 report recommended that this decision be reviewed as
new information became available. This is now the situation and a review of
colorectal cancer screening in New Zealand is appropriate. To this end, in April
2005 the National Screening Unit (NSU) of the Ministry of Health established the
Colorectal Screening Advisory Group and charged it with the following objective:

To provide the National Screening Unit with strategic advice and
recommendations on the appropriateness and feasibility of a population
colorectal cancer screening programme in New Zealand.

The findings and recommendations of the Advisory Group are summarised below.

• Colorectal cancer (CRC) is a major cause of illness and death in New
Zealand. Each year about 2500 people develop CRC and about 1100 people
die of the disease. Colorectal cancer is clearly an important health issue in
New Zealand. For this reason, a CRC screening programme merits
consideration.

• The Advisory Group considered CRC screening using the New Zealand
Criteria to Assess Screening Programmes (National Health Committee 2003).

• The Advisory Group’s conclusions with regard to the assessment of CRC
screening against the criteria are shown on page 16.

• Screening for CRC was considered for the following screening test options:

- the guaiac faecal occult blood test (FOBTg)
- the immunochemical faecal occult blood test (FOBTi)
- flexible sigmoidoscopy
- colonoscopy.

• The Advisory Group also considered the potential of other screening
modalities, particularly CT colonography.

• The only screening test option for which quality evidence from randomised
controlled trials is available is the guaiac faecal occult blood test (FOBTg), but
this test has been shown to have limited sensitivity in detecting CRC and the
mortality benefit remains modest.

• Immunochemical tests (FOBTi) have higher analytical sensitivity for detecting
faecal blood and although there is no RCT evidence, they would be assumed
to achieve an equal or even greater reduction in CRC mortality, compared
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with FOBTg. An FOBTi based screening programme would be more resource
intensive largely because of the higher colonoscopy demand following a
positive test result.

• The FOBT test positivity in a New Zealand population (a key determinant of
the potential benefit and the colonoscopy burden) is unknown.

• A screening programme based on one of the other screening modalities may
be an option in future. Evidence of mortality reduction from screening based
on flexible sigmoidoscopy or colonoscopy will not be available for many years.

• An effective CRC screening programme would require substantial workforce
planning, expansion and capital investment so that the New Zealand health
system could support it.

• This is crucial for colonoscopy services since all four screening modalities
require colonoscopy either for follow-up diagnosis or first line screening.

• The results of a colonoscopy capacity survey in NZ in 2005 (see Appendix 4)
have identified significant delays in the provision of colonoscopy, which may
be affecting outcomes from colorectal cancer. This is despite the fact that the
number of colonoscopies performed in the main centre public hospitals has
almost doubled between 1997 and 2005. There is an immediate and urgent
need to expand colonoscopy services within the public health sector.

• Existing public hospital colonoscopy capacity is insufficient to deliver timely
diagnostic colonoscopy for individuals with symptoms suggestive of CRC.
Based on the results of the 2005 colonoscopy capacity survey, nationally 930
patients in this category were estimated to have been waiting > 6 months for a
diagnostic procedure.

• Existing public hospital colonoscopy capacity is insufficient to deliver timely
surveillance procedures for those identified at increased risk of CRC as
outlined in the Surveillance and Management of Groups at Increased Risk of
Colorectal Cancer (New Zealand Guidelines Group 2004). Based on the
results of the 2005 colonoscopy capacity survey, nationally, 2790 patients
were estimated to have been waiting > 6months for a surveillance procedure.

• Preliminary considerations lead us to estimate that the total number of
colonoscopies performed per annum within the public sector would need to
increase by 10%-12% to ensure patients aged over 50 years with symptoms
suggestive of CRC are offered a diagnostic colonoscopy within the 8 week
time frame specified by the national colonoscopy referral guidelines (CPAC).

• Additionally it is estimated that the total number of colonoscopies performed
per annum within the public sector would need to increase by a further 15% to
ensure individuals identified at increased risk of CRC as outlined in the
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