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An effective, clearly
enunciated national policy is needed for
secondary prevention (screening and surveillance) of bowel cancer
in Australia. Bowel cancer meets the World Health Organization
criteria for screening, and is the commonest internal malignancy
affecting both sexes in Australia, causing more deaths than any other
cancer except lung cancer.1 Three randomised
controlled trials have shown that screening average-risk
populations (aged 50 years and over) by the crudest of faecal occult
blood tests (Hemoccult) is effective in reducing population
mortality from bowel cancer on an intention-to-screen
basis.1 Furthermore, calculations
of cost-effectiveness using Australian cost data and screening
outcomes of the poorly specific rehydrated Hemoccult test show that
screening for bowel cancer is about as cost effective as screening for
breast cancer.2
Given that neither mortality from bowel cancer nor cancer stage at
diagnosis has improved in various Australian States,3 we can assume
that current secondary prevention activities are only minimally
effective. Indeed, the incidence of bowel cancer continues to rise in
men.3
Why are we not conducting screening and surveillance? Why are we
missing out on their demonstrable benefit?
From a national perspective, two key issues arise: - How
should we implement screening to reduce population bowel cancer
mortality rates?; and
- While this question is being answered, what is reasonable action for
individuals interested in being screened or for those at risk of bowel
cancer?
Unfortunately, failure to separate these two issues has led to
confusion and misunderstanding of promulgated guidelines.
The issue of an effective population screening program was addressed
in the Australian Health Technology Advisory Committee (AHTAC)
report released in April 1998.1 A recent editorial in the
Journal called for the issues raised in that report to be addressed and
resolved.4 The AHTAC report proposed
"pilot and feasibility studies" to examine aspects of screening,
such as logistics, choice of screening tool, risks, costs,
acceptability, resources and education. It took an evidence-based
approach and considered the issues from a population
perspective. Early in 1998, the National Cancer Control Initiative
submitted a proposal to government seeking funds for pilot and
feasibility studies in the general population. These funds have not
yet been provided -- we will not have an effective program for the
general population until results of pilot studies are available.
In the meantime, doctors, and especially general practitioners
(GPs), remain confused as to what is reasonable practice. Evidence
for this confusion is presented by Sladden and Ward in this issue of the
Journal.5 They found that many GPs are
unaware of the evidence that screening is effective and are uncertain
about intervals for testing, the age to start, and how to apply the
screening/surveillance tools to an individual in a manner
appropriate to the individual's risk profile. Few GPs are "highly
likely" to recommend faecal occult blood screening (and presumably
any other type of screening for bowel cancer) during a health check,
even though we know that people who have biennial screening with
Hemoccult have about a 40% reduction in risk of dying from bowel
cancer.6 Sladden and Ward point out
that guidelines available in Australia are partly responsible for
the confusion, because of their inconsistency in recommendations.
This inconsistency arises partly because the issue is complex and the
evidence is incomplete. Also, there is a failure to appreciate the
difference in the guidelines between what is acceptable as a
population strategy and what is reasonable for the
individual who seeks screening. Given that the value of
early-detection programs in average-risk individuals is supported
by three randomised controlled trials of faecal occult blood
test-based screening and by several case-control studies of
flexible or rigid sigmoidoscopy screening, it is difficult to ignore
the individual seeking help.
The soon-to-be-promulgated Guidelines for the prevention,
early detection and management of colorectal cancer of the
National Health and Medical Research Council (NHMRC) and the
Australian Cancer Network have been developed by a process of
consensus, incorporating a national workshop and analysis of the
evidence. These guidelines should provide a path through the
confusion, provided they are endorsed and used by the medical
colleges and other professional and educational bodies. They will
also partly solve the problem of access to, and resourcing of, the
colonoscopies needed for effective secondary prevention.
Adherence to guidelines for colonoscopic surveillance of those at
increased risk of bowel cancer might then free this limited resource
for more effective deployment to a larger proportion of the
population.
The issues for the primary healthcare provider are complex: the GP
needs to check the presence or absence of symptoms, profile the
asymptomatic individual's risk, tailor the screening or
surveillance program to that risk, and deal with the population's
aversion to things anal or faecal. The media have been unhelpful in
this respect, with little publicity given to bowel
cancer.1,4 As pointed out by Sladden
and Ward, GPs' actions might be suboptimal if they cannot immediately
recall the necessary (rather complex) detail or access the services
needed. When a GP considers that secondary prevention might be
indicated, support in terms of education and access to carefully
coordinated secondary prevention services should be provided by
regional health services.
The GP's role is important to the success of secondary prevention,
whether it is part of a future coordinated mass program, or dealing
with the individual seeking guidance or needing motivation. Clearer
guidance will come from the NHMRC-Australian Cancer Network best
practice guidelines. However, the continued rise in the incidence of
bowel cancer and failure to lower its mortality will not be adequately
controlled by such an ad hoc approach;7 population pilot studies
are desperately needed, and so is government funding!
Graeme P Young
Professor of Gastroenterology, Flinders University of South Australia
Head, Gastrointestinal Services, Flinders Medical Centre, and
Repatriation General Hospital, Adelaide, SA
- Australian Health Technology Advisory Committee. Colorectal
cancer screening. Canberra: Commonwealth Department of Health and
Family Services, 1997.
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Salkeld S, Young G, Irwig L, et al. Cost-effectiveness analysis of
screening by faecal occult blood testing for colorectal cancer in
Australia. Aust J Public Health 1996; 20: 138-143.
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Bell JC, McCredie M, Coates MS, Armstrong B. Trends in colorectal
cancer incidence and mortality in New South Wales 1973-1992. Med J
Aust 1997; 166: 178-181.
-
Collett JA, Olynyk JK. Colorectal cancer screening in
average-risk, asymptomatic Australians [editorial]. Med J Aust
1998; 169: 14-15.
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Sladden MJ, Ward JE. Australian general practitioners' views and
use of colorectal cancer screening tests. Med J Aust 1999;
170: 110-113.
-
Hardcastle JD, Chamberlain JO, Robinson MHE, et al. Randomised
controlled trial of faecal-occult-blood screening for colorectal
cancer. Lancet 1996; 348: 1472-1477.
-
Neugut AI, Young GP. Screening for colorectal cancer: an overview.
In: Young GP, Levin B, Rozen P, editors. Prevention and early
detection of colorectal cancer. London: WB Saunders, 1996: 357-368.
©MJA 1998
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Ian F Yusoff, Neville E Hoffman and Hooi C Ee . Colonoscopic surveillance for family history of colorectal cancer: Med J Aust 2002; 176 (4): 151-154. [Research]