more holistic approach to evaluation, respect for
consumer autonomy in decision making, and pursuit of
informed choice in screening should lead to better
benefit:harm ratios and improve the framework for
assessing the worth of population screening pro-
Contributors and sources: LI is a medical epidemiologist who
has researched issues in screening for several decades. KMcC is
a behavioural scientist with expertise in decision making and the
psychosocial outcomes of screening. GS has published widely
on consumer preferences for screening and has a long-standing
interest in the application of economic methods for the evalua-
tion of screening. PB is a clinical epidemiologist who studies
methods to evaluate medical tests and to obtain patient
trade-offs of benefit and harm. This article arose from concerns
about how the incentive to achieve high participation in screen-
ing often runs counter to principles of informed choice. All
authors contributed to the development of ideas and the writing
of the manuscript. LI is the guarantor.
Funding: Supported in part by Australian National Health and
Medical Research Council NHMRC grants 211205 and 402764
to the Screening and Test Evaluation Program. The NHMRC
had no role in the writing this article.
Competing interest: None declared.
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Breastscreening: the facts.
(Accepted 11 March 2006)
Common susceptibility genes for cancer: search for the
end of the rainbow
Stuart G Baker, Jaakko Kaprio
The human genome map has started a hunt to find common genes that are associated with cancer.
But new research questions the likelihood of success.
Huge resources are being invested in the search for
common inherited genetic variants that increase
susceptibility to cancer. However, these studies are
expensive because they require large sample sizes to
rule out false positive results (table).1 2The US cancer
genetic markers of susceptibility project (http://
cgems.cancer.gov), for example, will cost $14m (£7.9m;
€11m).In addition,large replication studies may still be
necessary to confirm generalisability to other popula-
tions. For these studies to eventually lead to a clinical
therapeutic benefit, common genetic variants that
increase susceptibility to cancer must exist and it must
be feasible to rigorously evaluate the clinical benefit of
targeting these common genetic variants. Both these
requirements require formal consideration.
All benefits and harms of screening must be fully
ascertained and undergo community valuation
before screening is offered
Service providers should respect patient
autonomy and ensure that participation in
screening is an informed choice
Concordance between consumer preferences and
screening behaviour should replace participation
as one of the measures of success for screening
An explanation of sample size calculations for gene-cancer
association studies is on bmj.com
Analysis and comment
Stuart G Baker
S G Baker
BMJ VOLUME 33213 MAY 2006bmj.com