UICC World Cancer Congress 2006

Objective: To provide an overview of current theory, research, and principles of practice that inform population health approaches to cancer control.

Method: A literature review and analysis was undertaken.

Results: Of the 7 million deaths from cancer worldwide, 35% have been estimated to be due to 9 potentially modifiable risk factors. Nearly all of these avoidable deaths can be attributed to the behavior of individuals. [1]

“Cancer-related behavior” is any behavior which increases or decreases the probability of occurrence, or effects of, cancer in oneself or in those for whom one has responsibility, such as patients, pupils, employees or family, or even, in the case of elected representatives, one's constituency.

Early health educators assumed that provision of factual information about benefits of adopting preventive health advice would be sufficient for “logical” processing of that information and behavior change that would conform with the advice given. The discipline of health promotion extended the scope of influences that shape health-related behavior and has developed an evidence base that guides interventions to change the behavior of at-risk individuals, groups and populations. More recently, the boundaries of the influences on health and health behavior have been extended to include a complete ecological approach.[2] Studies on cancer-related behaviors are among those that provide the evidence base for the current theoretical perspective in population health.

Whilst interventions can be directed at population target groups, it is in individuals that cancer occurs, and so individual ways of responding to an intervention always need to be considered. Interventions to change environments usually work to reduce cancer because they lead to change in individual behavior.

Invariably, the objective of a population health intervention is to reduce the proportion of people in a population exposed to a factor that will adversely affect the health of some of them, i.e., reduce the proportion “at risk”. But individuals' perceptions of and response to risk are affected by experience and emotion, as well as objective analysis. Research is yielding new insights into the processing of risk information [3] and this needs to be taken into account when formulating strategies for communication and program delivery.

Research on cancer control interventions is heavily biased towards efficacy studies (which usually are modelled on the clinical randomised controlled trial) and there is a dearth of studies of sufficient scientific rigour examining the effectiveness of interventions when implemented beyond the controlled research setting. Funding agencies, methodologists, population health scientists, peer-reviewers and academic journals have roles to play in redressing this imbalance and advancing the field.

There are some universal principles that apply to behavior change, including motivation, modelling, enabling, prompting and positive and negative reinforcement. Examples of all these being found to be effective can be seen in the cancer control literature, but reported effects are not consistent. This is often because the context or setting of the interventions differed or, worse was ignored in designing the program. Attention to context is vital when trying to transplant effective programs in one culture/subculture into another.

Any intervention is more likely to succeed to the extent it maximises the number and intensity of behaviour change principles applied. The choice of principles to use and the emphasis will vary according to nature of the target behavior itself, in particular whether it is habitual (smoking, diet, physical activity), intermittent (screening) or one-off (vaccination).

There have been calls recently for greater involvement of policy-makers and program delivery agencies from the outset in population-research problem formulation and design. [4] The importance of this has been recognised for some time in Australia, where most of the state-based cancer control organizations have built dedicated, internationally competitive behavioral research centres which work in close partnership with professionals managing tobacco control, solar protection, diet/physical activity/obesity reduction, screening, cancer information and supportive care programs. These centres have not only published widely in the peer-reviewed literature, but more importantly have demonstrated a direct impact upon prevention program delivery. As well, such centres can do timely, highly focussed, policy-driven research studies that apply sound research methods to test or estimate the likely impact of adopting policy options under consideration by government.

[1] Donaei G et. al. Causes of cancer in the world: a comparative risk assessment of nine behavioural and environmental risk factors. The Lancet 2005; 366(17): 48-1793.

[2] Green LW, Kreuter MW. Health Program Planning: an educational and ecological approach. New York: McGraw Hill, 2005.

[3] Slovic P, Finucane M, Peters E, Macgregor D.G. Risk analysis and risk feelings: some thoughts about affect, reason, risk and rationality. Risk Analysis 2004; 24(2): 1-12.

[4] Kerner, J, Rimer, B, Emmons, K. Dissemination research and research dissemination: How can we close the gap? Health Psychology 2005; 24(5): 443-446.