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The development of health behaviour change interventions for childhood cancer survivors: The need for a behavioural science approach

Late effects of treatment, particularly second cancers and cardiovascular complications, account for significant morbidity and mortality in childhood cancer survivors (CCSs).1 Health behaviours such as eating healthily, abstaining from smoking tobacco and engaging in regular physical activity are important andmodifiable protective factors for CCS’s cardiometabolic health, and health in general.2 It may even be argued that due to their elevated risk of disease, the establishment and maintenance of healthy behaviours is more important for CCSs than similarly aged people without a history of cancer. Therefore, health behaviour change interventions (HBCIs) aiming tohelpCCSs adopt and maintain healthier behaviours are a key strategy to prevent ill health, prolong life andmaximise quality of life. Reviews have previously identified that few HBCIs exist for CCSs.3–6 Methodological limitations in the testing of interventions (eg, small samples) and heterogeneity between studies (eg, intervention content) also limit the interpretation and robustness of findings.3–6


INTRODUCTION
Late effects of treatment, particularly second cancers and cardiovascular complications, account for significant morbidity and mortality in childhood cancer survivors (CCSs). 1 Health behaviours such as eating healthily, abstaining from smoking tobacco and engaging in regular physical activity are important and modifiable protective factors for CCS's cardiometabolic health, and health in general. 2 It may even be argued that due to their elevated risk of disease, the establishment and maintenance of healthy behaviours is more important for CCSs than similarly aged people without a history of cancer. Therefore, health behaviour change interventions (HBCIs) aiming to help CCSs adopt and maintain healthier behaviours are a key strategy to prevent ill health, prolong life and maximise quality of life.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2020 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC However, a further significant limitation exists, which has not previously been highlighted -namely that HBCIs among CCSs are failing to adopt a behavioural science approach, particularly in their development phase. The consequence of this is that we lack high-quality evidence-and theory-based HBCIs that provide realistic potential to effectively encourage and support CCSs to adopt, and maintain, healthier behaviours.
Below, we discuss four main areas where adopting a behavioural science perspective could improve the development of HBCIs among CCSs and aid the advancement of knowledge and practice of behaviour change in this population.

USE OF FRAMEWORKS
Among recent advances in behavioural science is the establishment of several frameworks to support and guide researchers to rigorously develop interventions. [7][8][9] These frameworks outline systematic steps to increase the likelihood that the resulting intervention will be evidence based, appropriately use theory, will be effective and can be implemented in practice. Despite this, developers often favour the   Figure 1). 11 The intensive development phase begins by planning activities (eg, identifying the problem) and involves all actions through to publishing a paper describing the development process, producing a detailed intervention manual (including a training programme for those delivering the intervention, if needed) and having a prototype intervention ready to take to the feasibility/piloting or evaluation phase. These actions are not sequential but should be considered in a dynamic, iterative and flexible way. Even in situations where an effective intervention to change the behaviour of interest may already exist, further research, as described below, is needed to ensure that the intervention is adapted (retrofitted) to the new context and population. 12

UNDERSTANDING THE TARGET BEHAVIOUR
Prior to providing a solution, we need to understand the problem.  [13][14][15] ; these barriers are also present in the general population. 16 However, CCSs have also reported additional barriers specific to the cancer, including fatigue, the ongoing impact of treatment-related inactivity and frustration at not being as physically able as they had been prior to their cancer. [13][14][15] Determinants may even differ within specific (sub-)groups of CCSs.
For instance regarding physical activity or exercise, brain tumour survivors may be more likely to experience neurocognitive issues that make some activities difficult; those treated with anthracyclines may be warned against participating in extreme sports or weightlifting; solid tumour survivors may be more likely to experience physical limitations; and patients still in treatment may have ongoing side effects, while long-term CCSs may be dealing with late effects of treatment. The determinants of health behaviours such as physical activity will also differ depending on the developmental stage of the survivor (eg, childhood and adolescence) and (potentially) their gender. 17 Therefore, interventions should be both targeted to the needs and context of the group to which they pertain (eg, CCSs or a specific subgroup of CCSs) and tailored to the individuals within that (sub-)group. 7 Indeed, there is evidence from a range of areas that tailoring is a key determinant of intervention effectiveness. 18,19 Understanding can be achieved by reviewing existing evidence on the determinants of the target behaviour and, ideally, primary research with the intended recipients of the intervention. 7,8,11 Qualitative research using a tool such as the Theoretical Domains Framework (TDF) to inform interviews and/or coding/analysis can be useful to identify the many influences on the target behaviour. 20

USE OF THEORY
Intervention development frameworks advocate the use of theory. [7][8][9]11 Theory aims to describe the drivers of behaviour enactment and behaviour change. Although interventions based on theory are more likely to be effective, there are several theory-related and methodological issues that may hinder this (eg, inaccuracy of the theory itself, or not fully using the theory). 25

INVOLVING KEY STAKEHOLDERS
Involving stakeholders throughout the development process will increase the likelihood that the resulting intervention is perceived as relevant, acceptable, engaging, useable and feasible by those whom it aims to help (eg, CCSs and their parents/guardians), those who will deliver it (eg, health professionals) and even those who are expected to fund it (eg, policy makers). 7,11 Engagement is also crucial for legacy. Prioritising stakeholders' perspectives can help to recognise their needs and preferences and anticipate and address potential issues. Therefore, active involvement of CCSs and, in some instances, their parents (due to the role that they play in their child's health behaviour) 16 is key.
Despite, the importance of stakeholder involvement, only four HBCIs with CCSs identified by the reviews refer to user involvement of CCSs or their parents. 10,21,26,27 Stakeholders can be involved in various ways from giving input and feedback via interviews and surveys at key points throughout the development phase, through being involved in decision-making processes by participating in a steering group, to taking part in co-design workshops to help shape the actual intervention. 28 The person-based approach describes methods for capturing stakeholder perspectives through the development process. 29

CONCLUSION
Knowledge remains limited on how best to support CCSs to improve and maintain positive health behaviours. However, the research community can make significant progress in supporting CCSs by embracing recognised behavioural science principles of intervention development. Specifically, future HBCIs in CCSs should aim to employ a systematic and evidence-based approach to development, be based on a thorough understanding of the target behaviour and on recognised theories of behaviour change, and incorporate stakeholder perspectives. This will maximise the chances that HBCIs will be acceptable, feasible, effective and sustainable across time.

Morven Brown is supported by the Children's Cancer and Leukaemia
Group, the North East Children's Cancer Research Fund and the Children's Cancer Fund.