While several interventions have had promising results regarding the benefit of nutrition and PA interventions in adolescents with a history of childhood cancer, several issues must be considered. When considering these results in their entirety, it is important to note that the reported outcomes from several studies were limited due to small sample sizes and variable adherence rates.32–35 Additionally, the absence of long-term follow-up to assess maintenance of dietary and PA changes prevents drawing conclusions as to the intervention strategies and components necessary to improve durable changes in these behaviors. Specifically, only two studies evaluated long-term maintenance of PA behavior changes and the results were mixed.34,35 Self-reported PA, self-efficacy, and quality of life in the Li et al study34 and self-reported quality of life alone in the Keats and Culos-Reed study35 were maintained at 9 and 12 months, respectively. However, objective increases in physical fitness and/or concurrent fitness levels were not maintained, suggesting that interventions may need to modify or include additional components to increase long-term maintenance. Moreover, the discrepancy in findings also points to a need for the inclusion of objective measures during all time points.
Despite the lack of conclusive evidence to direct the development of interventions aimed at increasing diet and PA in adolescents with cancer, several recommendations are offered here for implementation and evaluation in future studies. While successful interventions include both educational and behavioral components and afford adolescents opportunities for skill development with trained professionals as well as at home or in the community, specific recommendations related to adolescent development may compliment these supported elements. First, the presentation and delivery of key intervention components should be tailored to the developmental stage associated with adolescence. During adolescence, individuals move from concrete thinking patterns to more abstract, logical thought processes while still being primarily self-focused, especially during early adolescence. Following this, engaging an adolescent in the development of his or her own individualized PA and nutrition plan could increase both the saliency of the intervention as well as the individual’s motivation and commitment to change. Thus, strategies may include the following: providing a rationale for why lifestyle changes are indicated, taking into account diagnoses and treatment information; defining change goals that are important to the adolescent and what changes they are willing to make; and, finally, providing guidance as to the specific ways in which they could implement these changes into their daily lifestyle given their current familial, social, and environmental context.
Additionally, as adolescents are beginning to form their own self-identity and associate more with their peers as opposed to their parents, the incorporation of peer social support in interventions may be important in addition to parental support. Research indicates that both family and peer support are unique predictors of adolescent cancer survivors’ PA levels.37 Interventions that incorporate peer support for adolescents may improve the outcomes of interventions on two levels – first, by increasing the direct impact of the intervention on the survivor through peer encouragement for and engagement in diet and PA changes, and, second, via ongoing accountability and social support after the intervention for continued engagement in a healthy lifestyle. Particularly salient to adolescents may be the engagement of peers through current technological means, including social media or smartphone applications that could allow for instantaneous and ongoing peer support. Moreover, these interventions overcome barriers of travel and distance, which are significant for this patient population.
Finally, the timing of the intervention should be considered. While evidence exists in support of interventions delivered at any time point in the cancer journey, the most effective interventions may be those aimed at adolescents prior to the onset of deficits or noted declines in key health behaviors. For this population, interventions introduced at diagnosis or shortly thereafter and incorporated as a standard of care for any child or adolescent undergoing treatment for cancer could prevent or at least mitigate the adoption of poor behaviors and subsequent late effects. Since over 90% of children and adolescents diagnosed with cancer in the USA are treated at Children’s Oncology Group (COG) affiliated institutions, offering these interventions within the context of the COG could also serve as a uniform means of dissemination.38 Because of this collaborative and systematic system of care for children and adolescents diagnosed with cancer, it is foreseeable that comprehensive health behavior interventions could be delivered in conjunction with standardized treatment protocols, thus reaching the majority of children and adolescents with cancer. Similar to the refinement of treatment protocols within COG member institutions, behavioral interventions could benefit from collaborative data sharing, allowing for ongoing development, evaluation, and refinement of these interventions, especially with regard to timing, dosing, and delivery.