Designing an exercise intervention for adult survivors of childhood cancers

Advancements in cancer detection and treatments mean that approximately 80% of all patients diagnosed with childhood cancers will survive for at least 5 years. However, cancer survivors often experience immediate and long-term treatment-related complications across a range of functional domains and exhibit an increased prevalence of chronic health conditions (e.g., cardiac, pulmonary, endocrine, reproductive, neurocognitive) [1]. A recent analysis by Hudson et al. of the St. Jude Life Cohort found that by age 45 years, 95.5% of survivors had at least one chronic health condition compared to 30.6% of the general U.S. population [2].

To promote good health and reduce the risk of multiple chronic diseases, the U.S Department of Health and Human Services recommends at least 150 min total of moderate-intensity, or 75 min total each week of vigorous-intensity aerobic activity, or a combination of moderate and intense activity [3]. Although one report has suggested that survivors of childhood cancer engage in physical activity at a rate comparable to the general population [1, 2], more recent studies have reported that survivors are less likely to meet physical activity guidelines recommended by the Centers for Disease Control [4‐7].

Persistent treatment-related side effects, as well as fatigue, reduced muscle strength, and emotional difficulties, have the potential to complicate or hinder healthy lifestyles for cancer survivors [8, 9]. Additional barriers to wellness activities among childhood cancer survivors include lack of resources, negative thoughts and feelings toward a healthy lifestyle, and negative environmental and social influences [10].

The purpose of this study was to better understand the specific needs and preferences of adult survivors of childhood cancer, and to inform the design of future intervention studies, by examining survivors’ current self-reported health and physical activity levels, interest in structured exercise programs, and their specific preferences for survivor-focused interventions.

Preventive care is a critical element of health care among the growing cohort of adult survivors of pediatric cancer; consequently, the focus of the current study was to better understand levels of interest in as well as potential barriers to and preferences for a physical activity/exercise intervention. Current level of physical activity was included to understand actual levels of exercise among participants, as well as their interest in a potential exercise intervention. This data was collected to inform the design of a survivor- informed exercise intervention to enhance feasibility and relevance to the target population of adult survivors of childhood cancers.

Published studies support the efficacy of physical activity in reducing the risk of both disease recurrence and secondary complications among cancer survivors [11‐13]. Recent research has also examined the feasibility and efficacy of a variety of physical activity or exercise interventions [14], yet persistent challenges remain to both recruiting and retaining participants in such studies.

Several studies have identified common facilitators of exercise and healthy diet that include social and cognitive motivators (e.g., the development of goals and routines), positive social relationships, wanting to gain a sense of control over physical, emotional and mental wellbeing, being equipped with “tools” for health behavior such as access to gyms, and general education on healthy diet and food preparation [9, 10, 15]. This aligns with results of the present study where cancer survivors expressed an interest in earlier and more comprehensive education about late effects, as well as a desire for better management of treatment-related physical and emotional stressors that may impede motivation. Consistent with observations in the present study, survivors have also sought improved social supports, possibly in the form of survivor exercise groups, and/or programs better tailored and more accommodating to survivor specific needs [16].

It was encouraging to note that 85% of participants indicated that they would be interested in participating in a structured exercise program. Although factors such as “time” and “distance” were commonly noted as potential barriers to participation, these barriers to participation did not differ by gender, age, treatment-related factors, or current activity level. These barriers, while challenging, are generally consistent with the prior literature in cancer survivors and in the general population [16, 17]. A survey of 144 survivors of pediatric cancers between the ages of 13–35 found that common barriers to exercise included being too tired (57%), a lack of time (53%), and not having a gym membership (48%) [16].

Study participants also expressed detailed preferences supporting the development of a more tailored, survivor-focused intervention. Contrary to a previous study [17], participants did not specifically endorse a program that involved exercising with other survivors, which may be related to potential concerns about time and location. Preferences for the location of a potential exercise program were diverse, which may reflect an underlying challenge for creating a “catch all” or even a “catch most” program. Of note, participants endorsed one supervised session weekly with the remaining sessions completed by them independently.

Based upon these responses, we envision that a survivor-informed exercise intervention would consist of one sixty-minute exercise session per week, with guidance for additional physical activity sessions to be completed at home. Furthermore, use of fitness trackers and diet and exercise apps for smartphones may be reasonable alternatives or additions to an exercise program that would facilitate interactions among participants. Researchers have begun to integrate wearable fitness technology and activity trackers in their study designs of exercise programs for cancer survivors [18, 19]. In a home-based, randomized controlled trial assessing the efficacy of a physical activity intervention for sedentary breast cancer survivors, 86 women were assigned to a physical activity group or a control group. After randomization, women in the physical activity group were initially counseled in person on how to do moderate-intensity exercises and each received a journal to log their physical activity and a Digiwalker (a pedometer) to wear while they exercised. Every week for 12 weeks, each woman in the physical activity group received exercise tip sheets as well as physical activity counseling via telephone. Analyses conducted after treatment revealed that women in the intervention group had engaged in significantly more physical activity than the control group. They also had significant improvements in fatigue reduction [20]. This type of approach may prove to be a pragmatic solution which could provide participants with desired structure and oversight while also addressing stated barriers.

Survivor input regarding a potential exercise intervention is generally consistent with other published studies. In one study, researchers implemented a 10-week intervention among adult survivors of pediatric cancers which encouraged a general increase in physical activity (e.g., walking, gardening, and housework) for participants to complete independently [18]. Participants reported their progress to a counselor via telephone at three, six, and 9 weeks, and used a pedometer to measure steps. Subjects were recruited from a long-term follow-up clinic: 67 met inclusion criteria, 21 refused to participate, 46 enrolled, and eight withdrew from the study. However, the 38 participants who completed the intervention showed improvements in both activity level and fatigue. Similarly, a home-based intervention among childhood cancer survivors treated with anthracyclines found improved cardiac function after 3 months of structured aerobic and weight bearing exercise [14]. Though successfully implemented, these interventions occurred over on limited time interval and did not track long-term participation and outcomes.

While not a primary focus of the current study, we were surprised to note that participants consistently expressed interest in further education on diet and nutrition. Although the majority of participants reported having previously discussed this topic with a clinician, a more detailed and comprehensive educational component appears warranted. This finding was generally consistent with recent literature suggesting that survivors desired more education on health behaviors, particularly as they relate to late effects of treatment [21]. One meta-analysis observed unhealthy diets across all age groups of cancer survivors, noting low fruit and vegetable intake, low calcium intake, and high fat intake [22]. While these behaviors are also observed in the general population, given long-term effects from cancer treatment and increased risks for future complications such as metabolic syndrome, heart failure, and type 2 Diabetes among survivors, diet and nutrition education could be of great importance. The proposed schedule of a single supervised session weekly would permit incorporating a focused educational diet/nutrition module and provide regular opportunity for follow-up and feedback by attendees.

Limitations of the study include a small number of participants recruited from a single cancer center and self-reported exercise and activity levels. In addition, similar to many studies, physical activity was assessed retrospectively by querying subjects as opposed to prospective assessment. Because participants were asked to project their interest in a future program, there is the possibility that their interest is over-estimated. However, information solicited from survivors on how to best construct this future program is nonetheless valuable.

Strengths of the current study include the relevant and unique insights regarding current levels of physical activity and desired features of an exercise intervention (e.g., time, place, frequency, component activities) as expressed by adult survivors of childhood cancers. Further, the current study provides specific program preferences expressed by survivors supporting the development of a more tailored approach to an exercise intervention, as well as the inclusion of other components such as diet and nutrition, which may prove to drive participant interest in a more holistic “wellness program”.

While multiple studies have established the importance of physical activity among childhood cancer survivors, the feasibility and implementation of programs for this purpose remains a challenge. Understanding current practices, barriers to participation, and survivor preferences will help to improve the quality, relevance and implementation of future exercise programs.

Childhood cancer survivors are at risk for long term health complications that can be mitigated with attention to nutrition and exercise. We demonstrate that adult survivors of childhood cancers are interested in both physical activity interventions and nutrition education, however these programs need to be accessible and convenient to participants.