Assessing Modifiable Health Behaviours and Late Effects in Survivors of Childhood Cancer

Abstract

Abstract Introduction This thesis explores the topic of cancer in young people and the potential association of long-term late effects related to treatment and health behaviours. This thesis, which contains six chapters, examines the association between health behaviours (as the exposure of interest) and the symptoms of late effects of cancer treatment (as the outcome of interest) at a specific point in time. Background Worldwide, cancer is a serious disease, and the number of reported cases has continued to rise over time; nearly 21.4 million new cancer cases are expected to be diagnosed by 2030. Recent estimates from 2015 show that the five-year survival rate increased from 71% to 84% across all cancer types. Most cancer diagnoses are in older people, and although cancer in young people is rare, it has a significant impact. Between 2011 and 2015, an average of 714 children between the ages of 0 and 14 years were diagnosed with cancer each year in Australia, with an annual estimated rate of 16 cases per 100,000 children. Across all childhood cancers, 85.3% of patients achieve 5-year disease-free survival. Many, however, will have significant treatment-related late effects. This study aimed to examine the association of health behaviours (physical activity, screen time, and sleep) with symptoms of late effects of cancer in order to acquire new knowledge of the association between health behaviours and long-term effects of cancer and therapy for childhood cancer. This knowledge can then be used to design and target interventions to improve health outcomes. Method An observational, cross-sectional study design was used, aiming to quantitatively measure both the health behaviours (exposure) and the outcomes of late effects for the participants in the studies at the same time. The study was undertaken in Queensland at the University of Technology at the Centre for Children’s Health Research. Thirty participants were directly recruited from the After Cancer Therapy Service (ACTS). Electronic medical records were used to obtain the relevant demographics and clinical information, including height, weight, and medical events. Late effects were measured using validated surveys, including the PRO-CTCAE, to measure symptom burden from 80 different possible symptoms through the RedCAP platform. A wearable Garmin device was used to objectively measure the participants’ activity (sleep, movement) over a two-week time period. Information was also collected about diet and other health behaviours via self-report. The data were dichotomised and categorised into high and low prevalence of late-effect symptoms and positive and negative categories for health behaviour variables. Correlation between variables and cross-sectional analysis was tested by using the bivariate statistical test. Fisher’s exact test was used to examine differences within and between groups. Results Thirty participants were included in the study, most of whom were female (n=17, 57%). Their ages ranged from 13–33 years old (mean ± SD =22 ±4). Their symptoms from cancer late effects were reported as moderate, severe, or very severe, and were grouped together to provide an overall understanding of the burden of symptoms experienced. The highest severe symptom reported was sadness or unhappy feelings, which was experienced by four (13%) participants, and the highest very severe symptom was fatigue (including tiredness or lack of energy), which was experienced by three (10%) participants. Participants were grouped into those with a high symptom burden (20 or symptoms rated as moderate or higher) or those with a low one (<20 symptoms reported as bothersome). Following this grouping, 11 (37%) participants were classified as having a low symptom burden and 19 (63%) as having a high symptom burden. The Body Mass Index (BMI) of participants in the present study ranged from 14