Using the multiphase optimisation strategy to improve physical activity in UK individuals with metastatic cancer

Physical activity is safe and feasible for individuals with metastatic cancer and may support quality of life. This PhD is situated in the preparation phase of the Multiphase Optimisation Strategy (MOST) and aimed to lay the foundation for the development of a Just-In-Time Adaptive Intervention (JITAI) to support UK individuals with metastatic cancer to be more physically active, which would be optimised in a Micro-Randomised Trial (MRT). Over three studies, I aimed to (1) improve understandings of the physical activity levels and needs of individuals with metastatic cancer, and (2) drive improvements in the design, delivery and analysis of MRTs by assessing the quality of reporting in the literature. Study One was a quantitative analysis of a survey exploring levels, perceptions and factors associated with physical activity in UK individuals with metastatic cancer (n=588). Study Two was a qualitative analysis of the beliefs, barriers and facilitators of physical activity for women with metastatic breast cancer (n=23). Study Three was a systematic review of MRT reporting (n=53), which assessed how the core features of MRTs were reported across the literature. This PhD showed for the first time that most individuals with metastatic cancer in the UK are not meeting physical activity guidelines, with individuals without university education and from ethnic minority backgrounds least likely to be active. It highlights a wide diversity of physical activity beliefs, barriers and facilitators in this population, suggesting a JITAI that adapts to their unique needs, would be beneficial. I also highlight that current support from healthcare providers is not sufficient, therefore wider changes to systems of support is also required. A quality appraisal of MRT reporting highlights relatively good practices in this fast-moving field, despite lack of guidance, but several areas require improvement and clarification, suggesting a need for more established guidance for MRT reporting.