Motivational interviewing in female breast cancer survivors and its influence on step count and quality of life: a randomised crossover pilot study

Up to 70% of female breast cancer survivors (fBCS) fail to achieve recommended physical activity (PA) levels due to unique geographical, financial, emotional, aspirational and physical barriers that commonly as a result of diagnosis and treatment. This is problematic as it can lead to a poor health prognosis long-term. Therefore, research into motivational strategies to improve adherence to PA is pivotal. However, studies commonly incorporate complex interventions that are not always feasible nor founded in established behavioural change theories. The overall aim of this cross-over randomised pilot study was to investigate the effect of a psychological tool, motivational interviewing (MI), on levels of self-directed PA (as measured by step count), quality of life (QoL), self-efficacy and self-regulatory types. The behavioural change theory used to inform the design of the intervention, the selfdetermination theory (SDT), focuses on enhancing an individual’s intrinsic motivators to change and developing a strong sense of autonomy over their behaviour. This pilot study is a component of a larger trial that will investigate the outcomes mentioned before in addition to immune function and psychological health. The results of this pilot study showed there was no effect of MI on any of the outcomes except for the breast cancer subscale within the QoL measure. There is great variation in these findings in comparison to other research, however, understanding the sources of the large heterogeneity found between studies is vital to finding the key moderators and help to inform future research. Limitations included the global COVID19 pandemic which impacted recruitment, health status and ability of the participants to engage in self-directed PA as well as the small sample size which means results should be interpreted with caution. Additional limitations were possible under-reporting of step count data from the FitBit monitor. Suggestions for future research are inclusion of other tools such as tailored print materials, additional self-reporting PA measures, a change of QoL measure, online support and group walking sessions. Additionally, increasing the number of MI sessions including an initial in-person session as well as other objective measures to ensure the fidelity of the MI. Finally, incorporating another behavioural framework to enhance social aspects of the self-directed PA components and intentional aspects of the intervention to facilitate greater changes as well as a two-armed RCT design rather than cross-over is recommended. This study has been invaluable in identifying key aspects of MI and study design to help inform future research that may produce evidence to ultimately improve the well-being of fBCS long-term.