The impact of a group intervention to promote nutritional improvement and behaviour change for women following treatment for breast cancer

Many women live with a history of breast cancer. Breast cancer diagnosis and treatment can have ongoing consequences for health and wellbeing while lifestyle improvement can mitigate some of these effects. The focus of this study was to contribute evidence about how behaviour change might best be facilitated. The University offers a physical activity and healthy eating programme for breast cancer survivors. This doctoral study aimed to find out whether this intervention was beneficial, how it might work and how it could be improved. This study focused on the impacts on nutritional health and capacity for behaviour change.

The design of this study was informed by the Medical Research Council (MRC) guidance for developing and evaluating complex interventions together with the principles of realist evaluation. The intervention was refined, a feasibility study was carried out, and it was subsequently trialled to investigate its impact. The trial was carried out within a pragmatic paradigm using a convergent parallel mixed methods approach and a quasi-experimental design. Forty-three participants were recruited and attended one of three 12-week intervention groups. Data were collected at baseline, at intervention start and end, and after 12 months. Data collection included evaluation and interview data, measures of dietary intake and physical health and ratings of self-efficacy, concerns and wellbeing.

This research study found that the intervention led to reduced mean intakes of energy, carbohydrate and reduced daily glycaemic load together with a reduction in mean body weight and body mass index. The intervention also led to improvements in mean self-efficacy, wellbeing and a reduction in concerns. The intervention was found to have exerted its effects by a complex interplay of mechanisms including increased knowledge and understanding, improved confidence and motivation, skill rehearsal and increased peer support. The impact of the intervention on individuals was affected by contextual factors including personal experiences of treatment, previous lifestyle and health, intervention timing within the patient journey and support from family and friends.

This study found that the group lifestyle intervention was acceptable and feasible for participants to attend. It was beneficial as it addressed and reduced key concerns raised by group members and promoted the capacity of participants to initiate and maintain behavioural changes including improved nutritional quality. This research study gave a voice to research participants and identified behaviour change mechanisms that could provide the basis for an iterative process of intervention development. These findings were likely to be transferable to other similar contexts.