Physical activity interventions using behaviour change theories for women with breast cancer : A systematic review and meta-analysis

Purpose
Physical activity is a well-established strategy to alleviate breast cancer-related adverse outcomes. To optimise health benefits, behaviour change theories provide frameworks to support women in improving their physical activity. This review aimed to evaluate (i) the effects of behaviour change theory-based physical activity interventions for women with breast cancer and (ii) the application of these theories.

Methods
Seven online databases were searched. Trials were included if randomised and controlled, involved physical activity interventions ≥ 12 weeks duration, used a behaviour change theory, and participants were < 3 years post-cancer treatment. Risk of bias and theory use were assessed. Data were synthesised narratively and meta-analysed.

Results
Forty articles describing 19 trials were included. Overall risk of bias was moderately high. Post-intervention pooled effect estimates were medium for self-reported (SMD = 0.57) and objectively measured physical activity (SMD = 0.52). Most trials cited the social cognitive theory (n = 10) and transtheoretical model (n = 9). Trials rarely applied theories in their entirety, expounded on behavioural mechanisms, or tailored interventions according to behavioural constructs. The most commonly used types of behavioural techniques were goals and planning (n = 18), shaping of knowledge (n = 18), feedback and monitoring (n = 17), and comparisons of outcomes (n = 17).

Conclusions
The included trials were effective for increasing physical activity in women with breast cancer. Theories were applied using a wide range of approaches and levels of rigour, although shared the use of common behavioural techniques.

Implications for Cancer Survivors
Future research may benefit breast cancer survivors by more comprehensively applying behaviour change theories, emphasising individual patient needs and goals.