Aim: To investigate the effectiveness of diet-and-exercise interventions to facilitate and sustain diet and exercise behaviours of prostate cancer (PCa) survivors.
Methods: Five databases were systematically searched using PRISMA guidelines between January 2012 and December 2022. Studies including PCa cancer survivors of any stage and treatment with a diet-and-exercise (D&E) intervention intended to change diet and exercise behaviour were eligible. Primary outcome measures of dietary behaviour included energy, nutrient and a priori dietary indices; direct exercise behaviour was physical activity and indirect measures included fitness, mobility and strength.
Results: Eighteen publications reporting on 14 trials (n=1024) were included. Average intervention duration was 14.1 weeks (range: 12-28), with 8 dietary sessions (range 1-18) of 34.6 minutes duration (range 20-60), and 10.8 exercise sessions (range 1-24) of 35.9 minutes duration (range 20-60). Three trials had 3-month, two 6-month, and one 12-month follow-up measures of D&E behaviour. Eight trials were informed by behaviour change theory and a total of 35 behaviour change techniques (BCTs) were identified across all trials. D&E behaviour change was mixed with ten publications reporting dietary behaviour change and eleven exercise behaviour change. Only two out of six publications reported sustained behaviour change at follow-up for diet and exercise respectively. Four trials facilitated both D&E behaviour change, common BCTs in these trials were goal setting (behaviour), action planning, instruction to perform a behaviour, and credible source. Problem solving and social support (unspecified) also supported D&E behaviour change in trials that included these BCTs. In addition, exercise behaviour change was facilitated through self-monitoring and having supervised sessions.
Conclusions: D&E behaviour change was facilitated through specific BCTs which may inform more effective D&E interventions for PCa survivors. Long-term maintenance of D&E behaviour change post-intervention warrants further investigation to enable sustained health benefits into survivorship.