Prostate cancer-Exercise and Metformin Trial (Pre-EMpT): study protocol for a feasibility factorial randomized controlled trial in men with localised or locally advanced prostate cancer

Background: Evidence from observational studies have shown that moderate intensity physical activity can reduce risk of progression and cancer-specific mortality in participants with prostate cancer. Epidemiological studies have also shown participants taking metformin to have a reduced risk of prostate cancer. However, data from randomised controlled trials supporting the use of these interventions are limited. The Prostate cancer-Exercise and Metformin Trial examines that feasibility of randomising participants diagnosed with localised or locally advanced prostate cancer to interventions that modify physical activity and blood glucose levels. The primary outcomes are randomisation rates and adherence to the interventions over 6 months. The secondary outcomes include intervention tolerability and retention rates, measures of insulin-like growth factor I, prostate-specific antigen, physical activity, symptomreporting, and quality of life. Methods: Participants are randomised in a 2 x 2 factorial design to both a physical activity (brisk walking or control) and a pharmacological (metformin or control) intervention. Participants perform the interventions for 6 months with final measures collected at 12 months follow-up. Discussion: Our trial will determine whether participants diagnosed with localised or locally advanced prostate cancer, who are scheduled for radical treatments or being monitored for signs of cancer progression, can be randomised to a 6 months physical activity and metformin intervention. The findings from our trial will inform a larger trial powered to examine the clinical benefits of these interventions.