A potential role for metformin in prostate cancer has been suggested and given its wide availability, tolerable side effect profile and safety record it may represent a therapeutic option for men with prostate cancer. However, the mechanism of action by which metformin exerts its anti-cancer effect has yet to be fully characterised. This 'window of opportunity' trial provides an opportunity to investigate this by comparing baseline prostate biopsies with post-treatment surgical specimen by focussing on assessment of the FASN/AMPK axis.~Patients with newly-diagnosed, early stage, prostate cancer scheduled for radical prostatectomy will either enter the main study and be randomised 1:1 to receive metformin (2g daily over 2 divided doses; Arm A) or placebo four weeks prior to prostatectomy (standard of care; Arm B). Or a subset of five patients will enter the exploratory PET-MRI Substudy . These five patients will all receive metformin and will undergo an additional two PET-MRI Scans.~Prostate tissue (at baseline from biopsy and post treatment from prostatectomy) will be used for analysis of p-AMPK, p-ACC, FASN by immunohistochemistry and proliferation will be measured using Ki67 and TUNEL in both metformin and placebo groups.
This is a randomized, placebo-controlled, double-blind, window of opportunity study investigating the biological mechanism of metformin in prostate cancer.