The Metformin Active Surveillance Trial (MAST) Study

Official Title

A Randomized, Double-Blind, Placebo-Controlled Trial of Metformin in Reducing Progression Among Men on Expectant Management for Low Risk Prostate Cancer: The MAST (Metformin Active Surveillance Trial) Study


This study aims to see if metformin can delay the time to progression in men with low risk prostate cancer when compared to a placebo.

Trial Description

Primary Outcome:

  • Time to progression
Secondary Outcome:
  • Time to primary therapy for prostate cancer
  • Time to pathological progression
  • Change from baseline in disease-related patient anxiety
  • Change from baseline in decisional satisfaction and decisional conflict
  • Change from baseline in prostate cancer diagnosis at repeat biopsy
  • Change in Gleason Score at repeat biopsy
  • Change in clinical stage of prostate cancer based on digital rectal examination
  • Assess the prognostic and predictive value of prostate cancer biomarkers
  • To determine the safety and incidence of (serious) adverse events from the administration of 36 months of metformin to men with early stage prostate cancer

View this trial on

Interested in this trial?

Print this page and take it to your doctor to discuss your eligibilty and treatment options. Only your doctor can refer you to a clinical trial.


Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society