Metformin Fails in 408-Patient Cancer Trial, Shows 40% Adenoma Risk Cut in Specific Precancers
Updated
Updated · peterattiamd.com · Jul 4
Metformin Fails in 408-Patient Cancer Trial, Shows 40% Adenoma Risk Cut in Specific Precancers
1 articles · Updated · peterattiamd.com · Jul 4
Summary
A 408-man Phase III trial in low-risk prostate cancer found metformin did not delay progression during active surveillance: 70 progressions on metformin versus 74 on placebo over a median three years.
That null result fits a broader pattern: a 22-trial meta-analysis in 5,943 cancer patients found no survival or progression benefit, while another review of 27 trials found no reduction in new cancer incidence.
The latest analysis argues earlier observational signals were likely distorted by bias in diabetic populations, weakening the case that metformin is a broad anticancer or anti-aging drug.
Specific precancer settings still show promise: in 151 nondiabetic patients after polyp removal, metformin cut new colorectal adenomas by 40%, and a 272-patient Chinese trial also found recurrence near 30% versus 48.9% in controls.
The takeaway is narrower use, not wider adoption: metformin may merit better trials in defined high-risk precancerous groups, rather than use as a general cancer-prevention drug.