MedWire News: Individuals with Type 2 diabetes who are treated with metformin may be at reduced risk for cancer, report researchers in the journal Diabetes Care.
“Recent research suggests that the antidiabetic drug metformin, which exerts its effects by activating the AMP-activated protein kinase (AMPK), may have potential for the treatment of cancer in humans,” explain Josie Evans (University of Dundee, UK) and colleagues.
“Activation of AMPK can suppress tumor formation and inhibit cell growth in addition to lowering blood glucose levels.”
To investigate further, the researchers carried out an observational cohort study using data from the Diabetes Audit and Research in Tayside Scotland (DARTS) database. The study began in 1993 and ended in 2003.
They identified a total of 4085 metformin users with Type 2 diabetes, aged 35 years or above, who newly began treatment with the drug between 1994 and 2003. These were matched with 4085 Type 2 diabetics who took no metformin during the same time period.
The researchers followed up participants until diagnosis of cancer, date of death, or the end of the study (31 December 2003).
Overall, 7.3% of the metformin users had a diagnosis of cancer compared with 11.6% of non-users, and median times to cancer onset were 3.5 and 2.6 years, respectively.
Following adjustment for factors such as gender, age, body mass index, glycated hemoglobin, smoking, and other drug use, metformin users were 37% less likely to develop cancer than non-users.
In addition, only 14.9% of metformin users died compared with 34.8% of non-users, with corresponding median survival times of 3.6 and 2.8 years, respectively.
“This study supports the hypothesis that users of metformin are at lower risk of cancer compared with people with Type 2 diabetes on other treatments,” conclude Evans et al.
“A plausible biological mechanism hinges on the discovery that the upstream LKB1 regulator of AMPK is a tumor suppressor and that activation of AMPK by LKB1 plays an important role in inhibiting cell growth when cellular energy levels are low,” they add.
“We believe that there is now a strong case to conduct a randomized trial to establish whether metformin is protective in a population at high risk for cancer.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
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