Metformin and Cancer Prevention

New cancer prevention strategies emerge daily. Targeting cancer cell energy metabolism has gained importance in recent years. Metformin, an antidiabetic drug, is being intensively researched with some positive findings.

Metformin is a first-line choice for type 2 diabetes with few side effects. Recent research indicates antitumor properties alongside its strong antidiabetic action.

Its discovery is interesting: used for influenza in the 1950s, it was observed to lower blood sugar and first entered diabetes treatment in 1957. Synthesized from Galega officinalis extract, it reduces liver glucose production and consequently increases insulin sensitivity. It is used for prediabetic insulin resistance, type-2 diabetes, nonalcoholic fatty liver and polycystic ovary syndrome. It is also studied in certain cancers, particularly breast cancer. More than 1000 studies have evaluated its effects in diabetes, obesity, cardiovascular disease and cancer.

To summarize these studies;

• A study published in 2009 followed treatment for 10 years among 8000 diabetic patients and found a 54 percent reduction in cancer incidence with metformin compared with others.
• Another 2009 study of 12.000 cancer patients found mortality 30 percent lower among metformin users than users of other antidiabetic drugs.
• A 2008 study found that more than 36 months of metformin in type2 diabetes reduced cancer incidence by 72 percent.

Besides prevention, metformin was observed to extend cancer patients' survival. Research found substantially prolonged survival among colorectal, breast and lung cancer patients starting metformin.

Diabesity and Cancer Development: Metformin's Protective Role

Its cancer-protective effects emerged from the obesity-diabetes-cancer relationship. Research has established higher risks of all cancer types in people with diabetes than healthy people. High blood sugar has been associated with kidney, breast and skin cancers.

Metformin mainly activates AMPK (adenosine monophosphate protein kinase), which can be viewed as the body's energy sensor. By monitoring cellular energy, it determines whether fat and carbohydrates are stored or used for energy. When blood sugar is very high, it reduces liver sugar release and increases glucose uptake from blood, maintaining insulin sensitivity and lowering glucose. AMPK effects on cancer cells have also been studied. It deprived cancer cells of nutrients, causing death. In the most detailed laboratory study, metformin addition rapidly induced programmed cell death.

Low-calorie diets and exercise can activate AMPK. Metformin is among the simplest, safest ways of activating it. Calorie restriction also activates it. Clinical research has established reduced cancer risk and increased survival with calorie restriction.

In summary; laboratory and clinical research has observed metformin's cancer-preventive and survival-prolonging effects. Understanding its protective action will be an important step toward treatments targeting cancer metabolism. However, because metformin lowers blood sugar, it must be used on a doctor's advice and under supervision.