Common Diabetes Drug Metformin May Reduce Oesophageal Cancer Risk by Over a Third

A diabetes drug long used to manage blood sugar levels may hold new promise as a cancer preventative, according to recent research. Metformin, available for less than 2p per tablet, could reduce oesophageal cancer risk by more than a third. This finding has sparked interest among oncologists and raised questions about how common treatments might address rare but deadly diseases.

Oesophageal cancer remains one of the world's most aggressive malignancies. It is linked to lifestyle factors such as obesity, alcohol use, and chronic acid reflux. Patients with Barrett's Oesophagus — a condition where stomach acid damages oesophageal cells over time — face an even higher risk. Could a drug already proven safe for millions now offer protection against this disease?

The study, published in JAMA Network Open, tracked over 13,000 cancer patients across Nordic countries between 1994 and 2023. Researchers matched these individuals with healthy controls to identify potential risk factors. Adjustments were made for variables like tobacco use, alcohol consumption, and statin intake. The results pointed to a clear trend: metformin users had lower odds of developing oesophageal cancer.

Of the 13,050 participants studied, 725 (about six per cent) used metformin regularly. In comparison, eight per cent of non-cancer patients took the drug. This discrepancy suggests a possible protective effect. The study found that those taking higher doses — over 1,278 daily tablets across five years — had even greater risk reduction.

Metformin works by lowering insulin levels, which may help slow cancer cell growth. Previous research has linked it to reduced risks of prostate and other cancers as well. For oesophageal squamous cell carcinoma (OSCC), the drug's impact was consistent regardless of age, sex, or smoking habits. This universality raises intriguing possibilities for future treatment strategies.

Professor Shai-Hau Xie, a gastrointestinal cancer expert, noted that metformin's role in prevention is