Metformin could be used to combat the progression of pancreatic cancer, according to new research.

The study, conducted by researchers at Massachusetts General Hospital, found that the drug improved the health outcomes of patients with pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer.

“[Metformin] is frequently prescribed to diabetic pancreatic cancer patients and has been shown to associate with a better outcome,” they wrote.

This is not the first study to find a link between metformin and pancreatic cancer. Previous research has found that patients given the drug have a lower risk of developing pancreatic cancer, and treatment in those who develop the tumour lowers the risk of death.

However, this is the first study to discover why and how metformin works to combat pancreatic cancer.

Metformin and pancreatic cancer: decreasing inflammation to slow progression

When the researchers tested the drug on animal and cellular models, they found that it decreased the inflammation and fibrosis characteristics of PDAC. Treatment also lowered levels of tumour-associated macrophages by 60 per cent in animal models, which suggests that it inhibited the progression of the cancer.

Metformin also stopped the activation of pancreatic stellate cells (PSC), which is considered a key strategy in the treatment of PDAC. Alleviation of desmoplasia, another beneficial strategy in the treatment of PDAC, was also observed in obese animal models that were given the drug.

“Understanding the mechanism behind metformin’s effects on pancreatic and other cancers may help us identify biomarkers – such as patient body weight and increased tumour fibrosis – that can identify the patients for whom metformin treatment would be most beneficial.”

The findings are published in PLOS ONE.