Metformin beneficial for breast cancer patients, new study suggests

Metformin may help protect against breast cancer and lower the risk of death from the disease in older non-diabetic women, according to a new Italian study that adds to previous studies which have linked the common diabetes drug with reduced incidence of various cancers.
The research, published in Clinical Breast Cancer, found that a 1500mg daily dose of the anti-diabetic medication significantly cut serum insulin and testosterone levels – 25 per cent and 23 per cent respectively – in menopausal women with breast cancer, but without diabetes, after a period of five months.
Lead author Patrizia Pasanisi, MD of Fondazione IRCCS Istituto Nazionale dei Tumori in Mila, Italy, and colleagues said serum concentrations of insulin and testosterone may affect both incidence and prognosis of breast cancer.
“Both these changes might have a prognostic importance for postmenopausal women with breast cancer, but no diabetes mellitus,” the authors reported.
As high serum insulin and testosterone levels are linked with increased risk of breast cancer, they concluded that metformin may have the ability to prevent or treat breast cancer in non-diabetic women.