A commonly used drug for treating type-2 diabetes may improve survival rates for some breast cancer patients, a new research has found.
In one study, the first to examine the effect of metformin on survival rates for breast cancer patients, researchers from University of Pennsylvania in the US examined clinical outcomes for 1,215 patients who were diagnosed and underwent surgical treatment for breast cancer between 1997 and 2013.
Ninety-seven patients examined reported using metformin before their diagnosis, and 97 reported use of the drug after diagnosis.
Results of the study showed that patients who used metformin before being diagnosed with breast cancer were more than twice as likely to die than patients who never used the drug, while patients who began using metformin after their cancer diagnosis were almost 50 per cent more likely to survive than non-users, researchers said.
"Using metformin as a cancer prevention strategy has been controversial and results have been inconsistent, but our analysis reveals that use of the drug is time-dependent, which may explain the disparity," said Yun Rose Li from University of Pennsylvania.
"While use of the drug may have a survival benefit for some breast cancer patients, those who developed breast cancer while already using Metformin may have more aggressive cancer subtypes," Yun said.
"Our study also illustrates the complex interaction between underlying metabolic risks and breast cancer outcomes, and underscore the importance of a multi-system approach to cancer treatment," she added.
Additional results of the study showed that patients who used metformin were more likely to be over the age of 50 at diagnosis and to be African-American, researchers said.
In the second study, researchers examined the effectiveness of using metformin as a treatment for women newly diagnosed with endometrial hyperplasia, a condition that occurs when there is a hormonally related unbalanced overgrowth of the uterine lining.
If left untreated, patients are at a significantly higher risk of developing uterine cancer.
Eighteen participants were enrolled in a multi-institutional trial and treated with metformin for three months.
Results showed 56 per cent of patients responded to treatment, defined as complete resolution of the hyperplasia, researchers said.
The effect was seen especially in women with simple hyperplasia without additional complications or irregularities, they said.
