Metformin Improves Cancer Survival for Postmenopausal Women


Metformin, one of the world’s most commonly-prescribed diabetes drugs may double-up as an effective method for reducing cancer mortality rates in postmenopausal women. The drug was found to considerably reduce mortality risk associated with a variety of cancer types, when prescribed to postmenopausal patients fighting both type 2 diabetes and cancer.

Published in the International Journal of Cancer this week, the study examined the records of around 145,000 women of postmenopausal age between 1993 and 1998, none of whom were diagnosed with diabetes before age 21. The researchers noted an apparent 45% elevated death risk among those with both cancer and diabetes, compared to those with cancer but without diabetes.

“Diabetes was associated with higher risk of total invasive cancer and of several site-specific cancers,” the researchers noted.

“Diabetes was also associated with higher risk of death from cancer. There was no overall difference in cancer incidence by diabetes therapy. However, there was a lower risk of death from cancer for metformin users, compared to users of other medications, relative to women without diabetes, overall and for breast cancer,”

Metformin Improves Cancer Survival for Postmenopausal Women

“Results also suggested that lower cancer risk associated with metformin may be evident only for a longer duration of use in certain cancer sites or subgroup populations.”

It was determined that postmenopausal women with type 2 diabetes were between 25% and 35% more likely to develop endometrial and colon cancers, with pancreatic and liver cancer risk almost doubling in these patients.

“Our findings from this large study may provide more evidence that postmenopausal women with diabetes and cancer may benefit from metformin therapy compared to other anti-diabetes therapy,” the research team wrote in a statement published by Health Day.

The team, led by  Zhihong Gong, assistant professor of oncology at the Roswell Park Cancer Institute, warned of the importance of further research having once again produced evidence linking postmenopausal diabetes with cancer.

“We provide further evidence that postmenopausal women with diabetes are at higher risk of invasive cancer and cancer death,” Gong’s team explained.

“Metformin users, particularly long-term users, may be at lower risk of developing certain cancers and dying from cancer, compared to users of other anti-diabetes medications,” they continued.

Some have remained skeptical about the results of the study, including Dr. Joel Zonszein of the Clinical Diabetes Center at Montefiore Medical Center in New York City. Zonszein, who was not involved in the study, said that more research may be needed on metformin’s impact on reducing the odds of cancer, which was something Gong did agree with somehow in her team’s statement.

“We still don’t understand the exact mechanism of action of this old drug used in diabetes,” he said in a statement. “It may have positive effects in decreasing cancer mortality and or increasing longevity as shown in this paper.”

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