Type 2 Diabetes Drug, Metformin, May Reduce Cancer Death Risk In Postmenopausal Women

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A widely prescribed drug for type 2 diabetes may also reduce the risk of dying from cancer in older women. Pixabay

A drug commonly prescribed to type 2 diabetes patients may also be able to cut cancer death risk in postmenopausal women, according to new research published in the International Journal of Cancer.

Diabetes is a common disease in the United States, affecting more than 29 million people, according to the American Diabetes Association. A common comorbidity for diabetes patients is cancer. In fact, people with the chronic condition, which usually results from too much sugar in the blood, have a double risk of developing liver, pancreatic, and endometrial cancer.

The new study, led by  Zhihong Gong of the Roswell Park Cancer Institute, revealed that women with type 2 diabetes and cancer had a 45 percent higher chance of dying from cancer compared to women with cancer who didn’t have diabetes, UPI reported. However, women with cancer who took metformin to treat their type 2 diabetes had a similar risk of dying of cancer as those without diabetes.

"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," said Gong, an assistant professor of oncology, according to UPI.

For the study, researchers combed through data of nearly 146,000 postmenopausal women between the ages of 50 and 79. The information, which came from the large Women’s Health Initiative study,  was collected between 1993 and 1998, Tech Times reported. In an effort to exclude those with type 1 diabetes — a condition in which the pancreas produces little to no insulin, and is usually diagnosed in children — they excluded those who had been diagnosed with the condition before age 21.

In addition to an elevated risk of liver and pancreatic cancer, the participants also had a 25 to 35 percent higher risk of developing colon and endometrial cancers, as well as non-Hodgkins lymphoma. Researchers say results from the study also suggest that the lower cancer risk associated with metformin may only be seen in those who use the drug for a longer period of time.

While the results seem promising, Gong cautioned that the study does not prove there is a cause and effect relationship between metformin and a reduced risk of dying from cancer, only that an association between the two was found.

"Our findings suggest that diabetes remains a risk factor for cancer and cancer-related death, and metformin therapy, compared to other diabetes medications, may have an important role in [managing] diabetes-associated cancer," Gong said.

This isn’t the first study to link metformin to health benefits other than diabetes control. Past research has found that the drug could increase the lifespan of non-diabetics. In terms of its relationship with cancer, it fares better than other diabetic medications. For example, a recent study found that other antidiabetic medications such as saxagliptin and sitagliptin, which contain antioxidant properties, may fuel the spread of cancer. Researchers speculate this has to do with their antioxidant properties; various studies have shown antioxidants can worsen cancer outcomes despite their protective properties.

Gong said more studies are needed to determine the long-term effects of metformin in cancer risk and survival.

Source: Gong Z, Aragaki A, Chlebowski R. Diabetes, Metformin and Incidence of and Death from Invasive Cancer in Postmenopausal Women: Results from the Women's Health Initiative. International Journal of Cancer. 2016.

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