The prognosis for women diagnosed with ovarian cancer is not very good. Only about 50 percent can expect to survive the disease for five years. But researchers say that the odds of making it to that five-year mark are significantly improved if women with ovarian cancer are also taking a common diabetes drug.
Researchers at
Mayo Clinic in Minnesota found that 67 percent of women diagnosed with ovarian cancer who were also taking the diabetes drug metformin lived five years or more after their cancer diagnosis. That's significantly better than the 50 percent of women who survived at least five years with cancer who were not taking the diabetes drug.
Sanjeey Kumar, a gynecologic oncologist at Mayo Clinic, says researchers are not sure how metformin extends the life expectancy of some ovarian cancer patients, but he says they have a number of theories. “Such as acting through stem cells, cancer stem cells, or depriving the cancer cells of energy supply or glucose,” he explained.
Stem cells are master cells that can transform into any tissue in the body. In the ovaries, the stem cells produce normal ovarian cells. But the influence of certain genes, which researchers are just now starting to identify, can turn the master cells into deadly cancer.
Metformin, an oral medication, reduces harmful levels of so-called bad cholesterol and blood fats known as triglycerides in type 2 diabetics. The drug also has been shown to prevent heart disease in people with diabetes, and is used occasionally to treat a condition known as polycystic ovarian disease, which causes small cysts on the ovaries and abnormal reproductive hormone levels.
In the Mayo Clinic study, researchers compared the survival of 61 ovarian cancer patients taking metformin to that of 178 women with cancer who were not on the drug.
After accounting for factors such as the patient’s weight, cancer severity and their chemotherapy regimens, they found that women on metformin were nearly four times more likely to survive at least five more years than women not on the drug.
There are very few treatment options available for ovarian cancer, which tends to be resistant to chemotherapy. So Kumar envisions - after larger clinical trials are conducted - eventually giving women with the disease metformin to improve their prognosis.
“And if the trials validate the findings of our study, then we would say that would say 'yeah,' that would be the time to change our practice and start recommending metformin for people who do not have diabetes,” Kumar stated.
The results of the study on the effectiveness of the diabetes drug metformin in treating ovarian cancer are published in the journal
Cancer.