Metformin, a drug used in the treatment of type 2 diabetes has been shown to improve the survival rates for some forms of breast cancer. The drug also may be able to be used as a treatment for patients who are diagnosed with endometrial hyperplasia.
In the first study, the effects of Metformin on survival rates for breast cancer patients were observed. Researchers observed 1,215 patients who were diagnosed and received surgical treatment for breast cancer between the years 1997 and 2013. Ninety seven patients reported having used Metformin before they were diagnosed; another ninety seven said they used the drug after being diagnosed.
Patients who had used Metformin prior to their diagnosis were over twice as likely to die as patients who had never taken the drug. Patients who began using Metformin after they were diagnosed with cancer were about 50 percent more likely to survive in comparison to those who did not use the drug.
Lead author of the study Yun Rose Li, explains that using Metformin as a cancer strategy has been controversial and results have not been as consistent as the team would like. However, their analysis shows that the drug is very dependent on time, which could explain the changing results. Those who develop breast cancer while already using Metformin may actually have more aggressive forms of the cancer. He says the study illustrates a very complex interaction between underlying metabolic risks and breast cancer outcomes, and underscore the importance of a multi-system approach to cancer treatment.
Other results showed that patients who used Metformin were more likely to be over the age of 50 when they were diagnosed. These people also were mainly African American. All groups studied had very similar disease progressions and tumor sizes. Patients who begin using Metformin after their diagnosis were more likely to have ER-PR positive tumors, whereas those who used it before being diagnosed had higher rates of Her2+ and Triple Negative tumors.
Authors say more investigation is required, as this is the first study to examine the effects of long-standing Metformin use in regards to breast cancer. The team would like to study the recurrence of cancer when the drug is used as well.
In a second study, researchers examined the effectiveness of using Metformin as a treatment for women who were recently diagnosed with endometrial hyperplasia. This condition happens when there is a hormonal imbalance overgrowth of the uterine lining. Patients who do not receive treatment are at a much higher risk of developing uterine cancer.
Eighteen people took part in a multi-institutional trial and were given treatment with Metformin for 90 days. 56 percent of patients responded to the treatments, with no signs of any complications or irregularities. Women with endometrial hyperplasia are generally treated with progesterone therapies through depot injections, intrauterine devices or oral medications. Progesterone counteracts the effects of estrogen and thinning the uterine lining. Such therapies are effective in up to 80 percent of cases but they lead to some pretty serious side effects, including weight gain, changes in mood and gastrointestinal distress.
Lead author of the study, Emily Ko says the results offer an alternative treatment for some forms of endometrial hyperplasia, minimizing the need for progesterone therapies or hysterectomy. The hope is that future prospective studies might be able to identify women that Metformin may benefit the most. The team also hopes to pinpoint specific dosing regimens.
These results appear in two studies that were conducted by researchers at the Perelman School of Medicine at the University of Pennsylvania at the American Society of Clinical Oncology (ASCO) Annual Meeting.