Metformin
In one study (abstract 1569), the first to examine the effect of metformin on survival rates for breast cancer patients, researchers examined clinical outcomes for 1,215 patients who were diagnosed and underwent surgical treatment for breast cancer between 1997 and 2013. 97 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 2X likely to die than patients who never used the drug, while patients who began using metformin after their cancer diagnosis were almost 50% more likely to survive than non-users.
“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,” said lead author Yun Rose Li, MD, PhD. “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.”
Additional results of the study showed that patients who used metformin were more likely to be >50 at diagnosis and to be African-American. While tumor size and disease progression were similar across all groups, the patients who began using the drug after their diagnosis were more likely to have ER/PR positive tumors while the patients who used it prior to their diagnosis had higher rates of Her2+ and Triple Negative tumors.
There is compelling biological evidence suggesting that the differences observed in breast cancer tumor markers may be due to mechanistic differences in cancer initiation in patients who develop cancer while taking metformin.
In the 2nd study (abstract 5592), 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.
18 participants were enrolled in a multi-institutional trial and treated with metformin for 3 months. Results showed 56% of patients responded to treatment, defined as complete resolution of the hyperplasia. The effect was seen especially in women with simple hyperplasia without additional complications or irregularities.
Typically, women with endometrial hyperplasia are treated with progesterone-based therapies via depot injections, intrauterine devices, or oral medications. Progesterone works by counteracting the effects of estrogen and thinning the uterine lining. While effective in up to 80% of cases, progesterone therapies have been shown to cause significant side effects such as weight gain, mood changes, and gastrointestinal distress. Hysterectomy (surgical removal of the uterus) is also an alternative therapy for women who are post-menopausal, or have completed child-bearing.
“The results of our study may present an alternative treatment for particular forms of endometrial hyperplasia, in contrast to standard progesterone-based therapies or hysterectomy,” said Emily Ko, MD, MSCR. “Future prospective studies may better identify women for which metformin may be most beneficial, as well as the most effective dosing regimens.” http://www.eurekalert.org/pub_releases/2016-06/uops-ddm060316.php
Recent Comments