Most medicines have only one or two uses, but some are remarkably versatile. One of these is metformin, a drug that is used as a first-line treatment for type 2 diabetes. Justifiably, it is widely prescribed for that problem. But its usefulness extends far beyond diabetes. One reader wrote about another somewhat unexpected benefit of taking the diabetes drug metformin.
Does the Diabetes Drug Metformin Control Thyroid Nodules?
Q. My endocrinologist has prescribed the diabetes drug metformin to control thyroid nodules and prevent thyroid cancer. I am not diabetic, so my other doctors wonder why I would be taking metformin. Is there any evidence that metformin has anticancer benefits?
A. Your endocrinologist is keeping up with medical research. A review in the journal Frontiers in Endocrinology (Nov. 14, 2017) discusses the anticancer activity of metformin, particularly with respect to thyroid cancer.
There is also evidence that this drug can reduce thyroid nodules and may both prevent and help treat thyroid cancer. A systematic review concluded that metformin might be helpful in treating colorectal and prostate cancer as well (Coyle et al, Annals of Oncology, Dec, 2016).
Diabetes Drug Metformin in Cancer Prevention:
Scientists have been studying exactly how metformin can reduce the risk of various types of cancer. They are also considering how it might be used in conjunction with more conventional therapies to treat certain cancers (Morales & Morris, Annual Review of Medicine, 2015). In addition to colorectal and prostate cancers, researchers suggest that its ability to keep cancer cells from proliferating could be valuable in treating lung cancer (Gupta et al, Panminerva Medica, online Jan. 25, 2018). They are even evaluating its usefulness in helping to treat glioblastoma multiforme, an aggressive brain cancer (Valtorta et al, Oncotarget, Dec. 2017). This medication suppresses cancer stem cells, including those from pancreatic, breast, colon and prostate cancers (Saini & Yang, Acta Biochimica et Biophysica Sinica, online Oct. 7, 2017).
The Diabetes Drug Metformin Reduces the Risk of Head and Neck Tumors:
Researchers have reported that metformin may also offer benefits against head and neck tumors (Curry et al, The Laryngoscope, Aug. 2017). In this pilot study, the researchers took tissue samples from 39 patients with head or neck tumors. The participants then took metformin at about half the dose used by people with diabetes. The scientists sampled the tumors again and compared the metabolic markers.
How Does Metformin Fight Cancer?
Metformin interferes with cancer cells’ ability to create energy for growth by changing the pathways they use. Cancer cells are fast-growing, so they need a lot of energy generated quickly. The medication also encourages cancer cell death by disrupting the cancer-support system. Because metformin is generally well-tolerated and far less toxic than standard cancer drugs, it may become a valuable adjunctive treatment for a variety of tumors.
Other Readers’ Experience:
Keep in mind that risk reduction is based on statistics. Nothing that we know of prevents cancer in everybody.
Everett wrote of his disappointment:
My dermatologist just did a full-body inspection and found a squamous cell cancer on my forehead. I’ve been taking metformin for two years, so in my opionion, its anticancer activity is overrated.”
Metformin does have negative side effects for some people. Be sure to check with your physician in light of your own medical history before you jump into taking it.”
You can read more about metformin side effects and how to overcome them here. If you have had experience taking the diabetes drug metformin to prevent or treat cancer, please tell us about it in the comment section below.