Among the serious side effects of ADT are the risks of diabetes and cardiovascular disease. These are typically associated with a collection of physiological changes known as “metabolic syndrome.“ Metabolic syndrome is characterized by an increase in body fat and a shift in various blood markers that are often precursors to diabetes and cardiovascular disease.
This has led a variety of researchers to ask whether preemptively treating patients for diabetes when they start ADT can reduce the incidence of metabolic syndrome and diabetes. The idea seems promising enough to have inspired a half a dozen or so clinical trials that are active right now. Those trials explore various versions of this hypothesis.
And the results are starting to come in.
In a recent multi-centred trial, 83 men who did not have diabetes nor metastatic disease, and were going on ADT to support radiotherapy for localized prostate cancer, were randomly assigned to one of two groups. One group received treatment with metformin (a medication commonly used to treat diabetes) and the other group did not (i.e., the control group). Both groups were followed for up to three years.
By the five-month mark, the researchers saw some sign of benefit associated with adding in metformin, but this was primarily in the men who were already overweight. By the end of the study, there was no evidence that taking metformin while on ADT significantly mitigated the increases in weight or waist circumference for men on ADT.
That is not great news. But the authors discuss another study where patients were prescribed both metformin and an intervention that encouraged a healthier diet plus exercise. There metformin seemed to have some benefit.
At this point we cannot count on metformin to be a miracle drug that, alone, can protect men on ADT from metabolic syndrome and the subsequent consequences of androgen deprivation.
To read the study abstract, see: https://pubmed.ncbi.nlm.nih.gov/35907513/
Reference:
Usmani, N., Ghosh, S., Sanghera, K. P., Ong, A. D., Koul, R., Dubey, A., Ahmed, S., Quon, H., Yee, D., Parliament, M., Sivananthan, G., Hunter, W., Danielson, B., Rowe, L., McDonald, M., & Kim, J. O. (2022). Metformin for Prevention of Anthropometric & Metabolic Complications of Androgen Deprivation Therapy in Prostate Cancer Patients Receiving Radical Radiotherapy: A Phase II Randomized Controlled Trial. International journal of radiation oncology, biology, physics, S0360-3016(22)00747-7. Advance online publication. https://doi.org/10.1016/j.ijrobp.2022.07.035