Yesterday’s post about the use of transdermal estrogen patches as an alternative to LHRHa drugs  elicited a question on the Malecare Health Unlocked Advanced Prostate Cancer Online Support Group.  The question raised, or I should say the comment made was that estrogen is used for the purposes of hot flash mitigation and the use of estrogen as an ADT drug was called into question.  This is true, estrogen is sometimes used to mitigate hot flashes, but it is also sometimes used as a first line ADT treatment itself.

Originally ADT was accomplished by surgery or the oral use of estrogens (DES), however using DES fell out of favor because it caused very significant cardio-vascular issues and complications.  As a result, today, DES has basically been abandoned in favor of the use of luteinizing hormone-releasing hormone agonists (LHRHa) since they produce castration levels of testosterone.  However, they too produce many toxicities including osteoporosis, fractures, hot flashes, erectile dysfunction, muscle weakness, increased risk for diabetes, changes in body composition, and CV toxicity.

Increasingly, we are seeing a new level of interest in an alternative ADT approach , using  parenteral estrogen (administered  elsewhere in the body than the mouth and alimentary canal), it suppresses testosterone, appears to mitigate the CV complications of oral estrogen by avoiding first-pass hepatic metabolism, thus avoids complications caused by the oral use of estrogen deprivation therapy.

Yes, Estrogen is also used along with the LHRHa drugs to mitigate hot flashes, so it is used today for both purposes, side effect mitigation and ADT.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4418092/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4052190/