Hormone treatment for prostate cancer was first discovered in the late 1930s, early 1940s. In fact, a urologist at the University of Chicago received a Nobel Prize for his work in this recognition. Dr. Charles Huggins noted that in animals and then in men, that removing sources of male hormones leads to regression of prostate cancer. The original approach was to remove the major source of male hormones, that is to do an orchiectomy, or to surgically remove the testicles; 80% to 90% of male hormones are produced by the testicles, and when you do that you almost always cause regression of prostate cancer.
We now have multiple medical approaches to essentially turning off the testicles, reducing the production of male hormones, the major one being testosterone, by the testicles. This can be achieved primarily by the use of a class of drugs called LH-RH analogs. These drugs fool the body into thinking that it has more than enough testosterone. The testicles stop making testosterone and almost all the time, initially after such hormone therapy is initiated, evidence of the prostate cancer will diminish, symptoms, if they are present, will diminish, and oftentimes long-term control of prostate cancer is achieved by reduction in the male hormone production by the testicles.