One of the earliest hormone therapies (ADT) given to men to treat prostate cancer was estrogen. Estrogen, commonly known as the female hormone, was used as an ADT treatment in the early 1950s.
Initially, the estrogen was administered orally and the most common estrogen drug used was diethylstilbestrol (DES). DES (estrogen) both reduces testosterone levels in men and it also directly kills prostate cancer cells thus providing a one, two punch. Although it was effective, its use fell out of favor when it became known that the estrogen also caused severe and dangerous cardiovascular side effects. The actual side effects included high blood pressure, blood clot formation, fluid retention and pulmonary embolisms. These side effects probably killed as many men as the drug helped.
Many now believe that current technology now allows for the successful management of these cardio-vascular problems. Diuretics, antihypertensive drugs and Coumadin, when properly used, can ameliorate many of the common problems caused by the oral estrogen drugs.