Hormonal therapy tries to slow down the prostate cancer cells from increasing by cutting off the supply of male hormones (androgens) such as testosterone that encourage prostate cancer growth. Testosterone primary purpose is to control the development of the sexual organs, including the prostate gland, and many male characteristics such as a deeper voice or muscle strength. Reduction of testosterone production in the body can be achieved by surgery to remove the testicles (the main source of testosterone) or by drugs. Most of the testosterone in your body (90-95 per cent) is produced by the testicles and a small amount comes from the adrenal glands, which sit above your kidneys.

Hormonal therapy focuses on cancer  cells which have spread beyond the prostate gland and is thus beyond the reach of local treatments such as surgery or radiation therapy. Hormonal therapy is also helpful in alleviating the painful and distressing symptoms of advanced disease. Further, it is being investigated as a way to stop cancer before it has a chance to metastasize. Although hormonal therapy cannot cure, it will usually shrink or halt the advance of disease, often for years.

Surgery to remove the testicles (orchiectomy or surgical castration) is usually an outpatient procedure. The testicles are removed through a small incision in the scrotum; the scrotum itself is left intact. To help offset the operation’s psychological toll, some men opt for reconstructive surgery in which the surgeon replaces the testicles with prostheses shaped like testicles.  Orchiectomies are seldom performed anymore, in most countries.

A variety of hormonal drugs can produce a medical castration by cutting off supplies of male hormones. Female hormones (estrogens) block the release and activity of testosterone. Anti-androgens block the activity of any androgens circulating in the blood. Still another type of hormone, taken as periodic injections, prevents the brain from signaling the testicles to produce androgens.

Possible problems
Either surgical castration (orchiectomy) or medical castration (hormonal drug therapy) can produce a striking response. Both approaches cause tumors and lymph nodes to shrink and PSA levels to fall. However, both castration methods can cause hot flashes, impotence, and a loss of interest