Male sex hormones (androgens) are naturally produced in the adrenal glands, testis, and fatty tissue in the body. When prostate cancer cells develop, their continued growth is dependent upon a type of androgen called testosterone. It has been found that cancer cells may produce their own androgens, contributing to their continued growth.
The goal of hormone therapy is to slow the growth of prostate cancer by reducing the availability of testosterone. This can be done surgically, by removing the source of testosterone, or by using medications that block the production of testosterone.
Orchiectomy is the surgical removal of the testes, where the majority of testosterone is produced.
LH-RH Analogue Therapy
LH-RH analogue therapy is administered by injections (normally every 3 – 4 months). This treatment blocks signals from the brain that instruct the testicles to produce testosterone.
Anti-androgen therapy is taken in a pill form. Anti-androgens block the action of the testosterone on cancer cells. It is usually administered in combination with either orchiectomy or LH-RH analogue therapy in delivering a Complete Androgen Blockade (CAB).
This procedure involves surgical removal of the testicles. This removes the main source of male hormones and by reducing the level of androgens prevents the growth of most cancers. This procedure may be done under local anaesthetic on an out-patient basis.
Luteinizing hormone-releasing hormone analogues block the signals from the brain that tell the testicles to produce testosterone. Research shows that these drugs may lower the level of testosterone as effectively as surgical removal of the testicles. Most LHRH analogues are given every 3 months by injection. Several products of LHRH analogues are currently used, e.g. Lupron® (leuprolide), Zoladex® (goserelin) or Eligard® (leuprolide).
Antiandrogens are drugs taken in a pill form, usually in combination with LHRH analogues. Antiandrogens block a form of testosterone from reaching prostate cancer cells. They block the small amount of androgens produced by the adrenal glands, and are used in combination with one of the other two therapies to form a complete androgen blockade (CAB).
Combination Therapy: several trials have suggested that the combination of a LH RH analogue and an antiandrogen or orchiectomy and an antiandrogen are more effective than an LHRH analogue or orchiectomy alone. Many clinicians believe that combination therapy is the treatment of choice for men with prostate cancer that has spread. Some other clinicians believe that this combination therapy has little if any benefit over more standard methods. Consult your physician for more information.
Hormone therapy us a systemic (affects the whole body, not just one part) prostate cancer treatment. For this reason it is most often recommended for cases where prostate cancer has spread beyond the prostate, or for those who are at high risk of experience recurrence after surgery or radiation therapy.
Hormone therapy is used primarily when initial forms of therapy such as radical prostatectomy or radiation have failed. It may also be used when a patient is either unable or unwilling to undergo surgery or radiation. Occasionally hormone therapy may be used in combination with another therapy such as radiation.
Hormone therapy is slows the growth of prostate cancer but is not considered to be curative. It can normalize serum levels of prostate specific antigen (PSA) in over 90 percent of patients and can improve quality of life (QOL) by reducing bone pain as well as the rates of complications due to metastases. However, the duration of its effectiveness varies from individual to individual. Some men experience relief for greater than 10 years while others may have relief for less than one year.