Hormone Therapy for Prostate Cancer
Prostate cancer growth is stimulated by androgens. Androgens are steroid hormones such as testosterone, which are produced by your testicles and adrenal glands. Androgens have important functions in may body systems including reproduction, libido and sexual performance, muscle and bone development and cognitive performance. Stopping androgen production results in remission of prostate cancer, usually for several years. This can be achieved in two ways:
Surgically removal of the testicles – this is a permanent form of androgen deprivation therapy (ADT).
Through the use of medications which either stop androgen production or block the effect of androgens on the cells of the body. The most commonly utilised drugs for this purpose are referred to as LHRH analogs (Zoladex, Eligard, Lucrin). They act at the level of the pituitary gland to stop production of LH which stimulates the testicles to produce testosterone. LHRH analogs are administered by a subcutaneous injection every 3-6 months.
Your response to ADT is monitored by regular PSA tests. As testosterone production falls the PSA level will also fall. This will take several months to reach a very low level. Most men have a very favourable response to ADT.
Who is suitable for ADT?
ADT is first line therapy for advanced prostate cancer. This includes men with metastatic disease (prostate cancer affecting bones), men with very large local tumours causing obstruction of urine flow and men in whom the prostate cancer has returned following initial treatment.
ADT can be administered in an intermittent fashion or as a continuous therapy. There are quality of life advantages to intermittent therapy and this will be discussed with you.
ADT is also used prior to prostate radiotherapy in men with localised aggressive prostate cancers.
What are the Risks of ADT?
ADT is usually a very well tolerated treatment. The most common side effects are hot flushes and loss of libido. Over a longer period of time there may be reduction in muscle and bone mass and effects on cholesterol levels. These effects are monitored during follow-up.