Tuesday, 20 November 2007

Injection of LHRH Implant

Attended the Urologist's Surgery in St Leonards to receive an injection of a luteinising hormone-releasing hormone (LHRH)- specifically a 'Goserelin acetate implant' (the generic name) or Zoladex (the product name).



For a video demonstration of the proper technique for administering Zoladex please click here.



What is hormonal therapy?

Hormonal therapy treats prostate cancer by decreasing the supply or blocking the action of male hormones (androgens) such as testosterone that encourage prostate cancer growth. Hormonal therapy can slow the growth of the cancer and reduce the size of the tumour(s).

The following are the main types of hormonal therapy which may be used in prostate cancer:


Orchidectomy or surgical castration

Orchidectomy is the surgical removal of the testes, which are the organs that produce 95% of the body’s testosterone. Since the testes are the major source of testosterone in the body, this procedure is classified as hormonal therapy rather than surgical treatment. The aim is to deprive the prostate cancer cells of testosterone, thereby causing the cancer to shrink and/or to prevent further growth of the tumour. The testicles are removed through a small incision in the scrotum.



Figure 1: Orchidectomy


Most men who undergo surgical castration will experience a loss of sexual desire and impotence. In addition, hot flushes frequently occur. Surgery is permanent and the effects cannot be reversed.



Medical castration

Medical castration is achieved by using luteinizing hormone-releasing hormone agonists (LHRHa’s) (e.g. goserelin - ‘Zoladex’, leuprolide). They work by ‘switching off’ the production of male hormones from the testicles by reducing the levels of a hormone called luteinizing hormone. This hormone, is produced by the pituitary gland (a pea-sized gland located at the base of the brain which regulates and controls the release of hormones which directly or indirectly affect most basic bodily functions).


LHRH implants work just as well as orchidectomy in advanced diseasebut do not involve surgery. They are also used in combination withradiotherapy as adjuvant therapy for earlier disease.They are given by injection either under the skin (subcutaneous) or into the muscle (intra-muscular). The injections are generally given every month or every 3 months.

Most men who undergo medical castration will experience a loss of sexual desire and impotence. In addition, hot flushes frequently occur. However, medical castration is potentially reversible. If treatment is stopped, testosterone is produced once again.


LHRH Agonists

The 'original' 3.6mg formulation of Zoladex has been available since 1989 as a monthly implant. The new formation, 10.8 mg goserelin acetate implant given every three months, offers greater convenience to subjects choosing treatment with a luteinizing-hormone-releasing hormone (LHRH) analogue.

The 'original' 3.6mg formulation of Zoladex was shown to be as effective as orchiectomy (surgical castration) in controlling the spread of prostate cancer, thus offering men a choice between medical treatment and surgery.

This 12-13 week formulation of Zoladex is, a white to cream coloured, cylindrical implant with a 1.5 mm diameter that contains 10.8 mg of goserelin. Given by subcutaneous injection, into the anterior abdominal wall, the biodegradable implant slowly dissolves, delivering therapeutic levels of the drug continuously over a period of 12 weeks. This means an injection will be required every 12 to 13 weeks.




Ongoing Treatment

The success of this treatment (in my case Goserelin 10.8mg every 3 months) will be monitored by regular blood tests which look specifically at the Prostate Specific Antigen (PSA) readings. A lower PSA indicates that the treatment is working.

Subsequent to this treatment and dependent upon how my body reacts to the LHRH, radiotherapy will then be considered.

As with most things, there is a down side to this treatment. Men receiving Hormone therapy may have side effects from the withdrawal of testosterone. This could include: increased tiredness, erection problems, reduced sex drive, weight gain, hot flushes, breast tenderness, depression, and loss of bone strength (osteoporosis).

These side effects can significantly affect the way a man functions, however there are treatments that can minimise the impact of the side effects.

In order to monitor the progress of the Hormone Treatment, I have been scheduled to have two further blood tests (December and February) with the expectation that my PSA readings will go down. At present my PSA is 84.8. Normal readings for someone my age would be between 0 and 3.5 - still a way to go!

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