Prostate cancer relies on the male hormone, testosterone, to enable it to grow. One way of controlling the cancer is to starve it of testosterone. Hormone therapy (Androgen deprivation therapy) reduces the amount of testosterone in the body and can slow or stop the growth of cancer cells for many years. Hormone therapy can be given as injections or tablets and there are several types of drugs which all work in different ways to lower testosterone levels:
- Luteinising hormone (LH) blockers which stop the pituitary gland making testosterone – they include goserelin (Zoladex), buserelin (Suprefact), leuprorelin (Prostap), histrelin (Vantas) and triptorelin (Decapeptyl) and are given by injection.
- Gonadotrophin releasing hormone (GnRH) blockers work by blocking messages from the brain that tell the testicles to produce testosterone – degarelix (Firmagon) is given by injection.
- Anti androgens stop testosterone from your testicles getting to the cancer cells – they include flutamide (also called Drogenil), bicalutamide (Casodex) and enzalutamide (Xtandi) and are taken as tablets.
- Abiraterone (Zytiga) blocks an enzyme called cytochrome p17. Without this enzyme, the testicles and other body tissue can’t make testosterone. It is taken as a tablet.
Some doctors prescribe continuous hormone therapy (taken all the time) and others recommend taking it intermittently (a few months treatment followed by a break). Intermittent therapy cuts down on side effects but may not control the cancer for quite as long. How and when hormone therapy is recommended depends on the grade and stage of the cancer. Hormone therapy can be given as:
- a long term follow on treatment after radiotherapy or surgery with the aim of reducing the chance of the cancer coming back (this is known as adjuvant therapy),
- taken on its own if the cancer has spread to another part of the body,
- if surgery or radiotherapy is not recommended because the cancer has grown too far into the tissue around the prostate gland for these treatments to be successful.
Many of the men interviewed were having hormone therapy, sometimes in combination with other treatments such as radiotherapy. Most were taking Casodex (bicalutamide) tablets or Zoladex (goserelin) injections, or a combination of the two. Drugs may be changed during the course of the disease.
Hormone treatment can dramatically reduce the PSA level.
Casodex taken without other hormones has relatively little effect on a man’s sex life, but it has to be taken daily, which may be hard to remember. One man reported that he had chosen to take Casodex alone, but he had by mistake been given too low a dose to make it effective. Although some men reported that hormone treatment suited them, others reported side effects such as erectile problems, hot flushes and sweating, breast tenderness, feeling tired and weak and mood swings. Other side effect include memory loss, weight gain, tumour flare (bone pain) and bone thinning (osteoporosis) for more information see ‘Side effects of treatments‘.