There are two ways of reducing male hormones:
• by surgery, where the testicles are removed (orchidectomy)
• by medication, either in the form of regular injections and/or tablets.
Both are effective.
The testicles provide over 95% of the male hormones and so surgery to remove the testicles reduces the blood hormone levels. This occurs very quickly after the operation.
An advantage of surgery is that the inconvenience and cost of regular medications is avoided.
The operation is usually done as day surgery. The scrotum (pouch of skin that holds the testes) remains and the testes are removed through a small incision. The operation, called an orchidectomy, is permanent.
Medications are available as an alternative to orchidectomy. Some are injected and others taken as tablets.
Injectable drugs act on the brain to reduce the production of male hormones in the testicles. They currently last from 1–6 months per injection. This means that regular monthly or 6-monthly injections are required to control the cancer cell growth. Should these be stopped in men with metastatic cancer, the cancer will start to grow again when male hormone levels begin to rise (after several months).
Drugs given as tablets are called anti-androgens. They block the action of the male hormone in the reproductive organs and are not as effective as injectables in controlling cancer growth. Treatment with both injectables and tablets is called combined androgen blockade. Sometimes doctors start with a tablet, then 2–4 weeks later give an injectable medication. This is to control a brief increase in testosterone activity (called ‘flare’), which passes with time.
The effectiveness of hormone treatment can be checked with a blood test for testosterone. Its effectiveness in controlling the cancer can be checked with a PSA blood test (see Mr PHIP No. 1 and 2), although this is not always reliable.
Sometimes hormone treatment may be given in cycles (i.e. started and stopped repeatedly). This type of treatment is called intermittent hormone treatment. Typically, the treatment is continued for several months until the PSA has reached a low level, then the hormone treatment is stopped.
The PSA then gradually rises. Once it rises to a particular level (and this can take many months), hormone treatment is restarted. The main benefit of this approach is reduced side effects (see the next section) without a significant reduction in tumour control. Trials suggest that cancer control is similar with both continuous and intermittent therapies.