Hormone Therapy
- Switching off the Ovaries
The ovaries are the main source of production of sex hormones such as oestrogen. As mentioned earlier, oestrogen seems to stimulate the growth of breast tumours. Women who have not gone through the menopause will have active ovaries, so removing this source of oestrogen may be desirable, resulting in regression of hormone-receptor-positive breast cancer. Ovarian function can be ‘switched off’ in three ways:
• Surgical removal – this is obviously irreversible and requires a general anaesthetic. The operation can be performed using keyhole surgery techniques and is called laparoscopic oophorectomy.
• Drugs – pharmaceutical companies have recently developed special drugs that can reversibly switch off the ovaries, such as goserelin (Zoladex). This drug is given by injection once a month. The side-effects of these drugs include decreased sexual desire, skin rashes, hot flushes, depression and diarrhoea.
• Radiation – this method is not commonly used nowadays because of potential side-effects and the development of more effective and safer alternatives.
The switching off of the ovaries with drugs such as goserelin can be used in the treatment of hormone receptor-positive metastatic breast cancer and as an alternative to chemotherapy for hormone receptor-positive early invasive breast cancer in premenopausal women.