The medicine contains the active substance letrozole and belongs to a group of medicines called aromatase inhibitors. The medicine is a hormonal (or “endocrine”) treatment for breast cancer.
What is the medicine used for?
The medicine is used to prevent breast cancer from coming back. It can be used either as the first treatment after breast surgery or after five years of treatment with the medicine tamoxifen. The medicine is also used to prevent the spread of breast cancer to other parts of the body in patients with advanced disease.
The medicine should only be used
in oestrogen and/or progesterone receptor positive breast cancer and
only in women after the menopause (after the menopause, i.e. when menstrual bleeding stops for good).
How does the medicine work?
The growth of breast cancer is often stimulated by oestrogens (female sex hormones). The medicine reduces the amount of oestrogen by inhibiting an enzyme involved in the formation of oestrogen (called ‘aromatase’), which can block the growth of breast cancer that needs oestrogen to grow. As a result, tumour cells stop growing or grow more slowly and/or spread of tumour cells to other parts of the body is prevented or slowed down.
Monitoring your treatment
You should only use this medicine under close medical supervision. Your doctor will examine you regularly to check that the treatment is having the desired effect.
The medicine may cause thinning or weakening of your bones (osteoporosis) by reducing the amount of oestrogen in your body. Therefore, your doctor may measure your bone density (a method of checking for osteoporosis) before, during and after treatment.
If you have any questions about how this medicine works or why it has been prescribed for you, please ask your doctor.