Women with HER2 positive breast cancer are treated with a monoclonal antibody called trastuzumab (Herceptin). Trastuzumab (Herceptin) is given intravenously once every week or three weeks, and is usually well-tolerated. Monoclonal antibodies are drugs that recognise and bind to specific proteins (receptors) that are found in particular cancer cells or in the blood stream.
In New Zealand, trastuzumab may be used for up to one year in early breast cancer.
In secondary breast cancer it can be continued until the cancer is no longer responding to it. When this occurs, lapatinib (a pill taken by mouth) can be used instead to shrink the cancer, usually in combination with further chemotherapy. As of 2011, this medicine is not funded in New Zealand.
Trastuzumab may cause some problems with heart pumping function. Before starting trastuzumab treatment your doctor will check your heart using an echocardiogram or a multi-gated acquisition (MUGA) scan. Your doctor will check your heart at intervals while you are receiving treatment.
An echocardiogram will be done every 12 to 18 weeks.
Echocardiogram: A type of ultrasound test that looks at the size, shape, and function of the heart.
Multi-gated acquisition (MUGA) scan: a test that measures how well the heart pumps blood.
Monoclonal antibodies may cause other side effects. Talk to your doctor about these.
Many breast cancers appear to be influenced by the female hormones, oestrogen and progesterone.
Pre-menopausal women may be offered tamoxifen, a hormone treatment taken as a tablet. They may also have menopause induced to stop their own production of hormones. This can be done by four-weekly injections with goserelin (Zoladex) or by surgical removal (laparoscopic oophorectomy) of the ovaries. Once you stop taking goserelin your periods will usually return.
Post-menopausal women may be offered oral hormone treatments - either tamoxifen or aromatase inhibitors, for example, anastrozole (Arimidex), letrazole (Letara), or exemestane (Aromasin) which reduce the production of hormones in the body (other than from the ovaries).
Generally, women with breast cancer should not take any hormone replacement therapy or have an interauterine device (IUD) that secretes hormones.
General side effects of hormone treatments
Side effects of hormone treatments may include:
menopausal symptoms such as hot flushes, vaginal dryness, and mood swings. For suggestions on coping with these it may be helpful to talk to another woman who has been through this or to call your local Cancer Society or phone the cancer information nurses on the Cancer Information Helpline 0800 CANCER (226 237) for more information. The Cancer Society has an Information Sheet titled 'Cancer and Early Menopause', which is available from our website.
effects on fertility–if you have not reached menopause it may still be possible to become pregnant while you are taking hormone therapies. If you are sexually active, with a male partner, it is recommended that you use reliable contraception, such as a diaphragm or condom. Sometimes you may have permanent menopause as a result of your hormone therapy. (See the information on infertility in the section ‘Chemotherapy’.)
aromatase inhibitors can cause more rapid loss of minerals from bones (osteoporosis) and fractures are slightly more common while on these medicines. It may be recommended that you have a bone density study before starting and at some time during treatment. Treatment may be given for several years. Osteoporosis can be treated with oral bisphosphonates (bone hardening drugs).
muscular and joint aches are common side effects of aromatase inhibitors.
Hormone drugs may cause additional side effects. Discuss these with your doctor.