Hormones are substances that occur naturally in the body and control the growth and activity of normal cells. The female hormones, oestrogen and progesterone, can also affect the growth of breast cancer cells that are determined to be hormone receptor-positive. Hormone therapy or endocrine therapy for breast cancer consists of treatments designed to prevent the action of female hormones on these breast cancer cells. These treatments include drugs in pill form as well as injections such as tamoxifen, aromatase inhibitors and goserilin (Zoladex). Tamoxifen is the one most commonly used. It works by preventing oestrogen from latching onto breast cancer cells and encouraging them to grow. Not all cases of breast cancer respond to hormone treatment so tests are carried out to decide whether it should be used or not. Tamoxifen is taken as a daily tablet and usually causes a few side-effects as described below.
The women we interviewed who were on hormone therapy had been advised that this would continue for at least 5, and possibly 10, years. For some women this was no problem as they hardly experienced any side-effects. Aliza called it her ‘magic pill’ as she was grateful that this treatment was sufficient for her kind of cancer.
When Margaret heard that more and more women were taking hormone therapy for 10 years instead of 5, she went back to her oncologist to request an additional 5 years of tamoxifen; the fact that he agreed has given her a positive and relieved feeling. She says that this experience has added a little more confidence in the system and in her own personal medical care.
Other women described experiencing one or more common side-effects including joint or other pain, fatigue, hot flashes, going into menopause, headaches, and other ageing-related problems, such as changes in skin features as an effect of the reduced hormone levels in the body. Other more rare side-effects were also mentioned including bruising, depression, anxiety, appetite changes, and dry eyes. Weight gain is a common side-effect as well and up to 20 pounds is normal.
In rare cases, hormone therapy will do no harm, but may not be the best therapy. For one of our interviewees, her care team suspected that she became or was resistant to tamoxifen and that is why her cancer came back. You can read more about this in Recurrent and metastatic (advanced) breast cancer
Despite the side-effects, most women wished to continue taking the medication to reduce their chance of recurrence. However some women suffered from the side-effects so much that they started looking for other options. Both Tina and Julia decided to stop taking the hormones because of the severity of the side-effects. Tina was feeling very unwell and Julia tried the therapy twice but experienced extreme fatigue and anxiety.
When Tina and Julia decided to stop, the oncologist told them that he/she was unable to continue with follow-up care as they were not adhering to the recommended treatment. Tina is now followed-up by her surgeon and Julia is now seeing a naturopath.
Christa stopped taking her tamoxifen after 2.5 years when she was hoping to get pregnant again and she had also been experiencing severe joint pain.
Several women described changing their hormone therapy in an attempt to reduce the side-effects.
May-Lie started having episodes of bleeding and when the cause could not be found, she requested a hysterectomy. Because of the hysterectomy, she could be treated with a different kind of hormone therapy. She is now experiencing a lot less bone pain and the bleeding has stopped. You can read more about this in the topic page surgery. Aliza changed her medication three times as she was experiencing bad headaches and is now doing well with a new medication.