Why is hormone therapy also useful after breast cancer?
In tumors that have hormone receptors, the estrogen produced by the body leads to faster tumor growth. In order to prevent or slow down the growth, it is therefore necessary either to stop the hormone production (by radiation or removal of the ovaries) or to prevent the effect of these hormones. Depending on the active substance, hormone therapy can reduce both the formation of hormones and their effect.
Hormone therapy can therefore be used to slow down tumor growth or, for example, to prevent the recurrence of tumors after removal of the tumor. If the tumor has been successfully removed, anti-hormonal therapy is recommended to reduce the risk of recurrence. Usually, such treatment lasts 5 years, although studies have shown that treatment for 10 years should reduce the risk of recurrence even more and thus prolong survival.
Patients who fall ill after the onset of menopause sometimes have an increased risk of tumor recurrence and are therefore particularly at risk. It is recommended that hormone therapy be administered to prevent a recurrence. Hormone therapy after breast cancer has been cured is therefore an important part of treatment and is intended to prolong the patient’s survival time.
What hormone therapies are available?
Hormone therapies can be effective at various points in the hormone control cycle.For this reason, a distinction is made between three large groups of active ingredients: Antiestrogens such as Tamoxifen are also called Selective Estrogen Receptor Modulators (SERMs). These agents do not inhibit hormone production, but block the receptors on the target organs. As a result of this blockade, estrogens can no longer bind to the receptor, which causes the cells to lose their growth stimulus.
As a result, the tumor cell can no longer divide and growth is stopped. As an alternative to tamoxifen, fulvestrant can also be used in advanced stages. Fulvestrant is stronger than tamoxifen in its effect.
Not only does it reduce hormone activity to a minimum, but it completely shuts it off and leads to the breakdown of receptors. Aromatase inhibitors represent a second class of active ingredients. This group of drugs bind to the so-called aromatase enzymes and thus interfere with the conversion of estrogen precursors into estrogen.
As a result, the estrogen level drops and the tumors lose the hormonal growth stimulus. However, aromatase inhibitors are only used in post-menopausal women, as it is only at this point that aromatase has a decisive effect on oestrogen production. In addition to antiestrogens and aromatase inhibitors, GnRH analogues are used.
GnRH (gonadotrophin-releasing hormone) is a hormone that develops its effect in the brain. It binds to receptors on the pituitary gland and causes the release of hormones (follicle stimulating hormone (FSH) and luteinizing hormone (LH)), which in turn stimulate estrogen production and release. GnRH analogues are similar in their structure to the body’s own GnRH and therefore bind to the same receptors, but do not cause hormone release. In this way, the tumor’s hormone supply is cut off and its growth is stopped.
- Antiestrogens
- Aromatase inhibitors
- GnRH analogues
