Breast cancer arises from originally normal breast epithelial cells that start to behave abnormally. It is therefore logical that most breast cancer cells still have many properties of the original breast epithelial cells. For example, more than eighty percent of breast cancers have estrogen receptors. This means that if estrogens are present, the breast cancer cells will divide faster.
This is of course something we don't want. Therefore, after surgery and radiotherapy, these estrogen will give sensitive tumors "anti-estrogens". These anti-estrogens are substances that inhibit cell division. Since it is always possible that cancer cells have come loose before the tumor has been discovered and have spread through the lymphatic vessels and blood vessels in the body, we will administer "anti-estrogens" after surgery. For example, we inhibit the growth of small groups of cancer cells in the body. In this way we give the body time to attack and destroy these groups of cells. If we do not do this, these cancer cells will organize into larger groups of cancer cells and we speak of metastases or metastases.
These "anti-estrogens" are called hormone treatment. It would actually be more correct to call it an "anti-hormone" treatment. But because it has become so common, we will now also speak of hormone treatment. This treatment is given as standard five years after surgery.
The best known treatment is tamoxifen (Nolvadex-d®, or a generic product with tamoxifen 20 mg). This material can be compared to a key that fits on the same lock as natural estrogen. As a result, tamoxifen occupies the lock and estrogen can no longer work and the cell division of the cancer cell stops. By default, this substance is given for five years. When the cancer is very aggressive (high degree of division or AI index) or when the tumor is already far advanced when the tumor is discovered (large tumors, or tumors with different glands in the armpit), tamoxifen will be administered for ten years. Tamoxifen is usually well tolerated. Sometimes, as it is an "anti-estrogen", complaints will occur such as: weight gain, joint stiffness, fatigue, swelling of the vagina, dryness.
Another way to counteract the effect of the estrogens is simply to interrupt the production of estrogens. Estrogens are made from their precursor: the male hormone "testosterone". The enzyme that converts male hormone into female hormone is called "aromatase". An aromatase inhibitor counteracts the aromatase enzyme. As a result, no female hormone is produced by the body at all. The substance is only given to menopausal women. Before menopause, the production of estrogens is still too abundant and the aromatase inhibitors are not sufficiently effective. After menopause, there is only local production of estrogen in certain tissues and breast cancer cells. That limited production is completely suppressed by aromatase inhibitors.
Aromatase inhibitors are given five years as standard. As with tamoxifen, the inhibitors are given for more than five years in extensive cancers. And just like tamoxifen, there are also side effects such as: weight gain, stiffness of the joints, fatigue, warmth, vagina dryness, bone loss. Sometimes the side effects are so strong that it is decided to replace aromatase inhibitors with tamoxifen. This is safe if the woman tries to take the aromatase inhibitors for three years. Aromatase inhibitors will also promote bone breakdown, which can lead to osteoporosis. In menopause when taking an aromatase inhibitor or when taking tamoxifen it is recommended to do a bone densitometry. It is also recommended to take bone strengthening agents.
In young women, with extensive tumors, the source of estrogen production, namely the ovaries, will be removed or stopped. Chemical castration can stop the pituitary gland by monthly injections. This stops the ovary from producing female hormone. In addition, an aromatase inhibitor can then also be given. The combination of these two treatments is very stressful.
When the basic treatments such as tamoxifen or aromatase inhibitors no longer work and there is therefore a relapse among these products, other "anti-hormonal" products can be administered. Certain substances will destroy the estrogen lock. On the other hand, certain antibodies or small molecules that act as a cell disruptor will be administered during anti-hormonal treatment. This is still a further line of treatment when there is a relapse.