Aromatase inhibitors for breast cancer: effects & side effects

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The most common types of cancer in Germany

What are aromatase inhibitors?

In most patients with breast cancer (breast cancer), tumor growth is influenced by hormones. Such tumors have receptors that respond to female messenger substances – usually estrogen: The hormones cause the tumor to continue to grow. Experts also speak of hormone-dependent breast cancer. Antihormone therapy (also endocrine therapy) works against this. Aromatase inhibitors, also known as aromatase inhibitors, are often used.

Aromatase inhibitors are divided into two groups. There are steroidal and non-steroidal aromatase inhibitors.

steroidal active ingredients:

non-steroidal active ingredients:

They block the production of estrogen in muscle and fat cells, but also in the cancer cells themselves, by binding to the necessary enzyme aromatase and thus deactivating it. However, all preparations in the active ingredient group aromatasemmers cannot prevent estrogen production in the ovaries: they are therefore generally only suitable for women who are already in menopause. Unlike tamoxifen and fulvestrant, they are not an anti-estrogen.

Use of aromatase inhibitors

The use of aromatase inhibitors is very simple: the active ingredient is taken orally as a tablet once a day. However, the treatment is lengthy: antihormone therapy has to be carried out for around five to ten years. This is intended to prevent the tumor from coming back (recurrence).

Endocrine therapy with aromatase inhibitors is usually carried out concurrently. Exclusive antihormone therapy cannot cure breast cancer. It is always linked to further treatments, for example

Experts then speak of adjuvant antihormone therapy. If the cancer is advanced and metastases are present, the drugs are used to contain the metastasis and increase life expectancy.

Depending on the other treatment methods, aromatase inhibitors are used at different times. If chemotherapy is necessary after surgical tumor removal, antihormone therapy is only given after this treatment has been completed. In the case of irradiation, this can begin at the same time.

In some cases the tumor is particularly large and therefore inoperable. An attempt can then be made to shrink the tumor using aromatase inhibitors. In this case we are talking about neoadjuvant therapy.

aromatase inhibitors and antiestrogens

In addition to other treatments such as chemotherapy, aromatase inhibitors and tamoxifen can both be used individually or one after the other. Which active ingredient patients receive first is determined by the doctor and varies from person to person.

Aromatase inhibitors in premenopause

Since aromatase inhibitors cannot inhibit estrogen production by the ovaries, the active ingredients are usually only used in postmenopausal patients.

In rare cases, for example if there is an intolerance to tamoxifen, aromatase inhibitors can also be given to younger women before menopause. Since the ovaries still produce estrogen despite the aromatase inhibitor, further measures must be taken to stop hormone production. To suppress the production of estrogen in the ovaries (ovarian suppression), removal of the ovaries and another medication are possible: so-called GnRH analogues.

GnRH analogues suppress ovarian estrogen production. This is why premenopausal women experience an artificial menopause. This artificial menopause is not final. After stopping the preparations, your period can start again. This does not mean that fertility is completely lost.

Studies also come to the conclusion that the effect of aromatase inhibitors in younger women is superior to the effect of tamoxifen in suppressing estrogen production in the ovaries. Nevertheless, depending on the case and the age of the patient, it must be considered which anti-hormone therapy is the right one.

Side effects of aromatase inhibitors

Aromatase inhibitors, such as tamoxifen, fulvestrant and GnRH analogues, can cause typical menopausal symptoms. Possible complaints are:

In addition, there are also frequent problems with the musculoskeletal system. Joint problems (arthralgias) and muscle pain (myalgias) are possible. It can also lead to a reduction in bone density. Experts then speak of osteoporosis. In order to check the condition of the bones, regular bone density measurements are carried out.

In very rare cases, serious side effects are possible. Taking it can sometimes lead to thrombosis, a stroke and malignant uterine tumors. However, the risk is very low.

Aromatase inhibitors: This is how symptoms can be reduced

Osteoporosis can be easily prevented with physical exercise. It promotes the bone-building processes and improves the bone structure. A balanced diet that contains sufficient calcium and vitamin D3 as well as a healthy body weight also have a positive effect on bone health. Calcium and vitamin D3 should be taken as supplements. If osteoporosis is already present, bisphosphonates can also be prescribed.

Painkillers help against joint pain. Regular physical exercise and acupuncture also improve joint mobility and reduce pain.

Relaxation exercises for hot flashes

Women affected by hot flashes and increased night sweats should first try to take general measures to combat them. This includes avoiding factors and situations that promote the onset of sweating attacks, such as:

• Stress,
• Smoking or
• certain foods and drinks.

Acupuncture, relaxation training and physical exercise can also help. Recent studies also show positive effects of certain preparations that are actually used to treat depression (antidepressants) in breast cancer patients with frequent heat attacks. Hormone replacement therapy, which can be used very effectively against the symptoms mentioned during menopause, is not an option for women with hormone-sensitive breast cancer. It would negate the anti-cancer effects of the aromatase inhibitors and increase the risk of relapse.

Discomfort in the intimate area

Due to the lack of estrogen, vaginal dryness is also common. However, locally acting hormone replacement therapy should not be used to provide relief, as some of the hormones are also distributed to the rest of the body. This increases the risk of the cancer coming back.

Special water-based lubricants, which are available in drugstores or pharmacies, can help. They improve the lubrication of the vagina and thus prevent pain during sex.