Hormone therapy

All about hormone therapy

80% of invasive breast cancers are hormone sensitive, 20% are not. In the latter case, this means that during their development, the cancer cells have changed and are no longer sensitive to hormones. They become very different from the normal breast, because they have lost this hormonal control: they are more aggressive cancers, for which hormone therapy is not effective.

For hormone-sensitive breast cancer, hormone therapy prevents the stimulation of tumor cells by hormones. It is one of the major treatments for breast cancer. It can halve the risk of recurrence.

Hormone therapies

Tamoxifen

Tamoxifen is a SERM (Selective Estrogen Receptor Modulators), a drug that blocks the estrogen receptors on the tumor cell. The principle of SERMs is to block these receptors: the hormones can no longer bind to them and no longer stimulate the tumor cells. It is like sticking chewing gum in a lock: the key can’t get in and the door stays closed. Estrogen continues to be secreted but it no longer stimulates the cancer cells.
Hormone therapy not only decreases the stimulation of tumor cells by hormones; the drugs will also act directly on the hormone receptors and lead to the destruction of the cancer cells.
This medication can be prescribed to both non-menopausal and menopausal women.

Aromatase Inhibitors

Aromatase inhibitors, called “anti-aromatases”, are reserved for women who no longer have ovarian activity, i.e. post-menopausal women.

Anti-aromatases block the function of aromatase, which is an enzyme that allows the body to continue to produce estrogen after menopause by converting androgens. The purpose of this drug is to suppress the “second circuit” of estrogen production. It is therefore of no use to non-menopausal women.

LHRH analogues

LHRH analogues induce a transient menopause by stopping the production of estrogen by the ovaries. They are always combined with aromatase inhibitors or tamoxifen. This option is used for cancers with a higher risk of recurrence.

Treatment with hormone therapy

Hormone therapy is usually prescribed after chemotherapy and radiation therapy if they are necessary. The recommended duration of treatment is usually 5 years, sometimes longer.

Side effects of hormone therapy

These treatments are sometimes responsible for undesirable effects, which vary depending on the woman and the treatment: fatigue, hot flashes, joint pain, aggravation of osteoporosis, depression, etc.

These adverse effects may cause the treatment to be changed.