Hormone therapy

Used to eliminate tumours expressing the ER- and PR-hormone receptors, hormonal therapy blocks the body’s response to hormones or decreases the amount of estrogen in the body. This treatment aims to stop or slow the cancer’s progression. It is often prescribed after surgery and radiation therapy to reduce the risk of recurrence.

There are different types of hormonal therapy, including the following:

Anti-estrogens

• Tamoxifen (blocks the ER receptor)
• Fulvestrant (degrades the ER receptor)

• Aromatase (the key enzyme in estrogen synthesis) inhibitors, such as Letrozole, Anastrozole Exemestane (decrease estrogen levels)

• Luteinizing hormone-releasing hormone analogues, such as Goserelin, Leuprolide, Buserelin (suppress estrogen production by the ovaries)

• Oophorectomy (surgery to remove the ovaries, the major estrogen producers): For pre-menopausal women who no longer wish to bear children

Hormonal therapy can cause various side effects, including:

• Hot flashes
• Weight gain
• Decreased libido
• Osteoporosis (in the case of aromatase inhibitors)
• Constipation, diarrhea or nausea
• Reduced fertility
• Fatigue
• Vaginal discharge
• Change in cholesterol levels
• Hair thinning (in the case of aromatase inhibitors)

Research continues to evaluate the possibility of giving hormonal therapy to women at high risk of breast cancer before cancer develops. The health risks have yet to be assessed.