Hormone Therapy for Breast Cancer

What is hormone therapy for breast cancer?

Hormone therapy slows or stops the growth of hormone-sensitive breast cancer.

About 70 – 80 percent of breast cancer are stimulated by the hormones oestrogen and progesterone. These breast cancer cells have proteins called hormone receptors. The receptors are activated when oestrogen and progesterone attach to them, which causes the cells to grow and divide.

Hormone therapy blocks hormones from attaching to the receptors on cancer cells or reduces the body’s production of hormones.

Types of hormone therapy for breast cancer

Your doctor may use different approaches to treat your breast cancer using hormone therapy. These include:

Medications to block hormones from attaching to cancer cells

Preventing hormones from attaching to cancer cells slows down the growth of the cancer. The cancerous cells may eventually die.

Medications to stop the production of oestrogen

Aromatase inhibitors are a class of medicines that reduce the amount of oestrogen in your body. This deprives cancer cells of the hormones they need to grow.

This therapy is only for women who have undergone menopause or have had their ovaries removed.

Treatments to stop ovarian functions

Women who are pre-menopausal may undergo treatments to stop their ovaries from producing hormones.

These include:

• Surgery to remove the ovaries
• Radiation therapy
• Medications

Stopping your ovarian functions allows you to take hormone therapy medications meant for women who have undergone menopause.

Hormone therapies combined with targeted therapy

This treatment option applies to hormone-sensitive breast cancer that has spread to other parts of the body.

Targeted therapy attacks specific pathways that drive breast cancer cell growth. Combining targeted and hormonal therapies can make the treatment more effective.

Why do you need hormone therapy for breast cancer?

Hormone therapy for breast cancer can:

• Be used after surgery to prevent cancer from recurring (adjuvant therapy)
• Be used to treat hormone sensitive breast cancer that has spread to other parts of the body
• Shrink a tumour before it is removed by surgery (neoadjuvant therapy)

What are the risks and complications of hormone therapy for breast cancer?

The side effects of hormone therapy for breast cancer depend on the type of treatment and medications used. Common side effects include:

• Changes to the menstrual cycle
• Fatigue
• Hot flashes
• Joint and muscle pain
• Mood changes
• Nausea
• Night sweats
• Vaginal dryness and discharge

Some patients may experience more serious side effects such as:

• Blood clots
• Cataracts
• Endometrial cancer or uterine cancer
• Osteoporosis

What can you expect in hormone therapy for breast cancer?

In most forms of hormone therapy for breast cancer, you will take daily medication in the form of pills. Some drugs are given through injections.

Estimated duration

If you undergo hormone therapy for breast cancer, be prepared to take medication for a period of 5 – 10 years.

Your doctor will see you regularly to monitor your condition and ask you about any side effects. Many side effects can be controlled. Your doctor may also recommend periodic tests to detect cancer recurrence or progression.