Hormone Therapy for Breast Cancer

Hormone therapy, also known as endocrine therapy, is a treatment for breast cancer that aims to reduce the growth and spread of cancer cells by blocking or reducing the production of hormones that fuel their growth. This type of therapy is typically used to treat hormone receptor-positive breast cancers, which are cancers that have receptors for estrogen and/or progesterone.

How Hormone Therapy Works

Hormone therapy works by either:

• Blocking the production of hormones that stimulate cancer cell growth (e.g., aromatase inhibitors)
• Blocking the receptors on cancer cells that receive these hormones (e.g., tamoxifen, fulvestrant)

Types of Hormone Therapy for Breast Cancer

There are several types of hormone therapy used to treat breast cancer, including:

• Tamoxifen: a selective estrogen receptor modulator (SERM) that blocks estrogen receptors on cancer cells
• Aromatase inhibitors (e.g., anastrozole, letrozole, exemestane): medications that reduce the production of estrogen in postmenopausal women
• Fulvestrant: a medication that blocks estrogen receptors and also reduces the number of estrogen receptors on cancer cells
• Progestin: a synthetic form of progesterone, sometimes used to treat hormone receptor-positive breast cancers

Benefits and Risks of Hormone Therapy for Breast Cancer

The benefits of hormone therapy for breast cancer include:

• Reduced risk of cancer recurrence
• Improved overall survival rates
• Ability to treat cancer that has spread to other parts of the body (metastatic disease)

The risks and side effects of hormone therapy for breast cancer include:

• Hot flashes and night sweats
• Vaginal dryness and decreased libido
• Mood changes, such as depression and anxiety
• Increased risk of blood clots and stroke
• Increased risk of osteoporosis (with aromatase inhibitors)

Who is Eligible for Hormone Therapy for Breast Cancer

Hormone therapy is typically recommended for women with hormone receptor-positive breast cancer, which includes:

• Estrogen receptor-positive (ER+) breast cancers
• Progesterone receptor-positive (PR+) breast cancers
• Human epidermal growth factor receptor 2 (HER2)-negative breast cancers

Duration of Hormone Therapy for Breast Cancer

The length of time a woman takes hormone therapy for breast cancer varies, but it is typically:

• 5-10 years for tamoxifen and aromatase inhibitors
• Until disease progression or unacceptable side effects occur (for fulvestrant and other medications)

Monitoring and Follow-up During Hormone Therapy for Breast Cancer

Women taking hormone therapy for breast cancer should be monitored regularly by their healthcare provider to:

• Assess treatment response and adjust the treatment plan as needed
• Monitor for side effects and manage them effectively
• Perform regular mammograms and other imaging tests to monitor for cancer recurrence