Hormone Therapy for Breast Cancer

What is hormone therapy for breast cancer?

Hormone therapy (also called endocrine therapy) is a common treatment for hormone receptor-positive (HR+) breast cancer. In HR+ breast cancer, you have cancerous tumors that rely on the hormones estrogen and progesterone to grow. Your body produces these hormones. HR+ breast cancer accounts for 2 of every 3 breast cancer cases in the U.S.

A tumor may be estrogen receptor-positive (ER+), progesterone receptor-positive (PR+) or both ER+ and PR+. ER+ is the most common type of breast cancer: About 8 out of 10 breast cancers are estrogen receptor- positive.

Hormone therapy for breast cancer works by:

• Blocking cancerous cells’ access to estrogen and progesterone.
• Lowering estrogen levels. Cancerous cells stop growing when they don’t get enough estrogen.

Hormone therapy for breast cancer isn’t the same as hormone therapy for menopause. Hormone therapy for menopause boosts hormone levels to relieve menopause symptoms.

Why do people receive hormone therapy for breast cancer?

Oncologists may use hormone therapy:

• To reduce the chance of breast cancer in people with high risk, such as mutations (changes) in their BRCA1 and BRCA2 genes.
• To reduce breast cancer risk in people with ductal carcinoma in situ (DCIS).
• Before breast cancer surgery to shrink cancerous tumors (neoadjuvant therapy).
• After breast cancer surgery to reduce the risk breast cancer will come back (recur) or develop in the other breast (adjuvant therapy).
• To treat metastatic breast cancer.

What are types of hormone therapy for breast cancer?

Hormone therapy for breast cancer may include aromatase inhibitors, selective estrogen receptor modulators (SERMs) or estrogen receptor down regulators (SERDs):

• Aromatase inhibitors: If you have ER-positive breast cancer and you’ve gone through menopause, your healthcare providers may use this type of hormone therapy. Exemestane (Aromasin^®), letrozole (Femara^®) and anastrozole (Arimidex^®) are commonly used aromatase inhibitors.
• Ovarian function suppression: Your provider may prescribe medications like leuprolide (Lupron^®) and goserelin (Zoladex^®, Zoladex 3-Month^®) if you develop ER+ breast cancer before you go through menopause. Ovarian suppression therapy slows down cancer growth by keeping your ovaries from making estrogen.
• Selective estrogen receptor modulators (SERM): Healthcare providers use SERM medications to treat estrogen receptor-positive (ER+) breast cancer. SERMs like tamoxifen (Nolvadex^®, Soltamox^®) and raloxifene (Evista^®) are effective treatments for some types of breast cancer.
• Selective estrogen receptor down regulators (SERDs): This treatment works by blocking estrogen and making it more difficult for estrogen to connect with cancerous cells. Examples are fulvestrant (Faslodex^®) and elacestrant (Orserdu^®).

How do people receive hormone therapy for breast cancer?

You may take prescription pills or liquid medication. Some drugs are given via injection at your healthcare provider’s office. Depending on your situation, you may need therapy for several years.

Side effects of hormone therapy for breast cancer

Side effects from hormone therapy vary from person to person. Common side effects may include:

• Fatigue.
• Hot flashes.
• Joint and muscle pain or stiffness.
• Less or loss of interest in sex.
• Mood swings.
• Nausea and vomiting.
• Tender or swollen breasts.
• Vaginal dryness.
• Weight gain.

What are the advantages of hormone therapy for breast cancer?

Advantages include:

• This treatment targets ER+ breast cancer, a very common breast cancer subtype.
• Healthcare providers can combine hormone therapy with other breast cancer treatments, including chemotherapy and targeted therapy.

What is the success rate for hormone therapy for breast cancer?

Success rates vary depending on specific studies, but overall research shows hormone therapy for breast cancer helps people live longer and reduces the risk that breast cancer will come back (recur).

When should I see my healthcare provider?

Most people see their healthcare providers throughout their treatment, but you should contact yours if you notice changes in your breasts. You should also contact your oncologist if you notice changes that may be signs of metastatic breast cancer.

Which is better for breast cancer: chemotherapy or hormone therapy?

Both chemotherapy and hormone therapy are effective breast cancer treatments, but hormone therapy targets a specific breast cancer subtype.

What is the best hormone therapy for breast cancer?

The best hormone therapy is the one that meets your specific needs and situation. Your provider will recommend treatments that they feel will be most helpful given your situation.

What if I don’t want hormone therapy?

If you have breast cancer, you should know you have many treatment options. Your oncologist recommends treatment plans based on what they know about the kind of breast cancer you have, your overall health, your lifestyle and your preferences. Take your time to study your options, talk to your oncologist and weigh the risks and benefits of hormone therapy.