Hormonal Therapy for Metastatic Breast Cancer

May 23, 2016

To help doctors give their patients the best possible care, the American Society of Clinical Oncology (ASCO) provides recommendations on the use of hormonal therapy for metastatic breast cancer. This guide for patients is based on the most recent recommendations.

About metastatic breast cancer

Metastatic breast cancer is cancer that has spread from the breast to another part of the body or has come back in another distant location. This area of spread is called a metastasis, or metastases if the cancer has spread to more than 1 area.

Some women are diagnosed with metastatic breast cancer after having received treatment for early-stage breast cancer.  For others, the first diagnosis of breast cancer is when it has already spread.

Treatment options for metastatic breast cancer depend on several factors. One of these factors is the levels of hormone receptors in the tumor. Cancers with high levels of hormone receptors, called hormone receptor-positive, use the hormones estrogen and progesterone to grow and spread. Hormonal therapy is a type of treatment specifically for hormone receptor-positive breast cancer. It may also be called endocrine therapy.

Understanding hormonal therapy

The goal of hormonal therapy is to lower the levels of estrogen and progesterone in the body or to block these hormones from getting to cancer cells. If the hormones cannot get to the cancer cells, the cancer cannot use them to grow.

There are different treatment options for hormone receptor-positive breast cancer. The choices vary depending on whether a woman is still menstruating or has gone through menopause. Younger women who menstruate on a regular basis have functioning ovaries. A woman’s ovaries typically stop producing estrogen around age 50.

Hormonal therapy for hormone receptor-positive breast cancer includes the following options:

  • Aromatase inhibitors (AIs) reduce the amount of estrogen in a woman's body by stopping tissues and organs other than the ovaries from making estrogen. It is important that women have gone through menopause before using AIs because AIs stimulate estrogen production in the ovaries of women who have not been through menopause. AIs include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara).

  • Tamoxifen blocks a cell’s ability to use estrogen, which stops or slows the growth of cells that depend on it. Tamoxifen is effective both for women who are premenopausal and for those who are postmenopausal.

  • Fulvestrant (Faslodex) binds to the estrogen receptors, completely blocking the ability of estrogen to attach to these receptors.

  • Ovarian suppression is use of drugs or surgery to stop the ovaries from producing estrogen. It may be used in addition to another type of hormonal therapy for women who have not been through menopause. There are 2 methods used for ovarian suppression:

    • Drugs called gonadotropin or luteinizing releasing hormone (GnRH or LHRH) analogs that stop the ovaries from making estrogen, causing temporary menopause. Goserelin (Zoladex) and leuprolide (Lupron) are GnRH agonists given by injection that stop the ovaries from making estrogen for 1 to 3 months.

    • Surgery to remove the ovaries, which also stops estrogen production. However, this is permanent.

Recommendations for hormonal therapy for metastatic breast cancer

In general, hormonal therapy is recommended for all patients with hormone receptor-positive breast cancer. Treatment options should be based on several factors: 

  • Your overall health

  • The type of treatment you have already received or are receiving

  • How long it had been before the cancer recurred

  • How widespread the cancer is and whether you have symptoms that need to be managed

In cancer care, the initial treatment a patient receives  after being diagnosed with metastatic cancer is usually called first-line therapy. Recommendations for hormonal therapy for women with metastatic hormone receptor-positive breast cancer include:

  • An AI for women who are postmenopausal.

  • Ovarian suppression and hormonal therapy with either tamoxifen or an AI for women who are premenopausal.

  • A combination of anastrozole or letrozole and fulvestrant is an option for patients who have not previously had hormonal therapy.

  • If first-line treatment no longer works, another type of hormonal therapy is an option unless the disease has worsened quickly and is affecting the functions of the body’s organs.

Recommendations for other types of treatment along with hormonal therapy

Some types of targeted therapy may be combined with hormonal therapy for metastatic breast cancer. However, chemotherapy is not recommended along with hormonal therapy.

  • Palbociclib (Ibrance) may be given along with anastrozole, letrozole, or fulvestrant for postmenopausal women who have not previously received hormonal therapy with these drugs

  • Everolimus (Afinitor, Zortress) may be an option along with the exemestane for postmenopausal women who have had the cancer worsen while receiving treatment with either anastrozole or letrozole.

  • HER2 targeted therapy along with an AI is an option to patients who also have HER2-positive cancer when they do not immediately need chemotherapy.

What This Means for Patients

For most patients, a diagnosis of metastatic cancer is very stressful and, at times, difficult to bear. It is important to remember that people with an advanced cancer such as metastatic breast cancer continue to have treatment options and can maintain a good quality of life for many years.

Each person’s chance of recovery depends on many factors. The most important of these factors is how well treatment is able to control the cancer’s growth.

Be sure to talk with your doctor about the goals of treatment, the next steps if the cancer worsens, and the best options to help maintain your quality of life. It may also help to talk about the way you are feeling with doctors, nurses, social workers, other members of the health care team, or a support group.

Questions to Ask the Doctor

  • Where has the cancer spread?

  • What is the hormone receptor status of the cancer? What does it mean?

  • What is the HER2 status of the cancer? What does it mean?

  • What is my prognosis (chance of recovery)?

  • What treatments have I already received?

  • What are my treatment options?

  • What are the benefits and risks of each option?

  • What clinical trials are available for me? Where are they located, and how do I find out more about them?

  • What treatment plan do you recommend? Why?

  • What is the goal of each treatment? Is it to eliminate the cancer, help me feel better, or both?

  • What are the next steps if the cancer worsens or comes back?

  • What side effects of the treatments are most common?

  • How can the symptoms and side effects be managed?

Helpful Links

Read the entire clinical practice guideline at a separate ASCO website.

Guide to Breast Cancer

Biomarkers to Guide Treatment for Metastatic Breast Cancer

When the First Treatment Doesn't Work

Treatment of Metastatic HER2-Positive Breast Cancer

Advanced Cancer Care Planning