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What is Metastatic Breast Cancer?

Metastatic breast cancer, or stage IV breast cancer, is cancer that has spread to a different part of the body.

If you have had been treated for breast cancer in the past and develop a new growth or cancer in a different part of the body, your doctor may perform tests to confirm if the cancer has recurred. The most common sites for breast cancer to spread to are the bones, lungs, liver, lymph nodes, adrenal gland and brain. If your cancer spreads to the bone, visit our bone metastases page.

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Advances in cancer research have helped doctors better understand what drives metastatic breast cancer cells to grow and has led to the development of more refined or targeted therapies. The goal of treatment for metastatic breast cancer is to improve or maintain a good quality of life and to extend life as long as possible.

It is important to know that metastatic breast cancer is a chronic condition that will always require some type of treatment and that they length of time that a treatment works before the cancer progresses again, or grows, will vary from person to person. When one treatment stops working your doctor will discuss what your next options are.

Treatment may include:


This type of treatment kills cells in the body that are dividing and rapidly growing. These include cancer cells but may also include cells related to hair and nail growth, bone marrow cells and cells in the digestive system. You may get one type of chemotherapy at a time (single-agent) or a few types together (combination therapy.) Most treatments are given intravenously but some are available in pills. Chemotherapy schedules typically involve ‘cycles’ that include periods of active treatment and periods of rest that allows the body to recover.

Hormonal Therapy

This type of treatment is used for estrogen receptor-positive or progesterone receptor-positive breast cancers. This treatment blocks the amount of the hormones that reach the cancer cell, slowing or stopping the cancer’s growth. If your initial cancer was hormone-receptor-positive, your doctor should confirm that the recurrence is still hormone-receptor positive. Sometimes this can change over time making hormonal therapy treatments less effective. This is tested at the time the site of recurrence is biopsied. Hormonal therapies are now also combined with new therapies that target other aspects of the hormonal drivers of growth. Examples are everolimus (Affinitor®) and palbociclib (Ibrance®).

Targeted Therapy

Attack specific proteins or genes on or within cancer cells that help the cells grow, sparing healthy cells and causing patients to experience fewer side effects. These treatments can only be used if your cancer has a specific marker that an available drug targets. Some are available today and many more are being developed and tested in clinical trials.

Questions to Ask Your Health Care Team:

  • Which treatments should I start with?
  • When should I switch from one treatment to another?
  • How do I know whether a treatment is working?
  • Should I participate in a clinical trial?
  • What clinical trials I should consider?
  • What can I expect from treatment, what will I experience?
  • What kind of side effects can I expect from treatment?
  • How long will side effects impact my lifestyle – and what can be done to manage potential side effects?
  • Who will be the members of my health care team? If I see a number of different clinicians who are part of the research team– who is my primary contact?
  • Can you put me in touch with other metastatic breast cancer patients?
  • What else can I do to stay as healthy as possible?

Clinical Trials

You have a right to a second, and even third, opinion at any point in your cancer experience. A second opinion can help you confirm your diagnosis, understand your treatment options, provide you with access to clinical trials, and help you determine which health care team you prefer to work with.

Clinical trials offer individuals with metastatic breast cancer potentially more treatment options as doctors test new drug combinations and doses to find more effective treatments. Participating in a clinical trial may enable patients to try treatments that being developed. Some clinical trials test new ways to use drug combinations, doses or techniques that are already approved, others test completely new and hopeful techniques.

Before enrolling in a clinical trial, you will be informed of the rationale for the trial, the possible benefits as well as the risks of being involved. If you participate in a clinical trial you may withdraw or end your participation at any time.

If you are facing a cancer treatment decision, Open to Options® is a research-proven program that can help you prepare a list of questions to share with your doctor. In less than an hour, our Open to Options® specialists can help you create a written list of specific questions about your concerns for your doctor.

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