Metastatic Breast Cancer: More Common Than You Think

Editor’s Note: In honor of Breast Cancer Awareness Month, we asked a Physician Assistant with years of experience in the field to tell us about a little-known form of breast cancer from the healthcare provider’s perspective. Next week’s post will focus on this issue from the patient advocate’s side of things. Please share to help spread awareness during this special month.

Metastatic breast cancer (also called “Stage IV” or “advanced breast cancer”) refers to the spread of breast cancer cells, as described here. These cells now spread to different parts of the body, (typically the bones, liver, lungs and brain). Most early stages of breast cancer are curable – if the cancer is confined to the breast and/or local lymph nodes. Treatments have improved vastly, but it’s when cancerous cells travel to a vital organ and the tumor burden is overwhelming to the body, that achieving a cure becomes difficult.

How Common Is It?

Metastatic breast cancer is more common than you think. According to the Metastatic Breast Cancer Network, an estimated 155,000 Americans are currently living with metastatic breast cancer. It accounts for approximately 40,000 deaths annually in the U.S. (6-10% of people are Stage IV from their initial diagnosis and 20-30% of people initially diagnosed with early stage disease will develop metastatic breast cancer).1 Metastatic breast cancer can occur 5, 10, or 15 years after a person’s original diagnosis, successful treatment checkups and annual mammograms. Young women and men of all ages can be diagnosed with metastatic breast cancer.

How Cancer Spreads

The spread of cancer usually happens through one or more of the following steps:

  1. Cancer cells invade nearby healthy cells. When a healthy cell is taken over, it too can replicate more abnormal cells.
  2. Cancer cells penetrate into the circulatory or lymph systems to the body, and these move through normal circulation through the body
  3. Cancer cells get caught in blood vessels (capillaries), then divide and move into the surrounding tissues
  4. New small tumors grow. Cancer cells can form small tumors at the new location (called micrometastases).

Signs and Smptoms

Symptoms of metastatic breast cancer may vary, depending on how far the breast cancer has spread and what type of tissue the new cancer growth has invaded:

  • Metastasis in the bone may cause severe, progressive pain, swelling and bones that are more easily fractured or broken
  • Metastasis to the brain may cause persistent, progressively worsening headache or pressure to the head, visual disturbances, seizures, vomiting or nausea, behavioral changes or personality changes
  • Metastasis to the lungs may cause chronic cough or inability to get a full breath, abnormal chest x-ray, chest pain
  • Other non-specific systemic symptoms of metastatic breast cancer can include fatigue, weight loss, and poor appetite, (but it’s important to remember these can also be caused by medication or depression)

Although metastatic breast cancer cannot be cured, this does not mean it cannot be treated. Treatment focuses on length and quality of life. Treatment is guided by many factors, including characteristics of the cancer cells, where the cancer has spread, a person’s symptoms, and past breast cancer treatments.

Survival for metastatic breast cancer varies greatly from person to person. One study found about 37 percent of women lived at least three years after diagnosis and some women may live 10 or more years beyond diagnosis.2 Modern treatments for both early-stage and metastatic breast cancer have improved survival for those diagnosed today, and this website has several resources for you if you are in this part of your cancer journey or newly diagnosed.


  1. Metastatic Breast Cancer Network. “Diagnosis: Metastatic Breast Cancer” at [Accessed October 3, 2016].
  2. Lobbezoo DJ, et al. Prognosis of metastatic breast cancer: are there differences between patients with de novo and recurrent metastatic breast cancer? Br J Cancer. 2015 Apr 28;112(9):1445-51.

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