Metastatic Breast Cancer

Metastatic Cancer: Meaning, Causes, Symptoms, Diagnosis & Treatment

Metastatic breast cancer is one of the most advanced stages of breast cancer. Breast cancer develops when abnormal cells in the breast start dividing uncontrollably. A tumor begins forming, a collection or mass of these abnormal cells.

Metastasis refers to the cancer cells that have spread to a new body area. In metastatic breast cancer, cells may apply to the following:

  • Lungs
  • Liver
  • Brain
  • Bones

Healthcare providers name cancer based on its primary origin. It means that breast cancer that also spreads to other body parts will still be known as breast cancer. The cancer cells are, however, breast cells. The care team will use breast cancer therapies, even if the cancer cells are in different areas.

Difference between the metastatic and stage 4 breast cancer

The two terms typically mean the same thing. Breast cancer, classified as stage 4, has spread outside the breast or metastasized to other body parts.

When are people diagnosed with metastatic breast cancer?

Metastatic breast cancer may occur at different points:

Distant recurrence

Most commonly, metastatic breast cancer is diagnosed after the initial breast cancer treatment. A recurrence refers to cancer spreading and returning to a different body part. It may happen even years after the original treatment and diagnosis.

De novo metastatic breast cancer

Most commonly, metastatic breast cancer is diagnosed after the initial breast cancer treatment. A recurrence refers to cancer that comes back and spreads to different body parts. It may happen even years after the initial treatment and diagnosis.

People at risk for metastatic breast cancer

Few people are at higher risk for metastatic cancer after finishing the cancer treatment. The risk depends on the many features of cancer, including:

  • Treatment received
  • The stage at your first diagnosis.
  • Tumor characteristics (including the kinds of cancer cells)

Causes of Metastatic Breast Cancer

Cancer cells are likely to invade the nearby blood vessels or lymph nodes. The cancer cells then travel throughout the body through blood vessels or lymph vessels. The vessels carry blood and fluid throughout the body. Cancer cells may also form small tumors in the new locations.

The reason behind metastatic breast cancer

Metastatic cancer most often occurs because the treatment doesn’t destroy the cancer cells. Sometimes, a few cells remain dormant, while others are undetectable and hidden.

De novo metastatic breast cancer means that the breast cancer has already spread out in the body parts at the initial diagnosis. In the absence of treatment, the cancer is likely to spread.

There is nothing you may do to keep the breast cancer from metastasizing. Breast cancer doesn’t happen because of something you did.

Symptoms of metastatic breast cancer

The symptoms of breast cancer depend on where the cells are included:

Symptoms of bone metastases

  • Swelling
  • Bones that fracture or break more easily
  • Bone pain

Symptoms of brain metastases

  • Personality or behavior changes
  • Vomiting and nausea
  • Seizures
  • Visual disturbances
  • Pressure in the head or worsening headaches

Symptoms of liver metastases

  • Vomiting, nausea, loss of appetite, and stomach pain
  • Rash or itchy skin
  • Jaundice

Symptoms of lung metastases

  • Chest pain
  • Difficulty in catching breath
  • Cough that won’t go away

Other symptoms of metastatic breast cancer:

  • Poor appetite
  • Unexplained weight loss
  • Fatigue

Diagnosis of metastatic breast cancer

If you have symptoms of metastatic cancer, your provider may recommend tests including:

  • Biopsy to remove the tissue from a suspicious area and analyze it.
  • Bronchoscopy uses a scope to look inside your lungs.
  • Blood tests, including the complete blood count and comprehensive metabolic panel.

Emerging treatments for metastatic breast cancer

The two significant new treatments for advanced breast cancer includes antibody-drug conjugates and CDK4/6 inhibitors.

Antibody-drug conjugates

Antibody-drug conjugates help treat a different subtype known as HER2-positive breast cancer. Instead of being fueled by hormones, breast cancer growth comes from a protein called human epidermal growth factor receptor 2.

Antibody-drug conjugates help the body’s immune system that targets and destroys cancer cells.

CDK4/6 inhibitors

CDK4/6 inhibitors help treat a subtype known as hormone receptor-positive breast cancer; in this type of breast cancer, the hormone progesterone and estrogen help fuel the growth of breast cancer cells. The subtype of breast cancer is traditionally treated with anti-estrogen therapies, which block the hormone from fueling the cancer cells.


Metastatic breast cancer is advanced breast cancer. Providers classify it as stage 4 breast cancer. It happens when the cancer cells are often left behind after the previous breast cancer treatment, starting to spread to the other body parts. While there is no cure for metastatic breast cancer, treatment may help you feel better and prolong your life.

Many medications are available, so your care team may try a different approach if one treatment is not working.

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