Stage 4 breast cancer is cancer that’s spread beyond the original site. It’s typically spread to one or more of the following:

  • distant lymph nodes
  • the brain
  • the liver
  • the lungs
  • the bones

Other terms you may have heard that describe this stage are metastatic breast cancer and advanced breast cancer.

Because there are many types of breast cancer, there are many types of breast cancer treatment. Options include:

Chemotherapy uses one or more drugs to kill cancer cells and slow cancer growth.

The drugs are taken orally or intravenously. Afterward, they travel through the bloodstream. This way, the drugs can target the original site of the cancer as well as areas in the body where the cancer cells have spread.

Chemotherapy drugs also affect noncancerous cells in the body. This is why people experience common chemotherapy side effects that can include:

The side effects will subside once chemotherapy is completed.

Radiation therapy uses strong X-rays or other forms of radiation to both destroy cancer cells and slow cancer growth. The radiation can be used in one of two ways:

  • focused, from the outside of the body, on the area where the cancer’s growing
  • inserted in or near a tumor with a needle, tube, or pellet

Radiation is most useful when the cancer is confined to a specific area. It’s commonly used on brain and bone metastases.

Radiation therapy can cause fatigue, skin burns, and skin irritation. It can also cause rare, but severe, complications such as inflamed lung tissue and heart damage.

Though surgery is not a common treatment for stage 4 breast cancer, it may be recommended in some situations to alleviate pain or other symptoms.

Surgical options for stage 4 breast cancer depend on where the cancer’s spread and its associated symptoms. For example, a well-defined tumor in the lung or liver could be removed through surgery.

Sometimes brain metastases are surgically removed. Cancerous lymph nodes may also be removed.

Potential complications will depend upon the location of your surgery. In general, complications associated with surgery include swelling, infection, and bleeding.

Hormone therapy is used in cases where the cancer is hormone receptor-positive. This means that estrogen or progesterone produced in the body is facilitating the growth and spread of the cancer.

Tamoxifen is one drug that blocks the estrogen receptors in breast cancer cells. This stops the cells from growing and dividing. Side effects include hot flashes and vaginal discharge.

Other drugs, called aromatase inhibitors (AIs), stop estrogen production and lower estrogen levels in the body. Common AIs include:

  • anastrozole (Arimidex)
  • letrozole (Femara)
  • exemestane (Aromasin)

Side effects of AIs include muscle pain and joint stiffness.

In general, hormone therapy can also lead to hormonal imbalance. If you’re taking medications to decrease your estrogen levels, your doctor will monitor you for conditions associated with low estrogen levels (such as osteoporosis).

Targeted therapies are drugs that work by targeting very specific sites on a cancer cell. They’re often used in combination with other treatments, such as chemotherapy.

One example of a targeted therapy is trastuzumab (Herceptin). It can be used to treat an aggressive type of cancer known as HER2-positive breast cancer.

HER2-positive breast cancer leads to elevated levels of human epidermal growth factor receptor 2 (HER2). HER2 is located on the cell surface, and it signals cell growth. Drugs such as trastuzumab target this protein and can slow or stop the growth of the cancer.

Side effects of targeted therapies include fatigue, low white blood cell (WBC) count, diarrhea, and allergic reaction.

First-line treatment for HER2-positive breast cancer

According to recent guidelines from the American Society of Clinical Oncology (ASCO), combination therapy should be the first-line treatment for most people with HER2-positive breast cancer. The following drugs should be used:

  • trastuzumab (Herceptin)
  • pertuzumab (Perjeta)
  • a taxane, a type of chemotherapy drug

However, taxanes should be avoided if there’s a contraindication.

People with both HER2-positive breast cancer and hormone receptor-positive breast cancer may receive endocrine therapy in addition to or instead of targeted therapies.

Subsequent treatment for HER2-positive breast cancer

If the HER2-positive breast cancer progresses during or after first-line treatment, ASCO recommends trastuzumab emtansine (Kadcyla) as the second-line treatment. If the second-line treatment stops working, clinicians may recommended a third-line treatment, such as lapatinib (Tykerb) plus capecitabine (Xeloda).

If you completed trastuzumab-based treatment at least 12 months prior to a recurrence, you should follow the same regimen as people receiving first-line treatment. This means taking trastuzumab, pertuzumab, and a taxane (unless the taxane’s contraindicated).

People with both HER2-positive breast cancer and hormone receptor-positive breast cancer should receive a combination of HER2-positive targeted therapy and chemotherapy, and possibly endocrine therapy as well.

Clinical trials are research studies using new drugs, or new combinations of drugs, that have been approved for use in human research. Trials are conducted when researchers believe that a drug has the potential to be better than current standard treatment.

It may seem risky to become a part of a research study. However, it’s important to remember that today’s standard treatments are only available for people with breast cancer because they were tested in a clinical trial.

Pain management is an important component of most cancer treatment regimens. While the treatments described above may help prolong your life, pain management can improve your quality of life.

There are many options for pain management, depending on the source and type of pain. They include:

  • arm and shoulder exercises
  • acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs)
  • opioids, such as morphine (Mitigo, MorphaBond) and oxycodone (Oxycontin)

Common side effects of acetaminophen and NSAIDS include headache and upset stomach. Rare, yet severe, side effects include liver damage and jaundice.

Common side effects of opioids include constipation, nausea, and vomiting. Rare, yet severe, side effects of opioids include drug dependence, low blood pressure, and seizures.

Talk to your doctor about your pain sooner rather than later, so that proper steps can be taken to help you feel better.

If you have stage 4 breast cancer, discuss your treatment options — and the possible side effects — with your doctor.

Not every treatment is appropriate for every person. Factors that can determine your treatment regimen include your age, your family history, and how fast the cancer is progressing.

Stage 4 breast cancer is considered incurable, but many treatment options exist that can extend your lifespan and improve your quality of life.