Stage 4 breast cancer is cancer of the breast 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
  • advanced breast cancer

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

  • chemotherapy
  • radiation therapy
  • surgery
  • hormone therapy
  • targeted therapy
  • biological therapy
  • clinical trials
  • palliative care

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:

  • fatigue
  • nausea
  • vomiting
  • constipation
  • hair loss
  • low blood counts

The side effects will generally subside once chemotherapy is completed. Anti-nausea medications, immune booster shots, and other supportive methods can help lessen these side effects.

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

For stage 4 breast cancer, radiation is generally used at a specific site of metastasis, such as in a bone or in the brain, that’s causing a problem.

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 select situations.

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.

Surgery in stage 4 breast cancer has generally not been shown to improve overall outcome, though research is still divided.

Sometimes brain metastases can be surgically removed.

Potential complications will depend on 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
  • joint stiffness

Hormone therapy can sometimes lead to symptoms of estrogen deprivation. There are therapies that can help with symptoms such as hot flashes.

There’s a newer category of targeted therapies called CDK4/6 inhibitors that have been shown to improve the efficacy of hormone therapies when given together. Some examples of CDK4/6 inhibitors include:

  • palbociclib (Ibrance)
  • ribociclib (Kisqali)
  • abemaciclib (Verzenio)

Targeted therapies are drugs that work by targeting specific receptors on a cancer cell or target pathways that cause abnormal cell increases. They’re often used in combination with other treatments.

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 can include:

  • fatigue
  • diarrhea
  • allergic reaction

Trastuzumab has a small risk of heart damage so heart function will be monitored while on this therapy.

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, or a reason it should not be used in a specific situation.

People with both HER2-positive breast cancer and hormone receptor-positive breast cancer may receive endocrine therapy in addition to 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. Trastuzumab is just one of many targeted therapies in use.

If the second-line treatment stops working, clinicians may recommend a third-line treatment, such as fam-trastuzumab deruxtecan-nxki (Enhertu) and tucatinib (Tukysa). The FDA recently approved both treatments.

Immunotherapy is used to stimulate a person’s immune system to destroy cancer cells. The body’s immune system usually has checks in place to prevent the body from attacking normal cells. Cancer cells are sometimes able to use this system to avoid being seen as something to attack.

Immune checkpoint inhibitors are drugs that can help the body recognize these cancer cells better. Atezolizumab (Tecentriq) is one such drug that has the potential to boost the immune system response to these cancer cells to slow their growth and shrink tumors.

At this time, immunotherapy has only been shown to be effective for triple- negative breast cancer. One study showed that patients treated with atezolizumab in combination with the chemotherapy drug abraxane had better antitumor responses than if they had received abraxane alone.

Clinical trials are research studies using new drugs or new combinations of drugs. 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.

Clinical trials improve current therapies and are a way to get medications that may be helpful but aren’t yet available outside of a clinical trial.

Here are ways to search for and find clinical trials for breast cancer:

Palliative care is an important component of cancer treatment regimens. It includes pain management as well as management of other symptoms such as shortness of breath or nausea.

While the treatments described above may help prolong your life, palliative care can help improve your quality of life.

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

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

Common side effects of opioids include constipation, nausea, and vomiting.

Talk to your doctor about your pain or other symptoms 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:

  • the subtype of breast cancer
  • your age
  • other medical problems
  • how fast the cancer is progressing

Stage 4 breast cancer is considered incurable, but many treatment options exist that can help extend your lifespan and improve your quality of life. Survival rates have been improving over the last few years based on many new therapies.