Metastatic (Stage 4) Breast Cancer

Stage 4 breast cancer (called metastatic cancer) is often diagnosed when cancer recurs, although it may sometimes be discovered at the initial diagnosis. Metastatic breast cancer is not curable, but treatment can help control the spread of the disease and provide quality of life.

Some people are able to thrive with this chronic disease, including writer Katherine Russell Rich, author of The Red Devil. She found a breast lump and was diagnosed with stage 4 breast cancer, which has a five-year survival rate of 29%. However, she survived 25 years after her diagnosis.

This article will give an overview of stage 4 breast cancer, what it means for most people, how it's treated, and its outlook.

Location of Metastases

Stage 4 breast cancer is diagnosed when cells from a primary tumor in the breast spread to other parts of the body and establish one or more secondary tumors.

Breast cancer can spread to nearly any organ of the body. The location of metastases can vary but tends to follow a similar pattern based on the type of breast cancer.

For example:

• Intraductal carcinoma usually spreads to the bones, liver, lungs, and brain.
• Lobular carcinoma tends to spread to the abdomen.
• Estrogen receptor-positive breast cancer often spreads to bones.
• HER2-positive tumors are likely to spread to the brain.

Cancers metastasize at different times and speeds. For example, estrogen receptor-positive tumors tend to be around 3 centimeters (1.2 inches) in diameter before they metastasize. By contrast, HER2-positive (human epidermal growth factor receptor 2-positive) tumors may be less than 1 centimeter (0.4 inches) before they spread to lymph nodes and beyond.

Breast cancer that spreads to the lungs, for example, would not be referred to as lung cancer. Rather, it would be deemed "breast cancer metastatic to the lungs." If you look at these cells under a microscope, they would be breast cancer cells, rather than lung cancer cells.

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Breast Cancer Staging

Cancer staging is performed to direct treatment and predict the likely outcome, or prognosis. The staging system most commonly used for breast cancer—and most other cancers—is called the TNM Classification of Malignant Tumors. In the TNM staging system:

• "T" refers to tumor size.
• "N" refers to the number of lymph nodes affected by cancer.
• "M" refers to metastasis.

The letters are followed by numbers to either characterize the size of the tumor (for example, T1 for a small tumor and T3 for a bigger tumor) or the extent of malignancy (with N0 meaning no affected lymph nodes and N4 meaning 10 or more affected lymph nodes).

Metastatic breast cancers are not all treated the same. The diagnosis would also include an assessment of the tumor location, tumor grade, tumor size, hormone receptor status, HER2 status, and many other factors, each of which directs the ultimate course of treatment.

How Is Stage 4 Breast Cancer Treated?

The aim of treatment is to improve the quality and length of life of people with stage 4 breast cancer. Each person will be treated differently based on the disease characteristics and the intended goals of treatment.

Most treatments aim at decreasing the tumor burden (number of cancer cells, size of the tumor, or amount of cancer) and stabilizing the disease. In general, stage 4 cancer treatments—although they may extend life in a significant number of people—are considered palliative (meant to relieve disease burden). This is because only a handful of people treated at this stage are cured of their disease.

Systemic Therapy

For those who decide to pursue treatment, systemic therapies (those that provide treatment throughout the body) are commonly used. These include:

• Hormonal therapy, including tamoxifen, aromatase inhibitors, and Faslodex (fulvestrant)
• Targeted therapy, like Herceptin (trastuzumab) and Perjeta (pertuzumab)
• Chemotherapy
• Immunotherapy, namely Keytruda (pembrolizumab), which is used in combination with chemotherapy to treat advanced triple-negative breast cancer (an aggressive cancer) expressing the protein PD-L1

A combination of therapies may be used, either together or in stages.

Drug Selection

The choice of systemic therapy is largely based on one's hormone receptor status (an indication of whether the hormones estrogen or progesterone affect the growth of a tumor) and/or HER2 status (whether a particular gene influences tumor growth).

A positive status means that receptors for these substances have been detected in cancer cells, while a negative status means that no receptors were found. Cancer cells obtained through biopsy (removing a sample for examination in a lab) or surgery are used by pathologists to determine this.

Based on these evaluations, the oncologist will typically recommend the following treatments:

• Hormone receptor-positive cancers are often treated with hormone therapy, such as tamoxifen or an aromatase inhibitor. This may be combined with a targeted drug such as Afinitor (everolimus), Ibrance (palbociclib), Kisqali (ribociclib), or Verzenzio (abemaciclib).
• Hormone receptor-negative cancers are typically treated with chemo.
• HER2-positive cancers may benefit from the targeted drug Herceptin when used in combination with chemo, hormonal therapy, or other HER2 medications.
• HER2-negative cancers are typically treated with chemo. Hormone therapy may be added if the cancer is hormone receptor-positive. The drug Lynparza (olaparib) is now being used as part of systemic therapy to treat early-stage and metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation that has previously been treated with chemotherapy—either before or after surgery.

Radiation and Surgery

In addition to systemic therapies, radiation and surgery may be helpful in specific circumstances. With radiation especially, the goal may be therapeutic (to slow the progression of the disease) or palliative (to provide comfort by reducing the tumor size).

Among the examples of how these treatments are used:

• Bone metastases often benefit from radiation to reduce pain and prevent bone fracture. In addition, bone-modifying drugs like Zometa (zoledronic acid) can reduce the risk of cancer-related bone loss (osteoporosis).
• Lung metastases are sometimes treated with surgery if the spread of cancer is limited. A specialized form of radiation therapy known as stereotactic body radiotherapy (SBRT) may also be considered.
• Brain metastases may also be treated with surgery or SBRT if only a single or a few metastases are found.
• Liver metastases may be treated with radiation, SBRT, or surgery to prevent blood vessel blockage in the liver.
• Spinal metastases are typically treated with SBRT or surgery to prevent the compression of the spinal cord.

Radiation can also shrink tumors that have penetrated the skin and caused an open wound on the breast or chest.

How Long Can You Live With Stage 4 Breast Cancer?

The five-year survival rate for stage 4 breast cancer is 29%, which means that 29 out of 100 women will live for at least five years. Some will live far longer, while others will live less long. The median life expectancy is three years.

As distressing as this may seem, the figures do not differentiate between the number of women who decide to be treated vs. those who don't. As such, you should not assume that having stage 4 breast cancer means that you have three to five years to live. Some women will live more than 10 years.

A number of factors are known to influence survival, including:

• Age
• Health at the time of the diagnosis
• Cancer stage at the time of diagnosis
• Location and extent of the metastases
• HER2 status
• Whether the cancer has recurred
• Treatments previously used

It is important to remember that these survival statistics are derived from a large population of women, all with differing circumstances. Moreover, as newer and more effective treatments are being developed, the survival rate five years from now may be much greater than today.

Monitoring Stage 4 Breast Cancer

While the goal of early-stage cancer treatment is to eliminate the malignancy and put the cancer into remission, the goals associated with stage 4 cancer are different. The primary aim is to keep the cancer from spreading, which requires ongoing monitoring.

The tool most commonly used for this is an imaging technique known as a positron-emission tomography/computed tomography (PET/CT) scan. It involves PET technology, which looks at cell activity, and CT technology, which uses X-rays to create 3D images of tissue to measure tumor size and disease progression.

Other techniques, like magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DEXA), may be used to monitor certain soft tissue or bone malignancies, respectively.

Serial blood tumor markers are also used to monitor disease status. These are blood tests that detect substances, referred to as tumor markers, that increase as cancer either spreads or advances. Examples include the tumor markers CA 15-3 and CA 27-29, which are elevated in more than 70% of people with metastatic breast cancer.

Disease Progression

While systemic treatment may keep the cancer stable for months or years, there may be times when it becomes unstable and starts to progress. When this happens, a change of treatment can often stabilize the malignancy.

Generally speaking, doctors will start with hormonal therapy (if hormone receptor-positive) or targeted therapy (if HER2-positive), changing individual agents if one starts to fail.

If these no longer work, chemotherapy will be used. However, each time that cancer progresses during chemo, the chances of the new drug working get lower. It is at this stage that palliative care may be considered.

Coping With Stage 4 Breast Cancer

It is natural to feel depressed, anxious, or even angry when you have been diagnosed with stage 4 breast cancer. It can leave you feeling as if you have no control over your health or future. Moreover, you may find that certain people will withdraw from you or suggest that you have metastatic cancer because you "left it too long."

It is important to shield yourself from these negative emotions and embrace people who can provide you with genuine support. These include loved ones, support groups, and your oncology team. If you are unable to cope, ask for a referral to a therapist who can provide you counseling or a psychiatrist able to dispense treatment.

With that being said, there are women who experience positive emotional growth after being diagnosed with stage 4 breast cancer. It is not uncommon to hear someone say that cancer helped them prioritize their life, allowing them to pursue what is truly important and connect with people on a deeper, more profound level.

Whatever your experience, don't go it alone. Seek support and work with your medical team as a full partner in your care.

Summary

Stage 4 breast cancer is also known as metastatic breast cancer, meaning the cancer has spread to other organs. While stage 4 breast cancer is not considered curable, treatments can control the spread and improve quality of life in many cases. The median survival is three years, but some people live 10 years or more after diagnosis. Treatments can include chemotherapy, radiation, surgery, hormone therapy, and targeted therapy.