Breast Cancer Stage IV

Stage 4 breast cancer means the cancer has spread beyond the breast to other parts of the body. While there is no cure, many people are living longer than ever before thanks to newer treatments that can control the disease and help maintain quality of life.

Table of contents

• What is Stage 4 Breast Cancer?
• How Breast Cancer Spreads
• Symptoms of Stage 4 Breast Cancer
• Understanding the Staging System
• Treatment Options
• Living with Stage 4 Breast Cancer

What is Stage 4 Breast Cancer?

Stage 4 breast cancer is also called advanced breast cancer or metastatic breast cancer. This means the cancer has spread from the breast to other parts of the body^[1]. When cancer spreads from where it started to a new location in the body, this process is called metastasis^[2].

The most common places where breast cancer spreads include the bones, liver, lungs, and brain. However, breast cancer may also spread to other organs^[2]. Even when breast cancer spreads to another part of the body, such as the bones, it is still considered breast cancer (not bone cancer) because that is where the cancer originated. The breast cancer cells have invaded the bones, and the disease is treated with breast cancer drugs rather than treatments for cancer that began in the bones^[10].

Stage 4 breast cancer can occur in two ways. Most people with metastatic breast cancer have been diagnosed with an earlier stage of breast cancer before. In this case, the original cancer in the breast is called the primary cancer^[2]. However, for some people, a diagnosis of metastatic breast cancer may be their first diagnosis of cancer. About 6% of breast cancer diagnoses in women are stage 4 at the time of first diagnosis. This is called de novo metastatic breast cancer^[10].

How Breast Cancer Spreads

When breast cancer comes back after treatment, it is typically because some cancer cells were left behind after the initial breast cancer treatment. These surviving cancer cells may stay inactive or hidden, making them undetectable until they start growing and spreading^[5].

Cancer cells can move into nearby tissue, lymph nodes, or the bloodstream before surgery or other treatments can remove them. These weakened cancer cells can remain in your body after treatment. Over time, the cells get stronger and start to grow and multiply again. These cells may travel through your bloodstream and lymphatic system (a network of tissues and organs that help rid the body of waste), using your lymph nodes and blood vessels to carry cancer to other areas of your body^[6].

Breast cancer cells may start forming new tumors right away, eventually causing symptoms that show the cancer has spread. Sometimes they remain inactive for years before growing into detectable tumors^[6].

Symptoms of Stage 4 Breast Cancer

Metastatic breast cancer can cause a number of symptoms. These symptoms can vary greatly depending on the part or parts of the body affected and may develop over time^[2].

General symptoms related to stage 4 breast cancer may include fatigue, unexplained weight loss, vomiting, or loss of appetite^[5]. However, specific symptoms depend on where the cancer has spread:

When cancer spreads to the bones: Patients may experience pain in the bones, back, neck, or joints. Bones may fracture (break) more easily. Some people notice numbness or muscle weakness in their arms and legs, or swelling in certain areas^[5][6].

When cancer spreads to the liver: Symptoms may include yellowing of the skin or the whites of the eyes (called jaundice), pain or swelling in the stomach, loss of appetite, itchy skin, or nausea^[5][6].

When cancer spreads to the lungs: People might experience difficulty catching their breath, shortness of breath, chest pain, a constant dry cough, or frequent chest infections^[5][6].

When cancer spreads to the brain: Patients could experience worsening headaches or pressure in the head, vision problems such as double vision or blurred vision, seizures, nausea and vomiting, changes in personality or behavior, dizziness, loss of balance, or confusion^[5][6].

It is important to remember that not every physical change means the cancer is getting worse. Some symptoms may be side effects of treatment rather than signs of cancer spreading. However, if you are experiencing any symptoms, it is important to talk to your healthcare provider^[6].

Understanding the Staging System

The stage of a cancer tells you how big it is and whether it has spread. It helps your doctor decide which treatment you need^[3].

In stage 4 breast cancer, the cancer can be any size, and the lymph nodes (small bean-shaped structures that are part of the immune system) may or may not contain cancer cells. What defines stage 4 is that the cancer has spread to other parts of the body such as the bones, lungs, liver, or brain^[3].

There are different systems used to stage breast cancer. Stage 4 is part of the number staging system. Doctors may also use the TNM staging system, which stands for Tumor, Node, and Metastasis. The T describes the size of the tumor, the N describes whether there are cancer cells in nearby lymph nodes, and the M describes whether the cancer has spread to parts of the body farther away from where it started. In the TNM staging system, stage 4 breast cancer is described as any T, any N, and M1, meaning the cancer has metastasized regardless of tumor size or lymph node involvement^[3].

Treatment Options

Healthcare providers cannot cure metastatic breast cancer, but they can recommend treatments that improve quality of life and help people live as long as possible. In fact, more people are living longer with metastatic breast cancer as medical researchers find new ways to treat the disease^[6].

The aim of treatment is to control the cancer and any symptoms it causes^[3]. Your doctor will take many different factors into account when deciding which treatment is best for you. These include the type of cells the cancer started in, which part of your body the cancer has spread to, the treatment you have already had, your general health, whether you have had menopause, whether the cancer is growing slowly or more quickly, and whether the cancer cells have receptors for particular cancer drugs^[3].

Hormone Therapy

Hormone therapy is a common treatment for metastatic breast cancer. It can often shrink and control the cancer wherever it is in the body. It works well if the cancer cells have particular proteins called hormone receptors. These are cancer cells that grow in response to certain hormones in the body^[3].

Hormone therapy is offered for hormone receptor-positive breast cancer that has spread to the bones and soft tissues, such as muscles or fat. It is also given when the cancer has spread to internal organs but is not causing symptoms^[13].

Medications used include drugs called aromatase inhibitors such as letrozole, anastrozole, and exemestane. These drugs work by lowering the amount of estrogen in the body. Another drug called tamoxifen may be offered if you cannot take aromatase inhibitors or if you have severe side effects from them^[3][13].

If one hormone therapy stops working well, your doctor might suggest you try a different one^[3].

Chemotherapy

Chemotherapy uses drugs to kill cancer cells or slow their growth. It is often the main treatment for stage 4 breast cancer and can help slow down the growth of the cancer^[8][12].

Your doctor might suggest chemotherapy if your cancer does not have hormone receptors or if it has spread to the liver or lungs^[3]. Chemotherapy is given for hormone receptor-negative breast cancer and is also offered for hormone receptor-positive breast cancer that has spread to internal organs and is causing symptoms^[13].

Chemotherapy drugs are often used alone to treat metastatic breast cancer because a single drug causes fewer side effects than a combination of drugs. You can receive chemotherapy in several different ways, including pills or liquids you take by mouth, but often the drugs are put directly into your veins. Treatment is usually given in cycles that allow your body breaks in between^[12][13].

Chemotherapy is given as long as the cancer responds to it and the side effects do not cause problems. Once the cancer no longer responds to treatment, a different drug or treatment may be offered^[13].

Targeted Therapy

Targeted therapy is a newer type of treatment. These drugs target specific proteins or characteristics of cancer cells. About 20% of women with breast cancer have too much of a protein known as HER2, and it makes the cancer spread quickly. Women with HER2-positive cancer that has spread often take a drug called trastuzumab. It stops the protein from making the cancer cells grow. Other targeted therapies for HER2-positive cancer may be prescribed as well^[12].

Other types of targeted therapies include CDK4/6 inhibitors, which block certain proteins and slow cancer growth. These drugs are given to certain women who have hormone receptor-positive and HER2-negative cancers^[12].

A class of drugs called PARP inhibitors has been found to help women who are HER2-negative but who have a specific genetic change called a BRCA mutation. These drugs target a protein that helps cancer cells grow^[12].

Targeted therapy for metastatic breast cancer is often given in combination with chemotherapy or hormone therapy^[13].

Radiotherapy

You might have radiotherapy if the cancer has spread to the bones or the skin near the breast. Radiotherapy uses high-energy rays to destroy cancer cells and can help relieve symptoms and control cancer growth in specific areas^[3].

Other Treatments

You may have other treatments to help manage symptoms and improve your quality of life. These include drugs that strengthen the bones called bisphosphonates, medicines to control symptoms that the cancer causes, and sometimes surgery to help relieve symptoms^[3].

Treatment of stage 4 breast cancer does not cure the disease, but by shrinking the cancer, it can often slow it down, help you feel better, and let you live longer. Patients with stage 4 breast cancer may live for years^[12].

Living with Stage 4 Breast Cancer

Adjusting to a diagnosis of metastatic breast cancer is different for each person, and it is an ongoing process. During the first few weeks and months after a diagnosis, you may be in shock and find it difficult to cope. It is not unusual to be consumed by fears about the future, how your diagnosis will impact your loved ones, and whether disease symptoms and treatment side effects will affect your ability to function. But these feelings can get better as you learn more about how to manage them^[15].

Taking Your Time

You may feel disoriented and afraid when you first find out you have metastatic breast cancer. Give yourself plenty of time to process it all. Just allow yourself to feel your emotions, and do not pressure yourself to make decisions right away. It might take a while before you are ready to educate yourself about your diagnosis, and that is okay. For many people, only time can help with regaining some feeling of normalcy^[15].

Building Your Healthcare Team

Think about whether you have good communication with your doctors and how you can work together with them to develop a treatment plan that is right for you. If you feel that a particular doctor is not treating you respectfully and answering your questions or does not have enough experience with metastatic breast cancer, do not hesitate to look for a new doctor. Also, remember that your treatment plan is not written in stone. You can always talk with your medical team about organizing your treatment so that you can have the best possible quality of life^[15].

Finding Support

No one is going to understand what you are going through like someone with the same diagnosis. A good support group, online or in person, can help you feel less isolated and more hopeful, and the group members may be able to share their coping strategies with you. When you are first diagnosed, it may be encouraging just to see that other members of the group are doing normal things like traveling, working, and taking care of their children or grandchildren^[15].

Family and friends are also very important. People who survive breast cancer have unique needs, but most breast cancer survivors share the need for emotional support^[17].

Managing Side Effects and Quality of Life

All metastatic breast cancer treatments have possible side effects. Most people have some side effects from treatment, but many side effects can be managed, and some can be prevented. Before any treatment begins, talk with your healthcare provider about possible side effects and ways to deal with them^[21].

Supportive care (also called palliative care) is all the care given to improve the quality of life for people with breast cancer. It includes managing symptoms as well as taking care of your emotional, social, and spiritual needs. Supportive care is not the same as end-of-life care—it is there to make sure your day-to-day life gets better^[21].

Understanding the short-term and long-term side effects of your specific treatment can help you plan. Knowing the possible side effects and what techniques or medications can relieve your symptoms allows you to prepare. There is no need to suffer silently through the side effects of breast cancer treatment. Talk to your healthcare professional about the likelihood of side effects and what you can do to relieve your symptoms. In many cases, medications, physical therapy, exercise, and other approaches can ease your discomfort^[17].

Living with Hope

It may help you to know that there are more sources of support and a larger community of people living with advanced-stage breast cancer than ever before. Researchers estimated that more than 150,000 women in the United States were living with metastatic breast cancer, and advances in treatment have helped make longer survival possible^[15].

Many people gain great strength from talking with others who have been diagnosed and can share in their experience. Some people find themselves thriving after a metastatic breast cancer diagnosis because of a newfound focus on the parts of life that bring the most meaning^[19].