If you have stage IV breast cancer, the cancer has spread from your breast to one or more distant parts of your body. This kind of spreading is called metastasis. So stage IV breast cancer is also called metastatic breast cancer.
If you are facing a diagnosis of stage IV breast cancer, the important thing to know is that this is not cause for despair or hopelessness. There are many treatment options available today.
In the past, the goal of treatment was to relieve symptoms, and help women live as long and as good a life as possible. But there have been some important advances recently that have given women with stage IV breast cancer many more treatment options. These include new chemotherapy drugs, the development of targeted therapies, and the development of better antihormonal therapy drugs.
Antihormonal Therapy
The growth of some breast cancer cells can be prevented or slowed by reducing their exposure to estrogen. This is the goal of antihormonal therapy in the treatment of breast cancer.
Estrogen is a hormone made by your ovaries and other tissue in your body. It serves many critical functions. These include developing your female sex organs in puberty, preparing your breasts and uterus for pregnancy in adulthood, and maintaining your cardiovascular and bone health. Without estrogen, your body cannot sustain pregnancy and is susceptible to heart disease and osteoporosis (thinning of your bones).
Estrogen can also make some cancers grow. Your breasts, uterus, and other female organs are made of cells that are stimulated to grow when exposed to estrogen. These cells have areas on their surface called estrogen receptors. Estrogen in your blood binds to these receptors and stimulates the cells to grow. When cells that have estrogen receptors become cancerous, exposure to estrogen increases the cancer's growth. Cancers that have estrogen receptors are called estrogen receptor-positive (ER-positive) cancers.
Removal of your ovaries, the organs that make most of your estrogen, is one effective way to stop estrogen production in premenopausal women. This is commonly used in many countries. Another way is to use drugs that have a similar effect, without removing your ovaries.
Many women with ER-positive breast cancer are initially treated with an antihormonal therapy drug called tamoxifen. Tamoxifen works by blocking the effects of estrogen by directly binding to a cell's estrogen receptors.
But a new group of drugs—called antiaromatase drugs or aromatase inhibitors—have more recently been developed and approved by the U.S. Food and Drug Administration for the treatment of ER-positive breast cancer in postmenopausal women. Antiaromatase drugs work by preventing the formation of a precursor to estrogen—aromatase. This is the enzyme that helps convert estrogen to its active form. Antiaromatase drugs inhibit aromatase. As a result, the level of active estrogen in your body falls.
Currently, three antiaromatase drugs are approved for the treatment of breast cancer in postmenopausal women: Femara® (letrozole), Arimidex® (anastrozole), and Aromasin® (exemestane).
Chemotherapy
Chemotherapy involves the use of drugs to kill cancer cells. Chemotherapy may help you if your breast cancer does not have estrogen or progesterone receptors, is not responding to antihormonal therapy, or is progressing rapidly (growing) and causing you symptoms.
Doctors currently use several standard combinations of drugs (called regimens) or single drugs in sequence. A small fraction of women who receive chemotherapy have a complete remission of their cancer. That means the cancer is no longer detectable, but may still be present at a microscopic level.
The type of chemotherapy that is selected depends on the goal of your treatment. If the goal is to reduce your symptoms and improve your quality of life, it may be better to select chemotherapy with few side effects. In other situations, in which shrinking the tumor is critical given the speed of the disease, chemotherapy regimens associated with higher response rates (but possibly more side effects) may be the best option.
It is important to carefully think about your goals for treatment. One reason for doing this is that in stage IV breast cancer, initial treatment is typically more effective than subsequent treatment. This is because cancer cells may become resistant to treatment.
If standard treatment approaches are not likely to be effective or have already been tried, you might want to consider participating in a clinical trial.
Taxanes
In recent years, a class of chemotherapy drugs—called taxanes—have been widely used in the treatment of breast cancer. Now many patients are receiving taxanes as a component of treatment for early stage breast cancer. Taxotere® (docetaxel) and Taxol® (paclitaxel) are both taxanes. The most recent addition to this class of drugs is Abraxane® (nanoparticle albumin-bound [NAB] paclitaxel). In metastatic breast cancer, using a taxane drug in combination or sequentially (one after the other) with other chemotherapy drugs appears to be more effective than chemotherapy that does not include a taxane drug. The best schedule for giving taxanes is still being studied.
Nanoparticle Albumin-Bound Paclitaxel
NAB paclitaxel uses albumin, the most abundant protein in your body, to deliver the treatment right to cancer cells. NAB paclitaxel has several potential advantages over regular paclitaxel, including less need for steroid premedication, less of a decrease in blood counts, and a shorter infusion time.
Combination Chemotherapy
Combinations of two or more chemotherapy drugs are called regimens. They are often used because each type of drug blocks different points in the life cycle of the cancer cell and may overcome problems of resistance that certain tumor cells have to certain chemotherapy drugs. Not all cancer cells are at the same phase of development at the same time. So chemotherapy regimens containing more than one drug may effect cancer cells differently.
Whether combination chemotherapy or single agents given in sequence is optimal is open to discussion and such a decision must be made on an individual basis by your physician.
Targeted Therapy
A targeted therapy is designed to treat only cancer cells and minimize the damage to healthy cells. This means that the side effects of targeted therapy are generally milder than those of standard chemotherapy. Targeted therapies can be easily combined with chemotherapy. There are now several different types of targeted therapies.
Herceptin® (trastuzumab) - Some breast cancers have too much of a protein called HER2 on their surface. These are called HER2-positive breast cancers. The HER2 protein binds only with other proteins in your blood—called growth factors. This binding leads to the uncontrolled growth of the cancer cells. About one in three women with breast cancer have HER2-positive breast cancer.
Trastuzumab is a type of targeted therapy called a monoclonal antibody. It binds to the HER2 protein. Results from an important clinical trial indicate that adding trastuzumab to chemotherapy improves survival for women with advanced HER2-positive breast cancer.
Because HER2-positive breast cancer responds to trastuzumab, it is important that your breast cancer be tested for HER2 at the time of diagnosis. This will determine whether trastuzumab should be part of your treatment.
Tykerb® (lapatanib) is a new oral tyrosine kinase inhibitor that was approved for treatment of HER2-positive breast cancer that has progressed following treatment with an anthracycline, taxane, and trastuzamab. The drug is indicated for metastatic breast cancer in combination with capecitabine.
Treatment of Stage IV Breast Cancers With Specific Characteristics
Some stage IV breast cancers have specific characteristics. These cancers can be treated in a way that is specific to those characteristics.
- Bone metastases - Cancer has spread to your bones.
- Local-regional recurrence - Cancer has recurred (come back) in your breast, your chest wall (muscles and ribs), or the skin over your breast.
- Stage IV no evidence of disease (NED) - You have had a recurrence in a single area that was removed with surgery or radiation.
Bone Metastases
Breast cancer cells that have spread to your bones are called bone metastases. Cancer can spread to your bones when cells break off from the original cancer and travel in the circulatory or lymph system to your bone. Then the cells grow into another tumor.
Bone metastases can be painful. And they can weaken your bones, even to the point where you get a fracture (a broken bone). But bone metastases can be treated with a group of drugs called bisphosphonates.
Bisphosphonates decrease the rate of bone destruction in women with cancer. Clinical studies have shown that these drugs can decrease the number of fractures caused by cancer that has spread to the bone and also reduce the pain from cancer in the bone. Radiation therapy can be administered locally to a very symptomatic area, and systemic therapy may also be used to treat the cancer and improve bone-related symptoms.
Local-Regional Recurrence of Breast Cancer
After having initial treatment for breast cancer—either a mastectomy or breast-conserving therapy (a lumpectomy plus radiation)—you may have a local recurrence. This is defined as cancer coming back in the same breast, in your chest wall, or in the skin over your breast. Or you may have a regional recurrence. That is defined as the cancer coming back in the nearby lymph nodes. If you have a regional recurrence, you are more likely to have the cancer spread to other parts of your body.
Treatment for local recurrences depends on how the cancer was initially treated:
- If you had a mastectomy, radiation therapy can effectively control your local recurrence. You may also need surgery before the radiation therapy.
- If you had breast-conserving therapy, a mastectomy may be the best approach, with or without radiation therapy.
Despite surgery and radiation therapy, the large majority of women who have a local recurrence later get cancer in other parts of their body. In some cases, your oncologist may recommend additional treatment with chemotherapy or antihormonal therapy to try to get rid of the remaining cancer cells that cause this to happen.
Stage IV -- No Evidence of Disease (NED)Your cancer may recur in a single area where it can be removed with surgery or radiation therapy, getting rid of all evidence of cancer. In this case, doctors say you have stage IV breast cancer, but with no evidence of disease (NED). This suggests that cancer was present in other locations where it could not be detected with currently available tests. Additional treatment with chemotherapy, endocrine therapy, or other treatment after surgery and/or radiation therapy may improve your outcome.
Bisphosphonate Drugs
Today, cancer that has spread to the bone is often treated with a class of drugs called bisphosphonates. These include Bonefos (clodronate)—only available in Canada—Boniva® (ibandronate), Aredia® (pamidronate), and Zometa® (zoledronic acid), which are used because of their ability to reduce the risk for fractures, spinal compressions, and other skeletal-related complications.
Research is in progress to refine existing treatments and develop new ones. For information on some of the techniques currently under investigation, see Strategies to Improve Treatment.
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