Metastatic breast cancer, also known as stage IV or advanced breast cancer, is a type of breast cancer that spreads beyond the breast to other organs in the body such as bones, liver, lungs or the brain. Though it spreads to other parts of the body, it is still considered and treated as breast cancer. In other words, if your breast cancer metastasizes, or spreads, to your bones, your oncologist would still talk to you about metastatic breast cancer treatment options, not bone cancer treatments.
Some women find out they have metastatic breast cancer on their first diagnosis. This type is called de novo metastatic breast cancer. Nonetheless, this is not very common in the U.S. as this is usually only about 5% of the diagnoses. Metastatic breast cancer arises a few months after a person has finished treatment for the early or locally advanced stage I, II or III breast cancer. This is also referred to as distant recurrence.
The risk of breast cancer mutating into metastatic breast cancer varies from person to person. It also depends significantly on the state of the tumor and the stage at the time of diagnosis. While there isn’t a cure for this stage of breast cancer, there are metastatic breast cancer treatment options available.
Metastatic breast cancer treatment options concentrate mainly on the length and quality of life. Your treatment plan is determined by many factors. Some of these factors are:
- The characteristics of the cancer cells
- The organs that cancer has spread to
- Visible signs and symptoms
- Past history of breast cancer treatments
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Metastatic Breast Cancer Treatment Options
- Hormone therapy is usually the preliminary treatment if the tumor is hormone receptor-positive. In case cancer is HER2-positive, anti-HER2 drugs like trastuzumab (Herceptin) are often on the table.
- Chemotherapy and radiation therapy may also come into play to slow down the growth of tumors or to alleviate the symptoms.
Nevertheless, these therapies do have side effects that can possibly affect the quality of life. Your doctor can help you to decide on the optimal treatment plan for you. Support groups can also help you understand these issues.
Treatment Guidelines
Though metastatic breast cancer treatment options differ from one person to another, guidelines help guarantee quality care. These rules are based on the latest research and agreement of experts.
The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are two organizations that update and post their guidelines online on a regular basis. The National Cancer Institute (NCI) also provides overviews of treatment preferences.
Prognosis
Metastatic breast cancer survival rates also vary from one person to another. About 37% of women live for at least three years after a metastatic breast cancer diagnosis while other may live up to 10 or more years beyond diagnosis.
It is, however, important to note that the basis for the survival rate data is women who got a diagnosis before some of the latest metastatic breast cancer treatment options became available. Modern drugs have improved the survival rates for women diagnosed today.
Monitoring Metastatic Breast Cancer
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Tumors frequently stop responding to drugs that are in use to treat metastatic breast cancer.
- Drug resistance
Some metastatic breast cancer cells require certain proteins or cell pathways in order for them to grow. Drugs that specifically target the proteins or pathways can slow down or completely stop the growth of these cancer cells for a certain period of time.
Think of these proteins as traffic signs and the pathways as roads, therefore breast cancer cells must pass through the signs in order to continue moving along the road. If the cancer cells hit a roadblock (which is the drug in this analogy), they can’t continue moving down the pathway. However, at some point, the cancer cells will find a diversion around the roadblock and use another pathway to continue growing.
- Restaging
As metastatic breast cancers often become resistant to drugs, it isn’t unheard of to change courses of treatment frequently. You usually start out with one drug therapy to find out whether the treatment halts the development of cancer. And of course, whether the side effects that come with the therapy are manageable. After a few months, you need to have a physical exam and imaging tests to see whether the cancer is responding positively to the treatment. This is known as “restaging.”
If the treatment is effective and you can handle the side effects by the time of restaging, then your oncologist continues with the treatment. If the treatment is not working anymore, then your doctor might advise you to go on a different drug.
- Blood Tests for Tumor Markers
In other cases, there are blood tests for tumors to aid in the observation of metastatic breast cancer. This means that you may be tested after every few months for cancer antigens. The tests are usually similar; one of the tests is carried out but not both of them at the same time. There is no test score that indicates whether the condition has worsened.
- Hormone Therapy
This is normally the initial treatment for hormone receptor-positive metastatic breast cancer. Hormone therapy drugs prevent the cancer cells from getting the estrogen they need to grow.
Menopausal status and previous hormone treatments for an earlier breast cancer diagnosis determine the choice of hormone therapy for women. Drugs like tamoxifen and aromatase inhibitors which are hormone therapy drugs are given as tablets. Others such as goserelin are given by injection.
- Chemotherapy
Chemotherapy is an initial treatment for people with:
- Hormone receptor-positive tumors which no longer respond to hormone therapy
- HER2-positive tumors (in combination with anti-HER2 treatments)
- Hormone receptor-negative tumors
One advantage of chemotherapy is its reaction time. Chemotherapy can shrink tumors faster than hormone therapy. Just like hormone therapies, if the first chemotherapy drug fails and the tumor starts to grow again, your doctor can administer a second or third drug.
A “line” refers to the use of each type of chemotherapy drug for metastatic breast cancer. The first chemotherapy is referred to as the “first-line” while the second is called the “second-line” treatment.
- Targeted therapy: Anti-HER2 drugs
HER2-positive breast cancer: Almost 20 percent of breast cancers contain high amounts of HER2, a protein present on the surface of the cancer cells. The HER2 protein is vital for the growth of cancer cells. Analyzing the tumor issue can affirm HER2 status.
- Trastuzumab (Herceptin)
Trastuzumab also known as Herceptin is an antibody that specifically targets the HER2-positive cancer cells. When trastuzumab attaches itself to the HER2 protein, it slows down or stops the growth of cancer cells.
Trastuzumab can only treat HER2-positive breast cancers intravenously. It can also shrink tumors and slow down the growth rate of HER2-positive metastatic breast cancers on its own or together with chemotherapy.
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