Many drugs are available to treat metastatic breast cancer. Metastatic breast cancer is any breast cancer that has spread to an area outside of the breast or nearby lymph nodes. Lymph nodes are small glands that are part of the immune system. While metastatic breast cancer can move to any part of the body, it’s found more often in the bones, liver, lungs, or brain.
Drugs that treat metastatic breast cancer may be used together or alone. There are two main types of drugs used to treat metastatic breast cancer: targeted therapy drugs and chemotherapy drugs. Here are the drugs used most often to treat metastatic breast cancer and what to expect if your doctor prescribes any of them for you.
Chemotherapy drugs are not tumor-specific. This means they’re less specific about the cells they attack. They can attack healthy cells as well as cancer cells. However, fast-growing cells absorb these drugs more quickly. Cancer cells tend to grow quickly, so they absorb the chemotherapy drugs faster than healthy cells do. As a result, the drugs kill the cancer cells first.
Chemotherapy drugs are used to treat many kinds of metastatic breast cancer. They can be used alone or with other drugs, and they don’t target a certain type of cancer cell. You can find them below listed by drug type.
Anthracycline drugs are a type of antibiotic that damages DNA in cancer cells. This action kills the cancer cells. Commonly used drugs in this category include:
Alkylating agents cause problems with the DNA in cancer cells. They also slow the growth of cancer cells. Commonly used drugs in this category include:
Vinca alkaloid drugs block the growth of cancer cells by stopping the cells from dividing. Commonly used drugs in this category include:
Antimetabolite drugs cause problems with the way cancer cells divide and function. Commonly used drugs in this category include:
Platinum-based agents are made from the element platinum. They work by keeping the DNA in cancer cells from replicating, or copying themselves. This drug action causes the cell to die. Commonly used drugs in this category include:
Taxanes block the growth of cancer cells by stopping the cells from dividing. Commonly used drugs in this category include:
Targeted therapy is newer and still developing. Targeted therapy drugs damage cancer cells by targeting certain proteins on the cells. By doing this, the drugs interfere with how these cells grow, multiply, and spread. This can keep the cells from growing. It can also kill them. Targeted therapy provides a focused treatment that helps avoid damaging healthy cells.
Targeted therapy is used to treat HER2-positive metastatic breast cancer and hormone receptor-positive metastatic breast cancer. These drugs can be used alone or with other medications. They’re listed below by the type of cancer they treat.
Drugs that treat HER2-positive metastatic breast cancer
HER2 is a type of protein that attaches to cells in the breast. HER2-positive metastatic breast cancer contains high levels of HER2. According to the American Cancer Society, about 20 percent of breast cancer cases are HER2-positive.
The following drugs are used to treat this type of cancer. They work by slowing or stopping the growth of these types of cancer cells.
Trastuzumab (Herceptin) is a monoclonal antibody. A monoclonal antibody is a type of man-made protein that attaches to one kind of substance in the body. These proteins can help treat cancer in several ways. For instance, they can carry drugs directly to a cancer cell. Trastuzumab can be used on its own, with pertuzumab, or with a chemotherapy drug.
Lapatinib (Tykerb) is a monoclonal antibody. It’s used in combination with one of the following drugs:
Ado-trastuzumab emtansine (Kadcyla)
Ado-trastuzumab emtansine (Kaydcyla) is an antibody-drug conjugate. This is a substance that contains a monoclonal antibody and a drug that’s linked to it. The antibody carries the drug to cancer cells. The drug enters the cancer cells and kills them. Ado-trastuzumab emtansine is used on its own, without other drugs.
Drugs that treat hormone receptor-positive metastatic breast cancer (ER/PR positive)
According to the American Cancer Society, about two out of three cases of breast cancer are hormone-positive breast cancer. This type of cancer is partly fed by the hormones estrogen, progesterone, or both. The following drugs can block these “food” sources.
Tamoxifen is a selective estrogen receptor modulator (SERM). A SERM is a drug that has different effects on different tissues in the body. On some tissues, it has the same effects of the hormone estrogen. On other tissues, it blocks the effects of estrogen. Tamoxifen is used alone or with one of the following drugs:
Fulvestrant (Faslodex) is a selective estrogen receptor downregulator (SERD). A SERD binds to the estrogen receptor of a cancer cell. It blocks the growth of breast cancer cells that are resistant to tamoxifen or sensitive to estrogen. Fulvestrant is used alone or with one of the following drugs:
Aromatase is an enzyme that’s found in fat and other body tissues. An aromatase inhibitor is a drug that lowers estrogen levels in the body. It does this by stopping aromatase from turning other hormones into estrogen. Aromatase inhibitor drugs include anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin). These drugs are used alone or with one of the following drugs:
Everolimus (Afinitor) is an mTOR inhibitor, which is a substance that blocks a protein in the body called mTOR. This protein helps cells grow and divide. Blocking mTOR may help slow the growth of cancer cells. Everolimus is used with exemestane.
Many drugs can treat metastatic breast cancer, and this is only a partial list. Other drugs are also available. Talk with your doctor about the drugs listed here and others that might help you. Be sure to ask any questions you have. Learning all you can about any medications prescribed to treat your metastatic breast cancer can help you feel more comfortable with your cancer care.
You asked, we answered
- I’ve been diagnosed with metastatic breast cancer. What are the typical survival rates for this condition?
Survival rates are estimates and don’t represent what will happen for any one person. That said, the relative five-year survival rate for metastatic breast cancer is about 22 percent. This means that a person with metastatic breast cancer is 22 percent as likely as a person without it to live for five years after the date of diagnosis. Keep in mind that many factors affect survival, such as age, overall health, how aggressive the cancer is, and how well the cancer responds to treatment. And newer treatments may improve outcomes. Only your cancer doctor can tell you about your own personal prognosis.- Monica Bien, MPA, PA-C