Is Chemotherapy Used to Treat Metastatic Breast Cancer?

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Chemotherapy is used as a treatment for most people with metastatic breast cancer at some time. Whether it is used first line or not depends on your receptor status, previous treatments, and other factors.

Chemotherapy is a systemic treatment which attacks cancer cells wherever they happen to be in the body. One exception to this, however, is the brain, with the passage of many of these drugs limited by the presence of the blood-brain barrier.

How It Works

Chemotherapy works by attacking rapidly growing cells such as cancer cells. Most of the chemotherapy drugs interfere with cancer cells at some point in the division process, but different portions of the cell cycle are interrupted with different drugs.

Since these treatments affect any rapidly growing cells, they also frequently damage normal cells in the body such as those in the digestive tract (nausea), hair follicles (hair loss), and bone marrow (anemia and low white blood cell counts).

When It Is Used

How soon chemotherapy is recommended for treatment depends largely on the particular type of breast cancer you have, whether or not your tumor is estrogen receptor or HER 2 receptor positive, and whether or not hormonal therapies are effective for your tumor.

Chemotherapy is usually recommended first line (as a first treatment for metastatic cancer):

  • For women with estrogen receptor-positive tumors which have become resistant to hormonal medications such as tamoxifen or aromatase inhibitors.
  • For women with HER2 positive tumors (along with targeted therapy such as Herceptin) that are estrogen receptor negative.
  • For women with tumors which are both estrogen receptor and HER2 negative (triple negative breast cancers).
  • It may be used along with hormonal therapies for those with estrogen receptor positive tumors responsive to hormonal medications if a rapid reduction in the tumor is needed.

    Frequency

    Chemotherapy is usually given in cycles which are spaced 21 to 28 days apart. The number of cycles you receive will depend on many things, including your response to the drug or drugs.

    Chemotherapy can work very well for metastatic breast cancer, although tumors almost always become resistant to any given drug or combination of drugs over time. It is not uncommon for people to undergo at least three different chemotherapy regimens during treatment.

    Chemotherapy for metastatic breast cancer may be given either continually (one combination of drugs after another without a break) or intermittently and there are pros and cons to each method. It’s been found that continuous chemotherapy may slow the growth of cancer somewhat more effectively than intermittent therapy, although there doesn’t appear to be a big difference in overall survival.

    In contrast, those who receive intermittent therapy tend to have a better overall quality of life. It is for many reasons such as this that your oncologist will want to understand your personal preferences with regard to managing your cancer.

    Goals

    The goals of chemotherapy treatment for metastatic breast cancer are usually different than the goals of chemotherapy treatment for early-stage disease, and this can be very confusing.

    For early-stage breast cancer, chemotherapy is most often given with the intent to cure the disease. For example, when chemotherapy is given after breast cancer surgery, it is hoped that the drugs will attack any remaining cancer cells in the body (that cannot be seen on imaging studies,) in a hope that cancer will be cured. Used in this way, the chemotherapy is referred to as adjuvant therapy.

    Chemotherapy may also be used with early-stage breast cancer to decrease the size of a tumor so that surgery is then possible. Used in this way, the chemotherapy is referred to as neoadjuvant therapy, and the goal is also a cure.

    Chemotherapy for metastatic breast cancer, however, is used with different goals. These goals are:

    • To extend your life
    • To improve your quality of life
    • To ease your symptoms

    In other words, in contrast to chemotherapy for early-stage breast cancer, chemotherapy for metastatic breast cancer is not given with an intent to cure the disease, but instead to control the disease as long as possible.

    Why Isn’t a Cure the Goal?

    It can be very painful and shocking when you come to understand the differences between what chemotherapy may offer for early-stage breast cancer and what it may accomplish for metastatic breast cancer.

    It is not that doctors don’t want to attempt to cure advanced breast cancer with chemotherapy. They do. It’s just that with the drugs we currently have, and the resistance which develops over time, the odds of chemotherapy curing an advanced cancer are very low. This is true even if you were to be treated with extremely high and aggressive doses of several of these drugs.

    Unfortunately, according to studies, many women (and men) are expecting a different response than oncologists, and are hoping that chemotherapy will cure their metastatic cancer. We share this not to take away your hope. There are some people who respond and continue to respond to chemotherapy for a long time. Yet, it’s important to understand what chemotherapy can and can’t do with the drugs we currently have.

    If you are still hoping for a cure, talk to your doctor. At this time there are not any approved medications which can cure metastatic breast cancer, though new medications are always being evaluated in clinical trials. For a few people, some of these newer medications, such as immunotherapy drugs, may (but we don’t know and that is why they are being studied) offer a greater chance for long-term survival.

    At the same time, however, there is an unknown, and until drugs are approved we can’t be certain that they will not make things worse as well.

    Chemotherapy Drugs

    If your cancer is a recurrence and you had chemotherapy the first time around, different drugs are usually used. It’s thought that cancer cells which have persisted beyond your initial treatment were likely resistant to the medications. In other words, the chemotherapy may have killed off many cancer cells but the remaining cells which were resistant to the drug were left behind.

    It’s not uncommon for someone to have at least three separate chemotherapy regimens used to treat their cancer. To differentiate these treatments, oncologists usually refer to a chemotherapy regimen as first line, second line, third line, and so on. Chemotherapy tends to become less effective over time as more regimens are needed.

    Categories of Medications

    There are several different categories of medications which can be used. A few of these chemotherapy medications used for metastatic breast cancer broken down into relative categories include:

    • Anthracyclines – Adriamycin (doxorubicine), Ellence (epirubicine)
    • Alkylating agents – Cytoxan (cyclophosphamide)
    • Taxanes – Taxol (paclitaxel), Taxotere (docetaxel)
    • Mitotic inhibitors – Halaven (eribulin)
    • Nucleoside analog drugs – Gemzar (gemcitabine) and DNA synthesis inhibitors Xeloda (capecitabine)
    • Antimetabolites - methotrexate
    • Microtubule inhibitors - Ixempra (ixabepilone), Navelbine (vinorelbine)
    • Platinum drugs – Platinol (cisplatin), Paraplatin (carboplatin)
    • Topoisomerase drugs - etoposide

    Single vs. Combination Therapy

    Unlike adjuvant therapy for early-stage breast cancer which almost always entail using a combination of drugs, single-agent therapy is often used for metastatic breast cancer. The use of combination chemotherapy is usually limited to times when a cancer is rapidly progressive in order to gain control of the disease.

    A few combinations which are commonly used include Xeloda (capecitabine) and Taxotere (docetaxel) and Gemzar (gemcitabine) and Taxol (paclitaxel).

    Brain Metastases

    While chemotherapy is able to treat cancer cells nearly everywhere in the body, many chemotherapy medications are unable to reach the brain. This is because of a specialized membrane of capillaries known as the blood-brain barrier.

    The blood-brain barrier is designed to prevent toxins from entering the sensitive tissues of the brain and spinal cord, but unfortunately, may prevent chemotherapy drugs from gaining access as well. Other treatment options, such as whole brain radiotherapy, may be needed to treat breast cancer which has spread to the brain.

    Common Side Effects

    Most people are aware that chemotherapy drugs often have side effects. While this is true, there have been significant advances in managing the side effects of chemotherapy in recent years, especially symptoms such as nausea and vomiting.

    The specific side effects of the different drugs can vary, and it’s important to talk to your doctor about possible adverse reactions you might expect.

    Fatigue – Fatigue is one of the most common chemotherapy side effects, and one of the more frustrating. Even though we don’t yet have any specific treatments for fatigue, as we do for nausea, there are many things you can do to make it more tolerable.

    Simple measures, such as pacing yourself through the day, prioritizing activities, and learning to delegate, can be very helpful. Keep in mind that at the same time as you are experiencing fatigue, your loved ones are probably suffering from a feeling of helplessness. Learning to delegate, and ask for and receive help may not only help you with your fatigue, but will allow your loved ones a way to cope with their feelings of helplessness.

    Hair loss – Hair loss is common with many of the chemotherapy drugs. For those who had chemotherapy “the first time around” this can be even more challenging this time around. And unlike adjuvant chemotherapy, there is often not a clear end in sight.

    If you didn’t invest in a wig before, this may be a good time to do so. Insurance often covers a portion of this, and several organizations provide free wigs from donated hair. Scarves and hats are also an option, and often more comfortable.

    There has been research in recent years looking at methods of preventing hair loss. While these methods, such as wearing an ice cap during your infusion, may decrease your hair loss, they can be very uncomfortable.

    Nausea and vomiting – While many of the drugs used for metastatic breast cancer can cause nausea and vomiting, there are many ways to address this. In fact, there are now many people who experience little or even no nausea related to treatment.

    There are several different categories of medications used, some which are designed to prevent nausea in the first place, and others which can be used to treat nausea. Make sure to talk to your doctor if you experience any nausea.

    While there are many treatments, some work better for some people than others, and it can be hard to know which anti-nausea drugs will work best for any individual person. You may hear people talk about acupressure bands, ginger, and other so-called “alternative” therapies for chemotherapy-induced nausea.

    While these measures may have some effect, they should be used only as an add-on to anti-nausea medications, and not as a substitute.

    Diarrhea may also manifest as a side effect. Work with your doctor to review what you can do decrease this side effect.

    Bone marrow suppression – The effect of chemotherapy drugs on bone marrow can lead to decreased levels of all the types of blood cells produced in the bone marrow. This can include red blood cells (anemia), white blood cells (leukopenia or neutropenia), and platelets thrombocytopenia.

    The greatest risk due to bone marrow suppression is a low white blood cell count. This can both predispose you to infections with bacteria that are otherwise usually harmless, and make it more difficult to fight an infection once it occurs. If you develop a fever while on chemotherapy (even one as low as 100.5) it is important to call your doctor right away.

    Most of these infections are very treatable, but prompt treatment can make a big difference. Your doctor will talk to you about methods of reducing infection, and it is important to review these. People on chemotherapy—whether or not their white blood cell count is low—are often told to avoid crowded places (especially during the winter months and flu season) and to minimize contact with loved ones who are ill. With some of the chemotherapy drugs, your doctor may prescribe a medication to increase your white blood cell count.

    Anemia can contribute to your fatigue. Talk to your doctor about your hemoglobin and when she would consider treating a low level. A low platelet count may increase your risk of bleeding. If your level is low, it’s a good idea to avoid activities which could result in bleeding or bruising.

    Peripheral neuropathy – Some of the chemotherapy drugs, can cause an uncomfortable combination of symptoms known as peripheral neuropathy. Symptoms may include burning, tingling, and numbness which occur in a “stocking and glove” distribution on the hands and feet.

    Since the decreased sensation in your feet may interfere with walking and balance, people using these drugs should look around their home environments to minimize their chances of a fall, avoid the use of obstacles such as throw rugs and practice caution when walking in ice and snow. While peripheral neuropathy may improve over time, some of these symptoms may be permanent after discontinuing treatment.

    Sources:

    DeVita, Vincent., et al. Cancer: Principles & Practice of Oncology. Cancer of the Breast. Wolters Kluwer, 2016.

    Liedtke, C., and H. Kolberg. Systemic Therapy of Advanced/Metastatic Breast Cancer—Current Evidence and Future Concepts. Breast Care. 2016. 11(4):275-281.

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