Using Local Treatments for Breast Cancer Metastasis

Why Local Treatments Have Limited Use in Metastatic Breast Cancer

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Radiation and surgery are local therapies, and as such have limited use for people with metastatic breast cancer. Instead, systemic treatments—treatments like hormonal therapieschemotherapy, targeted therapies, and immunotherapy, which address cancer wherever it happens to be in the body—are the mainstay of treatment.

If metastases to your bones, liver, lungs, or brain are not causing symptoms, or if they don’t put you at risk for complications such as a fracture, they are usually treated as part of your general therapy for breast cancer with systemic treatments.

When Are Local Treatments Used?

There are times, however, when direct treatment of metastases with surgery, radiation therapy, or other treatments is helpful. Reasons these treatments may be used include:

  • Control of pain (especially with bone metastases)
  • Bleeding or obstruction in the airways caused by lung metastases
  • Bone metastases which raise the risk of a fracture or could result in spinal cord compression
  • Brain metastases which are very symptomatic, such as those causing headaches, personality changes, visual disturbances, or seizures (the blood-brain barrier prevents many medications such as chemotherapy drugs from entering the brain or spinal cord)
  • To remove painful metastases to the skin or chest wall
  • Treatment of Oligometastases – Oligometastases is a term that is used to describe a single or only a few areas of metastatic disease. Most often breast cancer results in widespread metastases to more than one region of the body. In rare cases, treatment with surgery, radiation therapy, radiofrequency ablasion (RFA), or microembolization may be considered for those who have only a single (or perhaps a few) metastases in only one organ.

    While this has not yet been shown to improve survival for women and men with metastatic breast cancer, it has been shown, on rare occasions, to improve survival for people with metastases related to other solid tumors.

    Bone Metastases

    The treatment of bone metastases from breast cancer depends on the degree of metastases, the symptoms they cause, and other treatments you are receiving. Hormonal therapies, targeted therapies, and chemotherapy may all reduce the symptoms from breast cancer which has spread to the bones.

    Yet, sometimes, these general therapies are not enough. Local therapies such as radiation therapy may be used for pain that is not controlled well with systemic treatments, or to prevent fractures or spinal cord compression due to bone metastases. Your doctor may recommend a form of radiation or drugs referred to as “bone modifying agents.” Options include:

    • Radiation Therapy - Radiation therapy is commonly used to treat breast cancer metastases to bone which are weakening the bone and raising the risk of fracture.
    • Radiopharmaceutics – Radiopharmaceutics are drugs that carry radioactive particles directly to the bones. An example is strontium 89.
    • Bone-Modifying Agents - There are two categories of bone-modifying agents that may be used for bone metastases. Some of these are used for people with osteoporosis as well. As with radiation therapy, they may be used to prevent fractures, to prevent spinal cord compression, and to treat high calcium levels in the blood due to the breakdown of bone with bone metastases (hypocalcemia of malignancy).

    Examples of bisphosphonates include:

    • Aredia (pamidronate)
    • Zometa (zolendronic acid)
    • Boniva (ibandronate)

    RANK (receptor activator of nuclear factor kappa B) ligand inhibitors include:

    • Xgeva (denosumab)

    Liver Metastases

    Liver metastases may not cause any symptoms, and you may only be aware of these due to an increase in liver function tests on your blood tests or by finding these on imaging tests.

    When they are symptomatic, local treatments such as surgery or radiation therapy may be considered in addition to general treatments for metastatic breast cancer.

    Lung Metastases/Pleural Effusions

    As with other sites of metastases, treatment for lung metastases includes treatments for metastatic breast cancer in general. At times, lung metastases may cause airway obstruction or bleeding into the airways.

    When this occurs, radiation therapy may be effective in decreasing symptoms.

    Pleural effusions (the build-up of fluid between the membranes lining the lungs) are also common with metastatic breast cancer. Removal of this fluid with a needle (thoracentesis) can significantly reduce symptoms, but the effusion often recur. When this happens, a stent may be placed in the pleural cavity connected by a tube to the outside of your body (through your chest wall) which allows the fluid to be drained.

    Many people who have a stent placed are allowed to drain the fluid by themselves at home (with the help of a loved one) when the fluid increases their day to day symptoms.

    Brain Metastases

    Brain metastases can be difficult to treat with metastatic breast cancer as many chemotherapy drugs are unable to enter the brain and spinal cord. A network of tightly knit capillaries at the juncture of the brain called the blood brain barrier is designed to prevent toxins from entering the central nervous system. Unfortunately, this barrier also often prevents cancer drugs from reaching this area.

    There are two settings in which either radiation therapy or surgery may be considered to treat brain metastases.

    • Symptomatic metastases – If your brain metastases are causing significant symptoms, local treatment may improve your quality of life. This may include whole brain radiation therapy for diffuse and multiple metastases, or more localized and higher dosed radiation for single but large metastases.
    • Isolated metastases – For large single metastases which are causing symptoms, or if you only have one (or a few) brain metastases but no evidence of metastases elsewhere in your body, specialized types of radiation known as stereotactic body radiotherapy (SBRT or Cyberknife) or radiofrequency ablation (RFA) may be used. These treatments direct a high dose of radiation to a precise area in the brain. Instead, surgery may be considered to treat these metastases.

    Other Treatments

    There are other treatments being evaluated for the specific treatment of metastases due to breast cancer. Techniques such as microembolization and more may offer better treatments in the future. There are several clinical trials currently in progress studying the treatment of metastases.

    Managing Side Effects

    Radiation therapy, as with other treatments for cancer, may result in side effects. The specific side effects and how bothersome they are will vary depending on many factors including the area of your body which receives radiation. Some of the more common side effects include:

    • Skin irritation – The area over which you receive radiation therapy may develop redness and sometimes blistering, similar to a sunburn. Your radiation oncologist will talk to you about symptoms to watch for and may prescribe a lotion for you to use.
    • Fatigue – Fatigue is the most common side effect of radiation therapy, affecting most people who have these treatments to some degree. This tiredness tends to be cumulative and worsens over time.

      Like fatigue related to chemotherapy, these symptoms can also be caused by reversible problems (such as anemia) and it’s important to talk to your oncologist about your fatigue level.

      The best treatment for the tiredness is primarily to find ways to cope with the fatigue. Ask for help and allow others to help you. Rest when you need. And talk to your doctor about any sleep difficulties which are contributing to your tiredness.
    • Hair loss – Hair loss secondary to radiation therapy differs from hair loss related to chemotherapy, in that it can be permanent. Hair loss depends on the area of the body for which you are receiving radiation therapy.

      For example, whole brain radiation to your head can cause loss of hair on your head, whereas radiation to your chest, for lung metastases, will only cause loss of hair on your chest.
    • Cognitive dysfunction – Radiation therapy to the brain, especially whole brain radiotherapy, can cause symptoms such as memory problems and concentration difficulties (cognitive dysfunction.) It is important to carefully weigh the benefits of radiation therapy to the brain against these possible side effects of treatment.

      Radiation therapy to the brain also carries the risk of damage to normal structures in brain tissue through which the radiation passes.

    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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