Breast Cancer Metastasis
Article updated and reviewed by Jennifer A. Ligibel, MD, Instructor in Medicine, Harvard Medical School, Dana-Farber Cancer Institute, Medical Oncology – Breast and Gynecologic Cancer on June,1 2005.
When breast cancer spreads beyond the breast, it is said to be “metastatic”, meaning that it has traveled from the breast to another part of the body. Cancer cells can travel through either the lymphatic system or the blood vessels.
There are two types of metastatic breast cancer. When the cancer cells travel from the breast to the under arm (axillary) lymph nodes, it is still considered an “early” or potentially curable breast cancer. With proper surgery and systemic treatments, there is still a good chance that all cancer can be removed from the body.
If the cancer has traveled past the lymph nodes to another part of the body, a woman is said to have “distant metastasis”. The most common places that breast cancer spreads to are the bones, the liver, and the lungs. Many treatments are available for breast cancer that has spread to other parts of the body, but unfortunately once cancer has escaped from the breast and under arm lymph nodes, it is no longer curable. The goal of treatment in this case is to prevent the cancer from spreading further while at the same time minimizing side effects from the treatment.
A woman may be found to have a distant metastasis of her breast cancer at the time when her initial breast cancer is found, or months to years later. This occurs because breast cancer cells can escape from the breast before surgery and may take a long time to form a tumor in another part of the body. When breast cancer comes back months to years after it was originally found, it is called a breast cancer recurrence.
Once breast cancer has spread beyond the breast and under arm lymph nodes, it is considered a “systemic” disease, meaning that it is necessary to treat the whole body rather than just one particular spot. This is because, once the cancer has traveled through the blood stream or lymphatic system, there are likely to be breast cancer cells in many different parts of the body, even if scans only show a few spots. For this reason, treatments that reach all parts of the body, such as chemotherapy and hormonal therapy, are used to treat metastatic breast cancer instead of treatments that just treat one part of the body, such as surgery. In general, surgery is not a part of the treatment of metastatic disease because treating only one area allows cancer to grow in other places. It is unfortunately not possible to remove all of the parts of the body where the cancer has spread because it is impossible to measure the individual cancer cells that will grow into a tumor without chemotherapy or hormonal treatment.
Breast cancer often responds to many different kinds of treatments, and most patients can live for months to several years with metastatic breast cancer. Recent research has shown that there are many different types of breast cancer, and the best treatment plan for a particular patient needs to be decided by a woman and her medical oncologist.
In general, a woman might be treated with a hormonal therapy if she has a hormone responsive (estrogen or progesterone receptor positive) tumor and does not have a large amount of cancer in her liver or lungs. Women with tumors that are not responsive to hormonal therapies or who have a large amount of disease in their bodies are usually treated with chemotherapy. There are many different types of chemotherapy that are used for breast cancer. In general, it is important to remember that the goal of treatment is to stop the cancer from growing while still allowing the patient to live a normal life. Many times the chemotherapy that is chosen in this setting is less toxic than the chemotherapy given after breast cancer surgery.
In recent years, there has been much interest in developing new types of medicines that kill breast cancer cells in new and different ways. Some of these medicines, such as trastuzumab (Herceptin), are designed to work against a specific type of breast cancer. Others, such as becizamab (Avastin), may work well in combination with chemotherapy to increase the likelihood that a treatment will stop the tumor from growing for a longer period of time.
In general, most women with metastatic breast cancer will be treated with several different types of therapy over the course of their disease. Over time, cancer cells become resistant to a treatment, and will begin to grow. When this happens, a change in treatment is needed. Unlike many other types of cancer, breast cancer cells can be controlled by many different types of chemotherapy, and women with metastatic breast cancer are living longer and longer. Hopefully with further research, women will no longer die of this disease in the future.
Has my cancer spread beyond the breast and lymph nodes?
Where has the cancer spread?
Do I have cancer that would be responsive to hormonal treatment?
Do I have cancer that would respond to trastuzumab (Herceptin)?
Editorial review provided by VeriMed Healthcare Network.