Breast cancer affects both men and women. The spread of the cancer beyond the breast is called metastasis. Breast cancers typically metastasize to the lungs, liver, brain and bones, says the American Cancer Society (ACS). Metastatic breast cancer is classified as a stage IV cancer. According to the National Institutes of Health (NIH), the goal of treatment in metastatic breast cancer is usually to prolong life and relieve pain and discomfort.
Surgery
According to the ACS, surgery is not likely to result in a cure of metastatic breast cancer, but can still play a key role in therapy. Surgery can remove localized primary tumors or metastases in organs like the liver or lungs, when the metastatic sites are few in number.
Lumpectomy, or partial mastectomy, is the removal of the localized mass; mastectomy is the removal of the whole breast; and axillary lymphadenectomy is the removal of the surrounding lymph nodes.
When the metastasis in a particular organ is not widespread or causing severe symptoms like obstruction, surgery may serve to relieve the symptoms or remove the metastasis completely.
Radiation Therapy
Radiation therapy is the use of high-powered radiation to destroy cancer. Radiation therapy is used in the treatment of metastatic cancer with surgery or in the place of surgery, says the ACS, to treat localized metastasis, prevent bone fractures, or relieve pain and obstruction.
Radiation therapy for metastatic breast cancer includes external radiation like external beam radiation therapy, or EBRT; intensity modulated radiation therapy, or IMRT; and three-dimensional conformal radiation therapy, or 3D-CRT.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells or stop their growth and spread. Chemotherapy can be given systemically, where it travels throughout the body, like with tablets or injections into the veins. According to the ACS, metastatic cancer requires the use of systemic treatments like chemotherapy.
Chemotherapy drugs for breast cancer are typically used in combinations: AC, or doxorubicin and cyclophosphamide; EC, or epirubicin and cyclophosphamide; and CMF, or cyclophosphamide, methotrexate and 5-flourouracil. Other agents that may be used alone or in combination are capecitabine, docetaxel, paclitaxel, cisplatin, vinorelbine and gemcitabine.
Chemotherapy may also be used in regional therapy, where the drug or mixture of drugs are administered to a particular region of the body to maximize the benefits and reduce adverse effects on other parts of the body.
Hormone Therapy
Hormone therapy is another systemic treatment for metastatic breast cancer, according to the ACS. Here, the aim is to deprive the cancers of the help they get from the female hormones estrogen and progesterone. Hormonal therapy may be combined with chemotherapy to enhance the effects of treatment.
Drugs used for hormonal treatment in breast cancer include the anti-estrogens tamoxifene and toremifene; the estrogen receptor destroyer fulvestrant; the aromatase inhibitors lestrozol, anastrozol and exemestane; and luteinizing hormone releasing-hormone, or LHRH, analogs and androgens.
Other Treatments
Targeted therapy, which involves drugs designed to target specific cancer structures and functions, is also used in metastatic breast cancer. Bevacizumab, lapatinib and trastuzumab are the targeted treatments that can be combined with hormonal therapy and/or chemotherapy.
Bone pain and metastasis can be treated with bisphosphonates like pamidronate and zoledronic acid, along with calcium and vitamin D, according to the ACS.
Treatment considerations mentioned by the National Cancer Institute for metastatic breast cancer include a combination of hormone therapy, systemic chemotherapy and/or trastuzumab. Another combination has aromatase inhibitors, lapatinib and chemotherapy with capecitabine.
References
- American Cancer Society: How Is Breast Cancer Staged?
- National Institutes of Health/MedlinePlus: Breast cancer
- American Cancer Society: Treatment of Invasive Breast Cancer by Stage
- American Cancer Society: Breast Cancer Chemotherapy
- National Cancer Institute: Breast Cancer Treatment Options by Stage
