Once breast cancer has been diagnosed, the patient’s care team will perform additional tests to determine the stage of the cancer. The stage of breast cancer indicates how advanced the cancer is based on the tumor size, whether the cancer has spread, the tumor grade (how the cells look under a microscope), and certain biomarkers found in the cancer cells.
Breast cancer stages range from Stage 0 (non-invasive breast cancer) through Stage 4 (metastatic breast cancer). In general, lower stages indicate that the cancer is small and has not spread, while higher stages indicate more advanced disease. Breast cancer staging is based on information from imaging studies, the clinical examination, and pathology results from a biopsy or surgery. Additional tests may also be used when needed.
A breast cancer stage describes the size and extent of the cancer, including whether it has spread beyond the breast. Your stage will be determined using several factors, including the size of the tumor, whether cancer has spread to lymph nodes or other areas of the body, and certain characteristics of the cancerous cells. This information will help your care team recommend the most appropriate treatment plan for you.
While the stage is an important part of your diagnosis, it is only one piece of the puzzle. Many people with breast cancer—at every stage—respond well to treatment, and advances in care continue to improve outcomes. If you’ve recently been diagnosed, talking with your healthcare team about what your specific stage means can help you better understand your diagnosis and your treatment options.
In breast cancer, staging looks at several important factors, including the size and location of the tumor, whether the cancer has spread, the tumor grade (how the cells look under a microscope), and whether certain markers are present in the cancer cells. The TNM system, tumor grade, and biomarker results are used together to determine the stage of most breast cancers. Staging helps guide treatment decisions, but it cannot predict exactly how an individual will respond to treatment or what their future will look like.
Stage 0 is the earliest stage of breast cancer. It is non-invasive, meaning abnormal cells have not spread beyond the milk ducts or lobules into surrounding breast tissue. Stage 0 breast cancer is highly treatable when detected early and has an excellent prognosis. Treatment for Stage 0 breast cancer may include surgery (lumpectomy or mastectomy), radiation, and hormonal therapy. Chemotherapy is not typically used to treat Stage 0 breast cancer.
Stage 1 breast cancer is the earliest stage of invasive breast cancer. In Stage 1, cancerous cells have spread beyond the original location in the breast into nearby tissue or a small number of nearby lymph nodes. There are two substages of Stage 1 breast cancer: Stage 1A and Stage 1B. The substage is determined by the size of the tumor and whether it has spread to the lymph nodes. Treatment for Stage 1 breast cancer may include surgery, radiation, chemotherapy, targeted therapy, and hormonal therapy.
Stage 2 breast cancer is considered relatively early-stage invasive breast cancer. In Stage 2, the cancer is larger than Stage 1 or has spread to a small number of nearby lymph nodes but has not spread to distant parts of the body. There are two substages of Stage 2 breast cancer: Stage 2A and Stage 2B. The substage is determined by the size of the tumor and whether the cancer has spread to nearby lymph nodes. Common treatments for Stage 2 breast cancer may include surgery, chemotherapy, radiation, targeted therapy, and hormonal therapy.
Stage 3 breast cancer, also called locally advanced breast cancer, has spread beyond the breast to nearby lymph nodes, the chest wall, or the skin of the breast, but not to distant organs. Some people with Stage 3 breast cancer notice symptoms such as a breast lump, swelling, or changes to the skin or nipple, while others have few or no noticeable symptoms. Stage 3 breast cancer has three substages (Stage 3A, 3B, and 3C) determined by the size of the tumor and spread to the lymph nodes and surrounding tissue. Treatment options for Stage 3 breast cancer may include chemotherapy, surgery, radiation, targeted therapy, and hormonal therapy.
Stage 4 breast cancer, also called metastatic breast cancer, is advanced cancer that has spread (metastasized) from the breast to other areas of the body, typically the bones, lungs, liver, or brain. Even though Stage 4 breast cancer is found in other areas of the body, it is still considered breast cancer. Although Stage 4 breast cancer is not curable, it is usually treatable. Current advances in research and medical technology mean that many people are living longer, as advances in treatment help manage the disease as a chronic condition while maintaining quality of life. With care and support, Stage 4 breast cancer may respond to a number of treatment options.
