There are 5 stages of breast cancer. Determining the stage of your cancer is an important part of diagnosis and treatment. While your doctor will be the one to guide you through this process, this website is a good place to begin learning about breast cancer and the different breast cancer stages. Use this information to inform your dialogue with your healthcare providers.
Stages: General Information
- The stage of any breast cancer is shown as a numeral from 0 to IV. This numeral is based on the size of your tumor (if present) and whether the cancer has spread to your lymph nodes and other parts of your body.
- Your doctor(s) will ask questions about your medical history, perform a physical examination, and review tests and biopsy results to determine your cancer stage.
- Your stage is often not fully known until after the surgery to remove any tumor in your breast and sample the lymph nodes in your arm. Additional tests, such as blood work and X-rays, may be needed.
- Breast cancer staging is complex. As doctors and other healthcare professionals work to learn more about breast cancer, the classification system may change.
Stages: Specific Information for Stages 0-IV
Lower numbers indicate the earlier stages of cancer, while higher numbers indicate later stages. A brief description of the traits of each stage follows. Consult your doctor for more thorough information about each particular stage of breast cancer.
This stage describes noninvasive breast cancer that has not spread within the breast or to other parts of the body. In Stage 0, there is no evidence of cancer cells or non-cancerous abnormal cells invading surrounding normal tissue.
An early stage of invasive breast cancer, Stage I means that the tumor measures no more than 2 centimeters in diameter AND no lymph nodes are involved - the cancer has not spread outside of the breast.
Stage II is an invasive stage of breast cancer that is divided into two subcategories: IIA and IIB.
Stage IIA describes breast cancer for which one of the following is true:
- The tumor is between 2 cm and 5 cm and has not spread to the axillary (underarm) lymph nodes.
- The tumor measures 2 cm or smaller and has spread to the axillary lymph nodes.
- No tumor is present in the breast, but cancer is found in the axillary lymph nodes.
Stage IIB describes breast cancer that meets one of these conditions:
- The tumor is between 2 cm and 5 cm and has spread to the lymph nodes.
- The tumor is larger than 5 cm but has not spread to the lymph nodes.
By definition, stage III breast cancer - though invasive - has not spread to distant sites. Stage III is divided into 3 subcategories: IIIA, IIIB, and IIIC.
Stage IIIA cancer is a stage wherein there may be no tumor present in the breast or a tumor of any size and the cancer has spread to the axillary lymph nodes or the lymph nodes found near the breast bone. At this stage, any affected axillary lymph nodes clump together and attach to one another or surrounding structures.
Stage IIA cancer is a stage wherein:
- there may be no tumor present OR
- a tumor of any size AND
- cancer has spread to the axillary lymph nodes OR
- cancer has spread to the lymph nodes found near the breast AND
- any affected axillary lymph nodes clump together and attach to one another or surrounding tissues
In stage IIIB a tumor of any size may be present, and cancer has spread to tissue near the breast - including the skin and chest wall - and may have spread to axillary lymph nodes or lymph nodes near the breast bone. Cancer that has spread to the skin is inflammatory breast cancer, an uncommon but aggressive form of stage IIIB cancer.
Stage IIIC breast cancer involves a tumor of any size and cancer that has spread in any of the following ways:
- To ten or more axillary lymph nodes
- To lymph nodes above or beneath the collarbone and neck
- To axillary lymph nodes and to lymph nodes within the breast
Stage IV breast cancer is the most severe stage. At this stage, the cancer has spread to other, distant organs of the body - most frequently the lungs, liver, bones, or brain.