Breast Cancer Staging

Cancer stages refer to tumor size and whether the cancer has spread. Breast cancer stages are slightly different that other cancers.

    Stage 0 (or carcinoma in situ)

    Cancer cells are present in the lining of a breast lobule or duct, but they have not spread to the surrounding fatty tissue.

    Stage I

    Cancer has spread from the lobules or ducts to nearby tissue and is considered invasive. The tumor is 2 cm or less in diameter (a little less than an inch). The cancer has not spread to lymph nodes.

    Stage II

    The tumor is between 2 cm-5 cm in diameter. The cancer may have spread to the lymph nodes.

    Stage IIIA

    The tumor is at least 5 cm in diameter, or of a size where cancer cells have grown extensively into the underarm lymph nodes.

    Stage IIIB

    The tumor may be any size. The cancer has spread into the breast skin or chest wall tissues.

    Stage IV

    The tumor is metastatic, and the cancer has spread to other parts of the body, such as the bones, liver, lungs or brain.

    Read more about how cancer is staged and graded.