The stages of breast cancer

A breast is made up of lobules, ducts, fatty tissue, blood vessels, and lymph vessels. The lobules contain many tiny sacs that make milk during breastfeeding. The ducts are tubes that carry the milk from the lobules to the nipple. The fatty tissue surrounds the lobules and ducts. Blood vessels circulate blood throughout the body. Lymph vessels carry a clear liquid called lymph away from the breast.

Your doctor will look at a number of factors, including the size of the tumor, the role of lymph nodes, and how far the cancer has spread, to determine the stage of your breast cancer.

Breast cancer stages

Early breast cancer

Stages 0, I, IIA, IIB and some cancers of stage IIIA are considered early breast cancer. At these stages, the cancer has not spread beyond the breast or the axillary lymph nodes (under the arm). However, in these early stages, the cancer hasn't reached the skin of the breast or the tissues of the chest wall, and it hasn't spread to distant locations such as the liver, lungs, bones, or brain.

Locally advanced breast cancer

Stage IIIA can be defined two different ways. The first way is if the tumor size is not large but the cancer has spread to many axiliary (under the arm) lymph nodes or lymph nodes near the breast bone. The second way is if the tumor is large but there is little lymph node spread.

Stage IIIB describes advanced breast cancer in which the tumor has spread to the chest wall or the skin of the breast and may or may not have spread to lymph nodes.

Stage IIIC describes cancer that has spread to lymph nodes below or above the collarbone, to many axillary (under the arm) lymph nodes, or to lymph nodes near the breastbone. The tumor may be any size.

Metastatic breast cancer

Stage IV describes metastatic breast cancer in which the cancer has spread from the breast to other parts of the body, such as the bones (bone metastases), liver, lungs, or brain (visceral metastases). Learn more about metastatic breast cancer. Metastatic breast cancer often develops as a recurrence of a previously diagnosed breast cancer. In a small number of cases, metastatic breast cancer is diagnosed when there was no prior history of breast cancer.

Learn about breast cancer recurrence