National Breast Cancer Foundation, Inc.

Stage 0

Carcinoma in situ. Lobular carcinoma in situ (LCIS): Abnormal cells are in the lining of a lobule. LCIS seldom becomes invasive cancer. However, having LCIS in one breast increases the risk of cancer for both breasts.

Ductal carcinoma in situ (DCIS): Abnormal cells are in the lining of a duct, but have not spread outside the duct, nor invaded the nearby breast tissue. DCIS sometimes becomes invasive cancer if not treated.

Stage I

Early stage of invasive breast cancer. The tumor is no more than 2 centimeters across. Cancer cells have not spread beyond the breast.

Stage II

Stage II can be one of the following:

• The tumor in the breast is no more than 2 centimeters across. The cancer has spread to the lymph nodes under the arm.
• The tumor is between 2 and 5 centimeters. The cancer may have spread to the lymph nodes under the arm.
• The tumor is larger than 5 centimeters. The cancer has not spread to the lymph nodes under the arm.

Stage III

Stage III may be a large tumor, but the cancer has not spread beyond the breast and nearby lymph nodes. It is locally advanced cancer.

Stage IIIA

The cancer has spread to the underarm lymph nodes

Stage IIIB

The tumor has grown into the chest wall or the skin of the breast; the cancer has spread to lymph nodes behind the breastbone; or you could develop IBC.

Stage IIIC

A tumor of any size that has spread to the lymph nodes behind the breastbone and under the arm, or to the lymph nodes under or above the collarbone.

Stage IV

A distant metastic cancer that has spread to other parts of the body