Stages of Breast Cancer

After the diagnostic tests and biopsy confirming breast cancer have been completed, the specialists at the Cedars-Sinai Breast Cancer Program can determine the stage of breast cancer and the most effective treatment. Breast cancer is treatable in most instances.

When cancer is the cause of a tumor, it is called malignant. Malignant tumors can invade and damage nearby tissues and organs. Cancer cells can also break away from the malignant tumor and enter the bloodstream or lymphatic system. Once in the bloodstream or lymphatic system, breast cancer can spread and form secondary tumors in other parts of the body, including the lymph nodes, brain, lungs, bones, and liver. The spread of cancer to other parts of the body is called metastasis.

Breast cancer is a progressive disease. As it advances it goes through various stages. The staging system helps doctors determine the extent of the cancer, and can help them determine the best option for treatment.

Stage 0

Stage 0 is sometimes called noninvasive carcinoma or ductal carcinoma in situ (DCIS). The cancer has not spread from the duct into the surrounding breast tissues.

Stage I and Stage II

Stage I and stage II are also early stages of breast cancer, in which the cancer has spread beyond the lobe or duct and invaded nearby tissue in the breast. In stage I breast cancer, the cancer cells have not spread beyond the breast and the tumor is no more than two centimeters in size. In stage II, the cancer is two centimeters or smaller and has spread to underarm lymph nodes, or the tumor in the breast is larger than two centimeters but smaller than five centimeters and has not spread to lymph nodes under the arm.

Stage III

Stage III, or locally advanced cancer, means the tumor in the breast is larger than five centimeters and cancer has more extensively involved the axillary lymph nodes, causing them to be attached to each other or to other structures, or has spread to the other lymph nodes near the breast bone or other tissues such as the skin of the breast or chest wall.

Stage IV

Stage IV cancer means the tumor has spread from the breast to other parts of the body such as the brain, lungs, bones, and liver.

Recurrent Cancer

Recurrent cancer means that the disease has reappeared after a period of months or years following completion of treatment. Recurrence of cancer is still possible even though treatment seemed to be successful at first, either because undetected cancer cells remained in the body or the disease had spread before treatment could begin. Breast cancer can recur or return in the breast or chest wall (for those who were treated with mastectomy), underarm or neck lymph nodes, or elsewhere (distant recurrence), such as the brain, lungs, bones, and liver. Because distance recurrence can be treated but not cured, treatment of the original breast cancer usually involves more than just surgery.