Breast cancer stages are based on whether the cancer is invasive or non-invasive, whether the lymph nodes have been affected, whether the cancer cells have already spread beyond the breast, and the size of the tumor.

The purpose of identifying the stage in breast cancer is to organize the different factors and features of the cancer. In organizing the factors involved, the prognosis or the most likely outcome of the disease will be identified. The doctor can also provide the patient with the best treatment guide for the disease.

Stage 0. In this stage, the breast cancer is non-invasive. It just simply means that there is no sign of non-cancerous abnormal cells or cancerous cells getting out of the part of the breast where they started. These cells have not yet invaded other neighboring normal tissues in the breast.

Stage 1.

In this stage, the breast cancer is said to be invasive. The cancer cells are already breaking out of the part of the breast where they started and they have already invaded neighboring normal tissues. But in Stage 1, the lymph nodes are not affected or involved and the tumor measures up to 2 centimeters.

Stage 2.

Stage 2 is described as invasive breast cancer and is subdivided into two categories: Stage 2A and Stage 2B. In Stage 2A, there is no tumor in the breast but a 2 centimeters or less tumor can be found scattered in the axillary lymph nodes, which is the lymph node found under the arm.

Another case of Stage 2A is that, the tumor is larger than 2 centimeters but not more than 5 centimeters and has not spread in the axillary lymph nodes. In stage 2B, the tumor is also larger than 2 centimeters but not more than 5 and has already spread to the axillary lymph nodes or if the tumor is larger than 5 centimeters, the tumor has not yet spread the axillary lymph nodes.

Stage 3.

Stage 3 is described as one of the invasive breast cancer stages and is subdivided into 3 categories: Stage 3A, Stage 3B and Stage 3C. In Stage 3A, there is no tumor in the breast but it is found in the axillary lymph nodes or the lymph nodes near the breast bone. The tumor has the size of less than 5 centimeters or more and they are clustered together or they may stick to other structures.

In Stage 3B, the tumor may be of any size and found in the lymph nodes under the arm or near the breastbone, chest wall and/or skin of the breast, clustered together or sticking to other structures. In Stage 3C, there can still be no sign of cancer in the breast. The tumor may be of any size and found to be spread to the chest wall, lymph nodes above or below the collarbone, lymph nodes under the arm or breastbone.

Stage 4.

Stage 4 is described as one of the invasive breast cancer stages in which the cancer has already spread to other organs of the body; usually the brain, lungs, liver or bone.