After breast cancer diagnosis, are made some investigations to detect if cancer cells have spread inside the mammary gland or in the other parts of the body. The process which detect if the tumor has spread inside the mammary gland or other parts of the body is called staging. Information obtained following completion of the staging process, determine the stage of disease.

Stages of breast cancer:



Stage 0 (carcinoma in situ)

There are 2 types of carcinoma in situ:

- ductile carcinoma in situ which is a non-invasive tumor, a precancerous stage in which the proliferation of modified cells lining superficial layer that are lining the mammary gland ducts. These modified cells are confined to the ducts, not spreading in the other tissues of the breast. Although currently there are no known factors that predispose to ductile carcinoma in situ transformation into an invasive tumor, but in some instances, ductile carcinoma in situ may become an invasive tumor and may spread to other tissues.



- lobular carcinoma in situ it is the tumor stage in which changed cells have as a starting point lobules of the mammary gland. In rare cases, lobular carcinoma in situ may become an invasive tumor.

Stage I

In this stage, the tumor is 2 centimeters or smaller, and it does not spread outside the breast.

Stage II

Stage IIA

In this stage:

- the tumor is not detected in the mammary gland, but is detected in the auxiliary lymph nodes. (lymph nodes from armpits)

- the tumor is 2 centimeters or smaller and it spread to the axillary lymph nodes.

- the tumor is greater than 2 centimeters but no more than 5 centimeters, and it did not spread to the axillary lymph nodes.



Stage IIB

In stage IIB, mammary gland tumor can be:

- more than 2 centimeters but no more than 5 centimeters, and it spread to the axillary lymph nodes.

- more than 5 centimeters but it did not spread to the axillary lymph nodes.

Stage IIIA

- the tumor is not found in breast but in the axillary lymph nodes, which is a conglomerate mass, attached to each other or to other structures.

- the tumor is 5 centimeters or smaller and it spread to the lymph nodes
- the tumor is greater than 5 centimeters and it spread to the lymph nodes.



Stage IIIB

In stage IIIB, the tumor can be any size and:

- has spread to near the breast tissues (to skin or chest wall, including the ribs and muscle tissue of the chest).

- it can spread to the lymph nodes within the breast or armpits.
Stage IIIC

In stage IIIC, the tumor has spread to the lymph nodes under the clavicle and in the lymph nodes near the neck. Breast cancer in stage IIIC is classified as: a cancer that can be treated thru surgery and one that can’t be treat thru surgery.

Stage IV

In stage IV, the tumor has spread to other parts of the body, more often in bones, lung, liver or brain.