Breast cancer is classified by stages of development. The classification allows a better understanding of prognosis, it is better to choose the treatment (because treatment depends on the stage of disease) and in addition, the classification makes it possible to describe the breast cancer staging, so that was understandable to all doctors.

*       Early (zero) stage of breast cancer is considered as a state in which the malignancy is localized in the breast tissue and there are no signs of circulation to the lymph nodes.

*       Stage 1 of breast cancer: tumor size less than two centimeters, metastases to other organs and tissues are not available.

*        Stage 2A: tumor less than 2 cm in cross section with the involvement of the lymph node, or tumor from 2 to 5 cm without involvement of axillary lymph nodes.

*        Stage 2B: tumor more than 5 cm in cross section (the result of axillary lymph nodes research is negative for cancer cells) or tumor from 2 to 5 cm in diameter with the involvement of axillary lymph nodes.

*        Late (metastatic) stages of breast cancer occur when cancer cells spread to the lymph nodes and other tissues.

*        Stage 3A (also called local spread of breast cancer): tumor more than 5 cm with spread to axillary lymph nodes, or tumor of any size with metastases in axillary lymph nodes, which are knitted to each other or with the surrounding tissues.

*        Stage 3B: tumor of any size with metastases into the skin, chest wall or internal lymph nodes of mammary gland (located below the breast inside of chest).

*        Stage 3C: tumor of any size with a more widespread metastases and involvement of more lymph nodes.

*        Stage 4 of breast cancer is defined as the presence of tumors (regardless of the sizes), spread to parts of the body that are located far from the chest (bones, lungs, liver, brain or distant lymph nodes).