1 .- Stage 0
Noninvasive breast cancer or in situ.
a) Ductal carcinoma in situ (DCIS): Cancer cells are located within a duct, there is no invasion of surrounding fatty tissue.
b) Lobular carcinoma in situ (LCIS): The atypical cells grow inside the milk-producing glands, and do not penetrate through the walls of the lobe.
2 .- Stage I
The tumor is less than 2 centimeters in diameter. Has not spread beyond the breast.
3 .- Stage II
It is divided into IIA and IIB.
a) Stage IIA. It includes three categories: non-palpable tumor with positive lymph nodes but mobile, not fixed to each other, tumor less than or equal to 2 cm in greatest diameter with positive axillary nodes and tumors moving between 2 and 5 cm with negative axillary nodes.
b) Stage IIB. Two modes: Tumors between 2 and 5 cm in greatest diameter, axillary node-positive phones, tumors larger than 5 cm in greatest diameter, with negative lymph nodes in the armpit.
4 .- Stage III
This stage is divided into IIIA and IIIB:
a) Stage IIIA. They have the following modalities: non-palpable tumors, tumor diameter greater or less than 2 cm and tumors between 2 and 5 centimeters, if they have positive lymph nodes, fixed to each other or that have invaded other structures in the armpit. O tumors larger than 5 cm in greatest diameter with any positive node in the armpit.
b) Stage IIIB: Breast cancer of any size that has spread to the chest wall, skin of the breast or chest wall or skin and inflammatory carcinoma of the breast. Or any size tumor with positive nodes in the internal mammary tumor on the same side.
5 .- Stage IV
Cancer regardless of its size, has spread (metastasized) to distant organs such as bones, lungs or
