There are five stages of Breast Cancer. Stage 0 is called nonivasive carcinoma.  Stage I is when the tumor is no more than 2 cm across and has not spread past the breast.  Stage II has three conditions that could apply: the cancer has spread to the lymph nodes under the arm and is 2cm across or the tumor has not spread to the lymph nodes but is 2-5 cm or the tumor has not spread to the lymph nodes under the arm but is larger than 5cm. Stage III is known as locally advanced and in this stage the tumor is more than 5cm across in the breast and has spread to the underarm lymph nodes or has spread to other lymph nodes or tissues near the breast.  Stage IV is also known as Metastasized Cancer.  Here the cancer has spread to other parts of the body from the breast.