The process of detecting the growth of the cancer within the breast and its growth in other body parts is called staging. Breast cancer is divided into four stages out of which stage II and III are further broken into sub-stages. The analysis of the cancer according to the staging process is important to determine the breast cancer stage, in order to opt for appropriate treatment course.
At this stage, breast cancer does not metastasise to parts surrounding the area of origin. This non-invasive stage is also known as ductal or lobular carcinoma in situ (DCIS or LCIS). At stage 0, abnormal cells start appearing in the ducts of the breast. Cancer at this stage is easily detectable by mammogram screenings.
Stage I of breast cancer appears when tissue becomes invasive, i.e. it grows towards other areas surrounding the cancer site. Stage I of breast cancer is characterised by tumour, which is around 2 centimetres wide. At this stage, usually it has been seen that cancer does not spread to the lymph nodes.
At stage II, the cancer has not spread to any other organs but lymph nodes of armpits. This stage has been further divided into stage IIA and stage IIB. At stage IIA, cancer is not found in breasts but it has spread to lymph nodes under the arms. The tumour is sized between two to five centimetres.
In stage IIB, the tumour is bigger than five centimetres and has spread to the lymph nodes.
This stage is broken into three sub-stages-- stage IIIA, IIIB and IIIC.