Stages of Breast Cancer
Edited By: Stephanie Dawson
The stages of breast cancer are defined on a scale from 0 to IV. Stage 0 is the least dangerous and stage IV is the last stage and most dangerous. Stages describe the size, location, and severity of the cancer.
Stage 0 is generally a cancer which is non-invasive. In this stage there are no signs of cancer cells invading other parts of the body. In this stage cancer cells do not endanger neighboring tissues.
Stage I breast cancer refers to invasive cancer and can be divided into 2 parts.
Invasive cancer in which tumors are up to 2 centimeters in size and the cancer cells have not spread to other parts of the body.
In this stage there are no tumors. Small groups of cancer cells ranging from 0.2 mm to 2 mm in size are found on lymph nodes or there is a tumor in the lymph nodes.
Stage II is divided into two sub-stages
There is no breast tumor but the cancer (bigger than 2 mm) exists in 1 to 3 lymph nodes under the arms. It may also mean that the tumor is 2 cm in size and has invaded the axillary lymph nodes. Another interpretation of this stage is that the tumor has grown to more than 2 cm but still smaller than 5cm and has not spread to the axillary lymph.
Invasive breast cancer in which the tumor is bigger than 2 cm but is smaller than 5cm. Small groups of breast cancer cells which are larger than 0.2 mm in size but smaller than 2mm are present in lymph nodes. It may also mean that the tumor is larger than 5 cm but has not spread to lymph nodes.
Stage III is divided into 3 sub-stages
No tumor exists in the breast, cancer cells have reached 4 – 9 lymph nodes and have invaded the lymph nodes near the breast bone. Another interpretation may include a tumor larger than 5 cm, small groups of breast cancer greater 0.2 mm but smaller than 2 mm are present in the lymph nodes under the arms.
The tumor may be any shape and size invading the chest wall and spreading to breast skin causing swelling and ulcers. It may also mean cancer cells have spread to 9 lymph nodes and have invaded the lymph nodes near the breastbone. Cancer cells may also be found in the skin at this stage.
The tumor can be any shape and size and has reached more than 10 axillary lymph nodes, cancer cells have spread above and below the collarbone and all the lymph nodes have been invaded.
Cancer has invaded the entire breast and has reached other parts of the body including lungs, liver, brain, distant lymph nodes, and skin. Words such as advanced and metastatic are used to describe this final stage of breast cancer.
Cancer may be at stage IV in the first examination or it may be a result of reoccurrence of previous cancer that has invaded other parts of the body.