Breast cancer staging measures the spread of the disease upon diagnosis. In order to determine the choice of treatment, it is very important to stage the cancer.

The stage depends on the size of the tumor, where it has spread, and whether the lymph nodes are affected or not.

Breast cancer has five possible stages:

 

Stage Tumer size Lymph nodes Spreading 5-year survival rate
Stage 0

very small, inside
the glands

 no cancer

confined to the breast area,
not outside

 100%
Stage I less than 2 cm no cancer

confined to the breast area,
not outside

 98%
Stage II 2-5 cm affected by cancer

confined to the breast area,
​​​​​​​not outside

 87%
Stage III 5 cm and larger

affected by cancer;
cancer has reached
the muscles and skin

confined to the breast area,
not outside

 61%
Stage IV any size affected by cancer cancer has spread outside
​​​​​​​the breast area to any part of the body		 20%.