When first diagnosed with Breast Cancer, the cancer is staged depending on size and lymph node involvement. The stages are 0, I, II, III and IV. Why a site that focuses on Stage IV? Because early stages with no lymph node involvement are considered curable, Stage IV is not. (It must be noted, however, that some women in early stage with no lymph node involvement HAVE metastasized.) For more information on the complexities of individual staging (which involves hormone receptor types, ten types of Carcinomas and Paget’s Disease), please go here:

Web Path: The Internet Pathology Laboratory

Stage 0: Tumor is detectable only by mammogram or thermogram. No other involvement.
5 year survival rate = 98%; 7 year survival rate = 95%

Stage I: Tumor is 2 centimeters (3/4 inch) or smaller. Axillary lymph nodes are negative and there is no evidence of distant metastases.
5 year survival rate = 96%; 7 year survival rate = 92%

Stage II: Tumor is larger than 2 and up to 5 centimeters (3/4 to 2 inches) in size. Axillary lymph nodes may or may not be positive for cancer. (If tumor is smaller than 2 centimeters and lymph nodes are positive, cancer is considered Stage II.)
5 year survival rate = 81%; 7 year survival rate = 71%

Stage III: Tumor is larger than 5 centimeters and axillary lymph nodes are positive. Tumor may extend into the pectoral muscle or into the skin of the breast, but there are no distant metastases.
5 year survival rate = 52%; 7 year survival rate = 39%

Stage IV: If metastasis to other organs or bones has occurred, cancer is considered Stage 4 regardless of the size of the tumor in the breast or number of axillary lymph nodes affected.
5 year survival rate = 18%; 7 year survival rate = 11%

Each stage is further broken down into A and B levels.

~ Definitions from Department of Defense Breast Cancer Decision Guide for Military and Civilian Families (Site closed.)
~ Prognoses from Web Path: The Internet Pathology Laboratory
Diana Campbell, Survivor — Breast Cancer Stage IV

Note: The Internet Pathology Laboratory has changed since Diana originally referenced their information. I was unable to easily locate this information and will work on finding other sources to append this data.