Once your doctor has diagnosed your breast cancer, he or she works to establish the extent (stage) of your cancer. Your cancer’s stage helps determine your prognosis and the best treatment options.

Complete information about your cancer’s stage may not be available until after you undergo breast cancer surgery.

Tests and procedures used to stage breast cancer may include:

• Blood tests, such as a complete blood count
• Mammogram of the other breast to look for signs of cancer
• Breast MRI
• Bone scan
• Computerized tomography (CT) scan
• Positron emission tomography (PET) scan

Not all women will need all of these tests and procedures. Your doctor selects the appropriate tests based on your specific circumstances and taking into account new symptoms you may be experiencing. 

Breast cancer stages range from 0 to IV with 0 indicating cancer that is noninvasive or contained within the milk ducts. Stage IV breast cancer, also called metastatic breast cancer, indicates cancer that has spread to other areas of the body.