How are the stages of breast cancer assigned?

Breast cancer staging

Staging describes the type and severity of breast cancer. In the United States, the most common breast cancer staging method is the “TNM” system and is based on the following factors:

• How large is the primary tumor? (“T”)
• Are the lymph nodes affected? (“N”)
• How widespread are the cancer cells? (“M”)
• What type of breast tissue is affected?
• How abnormal are the cancer cells?

TNM grades are combined to assign the stage of breast cancer. Accessing the stage of cancer is important to determine the appropriate type of treatment plan.