Metastatic breast cancer

American Joint Committee on Cancer (AJCC): cancer staging manual. 8th Edition[1]Edge SB, Byrd DR, Brookland RK, et al (eds). AJCC cancer staging manual. 8th ed. New York, NY: Springer; 2017.

Defines metastatic (stage IV) breast cancer as disease that has spread beyond the breast and regional lymph nodes to distant organs (e.g., lungs, brain, liver, bone, distant lymph nodes).