Staging classification follows these models: The anatomic staging model, which is based on anatomy of the tumor and which is used in regions of the world where biomarkers cannot be routinely obtained (see table Anatomic Staging of Breast Cancer) The prognostic staging model, which is based on anatomy of the tumor as well as status of biomarkers and which is predominantly used in the US Table Fertility preservation Patients with breast cancer should not become pregnant while being treated for breast cancer.