Table 1.

Risk categories for early breast cancer according to the St. Gallen Guidelines. Reprinted from [25], with permission from the European Society for Medical Oncology

Low risk	Steroid hormone receptors expression, node-negative, and all of the following features:
	pT ≤ 2 cm
	Grade 1
	No peritumoral vascular invasion
	HER2/neu gene neither overexpressed nor amplified
	Age ≥35 years
Intermediate risk	Node-negative and at least one of the following features:
	pT > 2 cm
	Grade 2–3
	Peritumoral vascular invasion
	HER2/neu gene either overexpressed or amplified
	Age < 35 years
	Node positive (1–3 involved nodes) and HER2/neu gene neither overexpressed nor amplified
High risk	Node positive (1–3 involved nodes) and HER2/neu gene either overexpressed or amplified
	Node-positive (4 or more involved nodes)

HER2 human epithelial growth factor receptor 2

pT pathological tumor size (i.e. size of the invasive component)