Current National Comprehensive Cancer Network (NCCN) guidelines version 3.2012 do not recommend adjuvant chemotherapy or anti-HER2 therapy for T1aN0 tumors, and have only suggested considering these systemic therapies for patients with HER2-positive T1bN0 disease and additional unfavorable features, such as hormone receptor-negative (HR-negative) tumor, extensive lymphovascular space invasion, or moderately/poorly differentiated tumors. Here, ERBB2 is linked to neoplasm.