Stage I includes: IA: (T1, N0, M0, G1, HER2 Status: Positive, ER Status: Any, PR Status: Any); (T1, N0, M0, G1-2, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T1, N0, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T1, N0, M0, G3, HER2 Status: Positive, ER Status: Positive, PR Status: Any); (T0-1, N1mi, M0, G1, HER2 Status: Positive, ER Status: Any, PR Status: Any); (T0-1, N1mi, M0, G1-2, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T0-1, N1mi, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T0-1, N1mi, M0, G3, HER2 Status: Positive, ER Status: Positive, PR Status: Any); (MultiGene Panel-Oncotype Dx Recurrence Score Less Than 11, T1-2, N0, M0, G1-3, HER2 Status: Negative, ER Status: Positive, PR Status: Any); IB: (T1, N0, M0, G1, HER2 Status: Negative, ER Status: Positive, PR Status: Negative); (T1, N0, M0, G1, HER2 Status: Negative, ER Status: Negative, PR Status: Positive); (T1, N0, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Negative); (T1, N0, M0, G2, HER2 Status: Positive, ER Status: Negative, PR Status: Any); (T1, N0, M0, G2, HER2 Status: Negative, ER Status: Negative, PR Status: Positive); (T1, N0, M0, G3, HER2 Status: Positive, ER Status: Negative, PR Status: Any); (T1, N0, M0, G3, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T0-1, N1mi, M0, G1, HER2 Status: Negative, ER Status: Positive, PR Status: Negative); (T0-1, N1mi, M0, G1, HER2 Status: Negative, ER Status: Negative, PR Status: Positive); (T0-1, N1mi, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Negative); (T0-1, N1mi, M0, G2, HER2 Status: Positive, ER Status: Negative, PR Status: Any); (T0-1, N1mi, M0, G2, HER2 Status: Negative, ER Status: Negative, PR Status: Positive); (T0-1, N1mi, M0, G3, HER2 Status: Positive, ER Status: Negative, PR Status: Any); (T0-1, N1mi, M0, G3, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T2, N0, M0, G1-3, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T2, N0, M0, G1-2, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T1, N1, M0, G1-3, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T1, N1, M0, G1-2, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T2, N1, M0, G1, HER2 Status: Negative, ER Status: Positive, PR Status: Positive); (T2, N1, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T0-2, N2, M0, G1-2, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T3, N1-2, M0, G1, HER2 Status: Positive, ER Status: Positive, PR Status: Positive); (T3, N1-2, M0, G2, HER2 Status: Positive, ER Status: Positive, PR Status: Positive). T0: No evidence of primary tumor. T1: Tumor measuring 20 mm or less in greatest dimension. T2: Tumor measuring more than 20 mm, but not more than 50 mm in greatest dimension. T3: Tumor measuring more than 50 mm in greatest dimension. N0: No regional lymph node metastasis is identified or isolated tumor cell clusters (ITCs) are identified only. N1: Tumor with micrometastases; or metastases in 1-3 axillary lymph nodes; and/or clinically negative internal mammary nodes with micrometastases or macrometastases by sentinel lymph node biopsy. N1mi: Micrometastases (approximately 200 cells, larger than 0.2 mm, but none larger than 2.0 mm). N2: Tumor with metastases in 4-9 axillary lymph nodes; or positive ipsilateral internal mammary lymph nodes by imaging in the absence of axillary lymph node metastases. G1: Low combined histologic grade (favorable); SBR score of 3-5 points. G2: Intermediate combined histologic grade (moderately favorable); SBR score: 6-7 points. G3: High combined histologic grade (unfavorable); SBR score of 8-9 points. M0: No clinical or radiographic evidence of distant metastases. Imaging studies are not required to assign the M0 category. (AJCC 8th ed.) [from NCI]