Table 1. Proportion of N stage in T1–2 invasive breast cancer patients with clinical N0 but metastatic lymph node as sentinel lymph node biopsy.
| Characteristic | Total (n = 1,437) | N1 (n = 1,355) No. (%) | N2 or N3 (n = 82) No. (%) | p-value |
|---|---|---|---|---|
| No. of metastatic LN | < 0.001 | |||
| Metastatic LN = 1 | 1,109 | 1,074 (96.8) | 35 (3.2) | |
| Metastatic LN = 2 | 328 | 281 (85.7) | 47 (14.3) | |
| Metastatic LN = 1 | 0.128 | |||
| S1N0* | 1,004 | 975 (97.1) | 29 (2.9) | |
| S0N1† | 105 | 99 (94.2) | 6 (5.8) | |
| Metastatic LN = 2 | 0.107 | |||
| S1N1 | 108 | 87 (80.6) | 21 (19.4) | |
| S2N0 | 204 | 181 (88.7) | 23 (11.3) | |
| S0N2 | 16 | 13 (81.3) | 3 (18.7) | |
| Subtype | 0.295 | |||
| Luminal A-like | 1,056 | 996 (94.3) | 60 (5.7) | |
| Luminal B-like | 135 | 126 (91.9) | 9 (8.1) | |
| HER2 | 107 | 100 (93.5) | 7 (6.5) | |
| TNBC | 139 | 135 (97.2) | 4 (2.9) | |
| Luminal A-like | < 0.001 | |||
| Metastatic LN = 1 | 809 | 785 (97.0) | 24 (3.0) | |
| Metastatic LN = 2 | 249 | 213 (85.5) | 36 (14.5) | |
| Luminal B-like | 0.125 | |||
| Metastatic LN = 1 | 104 | 98 (94.2) | 6 (5.8) | |
| Metastatic LN = 2 | 31 | 26 (83.8) | 5 (16.2) | |
| HER2 | 0.664 | |||
| Metastatic LN = 1 | 82 | 77 (93.9) | 5 (6.1) | |
| Metastatic LN = 2 | 25 | 23 (92.0) | 2 (8.0) | |
| TNBC | 0.001 | |||
| Metastatic LN = 1 | 114 | 114 (100) | 0 | |
| Metastatic LN = 2 | 25 | 21 (84.0) | 4 (16.0) |
N1=nodal stage 1; N2=nodal stage 2; N3, nodal stage3; LN=lymph node; S, sentinel node; N, non-sentinel node; HER2=human epidermal growth factor receptor 2; TNBC=triple-negative breast cancer.
*S1N0, 1 metastatic sentinel lymph node and no metastatic non-sentinel lymph node during sentinel lymph node biopsy; †S0N1, no metastatic sentinel lymph node and 1 metastatic non-sentinel lymph node during sentinel lymph node biopsy.