| Characteristic | ARM positive (n = 9) | ARM negative (n = 21) | P value |
|---|
| n | % | n | % |
|---|
| Age, years | | | | | 1.000 |
| ≥ 50 | 6 | 66.7 | 14 | 66.7 | |
| < 50 | 3 | 33.3 | 7 | 33.3 | |
| cT stage | | | | | 0.188 |
| T1 | 1 | 11.1 | 8 | 38.1 | |
| T2 | 7 | 77.8 | 12 | 57.1 |
| T3 | 0 | 0.0 | 1 | 4.8 |
| T4 | 1 | 11.1 | 0 | 0 |
| cN stage | | | | | 0.093 |
| N0 | 2 | 22.2 | 1 | 4.8 | |
| N1 | 3 | 33.3 | 15 | 71.4 |
| N2 | 2 | 22.2 | 4 | 19.0 |
| N3 | 2 | 22.2 | 1 | 4.8 |
| Histological type | | | | | 0.128 |
| Ductal | 6 | 66.7 | 8 | 38.1 | |
| Lobular | 1 | 11.1 | 0 | 0 |
| Mixed | 2 | 22.2 | 11 | 52.4 |
| Unknown | 0 | 0 | 2 | 9.5 | |
| ER status | | | | | 0.300 |
| Positive | 8 | 88.9 | 21 | 100 | |
| Negative | 1 | 11.1 | 0 | 0 | |
| PR status | | | | | 0.418 |
| Positive | 4 | 44.4 | 14 | 66.7 | |
| Negative | 5 | 55.6 | 7 | 33.3 | |
| HER2 status | | | | | 0.666 |
| Positive | 3 | 33.3 | 5 | 23.8 | |
| Negative | 6 | 66.7 | 16 | 76.2 | |
| Ki-67 status | | | | | 0.229 |
| Positive | 7 | 77.8 | 10 | 47.6 | |
| Negative | 2 | 22.2 | 11 | 52.4 | |
| Neoadjuvant therapy | | | | | 1.000 |
| No | 6 | 66.7 | 15 | 71.4 | |
| Yes | 3 | 33.3 | 6 | 28.6 | |
| Axillary surgery | | | | | 0.204 |
| SLNB+ALND | 1 | 11.1 | 9 | 42.6 | |
| ALND | 8 | 88.9 | 12 | 57.4 | |
- cT clinical tumour, cN clinical lymph node, ER oestrogen receptor, PR progesterone receptor, Her-2 human epidermal growth factor receptor 2, SLNB sentinel lymph node biopsy, ALND axillary lymph node dissection, ARM axillary reverse mapping
