Table 1 Patients’ characteristics according to HER2 status of the relapsed site
| Â | Total n (%) | HER2-zero n (%) | HER2-low n (%) | HER2-positive n (%) | P-value |
|---|---|---|---|---|---|
Age at recurrence (Median, range) | Â | Â | Â | 0.268 | |
|  | 54 (26–93) | 54 (30–93) | 54 (26–88) | 52 (28–77) |  |
Age at recurrence (years) | Â | Â | Â | Â | 0.227 |
≤ 50 | 90 | 19 (21.1) | 41 (45.6) | 30 (33.3) |  |
> 50 | 157 | 34 (21.7) | 86 (54.8) | 37 (23.6) |  |
BCFI (months) | Â | Â | Â | Â | 0.217 |
< 12 | 31 | 5 (16.1) | 14 (45.2) | 12 (38.7) |  |
12–24 | 68 | 20 (29.4) | 31 (45.6) | 17 (25.0) |  |
> 24 | 148 | 28 (18.9) | 82 (55.4) | 38 (25.7) |  |
Type of the first relapse | Â | Â | Â | Â | 0.703 |
LRR | 89 | 19 (21.3) | 48 (53.9) | 22 (24.7) | Â |
DM | 92 | 22 (23.9) | 42 (45.7) | 28 (30.4) | Â |
CBC | 66 | 12 (18.2) | 37 (56.1) | 17 (25.8) | Â |
Site of biopsy or resection | Â | Â | Â | Â | 0.973 |
Ipsilateral breast | 34 | 8 (23.5) | 17 (50.0) | 9 (26.5) | Â |
Chest wall | 35 | 8 (22.9) | 20 (57.1) | 7 (20.0) | Â |
Lymph node | 20 | 3 (15.0) | 11 (55.0) | 6 (30.0) | Â |
Contralateral breast | 66 | 12 (18.2) | 37 (56.1) | 17 (25.8) | Â |
Lung | 21 | 6 (28.6) | 11 (52.4) | 4 (19.0) | Â |
Liver | 26 | 6 (23.1) | 11 (42.3) | 9 (34.6) | Â |
Bone | 18 | 4 (22.2) | 9 (50.0) | 5 (27.8) | Â |
Others | 27 | 6 (22.2) | 11 (40.7) | 10 (37.0) | Â |
HR status of relapse site |  |  |  | < 0.001 | |
Positive | 135 | 23 (17.0) | 92 (68.1) | 20 (14.8) | Â |
Negative | 112 | 30 (26.8) | 35 (31.3) | 47 (42.0) | Â |
Ki-67 index of relapsed site@ | Â | Â | Â | 0.267 | |
≤ 30% | 124 | 22 (17.7) | 69 (55.6) | 33 (26.6) |  |
> 30% | 94 | 24 (25.5) | 43 (45.7) | 27 (28.7) |  |