Table 1.
Patients’ characteristics according to HER2 status of the relapsed site
| Total n (%) |
HER2-zero n (%) |
HER2-low n (%) |
HER2-positive n (%) |
P-value | |
|---|---|---|---|---|---|
| Age at recurrence (Median, range) | 0.268 | ||||
| 54 (26–93) | 54 (30–93) | 54 (26–88) | 52 (28–77) | ||
| Age at recurrence (years) | 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) | 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 | 0.703 | ||||
| LRR | 89 | 19 (21.3) | 48 (53.9) | 22 (24.7) | |
| DM | 92 | 22 (23.9) | 42 (45.7) | 28 (30.4) | |
| CBC | 66 | 12 (18.2) | 37 (56.1) | 17 (25.8) | |
| Site of biopsy or resection | 0.973 | ||||
| Ipsilateral breast | 34 | 8 (23.5) | 17 (50.0) | 9 (26.5) | |
| Chest wall | 35 | 8 (22.9) | 20 (57.1) | 7 (20.0) | |
| Lymph node | 20 | 3 (15.0) | 11 (55.0) | 6 (30.0) | |
| Contralateral breast | 66 | 12 (18.2) | 37 (56.1) | 17 (25.8) | |
| Lung | 21 | 6 (28.6) | 11 (52.4) | 4 (19.0) | |
| Liver | 26 | 6 (23.1) | 11 (42.3) | 9 (34.6) | |
| Bone | 18 | 4 (22.2) | 9 (50.0) | 5 (27.8) | |
| Others | 27 | 6 (22.2) | 11 (40.7) | 10 (37.0) | |
| HR status of relapse site | < 0.001 | ||||
| Positive | 135 | 23 (17.0) | 92 (68.1) | 20 (14.8) | |
| Negative | 112 | 30 (26.8) | 35 (31.3) | 47 (42.0) | |
| Ki-67 index of relapsed site@ | 0.267 | ||||
| ≤ 30% | 124 | 22 (17.7) | 69 (55.6) | 33 (26.6) | |
| > 30% | 94 | 24 (25.5) | 43 (45.7) | 27 (28.7) | |
@ 29 patients had unknown Ki-67 index for relapsed site
Abbreviation: BCFI = Breast cancer-free interval, LRR = local-regional recurrence, DM = distant metastasis, CBC = contralateral breast cancer, HR = hormone receptor