Table 1.
Baseline clinicopathological characteristics according to HER2 status of 1363 BC patients
| Clinicopathological characteristics | Overall (N = 1363, %) | HER2-null (86, 6.3%) | HER2 ultra-low (395, 29.0%) | HER2-low (882, 64.7%) | P (HER2 status) | |
|---|---|---|---|---|---|---|
| Null vs ultra-low | Ultra-low vs low | |||||
| Age/years | ||||||
| Median/range | 52/24–89 | 52/30–79 | 51/24–85 | 53/25–89 | 0.791* | 0.129* |
| Mean ± SD | 53.2 ± 11.3 | 52.8 ± 11.4 | 52.5 ± 11.1 | 53.5 ± 11.3 | ||
| Menopaual status | ||||||
| Pre/perimenopausal | 771 (56.6) | 47 (54.7) | 232 (58.7) | 492 (55.8) | 0.487 | 0.325 |
| Postmenopausal | 592 (43.4) | 39 (45.3) | 163 (41.3) | 390 (44.2) | ||
| Breast position | ||||||
| Left | 696 (51.1) | 44 (51.2) | 206 (52.2) | 446 (50.6) | 0.868 | 0.600 |
| Right | 667 (48.9) | 42 (48.8) | 189 (47.8) | 436 (49.4) | ||
| Tumor size/cm | ||||||
| Median/range | 2/0.3–10 | 2/0.6–5.5 | 1.9/0.4–7.5 | 2/0.3–10 | 0.982* | 0.401* |
| Mean ± SD | 2.2 ± 1.1 | 2.1 ± 0.7 | 2.1 ± 1.0 | 2.2 ± 1.1 | ||
| Tumor multiplicity | ||||||
| Single | 1240 (91.0) | 79 (91.9) | 361 (91.4) | 800 (90.7) | 0.888 | 0.692 |
| Multiple | 123 (9.0) | 7 (8.1) | 34 (8.6) | 82 (9.3) | ||
| Histologic type | ||||||
| Ductal | 1145 (84.0) | 63 (73.3) | 331 (83.8) | 751 (85.1) | 0.016 | 0.817 |
| Lobular | 63 (4.6) | 10 (11.6) | 17 (4.3) | 36 (4.1) | ||
| Other | 155 (11.4) | 13 (15.1) | 47 (11.9) | 95 (10.8) | ||
| Grade | ||||||
| 1 | 81 (5.9) | 7 (8.1) | 26 (6.6) | 48 (5.4) | 0.057 | 0.066 |
| 2 | 929 (68.2) | 44 (51.2) | 256 (64.8) | 629 (71.3) | ||
| 3 | 353 (25.9) | 35 (40.7) | 113 (28.6) | 205 (23.2) | ||
| pT | ||||||
| 1 | 746 (54.7) | 47 (54.7) | 224 (56.7) | 475 (53.9) | 0.787 | 0.600 |
| 2 | 586 (43.0) | 38 (44.2) | 163 (41.3) | 385 (43.7) | ||
| 3 | 31 (2.3) | 1 (1.1) | 8 (2.0) | 22 (2.4) | ||
| pN | ||||||
| 0 | 184 (13.5) | 13 (15.1) | 54 (13.7) | 117 (13.3) | 0.261 | 0.048 |
| 1 | 265 (19.4) | 12 (14.0) | 62 (15.7) | 191 (21.7) | ||
| 2 | 85 (6.2) | 9 (10.5) | 18 (4.5) | 58 (6.6) | ||
| 3 | 51 (3.7) | 2 (2.3) | 15 (3.8) | 34 (3.8) | ||
| Unknown | 778 (57.1) | 50 (58.1) | 246 (62.3) | 482 (54.6) | ||
| HR status | ||||||
| Positive | 1156 (84.8) | 62 (72.1) | 320 (81.0) | 774 (87.8) | 0.064 | 0.001 |
| Negative | 207 (15.2) | 24 (27.9) | 75 (19.0) | 108 (12.2) | ||
| Ki67 | ||||||
| Median/range | 2/1–90 | 2/1–90 | 2/1–90 | 2/1–80 | 0.722* | <0.001* |
| Mean ± SD | 11.5 ± 18.9 | 16.5 ± 24.8 | 15.6 ± 22.4 | 9.2 ± 15.8 | ||
| TILs | ||||||
| Median/range | 10/1–90 | 5/1–80 | 5/1–80 | 10/1–90 | 0.677* | 0.517* |
| Mean ± SD | 13.6 ± 15.0 | 14.0 ± 19.0 | 13.2 ± 14.9 | 13.7 ± 14.7 | ||
| Unknown | 18 | 2 | 6 | 10 | ||
| Type of surgery | ||||||
| BCS/+BR | 343 (25.2) | 19 (22.1) | 104 (26.3) | 220 (24.9) | 0.717 | 0.049 |
| Mastectomy | 418 (30.6) | 31 (36.0) | 135 (34.2) | 252 (28.6) | ||
| Mastectomy + ALND | 602 (44.2) | 36 (41.9) | 156 (39.5) | 410 (46.5) | ||
| Recurrence or metastasis | ||||||
| Yes | 55 (4.0) | 6 (7.0) | 13 (3.3) | 36 (4.1) | 0.112 | 0.497 |
| No | 1308 (96.0) | 80 (93.0) | 382 (96.7) | 846 (95.9) | ||
| Postoperative chemotherapy | ||||||
| Yes | 847 (62.1) | 61 (70.9) | 251 (63.5) | 535 (60.7) | 0.141 | 0.456 |
| No | 507 (37.2) | 23 (26.8) | 141 (35.7) | 343 (38.9) | ||
| Unknown | 9 (0.7) | 2 (2.3) | 3 (0.8) | 4 (0.4) | ||
| Postoperative radiotherapy | ||||||
| Yes | 276 (20.3) | 19 (22.1) | 70 (17.7) | 187 (21.2) | 0.571 | 0.102 |
| No | 1070 (78.5) | 66 (76.7) | 317 (80.3) | 687 (77.9) | ||
| Unknown | 17 (1.2) | 1 (1.2) | 8 (2.0) | 8 (0.9) | ||
| Postoperative endocrine therapy | ||||||
| Yes | 980 (71.9) | 49 (57.0) | 273 (69.1) | 658 (74.6) | 0.020 | 0.061 |
| No | 352 (25.8) | 37 (43.0) | 114 (28.9) | 201 (22.8) | ||
| Unknown | 31 (2.3) | 0 (0.0) | 8 (2.0) | 23 (2.6) | ||
BC breast cancer; HR hormone receptor; TILS tumor infiltrating lymphocytes; BCS breast-conserving surgery; BR breast reconstruction; ALND axillary lymph node dissection; SD standard deviation
Bold indicates P < 0.05
*T-test; other testing methods are Chi-square test