Table 1.
Baseline patient characteristics by HER2 IHC/FISH status.
| Characteristics | Total n = 2296 (%) |
HER2 0 n = 368 (%) |
HER2 1+ n = 911 (%) |
HER2 2+/FISH− n = 1017 (%) |
p-Value |
|---|---|---|---|---|---|
| Age (y/o) | 0.798 | ||||
| <60 | 1270 (55.3) | 204 (55.4) | 511 (56.1) | 555 (54.6) | |
| ≥60 | 1026 (44.7) | 164 (44.6) | 400 (43.9) | 462 (45.4) | |
| Gender | 0.806 | ||||
| Female | 2277 (99.2) | 366 (99.5) | 903 (99.1) | 1008 (99.1) | |
| Male | 19 (0.8) | 2 (0.5) | 8 (0.9) | 9 (0.9) | |
| Histology | 0.004 | ||||
| IDC | 1935 (84.3) | 295 (80.2) | 756 (83.0) | 884 (86.9) | |
| Non-IDC | 361 (15.7) | 73 (19.8) | 155 (17.0) | 133 (13.1) | |
| TNM stage | 0.020 | ||||
| I | 1423 (62.0) | 242 (65.8) | 588 (64.5) | 593 (58.3) | |
| II | 859 (37.4) | 123 (33.4) | 317 (34.8) | 419 (41.2) | |
| III | 14 (9.6) | 3 (0.8) | 6 (0.7) | 5 (0.5) | |
| Tumor Size | 0.050 | ||||
| <2 cm | 1227 (53.4) | 201 (54.6) | 511 (56.1) | 515 (50.6) | |
| ≥2 cm | 1069 (46.6) | 167 (45.4) | 400 (43.9) | 502 (49.4) | |
| Breast surgery | 0.372 | ||||
| BCS | 1006 (43.8) | 166 (45.1) | 411 (45.1) | 429 (42.2) | |
| Mastectomy | 1290 (56.2) | 202 (54.9) | 500 (54.9) | 588 (57.8) | |
| ALN status | 0.001 | ||||
| Negative | 1919 (83.6) | 323 (87.8) | 777 (85.3) | 819 (80.5) | |
| Positive | 377 (16.4) | 45 (12.2) | 134 (14.7) | 198 (19.5) | |
| Histological grade | 0.334 | ||||
| I-II | 1879 (82.8) | 292 (79.3) | 755 (82.9) | 832 (81.8) | |
| III | 417 (18.2) | 76 (20.7) | 156 (17.1) | 185 (18.2) | |
| ER | 0.115 | ||||
| Negative | 5 (0.2) | 1 (0.3) | 4 (0.4) | 0 (0.0) | |
| Positive | 2291 (99.8) | 367 (99.7) | 907 (99.6) | 1017 (100.0) | |
| PR | 0.037 | ||||
| Negative | 250 (10.9) | 54 (14.7) | 95 (10.4) | 101 (9.9) | |
| Positive | 2046 (89.1) | 314 (85.3) | 816 (89.6) | 916 (90.1) | |
| Ki-67 | <0.001 | ||||
| <14% | 1065 (46.4) | 178 (48.4) | 467 (51.3) | 420 (41.3) | |
| ≥14% | 1231 (53.6) | 190 (51.6) | 444 (48.7) | 597 (58.7) | |
| Molecular subtype | 0.010 | ||||
| Luminal A | 733 (31.9) | 119 (32.3) | 321 (35.2) | 293 (28.8) | |
| Luminal B (HER2-) | 1563 (68.1) | 249 (67.7) | 590 (64.8) | 724 (71.2) |
Abbreviations: HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry; FISH, fluorescence in situ hybridization; y/o, years old; IDC, invasive ductal carcinoma; BCS, breast-conserving surgery; ALN, axillary lymph node; ER, estrogen receptor; PR, progesterone receptor.