Table 1. Patients’ baseline characteristics.
| All | Age≤35 | Age≥65 | χ2 | P | |
|---|---|---|---|---|---|
| N= 1222 | N= 483 (39.5%) | N= 739 (60.5%) | |||
| Family history | 11.322 | 0.001 | |||
| Breast cancer or ovarian cancer | 72 | 42 (8.7) | 30 (4.1) | ||
| No | 1150 | 441 (91.3) | 709 (95.9) | ||
| Type of surgery | 17.776 | <0.001 | |||
| Mastectomy | 893 | 321 (66.5) | 572 (77.4) | ||
| Breast-conserving surgery | 329 | 162 (33.5) | 167 (22.6) | ||
| Histology | 4.266 | 0.118 | |||
| In situ | 76 | 23 (4.8) | 53 (7.2) | ||
| Invasive | 1080 | 438 (90.7) | 642 (86.9) | ||
| Others | 66 | 22 (4.6) | 44 (6.0) | ||
| Tumor grade | 15.512 | <0.001 | |||
| Grade I | 76 | 20 (5.3) | 56 (7.9) | ||
| Grade II | 599 | 221 (58.8) | 378 (65.1) | ||
| Grade III | 282 | 135 (35.9) | 147 (25.3) | ||
| Pathologic tumor stage | 34.599 | <0.001 | |||
| T0 | 73 | 22 (4.6) | 51 (6.9) | ||
| T1 | 626 | 225 (46.6) | 401 (54.3) | ||
| T2 | 460 | 199 (41.2) | 261 (35.3) | ||
| T3 | 31 | 26 (5.4) | 5 (0.7) | ||
| T4 | 32 | 11 (2.3) | 21 (2.8) | ||
| Pathologic tumor stage | 11.991 | 0.001 | |||
| T0-1 | 699 | 247 (51.1) | 452 (61.2) | ||
| T2-4 | 523 | 236 (48.9) | 287 (38.8) | ||
| Pathologic node status | 19.717 | <0.001 | |||
| N0 | 630 | 233 (48.7) | 397 (61.1) | ||
| N1 | 280 | 129 (27.0) | 151 (23.2) | ||
| N2 | 125 | 68 (14.2) | 57 (8.8) | ||
| N3 | 93 | 48 (10.0) | 45 (6.9) | ||
| Pathologic node status | 16.989 | <0.001 | |||
| N0 | 630 | 233 (48.7) | 397 (61.1) | ||
| N1-3 | 498 | 245 (51.3) | 253 (38.9) | ||
| Primary tumor size | 24.969 | <0.001 | |||
| ≤5cm | 1175 | 448 (92.8) | 727 (98.4) | ||
| >5cm | 47 | 35 (7.2) | 12 (1.6) | ||
| ER | 5.564 | 0.018 | |||
| Positive | 917 | 345 (71.4) | 572 (77.4) | ||
| Negative | 305 | 138 (28.6) | 167 (22.6) | ||
| PgR | 0.862 | 0.353 | |||
| Positive | 875 | 353 (73.1) | 522 (70.6) | ||
| Negative | 347 | 130 (26.9) | 217 (29.4) | ||
| HER2 overexpression | 20.770 | <0.001 | |||
| Yes | 254 | 132 (27.3) | 122 (16.5) | ||
| No | 968 | 351 (72.7) | 617 (83.5) | ||
| Molecular subtype | 32.774 | <0.001 | |||
| ER/PgR+ and HER2- | 802 | 277 (57.3) | 525 (71.0) | ||
| ER/PgR+ and HER2+ | 171 | 98 (20.3) | 73 (9.9) | ||
| ER/PgR- and HER2+ | 85 | 35 (7.2) | 50 (6.8) | ||
| ER/PgR- and HER2- | 164 | 73 (15.1) | 91 (12.3) | ||
| Inflammatory breast cancer | 0.133 | 0.715 | |||
| No | 1194 | 471 (97.5) | 723 (97.8) | ||
| Yes | 28 | 12 (2.5) | 16 (2.2) | ||
| Lymphovascular invasion | 23.199 | <0.001 | |||
| No | 1108 | 414 (85.7) | 694 (93.9) | ||
| Yes | 114 | 69 (14.3) | 45 (6.1) | ||
| Adjuvant chemotherapy | 447.438 | <0.001 | |||
| No | 541 | 47 (9.7) | 494 (66.8) | ||
| Anthracycline-containing chemotherapy | 446 | 333 (68.9) | 113 (15.3) | ||
| Chemotherapy without anthracycline | 235 | 103 (21.3) | 132 (17.9) | ||
| Adjuvant radiotherapy | 238.343 | <0.001 | |||
| No | 759 | 172 (35.6) | 587 (79.4) | ||
| Yes | 463 | 311 (64.4) | 152 (20.6) | ||
| Endocrine therapy | 0.062 | 0.803 | |||
| No | 321 | 125 (25.9) | 196 (26.5) | ||
| Yes | 901 | 358 (74.1) | 543 (73.5) | ||
| Trautuzumab | 45.465 | <0.001 | |||
| No | 1144 | 424 (87.8) | 720 (97.4) | ||
| Yes | 78 | 59 (12.2) | 19 (2.6) |
Abbreviations: ER: estrogen receptor; PgR: progesterone receptor; HER2: human epidermal growth factor receptor 2.