| <35 years N = 741, No. (%) | ≥35 years N = 3705, No. (%) | χ2 | P-value | |
| T stage | 11.532 | 0.021 | ||
| T1 | 243 (32.8) | 1279 (34.5) |
|
|
| T2 | 339 (45.7) | 1795 (48.4) |
|
|
| T3 | 91 (12.3) | 399 (10.8) |
|
|
| T4 | 55 (7.4) | 198 (5.3) |
|
|
| Unknown | 13 (1.8) | 34 (0.9) |
|
|
| Lymph node status | 30.096 | <0.001 | ||
| N0 | 294 (39.7) | 1691 (45.6) |
|
|
| N1 | 210 (28.3) | 1137 (30.7) |
|
|
| N2 | 124 (16.7) | 535 (14.4) |
|
|
| N3 | 113 (15.2) | 342 (9.2) |
|
|
| Tumor stage |
|
| 26.383 | <0.001 |
| 1 | 160 (21.6) | 904 (24.4) |
|
|
| 2 | 314 (42.4) | 1,808 (48.8) |
|
|
| 3 | 260 (35.1) | 973 (26.3) |
|
|
| Unknown | 7 (0.9) | 20 (0.5) |
|
|
| Histologic grade |
|
| 42.810 | <0.001 |
| G1 | 68 (9.2) | 535 (14.4) |
|
|
| G2 | 256 (34.5) | 1553 (41.9) |
|
|
| G3 | 383 (51.7) | 1470 (39.7) |
|
|
| Unknown | 34 (4.6) | 147 (4.0) |
|
|
| ER status | 10.130 | 0.001 | ||
| Negative | 221 (22.8) | 899 (24.3) |
|
|
| Positive | 520 (70.2) | 2806 (75.7) |
|
|
| PR status | 4.995 | 0.025 | ||
| Negative | 225 (30.4) | 977 (26.4) |
|
|
| Positive | 516 (69.6) | 2728 (73.6) |
|
|
| HER2 status | 8.097 | 0.017 | ||
| Negative | 361 (48.7) | 2016 (54.4) |
|
|
| Positive | 180 (24.3) | 790 (21.3) |
|
|
| Unknown | 200 (27) | 899 (24.3) |
|
|
| Ki-67 (%) |
|
| 8.710 | 0.013 |
| <14% | 277 (37.4) | 1503 (40.6) |
|
|
| ≥14% | 438 (59.1) | 2130 (57.5) |
|
|
| Unknown | 26 (3.5) | 72 (1.9) |
|
|
| Tumor subtype | 22.173 | <0.001 | ||
| Luminal A | 89 (12.0) | 604 (16.3) |
|
|
| Luminal B | 369 (49.8) | 1923 (51.9) |
|
|