Table 1. Baseline characteristics of included 24,014 patients in the study.
| Characteristic | No. (%) | Characteristic | No. (%) |
|---|---|---|---|
| Sex | Radiation therapy | ||
| Female | 23,931 (99.7) | Done | 15,928 (66.3) |
| Male | 83 (0.3) | Undone | 6,589 (27.4) |
| Age (yr)* | 50 (20–91) | Unknown | 1,497 (6.2) |
| < 40 | 3,203 (13.3) | Hormonal therapy | |
| ≥ 40, < 50 | 8,999 (37.5) | Done | 15,461 (64.4) |
| ≥ 50, < 60 | 7,268 (30.3) | Undone | 6,691 (27.9) |
| ≥ 60 | 4,544 (18.9) | Unknown | 1,862 (7.8) |
| Pathology | Chemotherapy | ||
| IDC | 22,429 (93.4) | Neoadjuvant | 1,456 (6.1) |
| ILC | 578 (2.4) | Adjuvant | 14,818 (61.7) |
| IDC+ILC | 33 (0.1) | Undone | 7,740 (32.2) |
| Others | 974 (4.1) | Target therapy | |
| Histologic grade | Done | 4,342 (18.1) | |
| 1 | 4,458 (18.6) | Undone | 19,046 (79.3) |
| 2 | 10,987 (45.8) | Unknown | 626 (2.6) |
| 3 | 8,569 (35.7) | Anatomic stage | |
| ER | IA | 10,997 (45.8) | |
| Positive | 16,741 (69.7) | IB | 442 (1.8) |
| Negative | 7,273 (30.3) | IIA | 6,948 (28.9) |
| PR | IIB | 3,496 (14.6) | |
| Positive | 14,155 (58.9) | IIIA | 1,000 (4.2) |
| Negative | 9,859 (41.1) | IIIB | 88 (0.4) |
| HER2 | IIIC | 1,043 (4.3) | |
| Positive | 4,964 (20.7) | Clinical prognostic stage | |
| Negative | 19,050 (79.3) | IA | 9,426 (39.3) |
| Subtype | IB | 5,390 (22.5) | |
| Luminal A-like | 14,840 (61.8) | IIA | 3,818 (15.9) |
| Luminal B-like | 2,472 (10.3) | IIB | 2,810 (11.7) |
| HER2 | 2,492 (10.4) | IIIA | 692 (2.9) |
| TNBC | 4,210 (17.5) | IIIB | 1,476 (6.2) |
| IIIC | 402 (1.7) |
IDC=invasive ductal carcinoma; ILC=invasive lobular carcinoma; ER=estrogen receptor; PR=progesterone receptor; HER2=human epidermal growth factor receptor 2; TNBC=triple-negative breast cancer.
*Median (range).