Table 1.
Baseline characteristics of 5442 pT1-2N1 breast cancer patients who underwent modified radical mastectomy.
| Variable | Number of patients (%) |
|---|---|
| Treatment era | |
| 1997–2007 | 1911 (35.1) |
| 2008–2014 | 3531 (64.9) |
| Age (years) | |
| ≤40 | 957 (17.6) |
| >40 | 4485 (82.4) |
| Tumor location | |
| Inner quadrants | 1142 (21.0) |
| Other quadrants | 4090 (75.1) |
| Unknown | 210 (3.9) |
| Pathological type | |
| Invasive ductal carcinoma | 5090 (93.5) |
| Others | 351 (6.4) |
| Unknown | 1 (0.1) |
| pT stage | |
| pT1 | 2387 (43.9) |
| pT2 | 3055 (56.1) |
| Number of positive nodes | |
| 1 | 2725 (50.1) |
| 2 | 1673 (30.7) |
| 3 | 1044 (19.2) |
| Number of nodes removed | |
| <10 | 585 (10.7) |
| ≥10 | 4857 (89.3) |
| Tumor grade | |
| I | 131 (2.4) |
| II | 2939 (54.0) |
| III | 1146 (21.1) |
| Unknown | 1226 (22.5) |
| Lymphovascular invasion | |
| Yes | 607 (11.2) |
| No | 4525 (83.1) |
| Unknown | 310 (5.7) |
| Hormone receptors | |
| Positive | 4150 (76.3) |
| Negative | 1183 (21.7) |
| Unknown | 109 (2.0) |
| HER2 status | |
| Positive | 1045 (19.2) |
| Negative | 3575 (65.7) |
| Unknown | 822 (15.1) |
| Ki67 index | |
| <14% | 1698 (31.2) |
| ≥14% | 1456 (26.8) |
| Unknown | 2288 (42.0) |
| Molecular subtype | |
| Luminal HER2-negative | 2919 (53.6) |
| Luminal HER2-positive | 645 (11.9) |
| HER2-overexpressing | 400 (7.4) |
| Triple-negative | 654 (12.0) |
| Unknown | 824 (15.1) |
| Endocrine therapya (n = 4150) | |
| Yes | 3452 (83.2) |
| No | 466 (11.2) |
| Unknown | 232 (5.6) |
| Anti-HER2-targeted therapyb (n = 1045) | |
| Yes | 190 (18.2) |
| No | 813 (77.8) |
| Unknown | 42 (4.0) |
| Adjuvant chemotherapy | |
| Yes | 5118 (94.0) |
| No | 278 (5.1) |
| Unknown | 46 (0.8) |
| Adjuvant radiotherapy | |
| Yes | 1780 (32.7) |
| No | 3662 (67.3) |
a
Only patients with hormone receptor-positive cancer were analyzed.
b
Only patients with HER2-positive cancer were analyzed.