Table 1.
Patients' characteristics
| Age at surgery, years | |
| Median | 50.5 |
| Range | 22.7–84.5 |
| ER status at diagnosis, n (%) | |
| Positive | 239 (74.0) |
| Negative | 84 (26.0) |
| Missing | 2 (0.6) |
| PR status at diagnosis, n (%) | |
| Positive | 198 (62.3) |
| Negative | 120 (37.7) |
| Missing | 7 (2.2) |
| HER2 status at diagnosis, n (%) | |
| Positive | 90 (28.6) |
| Negative | 225 (71.4) |
| Missing | 10 (3.1) |
| Ki-67 status at diagnosis, n (%) | |
| ≥20% | 228 (79.7) |
| <20% | 58 (20.3) |
| Missing | 39 (12.0) |
| Tumor stage at diagnosis, n (%) | |
| X | 1 (0.3) |
| T1 | 5 (1.5) |
| T2 | 184 (56.6) |
| T3 | 31 (9.5) |
| T4 | 104 (32.0) |
| Nodal stage at diagnosis, n (%) | |
| N0 | 95 (29.2) |
| N1 | 199 (61.2) |
| N2 | 22 (6.8) |
| Metastasis at diagnosis, n (%) | |
| M0 | 285 (87.7) |
| M1 | 40 (12.3) |
ER = estrogen receptor, PR = progesterone receptor.