Table 1.
Patient and tumor characteristics
| Variable | No. (%) |
|---|---|
| No. of patients | 500 |
| Age, years | |
| Median (IQR) | 57 (48, 69) |
| Age, years | |
| ≤ 50 | 175 (35.0%) |
| > 50 | 325 (65.0%) |
| Neoadjuvant chemotherapy | |
| No | 349 (69.8%) |
| Yes | 151 (30.2%) |
| Type of breast surgery | |
| Breast conserving | 293 (58.6%) |
| Mastectomy +/– reconstruction | 207 (41.4%) |
| Tumor size at initial diagnosis, mm | |
| Median (IQR) | 28 (20, 40) |
| Clinical T stage at initial diagnosis | |
| T0 | 2 (0.4%) |
| T1 | 117 (23.4%) |
| T2 | 292 (58.4%) |
| T3 | 59 (11.8%) |
| T4 | 24 (4.8%) |
| Tis (DCIS) | 1 (0.2%) |
| Tx | 5 (1.0%) |
| Clinical N stage at initial diagnosis | |
| N1 by palpation | 226 (45.2%) |
| N1 by imaging | 227 (45.4%) |
| N2 | 22 (4.4%) |
| N3 | 25 (5.0%) |
| Postoperative N stage | |
| pN0 | 0 (0.0%) |
| pN1mi | 0 (0.0%) |
| pN1 | 206 (41.2%) |
| pN2 | 85 (17.0%) |
| pN3 | 43 (8.6%) |
| ypN0 | 1 (0.2%) |
| ypN0(ITC) | 4 (0.8%) |
| ypN1 | 122 (24.4%) |
| ypN2 | 28 (5.6%) |
| ypN3 | 9 (1.8%) |
| Unknown | 2 (0.4%) |
| Histology | |
| No special type (NST) | 389 (77.8%) |
| Lobular | 60 (12.0%) |
| Other | 50 (10.0%) |
| Unknown | 1 (0.2%) |
| Receptor status at initial diagnosis | |
| HR+/HER2− | 397 (79.4%) |
| HR+/HER2+ | 52 (10.4%) |
| HR−/HER2+ | 5 (1.0%) |
| HR−/HER2− | 35 (7.0%) |
| Missing/unknown | 11 (2.2%) |
| LVI | |
| Yes | 275 (55.1%) |
| No | 223 (44.7%) |
| Missing/unknown | 2 (0.4%) |
| Modified Bloom–Richardson score | |
| I | 32 (6.4%) |
| II | 294 (58.8%) |
| III | 169 (33.8%) |
| Missing/unknown | 5 (1.0%) |
IQR interquartile range, DCIS ductal carcinoma in situ, ITC isolated tumor cells, HR hormone receptor, HER2 human epidermal growth factor receptor 2, LVI lymphovascular invasion