Table 1.
Clinicopathological characteristics of the training and validation cohorts
| Variables | Training cohort (n=377) (%) | Validation cohort (n=377) (%) | P value |
| Age (years) | 58.73±13.19 | 59.90±12.94 | 0.22 |
| Race | 0.11 | ||
| White | 276 (73.2) | 295 (78.2) | |
| Other | 101 (26.8) | 82 (21.8) | |
| Marital status | 0.55 | ||
| Unmarried | 159 (42.2) | 151 (40.1) | |
| Married | 218 (57.8) | 226 (59.9) | |
| Laterality | 0.17 | ||
| Left | 205 (54.4) | 186 (49.3) | |
| Right | 172 (45.6) | 191 (50.7) | |
| Grade | 0.26 | ||
| I/II | 236 (62.6) | 221 (58.6) | |
| III/IV | 141 (37.4) | 156 (41.4) | |
| Hormone receptor status | 0.55 | ||
| Positive | 335 (88.9) | 340 (90.2) | |
| Negative | 42 (11.1) | 37 (9.8) | |
| Tumour size (mm) | 24.44±22.78 | 24.71±21.93 | 0.87 |
| <20 | 223 (59.2) | 204 (54.1) | 0.29 |
| 20–50 | 114 (30.2) | 134 (35.5) | |
| >50 | 40 (10.6) | 39 (10.3) | |
| Number of positive regional nodes | 0.99 | ||
| 0 | 179 (47.5) | 175 (46.4) | |
| 1–3 | 118 (31.3) | 121 (32.1) | |
| 4–9 | 45 (11.9) | 47 (12.5) | |
| ≥10 | 35 (9.3) | 34 (9.0) | |
| Stage | 0.73 | ||
| I | 141 (37.4) | 127 (33.7) | |
| II | 148 (39.2) | 160 (42.4) | |
| III | 82 (21.8) | 83 (22.0) | |
| IV | 6 (1.6) | 7 (1.9) | |
| Surgery | 0.34 | ||
| Conserving surgery | 208 (55.2) | 195 (51.7) | |
| Mastectomy | 169 (44.8) | 182 (48.3) | |
| Radiotherapy | 0.06 | ||
| Yes | 238 (63.1) | 213 (56.5) | |
| No | 139 (36.9) | 164 (43.5) |