Table 1. Clinicopathologic characteristics of the training cohort and validation cohort.
| Variable | Training cohort, n=1,201 (%) | Validation cohort, n=538 (%) | P |
|---|---|---|---|
| Age at diagnosis (years) | |||
| Median [range] | 48 [18–80] | 49 [18–82] | |
| ≤35 | 84 (6.99) | 40 (7.43) | 0.742 |
| 35–50 | 584 (48.63) | 251 (46.65) | |
| >50 | 533 (44.38) | 247 (45.91) | |
| Tumor size (cm) | <0.001 | ||
| ≤2 | 854 (71.11) | 523 (97.21) | |
| >2 | 347 (28.89) | 15 (2.79) | |
| Histologic type | <0.001 | ||
| IDC | 988 (82.26) | 514 (95.54) | |
| DCIS | 71 (5.91) | 5 (0.93) | |
| Others | 142 (11.82) | 19 (3.53) | |
| Lymph node status | <0.001 | ||
| Positive | 877 (73.02) | 323 (60.04) | |
| Negative | 324 (26.98) | 215 (39.96) | |
| Ki67 status | <0.001 | ||
| ≥20% | 533 (44.38) | 188 (34.94) | |
| <20% | 668 (55.62) | 350 (65.06) | |
| LVI status | 0.001 | ||
| Positive | 193 (16.07) | 121 (22.49) | |
| Negative | 1,008 (83.93) | 417 (77.51) | |
| Hormone receptor status | 0.006 | ||
| Positive | 1,043 (86.84) | 440 (81.78) | |
| Negative | 158 (13.16) | 98 (18.22) | |
| HER2 status | 0.117 | ||
| Positive | 359 (29.89) | 141 (26.21) | |
| Negative | 842 (70.11) | 397 (73.79) | |
| Molecular subtype | 0.190 | ||
| Luminal A | 356 (29.64) | 164 (30.48) | |
| Luminal B (HER2−) | 401 (33.39) | 179 (33.27) | |
| Luminal B (HER2+) | 286 (23.81) | 115 (21.38) | |
| HER2-enriched | 73 (6.08) | 26 (4.83) | |
| Triple negative | 85 (7.08) | 54 (10.04) | |
| Chemotherapy | <0.001 | ||
| Yes | 1,074 (89.43) | 448 (83.27) | |
| No | 127 (10.57) | 65 (12.08) | |
| Unknown | 0 | 25 (4.65) |
IDC, invasive ductal carcinoma; DCIS, ductal carcinoma in situ; LVI, lymphovascular invasion; HER2, human epidermal growth factor receptor 2.