Table 1.
Patient characteristics
| Training set | Validation set | |
|---|---|---|
| Number of patients | 92 | 95 | 
| Age median | 59 | 58 | 
| Histologic type |  |  | 
| IDC | 75 | 54 | 
| ILC | 8 | 8 | 
| Other | 9 | 33 | 
| Histologic grade |  |  | 
| G1 | 8 | 14 | 
| G2 | 33 | 31 | 
| G3 | 47 | 49 | 
| Missing | 4 | 1 | 
| Tumor size |  |  | 
| T ≤2 cm | 34 | 65 | 
| T >2 cm | 55 | 30 | 
| Missing | 3 |  | 
| Estrogen receptor |  |  | 
| Positive | 58 | 73 | 
| Negative | 28 | 22 | 
| Missing | 6 |  | 
| Progesterone receptor |  |  | 
| Positive | 48 | 73 | 
| Negative | 41 | 22 | 
| Missing | 3 |  | 
| HER2 overexpression |  |  | 
| Positive | 17 | 21 | 
| Negative | 60 | 73 | 
| Missing | 15 | 1 | 
| Lymph node involvement |  |  | 
| Positive | 43 | 36 | 
| Negative | 41 | 37 | 
| Missing | 8 | 22 | 
HER2, human epidermal growth factor receptor 2; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma.