Table 1.
Patient characteristics of the training set (N = 1030).
| Characteristics | No | % |
|---|---|---|
| Age (years) | ||
| Mean | 51.4 ± 10.4 | |
| Range | 24–82 | |
| Tumor size by pre-op US (cm) | ||
| Mean | 2.1 ± 1.0 | |
| Range | 0.3–5.0 | |
| Axillary LN involvement | ||
| ≤ 2 | 941 | 91.4 |
| ≥ 3 | 89 | 8.6 |
| Axillary LN classification | ||
| 1 | 343 | 33.3 |
| 2 | 378 | 36.7 |
| 3 | 168 | 16.3 |
| 4 | 63 | 6.1 |
| 5 | 59 | 5.7 |
| Unknown | 19 | 1.8 |
| PET/CT-ALN (SUV) | ||
| Positive (≥ 1.4) | 188 | 18.3 |
| Negative (< 1.4) | 665 | 64.6 |
| Unknown | 177 | 17.2 |
| Surgery-breast | ||
| Conservation | 768 | 74.6 |
| Mastectomy | 262 | 25.4 |
| Surgery-axilla | ||
| Sentinel LN biopsy | 735 | 71.4 |
| ALND | 295 | 28.6 |
| Pathology | ||
| Ductal | 964 | 93.6 |
| Lobular | 66 | 6.4 |
| Other | ||
| Pathologic tumor size | ||
| ≤ 2 cm | 572 | 55.5 |
| > 2 cm | 458 | 44.5 |
| Estrogen receptor | ||
| Positive | 791 | 76.8 |
| Negative | 224 | 21.7 |
| Unknown | 15 | 1.5 |
| Progesterone receptor | ||
| Positive | 661 | 64.2 |
| Negative | 358 | 34.8 |
| Unknown | 11 | 1.1 |
| HER2 receptor | ||
| Positive | 264 | 19.6 |
| Negative | 563 | 54.7 |
| Unknown | 202 | 19.6 |
Pre-op, Preoperative; US, Ultrasonography; LN, Lymph node; ALN, Axillary lymph node; PET/CT, Positron emission tomography/computed tomography; ALND, Axillary lymph node dissection; HER2, Human epidermal growth factor receptor 2.