Table 4.
Patient characteristics of the validation set (N = 781).
| Characteristics | No | % |
|---|---|---|
| Age (years) | ||
| Mean | 51.9 ± 10.4 | |
| Range | 25–85 | |
| Tumor size by pre-op US (cm) | ||
| Mean | 2.0 ± 1.0 | |
| Range | 0.5–5.0 | |
| Axillary LN involvement | ||
| ≤ 2 | 732 | 93.7 |
| ≥ 3 | 49 | 6.3 |
| Axillary LN classification | ||
| 1 | 258 | 33.0 |
| 2 | 328 | 42.0 |
| 3 | 106 | 13.6 |
| 4 | 46 | 5.9 |
| 5 | 33 | 4.2 |
| Unknown | 10 | 1.3 |
| PET/CT-ALN (SUV) | ||
| Positive (≥ 1.4) | 94 | 12.0 |
| Negative (< 1.4) | 586 | 75.0 |
| Unknown | 101 | 12.9 |
| Surgery-breast | ||
| Conservation | 516 | 66.1 |
| Mastectomy | 265 | 33.9 |
| Surgery-axilla | ||
| Sentinel LN biopsy | 644 | 82.5 |
| ALND | 137 | 17.5 |
| Pathology | ||
| Ductal | 740 | 94.8 |
| Lobular | 41 | 5.2 |
| Pathologic tumor size | ||
| ≤ 2 cm | 509 | 65.2 |
| > 2 cm | 272 | 34.8 |
| Estrogen receptor | ||
| Positive | 609 | 78.0 |
| Negative | 164 | 21.0 |
| Unknown | 8 | 1.0 |
| Progesterone receptor | ||
| Positive | 513 | 65.7 |
| Negative | 259 | 33.2 |
| Unknown | 9 | 1.1 |
| HER2 receptor | ||
| Positive | 102 | 13.1 |
| Negative | 620 | 79.4 |
| Unknown | 59 | 7.5 |
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.