Table 1. Patient characteristics for the total cohort.
| Variable* | No. (%) |
|---|---|
| Age, median [IQR], years | 51 [43–57] |
| US tumor size | |
| T1 | 21 (12.8) |
| T2 | 90 (54.9) |
| T3 | 53 (32.3) |
| US no. of suspicious LN | |
| ≤3 | 101 (62) |
| ≥4 | 62 (38) |
| US long-axis of LN, cm | |
| ≤1 | 24 (14.5) |
| 1–2 | 79 (47.9) |
| >2 | 62 (37.6) |
| US short-axis of LN, cm | |
| ≤1 | 88 (53.3) |
| >1 | 77 (46.7) |
| US shape of LN | |
| Regular | 152 (92.1) |
| Irregular | 13 (7.9) |
| US margin of LN | |
| Not circumscribed | 6 (3.6) |
| Circumscribed | 159 (96.4) |
| US cortex of LN | |
| No thickening | 5 (3.0) |
| Thickening | 160 (97.0) |
| US hilum of LN | |
| Normal | 18 (10.9) |
| Compressed or displaced | 147 (89.1) |
| US blood flow of LN | |
| Without NHBF | 113(68.5) |
| NHBF | 52 (31.5) |
| Tumor pathology‡ | |
| Invasive ductal cancer | 135 (80.8) |
| Other | 32 (19.2) |
| Tumor grade‡ | |
| I | 1 (0.9) |
| II | 39 (36.1) |
| III | 68 (63.0) |
| Hormone receptor status‡ | |
| Positive | 104 (73.2) |
| Negative | 38 (26.8) |
| Ki67 status‡¦ | |
| High | 107 (74.8) |
| Low | 36 (25.2) |
| HER2 status‡ | |
| Positive | 51 (39.8) |
| Negative | 77 (60.2) |
| N stage‡ | |
| N0 | 44 (28.9) |
| N1 | 48 (31.6) |
| N2 | 34 (22.4) |
| N3 | 26 (17.1) |
Values in parentheses are percentages unless indicated otherwise. *, some data are missing; ‡, data were obtained from surgery specimens; ¦, cut-off point 14%. IQR, interquartile range; US, ultrasound; LN, lymph node; NHBF, nonhilar blood flow; HER2, human epidermal growth factor receptor 2.