Table 1.
Baseline characteristics of all patients classified into the SLNB-only or ALND groups, before and after PSM.
| Before PSM | After PSM | ||||||
|---|---|---|---|---|---|---|---|
| Total | SLNB-only | ALND | p-value | SLNB-only | ALND | p-value | |
| N (%) | N (%) | N (%) | N (%) | N (%) | |||
| Patients | 521 | 293 (56.2) | 228 (43.8) | 200 (50.0) | 200 (50.0) | ||
| Age (in years ± SD) | 0.313 | 0.940 | |||||
| Mean | 50.0 ± 10.9 | 49.6 ± 11.1 | 50.6 ± 10.8 | 50.5 ± 10.6 | 50.6 ± 10.5 | ||
| Clinical T stage | 0.003 | 0.954 | |||||
| T1 | 45 (8.6) | 30 (10.2) | 15 (6.6) | 15 (7.5) | 13 (6.5) | ||
| T2 | 266 (51.1) | 160 (54.6) | 106 (46.5) | 104 (52.0) | 102 (51.0) | ||
| T3 | 138 (26.5) | 76 (25.9) | 62 (27.2) | 54 (27.0) | 55 (27.5) | ||
| T4 | 72 (13.8) | 27 (9.2) | 45 (19.7) | 27 (13.5) | 30 (15.0) | ||
| Clinical N stage | 0.250 | 1.000 | |||||
| N2 | 174 (33.4) | 104 (35.5) | 70 (30.7) | 55 (27.5) | 55 (27.5) | ||
| N3 | 347 (66.6) | 189 (64.5) | 158 (69.3) | 145 (72.5) | 145 (72.5) | ||
| Histologic grade | 0.086 | 0.841 | |||||
| G2 | 269 (51.6) | 161 (55.0) | 108 (47.4) | 101 (50.5) | 99 (49.5) | ||
| G3 | 252 (48.4) | 132 (45.0) | 120 (52.6) | 99 (49.5) | 101 (50.5) | ||
| Nuclear grade | 0.138 | 0.841 | |||||
| G2 | 266 (51.1) | 158 (53.9) | 108 (47.4) | 100 (50.0) | 98 (49.0) | ||
| G3 | 255 (48.9) | 135 (46.1) | 120 (52.6) | 100 (50.0) | 102 (51.0) | ||
| Estrogen receptor status | 0.252 | 0.919 | |||||
| Negative | 303 (58.2) | 164 (56.0) | 139 (61.0) | 120 (60.0) | 121 (60.5) | ||
| Positive | 218 (41.8) | 129 (44.0) | 89 (39.0) | 80 (40.0) | 79 (39.5) | ||
| Progesterone receptor status | 0.040 | 0.795 | |||||
| Negative | 415 (79.7) | 224 (76.5) | 191 (83.8) | 163 (81.5) | 165 (82.5) | ||
| Positive | 106 (20.3) | 69 (23.6) | 37 (16.2) | 37 (18.5) | 35 (17.5) | ||
| HER2 status | 0.137 | 0.841 | |||||
| Negative | 250 (48.0) | 149 (50.9) | 101 (44.3) | 93 (46.5) | 91 (45.5) | ||
| Positive | 271 (52.0) | 144 (49.2) | 127 (55.7) | 107 (53.5) | 109 (54.4) | ||
| Ki-67 index | 0.608 | 0.760 | |||||
| < 20% | 16 (3.1) | 10 (3.4) | 6 (2.6) | 5 (2.5) | 6 (3.0) | ||
| ≥ 20% | 505 (96.9) | 283 (96.6) | 222 (97.4) | 195 (97.5) | 194 (97.0) | ||
| Breast surgery type | 0.012 | 0.763 | |||||
| TM | 276 (53.0) | 141 (48.1) | 135 (59.2) | 109 (54.5) | 112 (56.0) | ||
| BCS | 245 (47.0) | 152 (41.9) | 93 (40.8) | 91 (45.5) | 88 (44.0) | ||
| Radiotherapy(RT) | |||||||
| Yes | 493(94.6) a | 271(92.5) b | 222(97.4) b | 0.014 | 198(99.0) b | 199(99.5) b | 0.223 |
| No | 28(5.4) a | 22(7.5) | 6(2.6) | 2(1.0) | 1(0.5) | ||
| Hormone therapy(HT) | |||||||
| Yes | 225(43.2) a | 135(46.1) c | 90(39.5) c | 0.131 | 87(43.5) c | 81(40.5) c | 0.543 |
| No | 296(56.8) a | 158(53.9) | 138(60.5) | 113(56.5) | 119(59.5) | ||
PSM propensity score matching, ALND axillary lymph node dissection, SLNB sentinel lymph node biopsy, SD standard deviation, HER2 human epidermal growth factor receptor 2, TM total mastectomy, BCS breast-conserving surgery.
aPercentages are based on the total number of patients (N = 521).
bPercentages are based on the group total within the RT group.
cPercentages are based on the group total within the HT group.