Baseline characteristics of patients before and after PSM
| Characteristics | Before PSM | After PSM | ||||
|---|---|---|---|---|---|---|
| Group A# (n = 833) | Group B# (n = 216) | P value | Group A# (n = 432) | Group B# (n = 216) | P value | |
| Age, years | 0.499 | 0.911 | ||||
| ≤ 50 | 411 (49.34) | 101 (46.76) | 204 (47.22) | 101 (46.76) | ||
| > 50 | 422 (50.66) | 115 (53.24) | 228 (52.78) | 115 (53.24) | ||
| Menopausal status | 0.360 | 0.824 | ||||
| Premenopausal | 431 (51.74) | 104 (48.15) | 212 (49.07) | 104 (48.15) | ||
| Menopausal | 402 (48.26) | 112 (51.85) | 220 (50.93) | 112 (51.85) | ||
| Histopathologic type | 0.100 | 0.604 | ||||
| Ductal | 805 (96.64) | 214 (99.07) | 430 (99.54) | 214 (99.07) | ||
| Lobular or mixed | 12 (1.44) | 2 (0.93) | 2 (0.46) | 2 (0.93) | ||
| Other | 16 (1.92) | 0 (0) | 0 (0) | 0 (0) | ||
| Ki-67 | 0.001* | 0.999 | ||||
| < 20% | 106 (12.73) | 11 (5.09) | 21 (4.86) | 11 (5.09) | ||
| ≥ 20% | 727 (87.27) | 205 (94.91) | 411 (95.14) | 205 (94.91) | ||
| Location | 0.211 | 0.399 | ||||
| Outside | 498 (59.78) | 119 (55.09) | 253 (58.56) | 119 (55.09) | ||
| Central/inside | 335 (40.22) | 97 (44.91) | 179 (41.44) | 97 (44.91) | ||
| Clinical T stage at presentation | < 0.001* | 0.906 | ||||
| T1 | 117 (14.05) | 48 (22.22) | 86 (19.91) | 48 (22.22) | ||
| T2 | 532 (63.87) | 146 (67.59) | 298 (68.98) | 146 (67.59) | ||
| T3 | 95 (11.40) | 17 (7.87) | 38 (8.80) | 17 (7.87) | ||
| T4 | 89 (10.68) | 5 (2.32) | 10 (2.32) | 5 (2.32) | ||
| Clinical N stage at presentation | 0.007* | 0.616 | ||||
| N0 | 75 (9.00) | 26 (12.04) | 47 (10.88) | 26 (12.04) | ||
| N1 | 550 (66.03) | 158 (73.15) | 303 (70.14) | 158 (73.15) | ||
| N2 | 135 (16.21) | 25 (11.57) | 63 (14.58) | 25 (11.57) | ||
| N3 | 73 (8.76) | 7 (3.24) | 19 (4.40) | 7 (3.24) | ||
| Subtype | < 0.001* | 0.086 | ||||
| HR+/HER2− | 316 (37.94) | 31 (14.35) | 70 (16.20) | 31 (14.35) | ||
| HER2+ | 339 (40.70) | 129 (59.72) | 219 (50.69) | 129 (59.72) | ||
| TNBC | 178 (21.36) | 56 (25.93) | 143 (33.10) | 56 (25.93) | ||
| Breast surgery | 0.463 | 0.857 | ||||
| Mastectomy | 612 (73.47) | 164 (75.93) | 330 (76.39) | 164 (75.93) | ||
| BCS | 221 (26.53) | 52 (24.07) | 101 (23.61) | 52 (24.07) | ||
| Axillary surgery | 0.583 | 0.692 | ||||
| SLNB | 330 (39.62) | 90 (41.67) | 173 (40.05) | 90 (41.67) | ||
| ALND | 503 (60.38) | 126 (58.33) | 259 (59.95) | 126 (58.33) | ||
| Radiotherapy | 0.175 | 0.529 | ||||
| Yes | 347 (41.66) | 79 (36.57) | 169 (39.12) | 79 (36.57) | ||
| No | 486 (58.34) | 137 (63.43) | 263 (60.88) | 137 (63.43) | ||
PSM, propensity score matching; HR+/HER2−, hormone receptor-positive/HER2-negative breast cancer; HER2+, HER2-positive breast cancer; TNBC, triple-negative breast cancer; BCS, breast-conserving surgery; SLNB, sentinel lymph node biopsy; ALND, axillary lymph node dissection. *Difference was statistically significant. Group A# = without 125I seed-marked group, Group B# = 125I seed-marked group.