Table 1.
Characteristics of patients in the training set, validation set and total population.
| Characteristics | Training set N = 378 (%) | Validation setN = 160 (%) | TotalN = 538 (%) | P-value |
|---|---|---|---|---|
| Age at diagnosis (years) | 49.2 ± 10.9 | 49.0 ± 9.2 | 49.1 ± 10.4 | 0.430 |
| Menstrual status | 0.629 | |||
| Premenopausal | 186 (49.2) | 86 (53.8) | 272 (50.6) | |
| Postmenopausal | 192 (50.8) | 74 (46.2) | 266 (49.4) | |
| Location of tumor | 0.146 | |||
| Left breast | 198 (52.4) | 69 (43.1) | 267 (49.6) | |
| Right breast | 180 (47.6) | 91 (56.9) | 271 (50.4) | |
| Clinical tumor size (cT) | 0.872 | |||
| cT1 | 31 (8.2) | 16 (10.0) | 47 (8.7) | |
| cT2 | 259 (68.5) | 99 (61.9) | 358 (66.5) | |
| cT3 | 51 (13.5) | 28 (17.5) | 79 (14.7) | |
| cT4 | 37 (9.8) | 17 (10.6) | 54 (10.0) | |
| Maximum diameter of breast tumor (mm) | ||||
| Before NST | 39.3 ± 18.0 | 39.6 ± 18.1 | 39.4 ± 18.0 | 0.983 |
| After NST | 19.2 ± 15.3 | 20.0 ± 16.9 | 19.4 ± 15.8 | 0.853 |
| Radiological response rate of breast tumor (%) | 51.4 ± 30.3 | 49.3 ± 33.3 | 50.7 ± 31.2 | 0.774 |
| Response evaluation of breast tumor | 0.673 | |||
| Complete response (CR) | 46 (12.2) | 15 (9.4) | 61 (11.3) | |
| Partial response (PR) | 250 (66.1) | 103 (64.4) | 353 (65.6) | |
| Stable disease (SD) | 78 (20.6) | 37 (23.1) | 115 (21.4) | |
| Progressive disease (PD) | 4 (1.1) | 5 (3.1) | 9 (1.7) | |
| Longest diameter of positive node (mm) | ||||
| Before NST | 19.2 ± 9.4 | 19.1 ± 9.4 | 19.2 ± 9.4 | 0.998 |
| After NST | 11.4 ± 6.6 | 11.9 ± 7.4 | 11.6 ± 6.8 | 0.753 |
| Radiological response rate of positive node (%) | 36.4 ± 29.6 | 33.9 ± 39.3 | 35.6 ± 32.7 | 0.708 |
| ER status | 0.716 | |||
| Negative | 144 (38.1) | 55 (34.4) | 199 (37.0) | |
| Positive | 234 (61.9) | 105 (65.6) | 339 (63.0) | |
| PgR status | 0.295 | |||
| Negative | 205 (54.2) | 75 (46.9) | 280 (52.0) | |
| Positive | 173 (45.8) | 85 (53.1) | 258 (48.0) | |
| HER2 status | 0.980 | |||
| Negative | 235 (62.2) | 98 (61.2) | 333 (61.9) | |
| Positive | 143 (37.8) | 62 (38.8) | 205 (38.1) | |
| Ki67 expression | 0.618 | |||
| ≤ 20% | 45 (11.9) | 24 (15.0) | 69 (12.8) | |
| > 20% | 333 (88.1) | 136 (85.0) | 469 (87.2) | |
| NST regimens | 0.718 | |||
| EC-T | 223 (59.0) | 95 (59.4) | 318 (59.1) | |
| EC-TH(P) | 129 (34.1) | 59 (36.9) | 188 (34.9) | |
| Others | 26 (6.9) | 6 (3.8) | 32 (5.9) | |
| Surgeries of breast | 0.924 | |||
| Mastectomy | 351 (92.9) | 147 (91.9) | 498 (92.6) | |
| Lumpectomy | 27 (7.1) | 13 (8.1) | 40 (7.4) | |
| Breast pCR (ypT0/is) | 0.976 | |||
| No | 292 (77.2) | 125 (78.1) | 417 (77.5) | |
| Yes | 86 (22.8) | 35 (21.9) | 121 (22.5) | |
NST, neoadjuvant systemic therapy; ER, estrogen receptor; PgR, progesterone receptor; HER2, human epidermal growth factor receptor 2; EC-TH(P), epirubicin and cyclophosphamide followed by taxane, trastuzumab and pertuzumab; pCR, pathologic complete response; ypT0/is, the absence of residual invasive carcinoma in the breast on postoperative pathology after NST, irrespective of in situ ductal carcinoma.