Table 2.
Characteristics of patients according to optimal cutoff for tumor-fat interface volume in the development and validation cohorts.
| Characteristics | Development Cohort | Validation Cohort | ||||
|---|---|---|---|---|---|---|
| Low (n = 608) | High (n = 396) | p-Value | Low (n = 81) | High (n = 55) | p-Value | |
| Age (median [IQR]) | 49.00 [42.00, 56.00] | 45.00 [38.00, 53.00] | <0.001 | 53.00 [48.00, 59.00] | 48.00 [43.00, 55.00] | 0.008 |
| Breast volume (cm3) (median [IQR]) | 509.50 [353.82, 717.03] | 664.70 [455.60, 904.62] | <0.001 | 628.36 [426.52, 806.93] | 684.99 [505.84, 1032.36] | 0.073 |
| Fat volume (cm3) (median [IQR]) | 384.16 [230.58, 550.14] | 477.44 [288.45, 687.47] | <0.001 | 455.51 [319.60, 593.58] | 535.64 [295.53, 822.07] | 0.178 |
| Normal fibroglandular tissue volume (cm3) (median [IQR]) | 115.10 [80.72, 158.67] | 147.88 [103.89, 202.52] | <0.001 | 121.35 [82.63, 164.36] | 152.97 [89.65, 227.67] | 0.063 |
| Tumor volume (cm3) (median [IQR]) | 8.01 [5.35, 12.07] | 23.82 [16.15, 35.74] | <0.001 | 7.08 [5.32, 11.64] | 22.04 [15.80, 32.68] | <0.001 |
| Operation method | ||||||
| Breast-conserving surgery | 442 (72.7) | 217 (54.8) | <0.001 | 65 (80.3) | 36 (65.5) | 0.053 |
| Mastectomy | 166 (27.3) | 179 (45.2) | 16 (19.7) | 19 (34.5) | ||
| BMI (median [IQR]) | 23.47 [21.61, 25.65] | 23.99 [21.82, 26.64] | 0.006 | 24.87 [22.49 26.73] | 25.20 [23.21 28.65] | 0.188 |
| BMI | ||||||
| <25 (kg/m2) | 420 (69.1) | 240 (60.6) | 0.007 | 42 (51.8) | 26 (47.3) | 0.600 |
| ≥25 (kg/m2) | 188 (30.9) | 156 (39.4) | 39 (48.2) | 29 (52.7) | ||
| NAC regimen | ||||||
| AC-T | 334 (54.9) | 242 (61.1) | 0.103 | 45 (55.5) | 28 (50.9) | 0.519 |
| AC-T/Herceptin | 157 (25.8) | 86 (21.7) | 17 (21.0) | 8 (45.6) | ||
| TCHP | 114 (18.8) | 63 (15.9) | 17 (21.0) | 17 (30.9) | ||
| AC | 3 (0.5) | 5 (1.3) | 2 (2.5) | 2 (3.6) | ||
| cT stage at diagnosis | ||||||
| 1 | 27 (4.4) | 19 (4.8) | <0.001 | 3 (3.7) | 2 (3.6) | 0.008 |
| 2 | 446 (73.4) | 195 (49.2) | 63 (77.8) | 29 (52.7) | ||
| 3 | 122 (20.1) | 141 (35.6) | 12 (14.8) | 21 (38.2) | ||
| 4 | 13 (2.1) | 41 (10.4) | 3 (3.7) | 3 (5.5) | ||
| cN stage at diagnosis | ||||||
| 0 | 76 (12.5) | 40 (10.1) | 0.107 | 7 (8.6) | 3 (5.5) | 0.633 |
| 1 | 206 (33.9) | 118 (29.8) | 55 (67.9) | 36 (65.4) | ||
| 2 | 214 (35.2) | 143 (36.1) | 9 (11.1) | 5 (9.1) | ||
| 3 | 112 (18.4) | 95 (24.0) | 10 (12.4) | 11 (20.0) | ||
| Estrogen receptor | ||||||
| Positive | 273 (44.9) | 178 (44.9) | >0.999 | 43 (53.1) | 37 (67.3) | 0.099 |
| Negative | 335 (55.1) | 218 (55.1) | 38 (46.9) | 18 (32.7) | ||
| Progesterone receptor | ||||||
| Positive | 191 (31.4) | 128 (32.3) | 0.816 | 34 (42.0) | 33 (60.0) | 0.039 |
| Negative | 417 (68.6) | 268 (67.7) | 47 (58.0) | 22 (40.0) | ||
| HER2 | ||||||
| Positive | 271 (44.6) | 149 (37.6) | 0.034 | 34 (42.0) | 25 (45.4) | 0.688 |
| Negative | 337 (55.4) | 247 (62.4) | 47 (58.0) | 30 (54.6) | ||
| Ki-67 | ||||||
| ≥20% | 524 (86.2) | 351 (88.6) | 0.299 | 66 (81.5) | 49 (89.1) | 0.228 |
| <20% | 84 (13.8) | 45 (11.4) | 15 (18.5) | 6 (10.9) | ||
| Molecular subtype | ||||||
| HR+/HER2− | 154 (25.3) | 120 (30.3) | 0.12 | 27 (33.3) | 23 (41.8) | 0.335 |
| HR+/HER2+ | 129 (21.2) | 65 (16.4) | 18 (22.2) | 15 (27.3) | ||
| HR−/HER2+ | 142 (23.4) | 84 (21.2) | 16 (19.8) | 10 (18.2) | ||
| HR−/HER2− | 183 (30.1) | 127 (32.1) | 20 (24.7) | 7 (12.7) | ||
| Menopausal status | ||||||
| Postmenopausal | 278 (45.7) | 138 (34.8) | 0.001 | 48 (59.3) | 24 (43.6) | 0.073 |
| Premenopausal | 330 (54.3) | 258 (65.2) | 33 (40.7) | 31 (56.4) | ||
| Background parenchymal enhancement (BPE) | ||||||
| 1 | 308 (50.7) | 148 (37.4) | <0.001 | 47 (58.0) | 23 (41.8) | 0.027 |
| 2 | 154 (25.3) | 104 (26.3) | 21 (25.9) | 16 (29.1) | ||
| 3 | 76 (12.5) | 64 (16.2) | 12 (14.8) | 9 (16.4) | ||
| 4 | 70 (11.5) | 80 (20.2) | 1 (1.2) | 7 (12.7) | ||
| Mammographic breast density | ||||||
| 1 | 10 (1.6) | 8 (2.0) | 0.439 | 2 (2.5) | 2 (3.6) | 0.960 |
| 2 | 108 (17.8) | 63 (15.9) | 12 (14.8) | 8 (14.6) | ||
| 3 | 303 (49.8) | 185 (46.7) | 37 (45.7) | 23 (41.8) | ||
| 4 | 187 (30.8) | 140 (35.4) | 30 (37.0) | 22 (40.0) | ||
| Pathologic response | ||||||
| pCR | 250 (41.1) | 119 (30.1) | <0.001 | 34 (42.0) | 11 (20.0) | 0.008 |
| Non-pCR | 358 (58.9) | 277 (69.9) | 47 (58.0) | 44 (80.0) | ||
NOTE: Unless otherwise noted, data indicate number of patients with percentages in parentheses. IQR, interquartile range; BMI, body mass index.