Table 1.
The basic characteristics of patients and breast cancers.
| Characteristics | Training cohort | Internal validation cohort | Test cohort A | Test cohort B |
|---|---|---|---|---|
| No. patients | 534 | 85 | 93 | 95 |
| Age (y) | ||||
| Mean ± SD | 59.30 ± 13.04 | 59.55 ± 11.31 | 56.33 ± 13.78 | 55.97 ± 14.56 |
| Median (range) | 60 (26-95) | 62 (35-81) | 57 (20-88) | 56 (26-87) |
| No. breast cancers | 545 | 85 | 93 | 95 |
| Tumor size | ||||
| T1 (< 2 cm) | 306 (56.1) | 39 (45.9) | 44 (47.3) | 39 (41.1) |
| T2 (2-5 cm) | 223 (40.9) | 42 (49.4) | 47 (50.5) | 54 (56.8) |
| T3 (> 5 cm) | 16 (3.0) | 4 (4.7) | 2 (2.2) | 2 (2.1) |
| Location | ||||
| Left | 280 (51.4) | 46 (54.1) | 46 (49.4) | 47 (49.5) |
| Right | 265 (48.6) | 39 (45.9) | 47 (50.6) | 48 (50.5) |
| Histologic type | ||||
| Invasive ductal cancer | 482 (88.4) | 78 (91.8) | 87 (93.5) | 86 (90.5) |
| Invasive lobular cancer | 12 (2.2) | 1 (1.2) | 4 (4.3) | 3 (3.2) |
| Mixed | 7 (1.3) | 0 (0.0) | 1 (1.1) | 0 (0.0) |
| Other | 44 (8.1) | 6 (7.0) | 1 (1.1) | 6 (6.3) |
| Histologic grade | ||||
| I | 46 (8.5) | 7 (8.2) | 9 (9.7) | 8 (8.4) |
| II | 271 (49.7) | 43 (50.6) | 46(49.5) | 47 (49.5) |
| III | 228 (41.8) | 35 (41.2) | 39 (40.8) | 40 (42.1) |
| BI-RADS | ||||
| 3 | 2 (0.4) | 1 (1.2) | 0 (0.0) | 0 (0.0) |
| 4a | 84 (15.4) | 9 (10.6) | 10 (10.8) | 12 (12.6) |
| 4b | 154 (28.3) | 17 (20.0) | 19 (20.4) | 20 (21.1) |
| 4c | 239 (43.8) | 41 (48.2)) | 41 (44.1) | 48 (50.5) |
| 5 | 66 (12.1) | 17 (20.0) | 23 (24.7) | 15 (15.8) |
| ER status | ||||
| Positive | 395 (72.5) | 66 (77.6) | 68 (73.1) | 67 (70.5) |
| Negative | 150 (27.5) | 19 (22.4) | 25 (26.9) | 28 (29.5) |
| PR status | ||||
| Positive | 349 (64.0) | 50 (58.8) | 55 (59.1) | 59 (62.1) |
| Negative | 196 (36.0) | 35 (41.2) | 38 (40.9) | 36 (37.9) |
| HER-2 status | ||||
| Positive | 135 (24.8) | 21 (25.0) | 28 (30.1) | 29 (30.5) |
| Negative | 410 (75.2) | 64 (75.0) | 65 (69.9) | 66 (69.5) |
| Ki-67 | ||||
| ≤ 14% | 118 (21.7) | 18 (24.7) | 16 (17.2) | 22 (23.2) |
| > 14% | 427 (78.3) | 67 (75.3) | 77 (82.8) | 73 (76.8) |
| Molecular subtypes | ||||
| Luminal A | 93 (17.1) | 15 (17.6) | 14 (15.1) | 16 (16.8) |
| Luminal B | 307 (56.3) | 52 (61.2) | 54 (58.1) | 51 (53.7) |
| Luminal B (-) | 240 (44.0) | 41 (48.3) | 42 (45.2) | 40 (42.1) |
| Luminal B (+) | 67 (12.3) | 11 (12.9) | 12 (12.9) | 11 (11.6) |
| HER-2 positive | 72 (13.2) | 7 (8.3) | 12 (12.9) | 9 (9.5) |
| Triple negative | 73 (13.4) | 11 (12.9) | 13 (13.9) | 19 (20.0) |
Note. —Unless otherwise specified, data in parentheses are percentages.
SD, standard deviation; BI-RADS, breast imaging reporting and data system; ER, oestrogen receptor; PR, progesterone receptor; HER-2, human epidermal growth factor receptor-2.