Table 1.
Characteristics of the BCAC European study participants
| Characteristics | ER-negative patients who received chemotherapy | Percent | ER-negative patients who did not receive chemotherapy | Percent | ER-positive patients who received chemotherapy | Percent |
|---|---|---|---|---|---|---|
| Number of patients | 1499 | 100.00 | 835 | 100.00 | 3151 | 100.00 |
| Age at diagnosis (mean ± SD, years) | 51.69 ± 10.85 | 59.46 ± 12.18 | 51.74 ± 9.88 | |||
| Family history | ||||||
| No | 974 | 64.98 | 457 | 54.73 | 2233 | 70.87 |
| Yes | 275 | 18.35 | 148 | 17.72 | 596 | 18.91 |
| Missing | 250 | 16.68 | 230 | 27.54 | 322 | 10.22 |
| Tumor stage | ||||||
| 1 | 356 | 23.75 | 401 | 48.02 | 606 | 19.23 |
| 2 | 804 | 53.64 | 259 | 31.02 | 1751 | 55.57 |
| 3 | 182 | 12.14 | 58 | 6.95 | 526 | 16.69 |
| Missing | 157 | 10.47 | 117 | 14.01 | 268 | 8.51 |
| Histological grade | ||||||
| Well-differentiated | 23 | 1.53 | 97 | 11.62 | 390 | 12.38 |
| Moderately differentiated | 293 | 19.55 | 310 | 37.13 | 1624 | 51.54 |
| Poorly/undifferentiated | 1183 | 78.92 | 428 | 51.26 | 1137 | 36.08 |
| Tumor size | ||||||
| ≤2 cm | 664 | 44.30 | 528 | 63.23 | 1387 | 44.02 |
| ≥2 cm to ≤5 cm | 744 | 49.63 | 271 | 32.46 | 1490 | 47.29 |
| ≥5 cm | 91 | 6.07 | 36 | 4.31 | 274 | 8.70 |
| Lymph node status | ||||||
| Negative | 735 | 49.03 | 651 | 77.96 | 976 | 30.97 |
| Positive | 764 | 50.97 | 184 | 22.04 | 2175 | 69.03 |
| PR status | ||||||
| PR-negative | 1271 | 84.79 | 633 | 75.81 | 546 | 17.33 |
| PR-negative HER2-negative | 692 | 46.16 | 315 | 37.72 | 304 | 9.65 |
Results are presented as number of patients unless stated otherwise. BCAC, Breast Cancer Association Consortium; ER, estrogen receptor; PR, progesterone receptor; SD, standard deviation; HER2, human epidermal growth factor receptor 2.