Table 1.
Clinicopathological characteristics of patients according to age at diagnosis (No. [%])
| Characteristics | Total | Age (y) | |||
|---|---|---|---|---|---|
| ~39 | 40‐59 | 60~ | P value | ||
| Race | |||||
| African American | 173 (18.5) | 18 (24.7) | 84 (18.3) | 71 (16.4) | .225 |
| White or others | 763 (81.5) | 55 (75.3) | 375 (81.7) | 362 (83.6) | |
| Histological type | |||||
| Infiltrating lobular carcinoma | 201 (19.0) | 0 (0.0) | 84 (17.3) | 117 (23.7) | <.001 |
| Infiltrating ductal carcinoma | 752 (71.3) | 68 (90.7) | 358 (73.5) | 326 (66.2) | |
| Other | 102 (9.7) | 7 (9.3) | 45 (9.2) | 50 (10.1) | |
| Clinical stage | |||||
| Stage I | 185 (17.5) | 12 (16.0) | 73 (14.99) | 100 (20.2) | .135 |
| Stage II | 619 (58.6) | 40 (53.3) | 300 (61.60) | 279 (56.5) | |
| Stage III | 252 (23.9) | 23 (30.7) | 114 (23.41) | 115 (23.3) | |
| Tumor size (cm) | |||||
| ≤2 | 890 (84.3) | 59 (78.7) | 420 (86.24) | 411 (83.2) | .164 |
| >2 | 166 (15.7) | 16 (21.3) | 67 (13.76) | 83 (16.8) | |
| Lymph node status | |||||
| Negative | 518 (49.2) | 27 (36.0) | 217 (44.65) | 274 (55.7) | <.001 |
| Positive | 535 (50.8) | 48 (64.0) | 269 (55.35) | 218 (44.3) | |
| ER | |||||
| Negative | 235 (23.3) | 20 (28.2) | 130 (27.90) | 85 (18.0) | <.001 |
| Positive | 775 (76.7) | 51 (71.8) | 336 (72.10) | 388 (82.0) | |
| PR | |||||
| Negative | 336 (33.3) | 26 (36.6) | 172 (36.99) | 138 (29.2) | .033 |
| Positive | 673 (66.7) | 45 (63.4) | 293 (63.01) | 335 (70.8) | |
| HER2 | |||||
| Negative | 745 (78.1) | 49 (76.6) | 351 (79.4) | 345 (77.0) | .656 |
| Positive/equivocal | 209 (21.9) | 15 (23.4) | 91 (20.6) | 103 (23.0) | |
ER, estrogen receptor; Her2, human epidermal growth factor receptor 2; PR, progesterone receptor. Bold values mean P < 0.05.