Table 1. Patient characteristics for the primary cohort.
| Characteristics | Primary cohort (%) | Cohort (%) | P value | |
|---|---|---|---|---|
| Training | Testing | |||
| Year of diagnosis | ||||
| 2010–2014 | 228 (46.34) | 166 (47.70) | 62 (43.06) | 0.347 |
| 2015–2019 | 264 (53.66) | 182 (52.30) | 82 (56.94) | |
| Age at diagnosis, years | ||||
| ≤60 | 249 (50.61) | 173 (49.71) | 76 (52.78) | 0.536 |
| >60 | 243 (49.39) | 175 (50.29) | 68 (47.22) | |
| Race | ||||
| White | 386 (78.46) | 272 (78.16) | 114 (79.17) | 0.964 |
| Asian | 45 (9.15) | 32 (9.20) | 13 (9.03) | |
| Black | 61 (12.40) | 44 (12.64) | 17 (11.81) | |
| Laterality | ||||
| Left | 267 (54.27) | 188 (54.02) | 79 (54.86) | 0.865 |
| Right | 225 (45.73) | 160 (45.98) | 65 (45.14) | |
| AJCC N stage | ||||
| N1 | 323 (65.65) | 231 (66.38) | 92 (63.89) | 0.597 |
| N2+ | 169 (34.35) | 117 (33.62) | 52 (36.11) | |
| ER | ||||
| Negative | 179 (36.38) | 127 (36.49) | 52 (36.11) | 0.936 |
| Positive | 313 (63.62) | 221 (63.51) | 92 (63.89) | |
| PR | ||||
| Negative | 296 (60.16) | 204 (58.62) | 92 (63.89) | 0.277 |
| Positive | 196 (39.84) | 144 (41.38) | 52 (36.11) | |
| HER2 | ||||
| Negative | 346 (70.33) | 244 (70.11) | 102 (70.83) | 0.874 |
| Positive | 146 (29.67) | 104 (29.89) | 42 (29.17) | |
| Tumor subtype | ||||
| Luminal A | 229 (46.54) | 160 (45.98) | 69 (47.92) | 0.940 |
| Luminal B | 88 (17.89) | 64 (18.39) | 24 (16.67) | |
| HER-2 positive | 58 (11.79) | 40 (11.49) | 18 (12.50) | |
| TNBC | 117 (23.78) | 84 (24.14) | 33 (22.92) | |
| Surgery | ||||
| No | 259 (52.64) | 181 (52.01) | 78 (54.17) | 0.663 |
| Yes | 233 (47.36) | 167 (47.99) | 66 (45.83) | |
| Radiotherapy | ||||
| No/unknown | 157 (31.91) | 118 (33.91) | 39 (27.08) | 0.140 |
| Yes | 335 (68.09) | 230 (66.09) | 105 (72.92) | |
| Chemotherapy | ||||
| No/unknown | 70 (14.23) | 50 (14.37) | 20 (13.89) | 0.890 |
| Yes | 422 (85.77) | 298 (85.63) | 124 (86.11) | |
| Cause of death | ||||
| Survive or die of other causes | 444 (90.24) | 310 (89.08) | 134 (93.06) | 0.176 |
| Died of breast cancer | 48 (9.76) | 38 (10.92) | 10 (6.94) | |
| Survival months | ||||
| ≤36 months | 217 (44.11) | 153 (43.97) | 64 (44.44) | 0.286 |
| 37–60 months | 94 (19.11) | 61 (17.53) | 33 (22.92) | |
| ≥61 months | 181 (36.79) | 134 (38.51) | 47 (32.64) | |
| Total | 492 | 348 | 144 | |
AJCC, American Joint Committee on Cancer; ER, estrogen receptor; PR, progesterone receptor; TNBC, triple-negative breast cancer.