Table 1 Comparison of clinicopathologic characteristics among the ACRIN 6698 training, ACRIN 6698 test and the external test cohorts
Characteristics | ACRIN 6698 Training (n = 153) | ACRIN 6698 Test (n = 74) | External Test (n = 245) | p* | p# |
|---|---|---|---|---|---|
Age (years) | 48 ± 15 | 48 ± 14 | 51 ± 15 | 0.912 | 0.062 |
Tumor size (cm) | 3.40 ± 1.90 | 3.85 ± 2.70 | 3.70 ± 2.40 | 0.018 | 0.298 |
Race | Â | Â | Â | 0.807 | NA |
 White | 109 (71.2) | 53 (71.6) | 0 |  |  |
 Black | 16 (10.5) | 9 (12.2) | 0 |  |  |
 Asian | 11 (7.2) | 3 (4.0) | 245 (100) |  |  |
 Other | 17 (11.1) | 9 (12.2) | 0 |  |  |
TNM stage | Â | Â | Â | NA | NA |
 II A | 0 | 0 | 30 (12.2) |  |  |
 II B | 0 | 0 | 95 (38.8) |  |  |
 III A | 0 | 0 | 50 (20.4) |  |  |
 III B | 0 | 0 | 29 (11.8) |  |  |
 III C | 0 | 0 | 41 (16.8) |  |  |
 Not available | 153 (100) | 74 (100) | 0 |  |  |
Nuclear grades |  |  |  | 0.648 | < 0.001 |
 1 | 3 (2.0) | 2 (2.7) | 1 (0.4) |  |  |
 2 | 45 (29.4) | 17 (23.0) | 156 (63.7) |  |  |
 3 | 104 (68.0) | 55 (74.3) | 88 (35.9) |  |  |
Missing | 1 (0.6) | 0 | 0 | Â | Â |
Enhancement type | Â | Â | Â | 0.101 | 0.053 |
 Mass | 141 (92.2) | 63 (85.1) | 213 (86.9) |  |  |
 Non-mass | 12 (7.8) | 11 (14.9) | 32 (13.1) |  |  |
Multi-focality or multi-centricity | Â | Â | Â | 0.494 | 0.269 |
 Yes | 88 (57.5) | 39 (52.7) | 127 (51.8) |  |  |
 No | 65 (42.5) | 35 (47.3) | 118 (48.2) |  |  |
HR | Â | Â | Â | 0.448 | 0.306 |
 Positive | 87 (56.9) | 46 (62.2) | 152 (62.0) |  |  |
 Negative | 66 (43.1) | 28 (37.8) | 93 (38.0) |  |  |
HER2 | Â | Â | Â | 0.769 | 0.002 |
 Positive | 40 (26.1) | 18 (24.3) | 102 (41.6) |  |  |
 Negative | 113 (73.9) | 56 (75.7) | 143 (58.4) |  |  |
Ki-67 | Â | Â | Â | NA | NA |
 ≤ 20% | 0 | 0 | 50 (20.4) |  |  |
 > 20% | 0 | 0 | 195 (79.6) |  |  |
 Not available | 153 (100) | 74 (100) | 0 |  |  |
Molecular subtypes | Â | Â | Â | 0.300 | 0.003 |
 Luminal HER2- | 62 (40.5) | 33 (44.6) | 95 (38.8) |  |  |
 Luminal HER2+ | 25 (16.3) | 13 (17.6) | 57 (23.3) |  |  |
 HER2 enriched | 15 (9.8) | 5 (6.7) | 45 (18.4) |  |  |
 TNBC | 51 (33.4) | 23 (31.1) | 48 (19.5) |  |  |
Treatment response | Â | Â | Â | 0.965 | 0.856 |
 pCR | 48 (31.4) | 23 (31.1) | 79 (32.2) |  |  |
 non-pCR | 105 (68.6) | 51 (68.9) | 166 (67.8) |  |  |