Table 1.
Baseline characteristics by radiological response group
| Complete response MRI | Partial response MRI | Total | |
|---|---|---|---|
| (n = 136) | (n = 31) | (n = 167) | |
| Age | 48 (42–56) | 50 (43–56) | 49 (42–56) |
| Clinical tumor stage | |||
| T1 | 32 (24%) | 4 (13%) | 36 (21%) |
| T2 | 87 (64%) | 20 (65%) | 107 (64%) |
| T3 | 17 (12%) | 6 (19%) | 23 (14%) |
| T4 | 0 | 1 (3%) | 1 (1%) |
| Clinical nodal stage | |||
| N+ | 68 (50%) | 16 (52%) | 84 (50%) |
| Imaging features | |||
| Multifocal | 31 (23%) | 9 (29%) | 40 (24%) |
| Non-mass | 27 (20%) | 6 (19%) | 33 (20%) |
| Calcifications | 36 (27%) | 9 (29%) | 45 (27%) |
| Tumor size (mm) | 27 (20–40) | 27 (22–40) | 27 (21–40) |
| Histology | |||
| Ductal | 121 (89%) | 25 (81%) | 146 (88%) |
| Lobular | 10 (7%) | 4 (13%) | 14 (8%) |
| Other | 5 (4%) | 2 (6%) | 7 (4%) |
| Tumor subtype | |||
| HR +/HER2 - | 32 (24%) | 11 (35%) | 43 (26%) |
| HR +/HER2 + | 36 (26%) | 5 (16%) | 41 (24%) |
| HR -/HER2 + | 21 (15%) | 2 (7%) | 23 (14%) |
| Triple-negative | 47 (35%) | 13 (42%) | 60 (36%) |
| Tumor grade | |||
| Grade 1 | 7 (5%) | 0 | 7 (4%) |
| Grade 2 | 41 (30%) | 15 (48%) | 56 (34%) |
| Grade 3 | 80 (59%) | 15 (48%) | 95 (57%) |
| Unknown | 8 (6%) | 1 (3%) | 9 (5%) |
Data are median (IQR) or n (%). All baseline characteristics were assessed before administration of neoadjuvant systemic therapy. Calcifications were assessed on mammography, other imaging features were assessed on MRI