Table 1 Clinicopathologic characteristics of the study population before and after neoadjuvant chemotherapy
Characteristics | Total (n = 323) | Non-pCRw/ mic (n = 25) | Non-pCRw/o mic (n = 196) | pCRw/ mic (n = 13) | pCRw/o mic (n = 89) | P value |
|---|---|---|---|---|---|---|
Age, years | 47 (40–54) | 45 (37–55) | 47 (39–54) | 48 (39–56) | 48 (41–52) | 0.907 |
Pre-NAC histologic type | Â | Â | Â | Â | Â | 0.686 |
 IDC | 301 (93.2) | 24 (96.0) | 181 (92.3) | 12 (92.3) | 84 (94.4) |  |
 ILC | 10 (3.1) | 1 (4.0) | 7 (3.6) | 0 (0) | 2 (2.2) |  |
 Mucinous | 2 (0.6) | 0 (0) | 1 (0.5) | 1 (7.7) | 0 (0) |  |
 Micropapillary | 1 (0.3) | 0 (0) | 1 (0.5) | 0 (0) | 0 (0) |  |
 Other | 9 (2.8) | 0 (0) | 6 (3.1) | 0 (0) | 3 (3.4) |  |
Pre-NAC IHC subtype |  |  |  |  |  |  < 0.001 |
 HR + /HER2- | 90 (27.9) | 6 (24.0) | 74 (37.8) | 1 (7.7) | 9 (10.1) |  |
 HR + /HER2 +  | 81 (25.1) | 5 (20.0) | 43 (21.9) | 3 (23.1) | 30 (33.7) |  |
 HR-/HER2 +  | 101 (31.3) | 10 (40.0) | 48 (24.5) | 8 (61.5) | 35 (39.3) |  |
 HR-/HER2- | 51 (15.8) | 4 (16.0) | 31 (15.8) | 1 (7.7) | 15 (16.9) |  |
Pre-NAC tumor size at MRI, mm | 47 (30–67) | 60 (33–72) | 48 (32–67) | 50 (27–55) | 40 (30–60) | 0.1 |
Pre-NAC Ki-67 ≥ 14% | 278 (87.7) | 22 (88.0) | 161 (84.3) | 11 (84.6) | 84 (95.5) | 0.069 |
NAC regimen | Â | Â | Â | Â | Â | 0.001 |
 AC followed by T | 118 (36.6) | 6 (24.0) | 88 (45.1) | 0 (0) | 24 (27) |  |
 AC followed by TH | 133 (41.3) | 14 (56.0) | 65 (33.3) | 9 (69.2) | 45 (50.6) |  |
 TCHP | 27 (8.4) | 1 (4.0) | 11 (5.6) | 1 (7.7) | 14 (15.7) |  |
 AT | 33 (10.2) | 3 (12.0) | 23 (11.8) | 2 (15.4) | 5 (5.6) |  |
 Other | 11 (3.4) | 1 (4.0) | 8 (4.1) | 1 (7.7) | 1 (1.1) |  |
Radiologic response on MRI |  |  |  |  |  |  < 0.001 |
 CR | 74 (22.9) | 2 (8.0) | 22 (11.2) | 9 (69.2) | 41 (46.1) |  |
 Non-CR | 249 (77.1) | 23 (92.0) | 174 (88.8) | 4 (30.8) | 48 (53.9) |  |
Type of surgery |  |  |  |  |  |  < 0.001 |
 Total mastectomy | 170 (52.6) | 0 (0) | 134 (68.4) | 0 (0) | 36 (40.4) |  |
 Partial mastectomy | 153 (47.4) | 25 (100.0) | 62 (31.6) | 13 (100.0) | 53 (59.6) |  |
 Post-NAC tumor size at MRI, mm | 18 (6–36) | 16.50 (9.75–31.75) | 22 (12.25–42.5) | 0 (0–13) | 7 (0–25) |  < 0.001 |
Post-NAC histologic type |  |  |  |  |  |  < 0.001 |
 IDC | 145 (45.2) | 13 (52.0) | 106 (54.1) | 4 (30.8) | 22 (25.8) |  |
 DCIS | 65 (20.1) | 0 (0) | 2 (1.0) | 7 (53.8) | 56 (62.9) |  |
 ILC | 99 (30.7) | 12 (48.0) | 87 (44.4) | 0 (0) | 0 (0) |  |
 LCIS | 1 (0.3) | 0 | 0 | 0 | 1 (1.1) |  |
 Other | 1 (0.3) | 0 (0) | 1 (0.5) | 0 (0) | 0 (0) |  |
none (only ypT0) | 12 (3.7) | 0 (0) | 0 (0) | 2 (15.4) | 10 (11.2) | Â |
Breast pCR (ypT0 and/or ypTis) | 102 (31.6) | 0 (0) | 0 (0) | 13 (100) | 89 (100) |  < 0.001 |
Post-NAC tumor size (invasive), mm | 16 (4.50–37) | 12 (3–18) | 21 (9–45) | 0 (0–0) | 0 (0–0) |  < 0.001 |
Post-NAC tumor size (in situ), mm | 24.50 (7–50) | 35 (9.5–50) | 30 (15–54.25) | 20 (7.75–36) | 10 (2–30) | 0.002 |
Post-NAC extensive intraductal component | 69 (28.2) | 6 (26.1) | 63 (32.3) | 0 (0) | 0 (0) | 0.001 |
Post-NAC lymphovascular invasion | 101 (34.1) | 7 (28.0) | 89 (45.4) | 0 (0) | 5 (7.5) |  < 0.001 |
Post-NAC Ki-67 ≥ 14% | 108 (50) | 12 (63.2) | 74 (48.7) | 4 (80) | 18 (45) | 0.305 |
Follow-up (months) | 74.6 (68.85–86.44) | 72.7 (69.39–78.26) | 75.2 (68.29–84.73) | 71.8 (68.99–86.37) | 74.7 (68.93–87.19) | 0.816 |
Local recurrence | 39 (12.1) | 5 (20.0) | 31 (15.8) | 0 (0) | 3 (3.4) | 0.007 |
Regional recurrence | 43 (13.3) | 4 (16.0) | 36 (18.4) | 0 (0) | 3 (3.4) | 0.003 |
Distant metastasis | 62 (19.2) | 6 (24.0) | 52 (26.5) | 1 (7.7) | 3 (3.4) |  < 0.001 |
Death | 38 (11.8) | 4 (16.0) | 31 (15.8) | 0 (0) | 3 (3.4) | 0.010 |