Table 1. Clinical Characteristics of Study Population.

Characteristics	All Patients (n = 39)	Minor Responders (n = 27)	Good Responders (n = 12)	P
Age at diagnosis (years)	45 (25–67)	47 (25–59)	45 (32–67)	0.658
Clinical TNM stage				0.169
II	17	14 (82.4)	3 (17.6)
III	22	13 (59.1)	9 (40.9)
Clinical T stage				0.012*
2	16	15 (93.8)	1 (6.2)
3	23	12 (52.2)	11 (47.8)
Histologic type				0.526
IDC	37	26 (70.3)	11 (29.7)
Non-IDC	2	1 (50.0)	1 (50.0)
Estrogen or progesterone receptor				0.734
Negative	15	11 (73.3)	4 (26.7)
Positive	24	16 (66.7)	8 (33.3)
HER2				> 0.999
Negative	23	16 (69.6)	7 (30.4)
Positive	16	11 (68.8)	5 (31.3)
Subtype				0.253
Luminal	24	16 (66.7)	8 (33.3)
HER2-enriched	6	3 (50.0)	3 (50.0)
Triple negative	9	8 (88.9)	1 (11.1)
NAC regimen				0.493
Anthracycline/cyclophosphamide	11	8 (72.7)	3 (27.3)
Anthracycline/taxane	23	16 (69.6)	7 (30.4)
Anthracycline/cyclophosphamide + taxane	2	2 (100.0)	0 (0.0)
Anthracycline/taxane + trastuzumab	3	1 (33.3)	2 (66.7)
Surgery				0.122
Breast conserving surgery	11	10 (90.9)	1 (9.1)
Mastectomy	28	17 (60.7)	11 (39.3)
Interval between two DCE-MRI (days)	44 (33–67)	44 (33–63)	44 (33–67)	0.234
Interval between two DCE-US (days)	21 (20–28)	21 (21–28)	21 (20–21)	0.067

Data are presented as median (range) or n (%). P values for differences were determined by Wilcoxon rank sum test for continuous variables and chi-square test or fisher's exact test for categorical variables. Histopathologic examination results were obtained from core needle biopsy specimen. In case of no available immunohistochemistry results before chemotherapy, data obtained from surgical specimen was presented. ^*Statistically significant differences (p < 0.05). DCE-MRI = dynamic contrast-enhanced magnetic resonance imaging, DCE-US = DCE ultrasound, HER2 = human epidermal growth factor receptor 2, IDC = invasive ductal carcinoma, NAC = neoadjuvant chemotherapy, TNM = tumor/node/metastasis