Table 1. Associations between presence of CTCs, patient characteristics and clinicopathological characteristics of the primary tumor.

Clinical variable at baseline	Total N = 642 (%)	CTC-negative N = 384	CTC-positive N = 258	P-value
pT				0.480
1	310 (48.3%)	190 (49.5%)	120 (46.5%)
2	273 (42.5%)	154 (40.1%)	119 (46.1%)
3	25 (3.9%)	16 (4.2%)	9 (3.5%)
4	9 (1.4%)	4 (1.0%)	5 (1.9%)
missing	25 (3.9%)	20 (5.2%)	5 (1.9%)
pN				0.510
0	339 (52.8%)	204 (53.1%)	135 (52.3%)
+ (1,2,3)	278 (43.3%)	160 (41.7%)	118 (45.7%)
missing	25 (3.9%)	20 (5.2%)	5 (1.9%)
Histology				0.235
Ductal	232 (36.1%)	128 (33.3%)	104 (40.3%)
lobular	23 (3.6%)	12 (3.1%)	11 (4.3%)
Other	360 (56.1%)	222 (57.8%)	138 (53.5%)
missing	27 (4.2%)	22 (5.7%)	5 (1.9%)
Grading				0.780
1	7 (1.1%)	5 (1.3%)	2 (0.8%)
2	230 (35.8%)	136 (35.4%)	94 (36.4%)
3	375 (58.4%)	219 (57.0%)	156 (60.5%)
missing	30 (4.7%)	24 (6.3%)	6 (2.3%)
ER status				0.924
negative	237 (36.9%)	140 (36.4%)	97 (37.6%)
positive	380 (59.2%)	223 (58.1%)	157 (60.9%)
missing	25 (3.9%)	21 (5.5%)	4 (1.6%)
PR status				0.986
negative	272 (42.4%)	160 (41.7%)	112 (43.4%)
positive	343 (53.4%)	202 (52.6%)	141 (54.7%)
missing	27 (4.2%)	22 (5.7%)	5 (1.9%)
Menopause				0.340
pre-menopausal	242 (37.7%)	139 (36.2%)	103 (39.9%)
post-menopausal	400 (62.3%)	245 (63.8%)	155 (60.1%)
Age (years)				0.061
< 50	231 (36.0%)	127 (33.1%)	104 (40.3%)
≥ 50	411 (64.0%)	257 (66.9%)	154 (59.7%)
Chemotherapy				0.922
FEC-DG	317 (49.4%)	189 (49.2%)	128 (49.6%)
FEC-D	325 (50.6%)	195 (50.8%)	130 (50.4%)

pT, pN, Histology, Grading, ER status, PR status tested using valid categories only (without missing information)

FEC-DG = epirubicin-fluorouracil-cyclophosphamide/gemcitabine-docetaxel chemotherapy

FEC-D = epirubicin-fluorouracil-cyclophosphamide docetaxel chemotherapy