Analysis of cancer-specific survival in patients with metastatic colorectal cancer: A evidence-based medicine study

Table 1 Demographic characteristics, n (%)

Variable	Total cohort (n = 15838)	Training cohort (n = 11088)	Validation cohort (n = 4750)	χ2	P value
Race				1.36	0.507
Black people	2303 (14.5)	1590 (14.3)	713 (15.0)
White race	12075 (76.2)	8480 (76.5)	3595 (75.7)
Other	1460 (9.2)	1018 (9.2)	442 (9.3)
Sex				0.027	0.869
Male	8560 (54.0)	5988 (54.0)	2572 (54.1)
Female	7278 (46.0)	5100 (46.0)	2178 (45.9)
Age at diagnosis (yr)				1.73	0.188
< 70	10 735 (67.8)	7480 (67.5)	3255 (68.5)
≥ 70	5103 (32.2)	3608 (32.5)	1495 (31.5)
Primary tumor location				0.264	0.607
Colon	7063 (44.6)	4930 (44.5)	2133 (44.9)
Rectum	8775 (55.4)	6158 (55.5)	2617 (55.1)
Tumor differentiation				0.014	0.906
Ⅰ-Ⅱ	11127 (70.3)	7793 (70.3)	3334 (70.2)
Ⅲ-Ⅳ	4711 (29.7)	3295 (29.7)	1416 (29.8)
T staging				0.08	0.777
1-2	2079 (13.1)	1461 (13.2)	618 (13.0)
3-4	13759 (86.9)	9627 (86.8)	4132 (87.0)
N stage				0.576	0.448
0	4209 (26.6)	2966 (26.7)	1243 (26.2)
1-2	11629 (73.4)	8122 (73.3)	3507 (73.8)
CEA status				2.721	0.099
Masculine	12378 (78.2)	8705 (78.5)	3673 (77.3)
Feminine	3460 (21.8)	2383 (21.5)	1077 (22.7)
Liver metastases				0.286	0.593
No	4731 (29.9)	3298 (29.7)	1433 (30.2)
Yes	11107 (70.1)	7790 (70.3)	3317 (69.8)
Lung metastases				2.202	0.138
No	12673 (80.0)	8838 (79.7)	3835 (80.7)
Yes	3165 (20.0)	2250 (20.3)	915 (19.3)
Bone metastases				0.724	0.395
No	15226 (96.1)	10669 (96.2)	4557 (95.9)
Yes	612 (3.9)	419 (3.8)	193 (4.1)
Brain metastases				1.032	0.31
No	15682 (99.0)	10973 (99.0)	4709 (99.1)
Yes	156 (1.0)	115 (1.0)	41 (0.9)
Surgical				0.014	0.906
No	3495 (22.1)	2444 (22.0)	1051 (22.1)
Yes	12343 (77.9)	8644 (78.0)	3699 (77.9)
Chemotherapy				0.026	0.872
None/unknown	4235 (26.7)	2969 (26.8)	1266 (26.7)
Yes	11603 (73.3)	8119 (73.2)	3484 (73.3)

CEA: Carcinoembryonic antigen.