Prognostic value of preoperative carcinoembryonic antigen/tumor size in rectal cancer

Table 2 Univariate analysis of prognostic factors for overall survival

Variable	Training cohort (n = 371)			Validation cohort (n = 185)
	Hazard ratio	95%CI	P-value	Hazard ratio	95%CI	P-value
Age	1.02	1.00-1.04	0.024a	1.03	1.00-1.06	0.070
Tumor size	1.04	0.92-1.18	0.506	1.14	0.95-1.37	0.164
Sex (ref = male)	1.43	0.88-2.31	0.145	0.85	0.41-1.77	0.665
TNM1 (ref = stage I)	1.74	1.26-2.41	0.001a	1.93	1.15-3.22	0.012a
Differentiation1 (ref = poor)	0.58	0.40-0.84	0.004a	0.53	0.30-0.94	0.030a
Lymphovascular invasion (ref = negative)	1.88	0.96-3.68	0.066	3.11	1.19-8.13	0.021a
Perineural invasion (ref = negative)	1.03	0.41-2.56	0.954	1.29	0.31-5.46	0.729
CEA (ref = CEA < 5)	1.81	1.11-2.94	0.017a	2.72	1.33-5.59	0.006a
CA 19-9 (ref = CA 19-9 < 37)	1.88	1.04-3.39	0.036a	2.14	0.92-4.99	0.078
CEA/tumor size (ref = low)	2.45	1.46-4.11	0.001a	3.57	1.70-7.52	0.001a

¹These variables were treated as ordinal categorical data;

^aP < 0.05. CEA: Carcinoembryonic antigen; CA 19-9: Carbohydrate antigen 19-9; CI: Confidence interval; ref: Reference.