Table 3. Univariate and multivariate analyses of prognostic factors for disease-free survival or disease-specific survival of patients with early stage (stage I-II) tumors in the study cohort.

Variables	Univariate analysisa			Multivariate analysisb
	HR	95 % CI	P value	HR	95 % CI	P value
Disease-free survival
Age (≥ 60/< 60 years)	1.812	1.002–3.275	0.049	1.780	0.980–3.232	0.058
Sex (male/female)	0.722	0.414–1.256	0.249
Tumor location (rectum/colon)	1.576	0.905–2.745	0.108
Tumor size (≥ 5/< 5 cm)	0.860	0.496–1.494	0.593
Bowel obstruction/perforation (yes/no)	1.294	0.315–5.325	0.721
Differentiation grade (poor/well + moderate)	1.857	1.035–3.332	0.038	1.392	0.747–2.594	0.298
Local invasion (T3–T4/T1–T2)	1.255	0.644–2.447	0.505
Serum CEA level (≥ 10/ < 10 ng/mL)	1.167	0.674–2.021	0.581
PRDX2 expression(high/low)	2.018	1.143–3.561	0.015	1.856	1.016–3.390	0.044
Disease-specific survival
Age (≥ 60/< 60 years)	2.300	1.120–4.721	0.023	2.235	1.083–4.613	0.030
Sex (male/female)	0.737	0.391–1.389	0.346
Tumor location (colon/rectum)	1.330	0.708–2.496	0.375
Tumor size (≥ 5/< 5 cm)	0.578	0.308–1.085	0.088
Bowel obstruction/perforation (yes/no)	1.713	0.412–7.112	0.459
Differentiation grade (poor/well + moderate)	2.190	1.146–4.183	0.018	1.585	0.801–3.137	0.186
Local invasion (T3–T4/T1–T2)	1.316	0.605–2.864	0.488
Serum CEA level (≥ 10/ < 10 ng/mL)	1.298	0.692–2.437	0.416
PRDX2 expression (high/low)	2.377	1.221–4.629	0.011	2.137	1.062–4.299	0.033

Abbreviations: CEA, carcinoembryonic antigen; CI, confidence interval; HR, hazard ratio; PRDX2, peroxiredoxin 2; TNM, tumor-node-metastasis.

^a In univariate analyses, log-rank tests were conducted.

^b In the multivariate Cox proportional hazard model, only variables with P < 0.05 in univariate analysis were included and the “enter method” was applied.