Postoperative circulating tumor DNA detection predicts recurrence and guides adjuvant chemotherapy duration in high-risk stage III colorectal cancer

Table 2 Univariable and multivariable Cox proportional hazards regression analysis of risk factors for recurrence-free survival in patients with high-risk stage III colorectal cancer

Parameter	Univariable analysis		Multivariate analysis
	HR (95%CI)	P value	HR (95%CI)	P value
Age (≥ 60 years vs <60 years)	0.613 (0.142-2.459)	0.512	-	-
Sex (male vs female)	0.257 (0.062-1.055)	0.059	-	-
Tumor location (rectum vs colon)	0.238 (0.044-1.273)	0.093	-	-
Tumor differentiation (moderate/well-differentiated vs poorly differentiated/mucinous carcinoma)	0.899 (0.222-3.631)	0.881	-	-
Tumor stage (IIIb vs IIIc)	0.172 (0.035-0.860)	0.032	0.241 (0.079-0.739)	0.013
T stage (T3 vs T4)	0.212 (0.044-1.015)	0.028	0.561 (0.193-1.632)	0.289
N stage (N1 vs N2)	0.212 (0.044-1.015)	0.052	-	-
Perineural invasion (no vs yes)	2.580 (0.529-12.573)	0.241	-	-
Vascular invasion (no vs yes)	1.277 (0.263-6.207)	0.761	-	-
Number of harvested lymph nodes (≥ 12 vs < 12)	1.678 (0.366-7.681)	0.505	-	-
Adjuvant chemotherapy duration (3 months vs 6 months)	2.852 (0.527-15.434)	0.224	-	-
CEA (ng/mL) (< 5 vs ≥ 5)	0.526 (0.116-2.381)	0.405	-	-
Postoperative ctDNA status (positive vs negative)	6.001 (1.203-29.927)	0.029	4.304 (1.412-13.115)	0.010

ctDNA: Circulating tumor DNA; HR: Hazard ratio; CI: Confidence interval; CEA: Carcinoembryonic antigen.