Optimal postoperative surveillance strategies for stage III colorectal cancer

Table 1 Demographic and clinical characteristics of participants according to surveillance intensity (n = 1888)

Variables	Surveillance intensity		P value
	Lower intensity (n = 1024)	Higher intensity (n = 864)
Age, mean (IQR)	60.0 (52.0–68.0)	58.0 (50.3–67.0)	0.178
Gender, n (%)			0.502
Male	607 (59.3)	528 (61.1)
Female	417 (40.7)	336 (38.9)
Cancer site, n (%)			0.795
Colon	365 (35.6)	303 (35.1)
Rectum	659 (64.4)	561 (64.9)
Differentiation, n (%)			0.027
WD/MD	945 (92.3)	781 (90.4)
PD/SRC/MUC	72 (7.0)	82 (9.5)
Unknown	7 (0.7)	1 (0.1)
Total lymph nodes, n (%)			0.001
< 12	129 (12.6)	49 (5.7)
≥ 12	895 (87.4)	815 (94.3)
(y) pT, n (%)			0.002
0	12 (1.2)	6 (0.7)
1	66 (6.4)	36 (4.2)
2	126 (12.3)	89 (10.3)
3	770 (75.2)	660 (76.4)
4	50 (4.9)	73 (8.4)
(y) pN, n (%)			0.010
1c	14 (1.4)	8 (0.9)
1	735 (71.8)	570 (66.0)
2	275 (26.8)	286 (33.1)
Perineural invasion, n (%)	219 (21.4)	262 (30.3)	< 0.001
Lymphovascular invasion, n (%)	371 (36.2)	344 (39.8)	0.110
Resection margin, n (%)			0.004
Positive	18 (1.7)	41 (4.7)
Unknown	7 (0.7)	8 (0.9)
APCT, mean ± SD	1.49 ± 0.47	2.67 ± 1.31	< 0.001
CCT, mean ± SD	0.62 ± 0.41	1.48 ± 0.91	< 0.001
Total imaging studies, mean ± SD	2.11 ± 0.58	4.14 ± 1.64	< 0.001

IQR: Inter-quartile range; WD: Well differentiated; MD: Moderately differentiated; PD: Poorly differentiated; SRC: Signet ring cell type; MUC: Mucinous carcinoma; APCT: Abdomino-pelvic computed tomography; SD: Standard deviation; CCT: Chest computed tomography.