Predicting lymph node metastasis in colorectal cancer: An analysis of influencing factors to develop a risk model

Table 1 Clinicopathological characteristics of the study population (%)

Variable	Training set (n = 188)	Validation set (n = 70)	P value
Age (yr)			0.86
mean ± SD	60.4 ± 13.1	60.6 ± 13.5
Median (range)	61 (18-95)	61 (20-93)
Sex			0.91
Male	112 (59.6)	42 (60)
Female	76 (40.4)	28 (40)
Tumor location			0.97
Right colon	60 (31.9)	22 (31.4)
Left colon	60 (31.9)	23 (32.9)
Rectum	68 (36.2)	25 (35.7)
Tumor size (cm)			0.83
mean ± SD	4.2 ± 2.1	4.2 ± 2.0
Median (range)	4 (1-15)	4 (1-12)
Tumor differentiation			0.99
Well/moderate	162 (86.2)	60 (85.7)
Poor/undifferentiated/others1	26 (13.8)	10 (14.3)
Tumor invasion depth			0.98
Tis	3 (1.6)	1 (1.4)
T1	14(7.4)	5(7.1)
T2	32 (17)	11 (15.7)
T3	121 (64.4)	45 (64.3)
T4a	15 (8)	6 (8.6)
T4b	3 (1.6)	2 (2.9)
Lymphovascular invasion			0.95
Negative	147 (78)	55 (78.6)
Positive	41 (21.7)	15 (21.4)
Indeterminate2	N/A	N/A
Perineural invasion			0.96
Negative	168 (89.4)	63 (90)
Positive	20 (10.3)	7 (10)
Indeterminate	N/A	N/A
Tumor budding			0.09
Absent3	121 (64.3)	38 (54.3)
Low	44 (23.7)	19 (27.1)
High	23 (12)	13 (18.6)
LNM status			0.90
Negative	141 (74.9)	52 (74.3)
Positive	47 (25.1)	18 (25.7)

¹Others included mucinous, signet-ring cell, neuroendocrine differentiation, medullary carcinoma, mixed adenoneuroendocrine carcinoma, micropapillary carcinoma, and serrated adenocarcinoma.

²Indeterminate means that the presence or absence of lymphovascular invasion or perineural invasion cannot be determined.

³Absent: No tumor budding; Low: ≤ 10 tumor buds per high-power field; High: > 10 tumor buds per high-power field.

LNM: Lymph node metastasis; N/A: Not applicable; Tis: Carcinoma in situ; T1: Tumor invades submucosa; T2: Tumor invades muscularis propria; T3: Tumor invades through muscularis propria into pericolorectal tissues; T4a: Tumor penetrates to the surface of the visceral peritoneum; T4b: Tumor directly invades or is adherent to other organs or structures.