Table 1.

Demographic statistics of patients in the training and validation cohorts

		Training cohort			Validation cohort			P†
Characteristics		LN+	LN-	P	LN+	LN-	P
		n = 42	n = 98		n = 19	n = 38		0.734
Gender								0.453
	Male	16	51	0.130	12	26	0.769
	Female	26	47		7	12
Age								0.919
	Mean	59.5	63.6	0.004*	63.2	62.2	0.660
	Median	60.0	64.5		63.0	62.5
	Range	42~74	46~86		50~79	50~75
	SD	7.4	7.6		7.5	7.3
Position								0.863
	0	5	13	0.912	3	6	0.827
	1	20	49		10	17
	2	17	36		6	15
T stage								0.372
	1	0	18	0.005*	1	10	0.209
	2	6	24		5	10
	3	33	52		12	15
	4	3	4		1	3
N stage								0.957
	0	-	98		-	38
	1	23	-		11	-
	2	15	-		6	-
	3	4	-		2	-
CT Report								0.093
	0	24	65	0.430	15	29	0.970
Number	1~2	17	29		3	7
	>3	1	4		1	2

Note:

P value is calculated from the univariable association test between sub-groups

χ² test and Fisher’s exact test for categorized variables; two-sample t-test for continues variables

* P value < 0.05

† The comparison between the training cohort and validation cohort

Abbreviations: LN, lymph node; +, metastasis positive; - metastasis negative, CT, computed tomography; SD, standard deviation.