1. Clinical characteristics of patients in D2 and D2-plus groups before and after PSM.

Characteristics	Entire cohort		P	PSM		P
	D2 group (n=101)	D2-plus group (n=102)		D2 group (n=52)	D2-plus group (n=52)
PSM, propensity score matching; LN, lymph node; *, Fisher’s exact test.
Sex			0.033			0.836
Male	71	57		35	34
Female	30	45		17	18
Age (year)			0.413			0.502
≤65	69	75		40	37
>65	32	27		12	15
Tumor size (cm)			0.623			0.844
≤4.0	49	53		26	25
>4.0	52	49		26	27
Lauren type			0.061*			0.807
Intestinal	28	20		10	11
Diffuse	72	77		42	41
Mixed	1	5		50	50
pT stage			0.790			1.000
T2	20	19		59	59
T3	5	7		51	51
T4a	74	72		41	41
T4b	2	4		51	51
pN stage			0.084			0.877*
N0	50	37		24	25
N1	13	26		10	12
N2	21	16		7	4
N3a	10	17		8	9
N3b	7	7		3	2
pTNM stage			0.600			0.847*
IA	0	0		0	0
IB	16	12		7	8
IIA	6	6		2	0
IIB	29	25		16	19
IIIA	33	33		16	14
IIIB	10	19		8	9
IIIC	7	7		3	2
Number of total LNs dissected			0.266			0.604
<16	22	16		10	8
≥16	79	86		42	44
Proportion of LNs metastasis			0.311			0.406
0	49	37		24	25
<10%	14	17		9	9
10%−40%	26	36		11	15
>40%	12	12		8	3
Extent of LNs metastasis			0.140			0.512
Peri-gastric	75	66		39	36
Extra-gastric	26	36		13	16
Number of LNs metastasis in D2 lymphadenectomy region ( )	3.06±4.67	3.42±6.10	0.635	3.92±5.89	3.20±5.18	0.511