Table 3.

Chi-square analysis of the number of removed lymph nodes and patient characteristics in the pT1-pT4 subgroups in the Chinese training cohort

Characteristics	pT1 (1106), RLNs			P value	pT2 (745), RLNs			P value	pT3 (1583), RLNs			P value	pT4 (1534), RLNs			P value
	≤ 12	13-25	≥ 26		≤ 17	18-30	≥ 31		≤ 19	20-38	≥ 39		≤ 16	17-44	≥ 45
Sex				0.114			0.803					0.006				0.132
Male	112	353	320		109	274	188		230	677	240		119	851	161
Female	31	150	140		32	80	62		73	295	68		43	286	74
Age (yr)				< 0.001				0.699				0.002				0.273
≤ 60	74	302	323		80	214	152		137	523	183		82	637	138
> 60	69	201	137		61	140	98		166	449	125		80	500	97
Tumor location				0.003				0.216				0.036				0.025
Upper third	17	24	19		17	34	15		54	139	36		34	137	26
Middle third	14	59	68		17	40	37		63	164	68		25	211	45
Lower third	112	420	373		107	280	198		186	669	204		103	789	164
Tumor size (mm)				0.005				0.004				< 0.001				< 0.001
≤ 50	139	477	417		129	287	196		202	514	147		87	549	81
> 50	4	26	43		12	67	54		101	458	161		75	588	154
Histological type				0.008				0.689				0.878				0.145
Well-moderately differentiated	67	273	229		67	160	104		125	378	116		73	391	73
Poorly-undifferentiated	39	153	158		63	148	113		122	426	141		75	631	135
Signet ring cell	14	36	43		6	24	17		36	113	32		7	57	12
Others	23	41	30		5	22	16		20	55	19		7	58	15
pN stage				< 0.001				0.128				< 0.001				< 0.001
pN0	125	43	374		85	195	127		112	241	62		54	220	37
pN1	15	49	45		32	80	57		86	206	54		41	240	22
pN2	3	22	28		21	50	40		68	237	64		42	275	43
pN3	0	2	13		3	29	26		37	288	128		25	402	133
pTNM				0.014				0.045				< 0.001				0.003
I	140	479	419		85	195	127		0	0	0		0	0	0
II	3	24	40		53	130	97		198	447	116		43	201	31
III	0	0	1		3	29	26		105	525	192		119	936	204

Tumor location, tumor size, pTNM stage, histological type and the number of removed lymph nodes were determined according to the postoperative pathology report. Statistically significant P values are in bold (P < 0.05).

RLNs: Retrieved lymph nodes.