Metastatic lymph nodes and prognosis assessed by the number of retrieved lymph nodes in gastric cancer

Table 4 Chi-square analysis of the number of removed lymph nodes and patient characteristics in the pT1-pT4 subgroups in the Surveillance, Epidemiology, and End Results validation cohort

Characteristics	pT1 (2746), RLNs			P value	pT2 (1534), RLNs			P value	pT3 (4570), RLNs			P value	pT4 (2304), RLNs			P value
	≤ 12	13-24	≥ 25		≤ 17	18-30	≥ 31		≤ 19	20-38	≥ 39		≤ 16	17-44	≥ 45
Sex				0.521				0.263				0.033				0.668
Male	727	678	288		584	305	121		1988	1012	223		576	630	82
Female	428	439	186		316	138	70		775	469	103		448	511	57
Age (yr)				0.018				0.049				0.006				0.054
≤ 60	278	305	145		252	133	64		869	499	130		306	384	53
> 60	877	810	329		648	410	127		1894	982	196		718	757	86
Tumor location				0.008				0.001				< 0.001				< 0.001
Upper third	354	382	140		348	168	54		1391	709	93		159	143	13
Middle third	134	139	81		93	59	39		188	146	54		109	172	34
Lower third	667	596	253		459	216	98		1184	626	179		756	826	92
Tumor size (mm)				0.575				0.009				< 0.001				0.002
≤ 50	966	934	387		695	314	132		1581	749	149		443	417	46
> 50	189	183	87		205	129	59		1182	432	177		581	724	93
Histological type				0.648				0.945				0.951				0.193
Well-moderately differentiated	538	502	217		304	138	67		782	427	86		169	147	25
Poorly-undifferentiated	316	314	141		304	158	62		1212	628	144		397	469	52
Signet ring cell	187	193	64		123	58	26		406	228	51		238	288	37
Others	114	108	52		169	89	36		363	198	45		220	237	25
pN stage				< 0.001				< 0.001				< 0.001				< 0.001
pN0	1008	885	369		547	255	96		1196	526	94		253	166	16
pN1	115	148	53		216	91	39		664	275	48		236	135	19
pN2	28	63	30		106	52	31		561	311	55		298	212	21
pN3	4	21	22		31	45	25		342	369	129		237	628	83
pTNM				< 0.001				< 0.001				< 0.001				< 0.001
I	1123	1033	422		547	255	96		0	0	0		0	0	0
II	32	82	46		322	143	70		1860	801	142		180	130	13
III	0	2	6		31	45	25		903	680	184		844	1011	126

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.