Survival benefit of younger gastric cancer patients in China and the United States: A comparative study

Table 3 Univariate Cox regression analysis of younger gastric cancer patients in China and the United States

Characteristics		Total		P value	China		P value	United States		P value	China vs United States		P value
		HR	95%CI		HR	95%CI		HR	95%CI		HR	95%CI
Region	China	1
	United States	2.06	1.84-2.31	< 0.0001
Race	Chinese	1						1			1.24	1.00-1.54	0.11
	White	2.08	1.85-2.33	< 0.0001				1.22	0.95-1.56	0.12
	Black	2.14	1.85-2.47	< 0.0001				1.26	0.97-1.63	0.08
	Others	2.07	1.79-2.38	< 0.0001				1.26	0.97-1.64	0.08
Period of diagnosis	Period 1 (2000-2003)	1			1			1			1.12	0.83-1.49	0.55
	Period 2 (2004-2008)	0.90	0.81-0.99	0.009	0.67	0.45-1.00	0.05	0.95	0.85-1.05	0.30	1.52	1.27-1.80	< 0.0001
	Period 3 (2009-2013)	0.87	0.78-0.96	0.008	0.84	0.57-1.22	0.35	0.91	0.82-1.01	0.09	1.36	1.19-1.55	< 0.0001
	Period 4 (2014-2018)	0.84	0.76-0.94	0.008	0.74	0.49-1.10	0.14	0.91	0.82-1.02	0.10	2.03	1.72-2.41	< 0.0001
Gender	Male	1			1			1			1.70	1.51-1.91	< 0.0001
	Female	0.85	0.80-0.91	< 0.0001	1.05	0.87-1.26	0.64	0.82	0.76-0.88	< 0.0001	1.52	1.27-1.80	< 0.0001
Primary tumor location	Proximal	1			1			1			1.30	1.08-1.57	0.02
	Distal	0.68	0.62-0.75	< 0.0001	0.59	0.47-0.75	< 0.0001	0.77	0.70-0.85	< 0.0001	1.56	1.40-1.74	< 0.0001
Differentiation	Well	1			1			1			1.10	0.33-3.62	0.90
	Moderate	2.82	2.05-3.88	< 0.0001	1.62	0.39-6.76	0.51	3.17	2.28-4.42	< 0.0001	2.14	1.56-2.94	< 0.0001
	Poor/Undifferentiated	5.27	3.91-7.11	< 0.0001	2.19	0.54-8.83	0.27	6.15	4.53-8.35	< 0.0001	3.20	2.83-3.62	< 0.0001
Linitis plastica	Yes	1.95	1.58-2.40	< 0.0001	3.69	2.41-5.65	< 0.0001	1.89	1.41-2.52	< 0.0001	1.03	0.66-1.60	0.91
	No	1			1			1			2.25	2.03-2.50	< 0.0001
Signet ring cell carcinoma	Yes	1.61	1.52-1.72	< 0.0001	0.80	0.61-1.05	0.18	2.01	1.86-2.17	< 0.0001	6.53	5.33-7.99	< 0.0001
	No	1			1			1			2.45	2.02-2.96	< 0.0001
pTNM stage (AJCC TNM 8th)	1			1	1			1			9.88	4.28-22.83	< 0.0001
	2.85	2.25-3.60	< 0.0001	2.85	19.50	7.04-54.05	< 0.0001	2.27	1.76-2.93	< 0.0001	1.27	0.96-1.67	0.16
	6.18	5.04-7.58	< 0.0001	6.18	46.77	17.36-125.96	< 0.0001	4.88	3.93-6.07	< 0.0001	1.31	1.13-1.53	0.003
	19.52	16.09-23.68	< 0.0001	19.52	137.73	50.88-372.83	< 0.0001	14.25	11.69-17.36	< 0.0001	1.46	1.26-1.68	< 0.0001
Surgery	Yes	0.36	0.34-0.38	< 0.0001	0.23	0.19-0.28	< 0.0001	0.41	0.37-0.44	< 0.0001	1.29	1.15-1.45	0.0002
	No	1			1			1			1.25	1.08-1.25	0.01
Chemotherapy	Yes	1.71	1.59-1.84	< 0.0001	0.93	0.77-1.13	0.45	1.80	1.66-1.95	< 0.0001	2.10	1.84-2.40	< 0.0001
	No	1			1			1			0.97	0.87-1.09	0.69
Lymphadenectomy with at least 15 lymph nodes	Yes	0.56	0.49-0.63	< 0.0001	0.64	0.47-0.87	< 0.0001	0.73	0.63-0.86	0.0001	2.49	2.12-2.91	< 0.0001
	No	1			1			1			3.86	3.21-4.65	< 0.0001

AJCC: American Joint Committee on Cancer; CI: Confidence interval; HR: Hazard ratio; pTNM: Pathological Tumor-Node-Metastasis.