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

Table 4 Multivariate Cox regression analysis of younger gastric cancer patients in China and the United States

Characteristics		Total1		P value	China2		P value	United States3		P value
		HR	95%CI		HR	95%CI		HR	95%CI
Region	China	1
	United States	2.42	1.35-4.33	0.01
Race	Chinese	1						1
	White	0.80	0.45-1.41	0.52				1.21	0.94-1.55	0.13
	Black	0.84	0.46-1.53	0.63				1.48	1.14-1.92	0.003
	Others	0.76	0.42-1.38	0.45				1.19	0.91-1.55	0.20
Period of diagnosis	Period 1 (2000-2003)	1			1			1
	Period 2 (2004-2008)	0.62	0.27-0.78	0.02	0.51	0.29-0.89	0.047	0.55	0.47-0.64	< 0.0001
	Period 3 (2009-2013)	0.54	0.25-0.73	0.01	0.39	0.22-0.67	0.004	0.50	0.43-0.59	< 0.0001
	Period 4 (2014-2018)	0.48	0.16-0.49	0.0002	0.07	0.03-0.14	< 0.0001	0.47	0.40-0.56	< 0.0001
Gender	Male	1						1
	Female	0.92	0.80-1.07	0.35				0.85	0.79-0.92	< 0.0001
Primary tumor location	Proximal	1			1			1
	Distal	0.92	0.75-1.12	0.47	0.88	0.60-1.29	0.58	0.88	0.80-0.98	0.02
Differentiation	Well	1						1
	Moderate	2.89	0.88-9.48	0.14				1.90	1.36-2.65	0.0002
	Poor/Undifferentiated	4.77	1.47-15.44	0.03				2.97	2.16-4.07	< 0.0001
Linitis plastica	Yes	1.73	1.12-2.68	0.04	6.70	2.72-16.50	0.0005	1.63	1.21-2.19	0.001
	No/unknown	1			1			1
Signet ring cell carcinoma	Yes	1.07	0.92-1.24	0.47				1.48	1.36-1.61	< 0.0001
	No/unknown	1						1
pTNM stage (AJCC TNM 8th)	I	1			1			1
	II	10.96	5.05-23.75	< 0.0001	18.69	5.55-62.96	< 0.0001	2.35	1.81-3.04	< 0.0001
	III	27.32	12.87-58.00	< 0.0001	58.95	18.18-191.13	< 0.0001	4.51	3.57-5.69	< 0.0001
	IV	57.20	26.58-123.10	< 0.0001	158.6	43.85-573.93	< 0.0001	8.26	6.72-10.16	< 0.0001
Surgery	Yes	0.50	0.36-0.70	0.0005	0.46	0.20-1.03	0.11	0.42	0.37-0.46	< 0.0001
	No	1			1			1
Chemotherapy	Yes	0.69	0.58-0.84	0.001				0.82	0.75-0.90	< 0.0001
	No	1						1
Lymphadenectomy with at least 15 lymph nodes	Yes	0.74	0.63-0.86	0.001	0.88	0.64-1.20	0.49	1.04	0.90-1.20	0.64
	No	1			1			1

¹Adjusted factors for total patients: region, race, period, sex, primary tumor location, differentiation, linitis plastica, signet ring cell carcinoma, pathological Tumor-Node-Metastasis (pTNM) stage, surgery, chemotherapy, lymphadenectomy with at least 15 lymph nodes.

²Adjusted factors for patients from China cohort: period, primary tumor location, linitis plastica, pTNM stage, surgery, lymphadenectomy with at least 15 lymph nodes.

³Adjusted factors for patients from the United States cohort: race, period, sex, primary tumor location, differentiation, linitis plastica, signet ring cell carcinoma, pTNM stage, surgery, chemotherapy, lymphadenectomy with at least 15 lymph nodes.

AJCC: American Joint Committee on Cancer; CI: Confidence interval; HR: Hazard ratio.