Gastric cancer patients at high-risk of having synchronous cancer

Table 1 Clinicopathological features of patients with or without synchronous cancer

Synchronous	Synchronous cancer With n (%)	Characteristics cancer Without n (%)	P value
Age (yr, mean±SD)	64.6 ± 9.5	59.4 ± 12.5	< 0.001
Sex			0.002
Male	90 (81.1)	2144 (67.4)
Female	21 (18.9)	1036 (32.6)
Multiplicity			0.009
Single	106 (95.5)	3146 (98.9)
Multiple	5 (4.5)	34 (1.1)
Preoperative Stage			< 0.001
Early gastric cancer	62 (55.4)	1135 (35.7)
Advanced gastric cancer	50 (44.6)	2045 (64.3)
Differentiation			< 0.001
Differentiated	94 (84.7)	1383 (43.4)
Undifferentiated	17 (15.3)	1797 (56.6)

Table 2 Distribution of synchronous cancer according to gastric cancer location and diagnosis

Location	Time interval between the diagnoses of synchronous and gastric cancers
	6 mo ~(n=45)	Simultaneos(n=43)	~ 6 mo(n=25)	Total(n=1131, %)
Colorectal	28	6	8	42 (37.2)
Lung	3	11	7	21 (18.6)
Esophagus	8	11	0	19 (16.8)
Liver	2	8	1	11 (9.7)
Breast	0	0	1	1 (0.9)
Kidney	0	2	3	5 (4.4)
Gynecologic	0	1	0	1 (0.9)
Prostate	1	0	2	3 (2.7)
Head and neck	1	1	0	2 (1.8)
GB, bile duct	0	2	0	2 (1.8)
Others	2	1	3	6 (5.3)

¹Two patients have double synchronous cancers.

Table 3 Logistic regression analyses of risk factors

Covariate	β	SE	RR (95% CI)	P value
Age, yr (< 62 vs≥ 62)	0.471	0.223	1.601 (1.035-2.477)	0.035
Sex (Male vs Female)	-0.430	0.250	0.650 (0.398-1.061)	0.085
Histology (Diff. vs Undiff.)	- 1.691	0.276	0.184 (0.107-0.316)	< 0.001
Multiplicity (Single vs Multiple)	0.288	0.412	1.334 (0.595-2.994)	0.484
Stage (EGC vs AGC)	-0.431	0.202	0.650 (0.437-0.966)	0.033

SE: Standard error; RR: Relative risk; CI: Confidence interval.