Diagnostic utility of small-caliber and conventional endoscopes for gastric cancer and analysis of endoscopic false-negative gastric cancers

Table 1 Patient demographics

	SC-E	C-E
Endoscopic examinations	6831	14807
Male/female	4959/1872	11000/3807b
Age (yr) mean ± SD	50.98 ± 9.89	52.05 ± 10.44b

^bP < 0.01 vs small caliber-endoscope (SC-E). C-E: Conventional-endoscope.

Table 2 The detection rate of gastric cancer and false negative-gastric cancer n (%)

Scope examinations	Detected GCs	Detected FN-GCs	FN-GCs/GCs
SC-E (n = 6831)	16 (0.23)	4 (0.059)	25.0%
C-E (n = 14807)	94 (0.63)	13 (0.088)	13.8%
P value	0.01	0.48	0.27
SC-E1 (n = 6657)	16 (0.24)	4 (0.060)	25.0%
C-E1 (n = 11644)	40 (0.34)	13 (0.112)	32.5%
P value	0.23	0.27	0.75

¹3352 secondary endoscopic examinations that including 54 gastric cancer cases were excluded from a total 21638 endoscopic examinations because most of secondary endoscopic examinations tended to be performed by conventional-endoscope (C-E). GC: Gastric cancer; FN-GC: False negative-gastric cancer; SC-E: Small caliber-endoscope.

Table 3 Clinical characteristics of 17 patients of false negative-gastric cancer

Characteristics	Value
SC-E/C-E	4/13
Age (mean ± SD)	57.6 ± 9.4
Male/female	14/3
Duration1 (mean ± SD)	14.6 ± 8.2 (M)
	(m: 13.2 ± 3.0, sm: 14.5 ± 2.5)
Depth of invasion	m: 9, sm: 6, mp: 0, unknown: 2
Macroscopical types	Elevated type: 5, depressed type: 12
Histopathological types	tub1: 8, tub2: 4, por/sig: 5
Treatment	Endoscopic (EMR, ESD): 6
	Surgical: 9
	Unknown: 2
The previous endoscopic findings	Undetected error: 3
	Incomplete visualization: 6
	Misdiagnosis as benign: 7
	No findings: 1

¹From the last time endoscopy to the day of cancer detected by endoscopy. SC-E: Small caliber-endoscope; C-E: Conventional-endoscope; m: Mucosal layer; sm: Submucosal layer; mp: Muscularis propria; tub1: Well differentiated tubular adenocarcinoma; tub2: Moderately differentiated adenocarcinoma; por: Poorly differentiated adenocarcinoma; sig: Signet ring cell carcinoma; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection.

Table 4 The comparison of endoscopic macroscopic types between false negative-gastric cancer and firstly found-gastric cancer

	FN-GC	FF-GC
Types
I	0 (0)	7 (7.5)
IIa	5 (29.4)	12 (12.9)
IIb	1 (5.9)	0 (0)
IIc	9 (52.9)	33 (35.5)
III	2 (11.8)	16 (17.2)
Advanced	0 (0)	20 (21.5)a
Unknown	0 (0)	5 (5.4)

^aP < 0.05. FN-GC: False negative-gastric cancer; FF-GC: Firstly found-gastric cancer.

Table 5 The comparison of histopathological types between false negative-gastric cancer and firstly found-gastric cancer

	Pap/Tub1/Tub2	Por/Sig	Unknown	Total
FN-GC	12 (70.6%)	5 (29.4%)	0 (0%)	17
FF-GC	40 (43.0%)	50 (53.8%)	3 (3.2%)	93

False negative-gastric (FN-GC) false negative-gastric cancer; Firstly found-gastric cancer (FF-GC) firstly found-gastric cancer. P = 0.048.