Endoscopic detection and diagnostic strategies for minute gastric cancer: A real-world observational study

Table 1 Clinicopathological characteristics of minute gastric cancers (patients and lesions)

Item	Value
Patients, n	184
Sex (male/female)	107/77
Age, range (median), yr	38-85 (59)
Lesions	191
Endoscopy (ME-NBI/WLE or WLE-NBI)	131/60
Size, range (median), mm	1.0-5.0 (4.0)
Location (upper/middle/lower)	12/22/157
JGCA classification1 (Tub1/Tub2/Sig/GA-FG/GA-FGM/OGA)	65/10/5/8/2/1
Nakamura classification (differentiated/undifferentiated)	186/5
Therapy (ESD/surgery)	179/12
Depth of invasion (mucosa/submucosa)	180/11
Multiple cancer (absent/synchronous/heterochronous)	135/40/16
Morphology change (protruding/flat/depressed)	95/28/68
Colour change (reddish/yellowish-red/no colour change/whitish)	65/55/45/25

¹GA-FG/GA-FGM/OGA were classified as rare subtypes of gastric adenocarcinoma according to the fifth edition of the World Health Organization. For statistical convenience, they were merged with the Japanese Gastric Cancer Association classification.

JGCA: Japanese Gastric Cancer Association; ESD: Endoscopic submucosal dissection; WLE: White light endoscopy; NBI: Narrow-band imaging; ME-NBI: Magnifying endoscopy with narrow-band imaging; Tub1: Well differentiated tubular adenocarcinoma; Tub2: Moderately differentiated tubular adenocarcinoma; Por1/2: Poorly differentiated adenocarcinoma; Sig: Signet ring cell carcinoma; GA-FG: Gastric adenocarcinoma of fundic gland type; GA-FGM: Gastric adenocarcinoma of fundic gland mucosa type; OGA: Oxyntic gland adenoma.

Table 2 Differences between minute gastric cancers found by white light endoscopy and narrow-band imaging

	Found by WLE (n = 161)	Found by NBI (n = 27)	P value
Color change			P = 0.444
Reddish	58	6
Yellowish red	44	10
No color change	36	8
Whitish	22	3
Morphological change			P < 0.001
Protruding	84	6
Flat	15	14
Depressed	62	7
Covering with thin white moss			P = 0.130
Present	60	6
Absent	101	21
Spontaneous bleeding			1
Present	11	0
Absent	150	27

¹Unapplicable to statistics.

WLE: White light endoscopy; NBI: Narrow-band imaging.

Table 3 Diagnostic efficiency of magnifying endoscopy with narrow-band imaging, n (%)

	Only visible (n = 40)	Low confidence (n = 65)	High confidence (n = 86)	P value
Endoscopy				P < 0.001
ME-NBI (n = 131)	13 (32.50)	37 (56.92)	81 (94.19)
WLE/WLE-NBI (n = 60)	27 (67.50)	28 (43.08)	5 (5.81)
Indigo carmine				P < 0.001
Used (n = 124)	14 (35.00)	33 (50.77)	77 (89.53)
Unused (n = 67)	26 (65.00)	32 (49.23)	9 (10.47)

NBI: Narrow-band imaging; WLE: White light endoscopy; ME-NBI: Magnifying endoscopy with narrow-band imaging.