Treatment strategy for gastric non-invasive intraepithelial neoplasia diagnosed by endoscopic biopsy

Table 1 Definition of intraepithelial neoplasia

	Definition
	Japanese view	Western view
Indefinite for intraepithelial neoplasia	A temporary term	A temporary term
	It is difficult to distinguish whether a lesion is neoplastic or non-neoplastic, or reactive or regenerative
LGIN	Characterized by a slightly modified mucosal architecture, including the presence of tubular structures with budding and branching, papillary enfolding, crypt lengthening with serration and cystic changes
HGIN	Characterized by an increasing architectural distortion with glandular crowding and prominent cellular atypia without stromal invasion
Adenocarcinoma/carcinoma	Diagnosed on nuclear and structural atypia, even when invasion is absent[45]	Diagnosed when evident invasive growth of neoplastic epithelium into the lamina propria of the mucosa or beyond is observed[46]

LGIN: Low-grade intraepithelial neoplasia; HGIN: High-grade intraepithelial neoplasia.

Table 2 Histological discrepancy rates between biopsy and endoscopic resection sample n (%)

Reports (yr)	Endoscopic biopsy	Resected specimens		Overall
		Underdiagnosis1	Overdiagnosis2	Discrepancy3
Yoon et al[47], 2006	Tubular adenoma	2/41 (4.9)	2/41 (4.9)	4/41 (9.8)
Jung et al[29], 2008	LGIN	31/74 (42)	-	-
	HGIN	36/40 (90)	2/40 (5)	38/40 (95)
Lee et al[48], 2010	IN	114/311 (37)	41/311 (13)	155/311 (50)
	Carcinoma	7/86 (8.1)	16/86 (19)	23/86 (26)
	Total	121/397 (30)	57/397 (14)	178/397 (45)
Kato et al[27], 2010	IN	255/468 (44)	4/468 (1.7)	259/468 (46)

¹Underdiagnosis was defined as if endoscopic biopsy showed tubular adenoma/ intraepithelial neoplasia but resected specimens finally led to the diagnosis of adenocarcinoma/carcinoma;

²Overdiagnosis was defined as if endoscopic biopsy showed tubular adenoma/intraepithelial neoplasia or adenocarcinoma/carcinoma but resected specimens finally led to the diagnosis of non-neoplastic, reactive, regenerative or tubular adenoma, respectively;

³Discrepancy was defined as if endoscopic biopsy does not correspond with resected specimen. This can be calculated using resected specimen as a golden standard. LGIN: Low-grade intraepithelial neoplasia; IN: Intraepithelial neoplasia; HGIN: High-grade intraepithelial neoplasia.

Table 3 Histological follow-up studies of gastric intraepithelial neoplasia through mild to severe dysplasia

Reports (yr)	LGIN (including mild to moderate dysplasia)		HGIN (including severe dysplasia)
	Detection of carcinoma n (%)	Interval (mean) n (%)	Detection of carcinoma	Interval (mean)
Saraga et al[49], 1987	1/64 (2)	4 yr	17/21 (81)	4 mo
Lansdown et al[46], 1990	0/7 (0)	-	11/13 (85)	5 mo
Rugge et al[50], 1991	12/69 (17)	1 yr	6/8 (75)	4 mo
Fertitta et al[51], 1993	7/30 (23)	10 mo	25/31 (81)	5 mo
Farinati et al[52], 1993	-	-	16/49 (33)1	-
Di Gregorio et al[53], 1993	6/89 (7)	2 yr	6/10 (60)	11 mo
Bearzi et al[54], 1994	8/81 (9.9)	-	27/44 (61)	-
Rugge et al[55], 1994	13/90 (14)	2 yr	14/18 (78)	9 mo
Kolodziejczyk et al[56], 1994	2/351 (5.72)	-	7/7 (100)	-
Kokkola et al[57], 1996	0/9 (0)	-	2/3 (67)	1.5 yr
Rugge et al[19], 2003	8/90 (8.9)	4 yr	11/16 (69)	34 mo
Yamada et al[58], 2004	0/38 (0)	-	1/10 (10)	54 mo
Park et al[59], 2008	3/26 (12)	58 mo3	1/1 (100)	58 mo3
Overall	60/628 (9.5)		145/231 (63)

Proportion progressing to carcinoma and mean interval.

¹Moderate or severe;

²Mild or moderate dysplasia;

³Overall follow-up interval. LGIN: Low-grade intraepithelial neoplasia; IN: Intraepithelial neoplasia; HGIN: High-grade intraepithelial neoplasia.

Table 4 Endoscopic submucosal dissection and endoscopic mucosal resection for early gastric cancer[60]

	EMR	ESD
Merits	Minimally invasive technique which is safe, convenient and efficacious	The advantage of achieving large en-bloc resections, not necessarily limited by lesion size
Demerits	Insufficient when treating larger lesions, especially larger that 15 mm	Requiring significant additional technical skills and a longer procedure time
		Prolonged learning curve
	High risks of local recurrence, especially when resections are not performed en bloc or when the resection margins are involved by tumor	A higher complication rate compared to standard EMR

ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.