Endoscopic submucosal dissection for early signet ring cell gastric cancer: A systematic review and meta-analysis

Table 1 Clinical characteristics of included studies

Ref.	Location (language)	Total patients	Age (yr)	Gender (male/female)	Size; mm	Tumor location	Gross type; n	Ulceration; n
Kang et al[10], 2010	South Korea (English)	30	55.4 ± 11.3	14/16	13.6 ± 5.4	Upper: 0; Middle: 7; Lower: 23	Elevated and flat: 8; Depressed: 19; Mixed: 3	Positive: 7
Choi et al[11], 2013	South Korea (Korean)	27	50.9 ± 11.2	14/13	≤ 10: 8; >10, ≤ 20: 20	Upper: 2; Middle: 13; Lower: 13	Elevated: 5; Flat: 13; Depressed: 10	NA
Kim et al[12], 2014	South Korea (English)	126	55 (range: 28–85)	70/56	< 10: 43; ≥ 10, < 20: 43; ≥ 20: 40	Upper: 9; Middle: 66; Lower: 55	Elevated: 10; Flat: 33; Depressed: 20; Mixed: 63	NA
Jeon et al[13], 2018	South Korea (English)	36	63.6 ± 11.1	14/22	≤ 20: 32; > 20: 4	Upper: 1; Middle: 14; Lower: 21	Elevated: 5; Flat: 8; Depressed: 23	Positive: 0
Horiuchi et al[15], 2018	Japan (English)	129	54.6 ± 11.0	73/56	> 20: 2	Upper: 2; Middle: 13; Lower: 16	Elevated and flat: 8; Depressed: 19; Mixed: 7	Positive: 0
Kwak et al[14], 2018	South Korea (English)	176	52.2 ± 10.8	153/178	NA	NA	Elevated: 39; Flat/Depressed: 292	Positive: 56
Ahn et al[16], 2020	Japan (English)	129	53.6 ± 12.1	52/77	Median (IQR): 12 (10–15)	Upper: 6; Middle: 65; Lower: 58	Elevated: 13; Flat: 13/Depressed: 116	NA

NA: Not applicable.

Table 2 Clinical characteristics of early signet ring cell carcinoma after endoscopic submucosal dissection

Ref.	Location (language)	Total patients	Depth of invasion, n (%)	Marginal residual tumor	Resection method, n (%)	Result of resection, n (%)	Procedure-related adverse events
Kang et al[10], 2010	South Korea (English)	30	Mucosa: 25 (83.3); SM: 5 (16.7)	Vi(+): 1 (3.3)	NA	Cr: 16 (53.3); Ir: 14 (46.7)	NA
				Li(+): 5 (16.7)
				Lmi(+): 9 (30)
				Vmi(+): 4 (13.3)
Choi et al[11], 2013	South Korea (Korean)	27	Mucosa: 25 (89.3); SM: 3 (10.7)	Li(+): 1 (3.6)	Ebr: 26 (92.9); Pr: 2 (7.1)	Cr: 25 (89.3); Ir: 3 (10.7)	NA
				Lmi(+): 1 (3.6)
				Vmi(+): 1 (3.6)
Kim et al[12], 2014	South Korea (English)	126	Mucosa: 108 (85.6); SM1: ≤ 500 μm: 4 (3.2); SM2: > 500 μm: 14 (11.2)	Li(+): 6 (4.8)	Ebr: 117 (92.9); Pr: 2 (7.1)	Cr: 81 (64.3); Ir: 45 (35.7)	Gh: 3 (2.4); Gp: 3 (2.4)
				Lmi(+): 24 (19.0)
				Vmi(+): 3 (2.4)
				Bmi(+): 3 (2.4)
Jeon et al[13], 2018	South Korea (English)	36	Mucosa: 30 (83.3); SM: 6 (16.7)	Li(+): 1 (2.8)	Ebr: 36 (100.0); Cr: 24 (66.7)	Cr: 28 (77.8); Ir: 8 (22.2)	Gh: 3 (8.3); Gp: 0
				Lmi(+): 7 (19.4)
				Vmi(+): 0
Horiuchi et al[15], 2018	Japan (English)	129	Mucosa: 125 (96.9); SM1: ≤ 500 μm: 3 (2.3); SM2: > 500 μm: 1 (0.8)	Li(+): 0	Ebr: 129 (100); Cr: 121 (93.8)	NA	Gh: 2 (4.8); Gp: 0
				Hmi(+): 2 (1.6)
				Vmi(+): 0
				Vi(+): 0
Kwak et al[14], 2018	South Korea (English)	176	NA	Li(+): 10 (11.0%)	Cr: (48.3); size criterion = 1.5 cm, 54.9%; size criterion = 1.0 cm, 63.3%; size criterion = 0.6 cm, 63.6%	NA	NA
Ahn et al[16], 2020	Japan (English)	129	Lamina propria: 95 (73.6)	NA	NA	NA	NA
			Muscularis: 87 (39.9)

Bmi(+): Both margin invasion(+); Cr: Curative resection; Ebr: En bloc resection; ESD: Endoscopic submucosal dissection; Hmi(+): Horizontal margin invasion(+); Ir: Incomplete resection; Gp: Gastric perforation; Gh: Gastric hemorrhage; Lmi(+): Lateral margin invasion(+); Li(+): Lymphovascular invasion(+); LNM(+): Lymph node metastasis(+); Pr: Piecemeal resection; SM: Submucosa; SRC: Signet ring cell carcinoma; Vi(+): Vascular invasion(+); Vmi(+): Vertical margin invasion(+); NA: No application.

Table 3 Methodological quality of included studies measured by the Newcastle-Ottawa Scale

Ref.	Selection	Comparability	Exposure or outcome	Total
Kang et al[10], 2010	4	1	2	7
Choi et al[11], 2013	4	2	3	9
Kim et al[12], 2014	4	1	3	8
Jeon et al[13], 2018	4	1	2	7
Horiuchi et al[15], 2018	4	1	3	8
Kwak et al[14], 2018	4	1	3	8
Ahn et al[16], 2020	4	1	3	8