Mastering gastric endoscopic submucosal dissection: A learning curve analysis of over 100 consecutive cases performed by Western endoscopist

Table 1 Outcomes of the learning curve in gastric endoscopic submucosal dissection in four chronological phases

	Phase I (case 1-40) (n = 40)	Phase II (case 41-80) (n = 40)	Phase III (case 81-120) (n = 40)	Phase IV (case 121-162) (n = 42)	P value
Age	65.2 years (23-86)	65.8 years (30-85)	65.6 years (19-89)	69.5 years (24-88)	0.71
Male/female	18/22	16/24	23/16	14/27	0.14
En bloc resection	97.5 (39/40)	95 (38/40)	92.5 (37/40)	90.4 (38/42)	0.58
Complete resection (R0)	92.5 (37/40)	87.5 (35/40)	87.5 (35/40)	83.3 (35/42)	0.66
Curative resection	87.5 (35/40)	80 (32/40)	82.5 (33/40)	78.5 (33/42)	0.73
Size	21.5 mm (10-40)	32.1 mm (15-60)	26.2 mm (10-60)	25.6 mm (10-80)	< 0.01
Procedure time (minute) (mean ± SD)	99.4 ± 40.9	105.8 ± 60.2	110 ± 52.4	107.7 ± 57.5	0.87
Adverse events
Overall adverse event rate	0	5 (2/40)	2.5 (1/40)	7.1 (3/42)	0.35
Digestive bleeding	0	5 (2/40)	0	7.1 (3/42)	0.14
Perforation	0	0	2.5 (1/40)	0	0.38
Histological type of lesions
Benign neoplasms	32.5 (13/40)	20 (8/40)	15 (6/40)	7.1 (3/42)	0.02
Low grade dysplasia	12.5 (5/40)	10 (4/40)	27.5 (11/40)	26.1 (11/42)	0.09
High grade dysplasia	17.5 (7/40)	20 (8/40)	30 (12/40)	35.7 (15/42)	0.19
Adenocarcinoma	37.5 (15/40)	50 (20/40)	27.5 (11/40)	30.9 (13/42)	0.16
Intramucosal	27.5 (11/40)	40 (16/40)	22.5 (9/40)	23.8 (10/42)	0.28
SM1 invasion	2.5 (1/40)	0	2.5 (1/40)	2.3 (1/42)	0.80
SM2 invasion	7.5 (3/40)	10 (4/40)	2.5 (1/40)	4.7 (2/42)	0.53
Undifferentiated type (signet ring)	2.5 (1/40)	0	2.5 (1/40)	9.5 (4/42)	0.11
Location of the lesion
Lower third of the stomach	57.5 (23/40)	72.5 (29/40)	70 (28/40)	66.6 (28/42)	0.50
Upper-middle third of the stomach	42.5 (17/40)	27.5 (11/40)	30 (12/40)	33.3 (14/42)	0.50

SM1: Superficial submucosa; SM2: Deep submucosa.