What can be the criteria of outpatient-based endoscopic resection for colon polyp?

Table 1 Baseline characteristics of patients with colon polyps removed by endoscopic mucosal resection n (%)

	n = 3015
Age, mean ± SD, yr	59.6 ± 10.4
Male	1771 (70.0)
Comorbidity
Hypertension	564 (18.7)
Cardiovascular or cerebrovascular disease	389 (12.9)
Chronic renal failure	23 (0.8)
Liver cirrhosis	75 (2.5)
Diabetes mellitus	157 (5.2)
Cancer history	353 (11.7)
Anti-coagulants and anti-platelets
Aspirin	253 (8.3)
Clopidogrel	57 (1.9)
Warfarin	43 (1.4)
Size of lesion, mean ± SD, mm	11.1 ± 6.8
Locations
Right side colon	1296 (43.0)
Cecum	109 (3.6)
Ascending colon	805 (26.7)
Transverse colon	382 (12.7)
Left side colon	1719 (57.0)
Descending colon	346 (11.5)
Sigmoid colon	817 (25.9)
Rectum	556 (18.4)
Morphologic classification
Pedunculated type	550 (18.2)
Piecemeal resection	130 (4.3)
Pathologic complete resection	2956 (98.0)
Horizontal margin involvement	31 (1.0)
Vertical margin involvement	10 (0.3)
Serious immediate bleeding1	78 (2.6)
Prophylactic hemostatic clipping	345 (11.4)
Delayed bleeding	25 (0.8)
Spurting, n	2
Oozing, n	13
Clots with or without vessel exposure, n	10
Onset of delayed post-EMR bleeding, mean ± SD (range), h	9.9 ± 0.4
	(7-72)
Perforation	6 (0.2)
Histology
Adenoma	2357 (78.2)
Tubular adenoma	2026 (67.2)
Tubulovillous adenoma	233 (7.7)
Villous adenoma	99 (3.3)
Serrated adenoma	66 (2.2)
Carcinoma	89 (3.0)
Submucosal invasive carcinoma	10 (0.3)
Hyperplastic polyp	413 (13.6)
Others	90 (3.0)

¹Serious immediate bleeding was defined as bleeding which required hemostatic clip application just after EMR. EMR: Endoscopic mucosal resection.

Table 2 Comparison between the delayed bleeding group and the uneventful group n (%)

	Delayed bleeding n = 25	Uneventful group n = 2990	P value
Age, mean ± SD, yr	58.4 ± 10.1	59.6 ± 10.4	0.646
Male	15 (60.0)	1756 (58.7)	0.898
Laboratory before EMR
Hemoglobin, g/dL	13.2 ± 1.4	13.66 ± 1.8	0.187
Platelet, × 103 count/mm3	60.5 ± 12.1	71.9 ± 1.3	0.81
Prothrombin time, INR	0.984 ± 0.067	0.989 ± 0.528	0.785
Activated partial thromboplastin time, s	33.8 ± 4.4	34.9 ± 23.2	0.665
Comorbidity
Hypertension	5 (20.0)	559 (18.7)	0.800
Cardiovascular or cerebrovascular disease	5 (20.0)	384 (12.8)	0.362
Chronic renal failure	2 (8.0)	21 (0.7)	0.015
Liver cirrhosis	1 (4.0)	74 (2.5)	0.131
Diabetes mellitus	3 (12.0)	154 (5.1)	0.140
Cancer history	3 (12.0)	350 (11.7)	1.000
Anti-coagulants and anti-platelets
Aspirin	3 (12.0)	250 (8.4)	1.000
Clopidogrel	1 (4.0)	56 (1.9)	0.381
Warfarin	0 (0.0)	43 (1.4)	1.000
Size of lesion, mean ± SD, mm	25.8 ± 11.6	11.0 ± 6.6	< 0.001
Locations
Right side colon1	8 (32.0)	1288 (43.1)	0.314
Morphologic classification
Pedunculated	11 (44.0)	539 (18.0)	0.003
Piecemeal resection	6 (24.0)	124 (4.1)	0.001
Pathologic complete resection	25 (100.0)	2954 (79.9)	1.000
Horizontal margin involvement	0 (0.0)	31 (1.0)	1.000
Vertical margin involvement	0 (0.0)	10 (0.3)	1.000
Serious immediate bleeding2	3 (12.0)	75 (2.5)	0.025
Prophylactic hemostatic clipping	4 (16.0)	341 (11.4)	0.319
Histology
Adenoma	23 (92.0)	2337 (78.2)	0.140
Carcinoma	1 (4.0 )	88 (18.4)	0.529
Hyperplastic polyp	1 (4.0)	412 (13.8)	0.240
Others	0 (0.0)	90 (3.0)	1.000

¹Right side colon includes cecum, ascending colon and transverse colon;

²Serious immediate bleeding was defined as bleeding which required hemostatic clip application after EMR. EMR: Endoscopic mucosal resection.

Table 3 Multivariate analysis to define independent risk factors for delayed bleeding

	OR	95%CI	P value
Size	1.1291	1.096-1.164	< 0.001
Pedunculated type	1.497	0.634-3.534	0.357
Immediate serious bleeding	9.150	0.591-3.506	0.413
Piecemeal resection	2.265	0.815-6.292	0.117
Chronic renal failure	9.150	1.856-45.106	0.007
Immediate post-EMR bleeding2	1.447	0.597-3.506	0.413

¹The risk of delayed bleeding after endoscopic mucosal resection increases 12.9% as the size of the polyp increases 1 mm;

²Serious immediate bleeding was defined as bleeding which required hemostatic clip application.