Efficacy of cap-assisted colonoscopy according to lesion location and endoscopist training level

Table 1 Baseline characteristics of enrolled patients n (%)

Characteristics	Total	CAC	SC	P value
Patients	1023	515	508
mean age ± SD	54.75 ± 10.52	55.06 ± 10.29	54.44 ± 10.74	0.342
Gender				0.650
Male	549 (53.7)	280 (54.4)	269 (53.0)
Female	474 (46.3)	235 (45.6)	239 (47.0)
Withdrawal time of total colonoscopies (min)	13.83 ± 7.50	14.67 ± 7.70	12.97 ± 7.20	< 0.001
No. of patients of non therapeutic colonoscopies	566	265	301
Withdrawal time of non therapeutic colonoscopies (min)	10.50 ± 3.75	10.68 ± 3.09	10.33 ± 4.24	0.272
Bowel preparation(Aronchick scale)				0.244
Excellent	38 (3.7)	19 (3.7)	19 (3.7)
Good	646 (63.1)	316 (61.4)	330 (65.0)
Fair	339 (33.1)	180 (35.0)	159 (31.3)

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy.

Table 2 Polyp detection with cap-assisted colonoscopy vs standard colonoscopy on the all ages and both genders n (%)

Whole colon	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Total polyps	967	549	418	0.008
Polyps per patient	0.95 ± 1.46	1.07 ± 1.59	0.82 ± 1.31	0.008
PDR	457 (44.7)	250 (48.5)	207 (40.7)	0.012
Right-side colon	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Total polyps	547	339	208	< 0.001
Polyps per patient	0.53 ± 1.03	0.66 ± 1.18	0.41 ± 0.83	< 0.001
PDR	317 (31.0)	182 (35.3)	135 (26.6)	0.002
Polyps of segment	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Cecum	85	42	43	0.888
Ascending colon	266	179	87	< 0.001
Hepatic flexure	80	56	24	0.001
Transverse colon	116	62	54	0.560
Splenic flexure	30	24	6	0.001
Descending colon	65	31	34	0.683
Sigmoid colon	223	105	118	0.406
Rectum	102	50	52	0.804

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate.

Table 3 Adenoma detection with cap-assisted colonoscopy vs standard colonoscopy on the all ages and both genders n (%)

Whole colon	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Total adenomas	623	370	253	0.003
Adenomas per patient	0.61 ± 1.18	0.72 ± 1.32	0.50 ± 1.01	0.003
ADR	328 (32.1)	184 (35.7)	144 (28.3)	0.011
Right-side colon	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Total adenomas	365	236	129	< 0.001
Adenomas per patient	0.36 ± 0.84	0.46 ± 0.97	0.25 ± 0.67	< 0.001
ADR	225 (22.0)	139 (27.0)	86 (16.9)	< 0.001
Adenomas of segment	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Cecum	45	20	25	0.490
Ascending colon	179	129	50	< 0.001
Hepatic flexure	62	44	18	0.002
Transverse colon	79	43	36	0.529
Splenic flexure	28	22	6	0.003
Descending colon	46	23	23	0.966
Sigmoid colon	130	61	69	0.490
Rectum	54	28	26	0.829

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; ADR: Adenoma detection rate.

Table 4 Total number of polyps and adenomas according to size

Total number	Total (n = 1023)	CAC (n = 515)	SC (n = 508)	P value
Polyps < 5 mm, n	698	398	300	0.011
Per patient	0.68 ± 1.15	0.77 ± 1.27	0.59 ± 1.00	0.011
Adenomas < 5 mm, n	418	253	165	0.003
per Patient	0.41 ± 0.89	0.49 ± 1.03	0.32 ± 0.71	0.003
Polyps ≥ 5 mm, n	269	151	118	0.168
per Patient	0.26 ± 0.70	0.29 ± 0.76	0.23 ± 0.63	0.168
Adenomas ≥ 5 mm, n	205	117	88	0.178
Per patient	0.20 ± 0.64	0.23 ± 0.70	0.17 ± 0.56	0.178

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy.

Table 5 Polyp detection rate, adenoma detection rate, and the number of polyps and adenomas of whole colon based on age n (%)

Whole colon
Age (yr)	Total	CAC	SC	P value
20-49	308	147	161
Polyps per patient	0.51 ± 1.07	0.63 ± 1.32	0.41 ± 0.77	0.078
PDR	94 (30.5)	51 (34.7)	43 (26.7)	0.128
Adenomas per patient	0.26 ± 0.77	0.37 ± 1.02	0.16 ± 0.41	0.013
ADR,	57 (18.5)	35 (23.8)	22 (13.7)	0.022
50-65	544	293	251
Polyps per patient	1.01 ± 1.47	1.09 ± 1.57	0.92 ± 1.34	0.194
PDR	260 (47.8)	146 (49.8)	114 (45.4)	0.305
Adenomas per patient	0.67 ± 1.22	0.76 ± 1.34	0.57 ± 1.04	0.068
ADR	190 (34.9)	107 (36.5)	83 (33.1)	0.400
66-75	154	68	86
Polyps per patient	1.55 ± 1.84	1.93 ± 1.91	1.26 ± 1.74	0.024
PDR	91 (59.1)	47 (69.1)	44 (51.2)	0.024
Adenomas per patient	1.04 ± 1.53	1.28 ± 1.62	0.85 ± 1.43	0.084
ADR	71 (46.1)	38 (55.9)	33 (38.4)	0.030
≥ 76	17	7	10
Polyps per patient	1.24 ± 1.20	1.14 ± 0.90	1.30 ± 1.41	0.959
PDR	12 (70.6)	6 (85.7)	6 (60.0)	0.338
Adenomas per patient	1.00 ± 1.11	0.71 ± 0.75	1.20 ± 1.31	0.502
ADR	10 (58.8)	4 (57.1)	6 (60.0)	1.000

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate; ADR: Adenoma detection rate.

Table 6 Polyp detection rate, adenoma detection rate, and the number of polyps and adenomas of right-side colon based on age n (%)

Right-side colon
Age (yr)	Total	CAC	SC	P value
20-49	308	147	161
Polyps per patient	0.25 ± 0.82	0.35 ± 1.09	0.15 ± 0.45	0.030
PDR	49 (15.9)	30 (20.4)	19 (11.8)	0.039
Adenomas per patient	0.13 ± 0.61	0.20 ± 0.83	0.06 ± 0.25	0.033
ADR	28 (9.1)	20 (13.6)	8 (5.0)	0.008
50-65	544	293	251
Polyps per patient	0.59 ± 1.00	0.68 ± 1.13	0.49 ± 0.82	0.025
PDR	194 (35.7)	110 (37.5)	84 (33.5)	0.322
Adenomas per patient	0.41 ± 0.86	0.50 ± 1.00	0.31 ± 0.66	0.009
ADR	138 (25.4)	82 (28.0)	56 (22.3)	0.129
66-75	154	68	86
Polyps per patient	0.91 ± 1.31	1.21 ± 1.38	0.67 ± 1.21	0.012
PDR	86 (55.8)	38 (55.9)	30 (34.9)	0.009
Adenomas per patient	0.62 ± 1.04	0.81 ± 0.99	0.47 ± 1.07	0.043
ADR	54 (35.1)	34 (50.0)	20 (23.3)	0.001
≥ 76	17	7	10
Polyps per patient	0.59 ± 1.00	0.86 ± 1.06	0.40 ± 0.96	0.167
PDR	6 (35.3)	4 (57.1)	2 (20.0)	0.162
Adenomas per patient	0.41 ± 0.71	0.57 ± 0.78	0.30 ± 0.67	0.362
ADR	5 (29.4)	3 (42.9)	2 (20.0)	0.593

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate; ADR: Adenoma detection rate.

Table 7 Polyp detection rate, adenoma detection rate, and the number of polyps and adenomas based on gender n (%)

Gender	Total	CAC	SC	P value
Whole colon
Male, n	549	280	269
Polyps per patient	1.25 ± 1.67	1.37 ± 1.84	1.12 ± 1.47	0.082
PDR	300 (54.6)	158 (56.4)	142 (52.8)	0.392
Adenomas per patient	0.81 ± 1.38	0.90 ± 1.53	0.71 ± 1.20	0.109
ADR	219 (39.9)	114 (40.7)	105 (39.0)	0.688
Female	474	235	239
Polyps per patient	0.60 ± 1.08	0.71 ± 1.14	0.49 ± 1.00	0.029
PDR	157 (33.1)	92 (39.1)	65 (27.2)	0.006
Adenomas per patient	0.38 ± 0.84	0.50 ± 0.98	0.26 ± 0.67	0.002
ADR	109 (23.0)	70 (29.8)	39 (16.3)	< 0.001
Right-side colon
Male	549	280	269
Polyps per patient	0.70 ± 1.20	0.87 ± 1.39	0.52 ± 0.94	0.001
PDR	205 (37.3)	118 (42.1)	87 (32.3)	0.018
Adenomas per patient	0.49 ± 1.00	0.60 ± 1.14	0.37 ± 0.82	0.007
ADR	153 (27.9)	90 (32.1)	63 (23.4)	0.023
Female	474	235	239
Polyps per patient	0.35 ± 0.73	0.41 ± 0.78	0.28 ± 0.67	0.066
PDR	112 (23.6)	64 (27.2)	48 (20.1)	0.067
Adenomas per patient	0.21 ± 0.56	0.29 ± 0.67	0.13 ± 0.42	0.002
ADR	72 (15.2)	49 (20.9)	23 (9.6)	0.001

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate; ADR: Adenoma detection rate.

Table 8 Polyp detection rate and adenoma detection rate of trainees n (%)

Trainees	Total (n = 847)	CAC (n = 439)	SC (n = 408)	P value
Whole colon
PDR	367 (43.3)	205 (46.7)	162 (39.7)	0.040
ADR	255 (30.1)	149 (33.9)	106 (26.0)	0.012
Right-side colon
PDR	258 (30.5)	150 (34.2)	108 (26.5)	0.015
ADR	176 (20.8)	111 (25.3)	65 (15.9)	0.001

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate; ADR: Adenoma detection rate.

Table 9 Polyp detection rate and adenoma detection rate of experts n (%)

Experts	Total (n = 176)	CAC (n = 76)	SC (n = 100)	P value
Whole colon
PDR	90 (51.1)	45 (59.2)	45 (45.0)	0.062
ADR	73 (41.5)	35 (46.1)	38 (38.0)	0.283
Right-side colon
PDR	59 (33.5)	32 (42.1)	27 (27.0)	0.035
ADR	49 (27.8)	28 (36.8)	21 (21.0)	0.020

CAC: Cap-assisted colonoscopy; SC: Standard colonoscopy; PDR: Polyp detection rate; ADR: Adenoma detection rate.