Refined endoscopic technique combined with cold forceps polypectomy for diminutive colorectal polyps

Table 1 Baseline characteristics of patients

Parameter	Total (n = 124)	CSP (n = 63)	CFP-NBI-flush (n = 61)	P value
Age (year)	57.4 ± 9.1	56.1 ± 8.5	58.7 ± 9.5	0.062
Sex				0.879
Male	67 (54.0)	34 (54.0)	33 (54.1)
Female	57 (46.0)	29 (46.0)	28 (45.9)
BBPS	7.47 ± 0.70	7.50 ± 0.69	7.44 ± 0.70	0.584

Data are presented as mean ± SD or n (%). Continuous variables were compared using Student’s t test or the Mann-Whitney U test, and categorical variables using the χ² test or Fisher’s exact test. BBPS: Boston Bowel Preparation Score; CFP: Cold forceps polypectomy; NBI: Narrow-band imaging; CSP: Cold snare polypectomy.

Table 2 Clinical and pathological characteristics of the diminutive colorectal adenomas

Parameter	Total (n = 170)	CSP (n = 84)	CFP-NBI-flush (n = 86)	P value
Size (mm)	3.41 ± 0.78	3.44 ± 0.78	3.38 ± 0.79	0.803
2	17 (10.0)	7 (8.3)	10 (11.6)
3	80 (47.1)	41 (48.9)	39 (45.3)
4	59 (34.7)	28 (33.3)	31 (36.0)
5	14 (8.2)	8 (9.5)	6 (7.1)
Location				0.613
Cecum/ascending colon	46 (27.1)	19 (22.6)	27 (31.4)
Transverse colon	58 (34.1)	29 (34.5)	29 (33.7)
Descending	19 (11.2)	9 (10.7)	10 (11.6)
Sigmoid colon	39 (22.9)	23 (27.4)	16 (18.6)
Rectum	8 (4.7)	4 (4.8)	4 (4.7)
Morphology				0.308
0-IIa (1)	110 (64.7)	51 (60.7)	59 (68.6)
0-IIb (2)	8 (4.7)	4 (4.8)	4 (4.7)
0-Isp (3)	21 (12.4)	9 (10.7)	12 (14.0)
0-Is (4)	31 (18.2)	20 (23.8)	11 (12.7)
Histology				/
Low-grade adenoma	170 (100)	84 (100)	86 (100)

Data are presented as mean ± SD or n (%). Continuous variables were compared using Student’s t test or the Mann-Whitney U test, and categorical variables using the χ² test or Fisher’s exact test. CFP: Cold forceps polypectomy; NBI: Narrow-band imaging; CSP: Cold snare polypectomy.

Table 3 Outcomes of clinical outcomes between cold forceps polypectomy-narrow-band imaging-flush and cold snare polypectomy for diminutive colorectal adenomas, n (%)

Parameter	Total (n = 170)	CSP (n = 84)	CFP-NBI-flush (n = 86)	P value
Local recurrence	8/158 (5.1)	6/80 (7.5)	2/78 (2.6)	0.277
95%CI	0.022-0.097	0.028-0.156	0.003-0.09
En bloc resection rate	148 (87.1)	78 (92.9)	70 (81.4)	0.038
Time taken for polypectomy (second)	41.5 (32.0, 52.0)	50.5 (44.0, 60.8)	32.0 (29.0, 37.0)	< 0.001
Number of tissue retrieval	164 (96.5)	78 (92.9)	86 (100)	0.013
Surgical treatment cost (CNY)	373.7 ± 50.5	398.3 ± 55.1	349.7 ± 30.6	< 0.001
IPB	12 (7.1)	7 (8.3)	5 (5.8)	0.563
DPPB	0 (0)	0 (0)	0 (0)	/
Perforation	0 (0)	0 (0)	0 (0)	/
Rate of metal clip usage	12 (7.1)	7 (8.3)	5 (5.8)	0.563

Data are presented as n (%), mean ± SD or median (interquartile range). Categorical variables were compared using the χ² test or Fisher’s exact test; continuous variables using Student’s t test or the Mann-Whitney U test. Recurrence was assessed only in polyps with available 6-month surveillance colonoscopy results (n = 158; cold forceps polypectomy: 80/84; cold forceps polypectomy-narrow-band imaging-flush: 78/86). All other outcomes were assessed in all resected polyps (n = 170), unless otherwise specified. CFP: Cold forceps polypectomy; NBI: Narrow-band imaging; CSP: Cold snare polypectomy; IPB: Immediate procedural bleeding; DPPB: Delayed post-polypectomy bleeding.

Table 4 Predictors of local recurrence rate of diminutive adenomatous polyps based on univariate analysis and multivariable analysis, n (%)

Factors	Total (n = 158)	No local recurrence (n = 150)	Local recurrence (n = 8)	P value (univariate analysis)	Multivariate logistic regression analysis			Multivariate logistic regression analysis (confounding excluded)
					P value	OR	95%CI	P value	OR	95%CI
Age (year)				0.6801	/	/	/	/	/	/
≤ 65	127 (80.4)	120 (80.0)	7 (87.5)
> 65	31 (19.6)	30 (20.0)	1 (12.5)
Sex				0.4761	/	/	/	/	/	/
Male	83 (52.5)	80 (53.3)	3 (37.5)
Female	75 (47.5)	70 (46.7)	5 (62.5)
BBPS				0.8611	/	/	/	/	/	/
6	11 (7.0)	10 (6.6)	1 (12.5)
7	66 (41.8)	63 (42.0)	3 (37.5)
8	75 (47.4)	71 (47.3)	4 (50.0)
9	6 (3.8)	6 (4.0)	0 (0)
Size (mm)				0.2971	0.230	0.390	0.076-1.996	0.105	6.516	0.677-62.683
≤ 3	88 (55.7)	82 (54.7)	6 (75.0)
> 3	70 (44.3)	68 (45.3)	2 (25.0)
Location				0.7111	/	/	/	/	/	/
Right	99 (62.7)	93 (62.0)	6 (75.0)
Left	59 (37.3)	57 (38.0)	2 (25.0)
Morphology				0.2091	/	/	/	/	/	/
0-Isp	19 (12.0)	19 (12.7)	0 (0)
0-Is	30 (19.0)	30 (20.0)	0 (0)
0-IIa	102 (64.6)	94 (62.7)	8 (100)
0-IIb	7 (4.4)	7 (4.6)	0 (0)
Therapeutic approaches				0.7191	0.466	0.584	0.135-2.532	0.510	0.558	0.098-3.165
CFP-NBI-flush	78 (49.4)	75 (50.0)	3 (37.5)
CSP	80 (50.6)	75 (50.0)	5 (62.5)
En bloc resection rate				0.0711	0.072	0.224	0.049-1.017	0.012a	0.084	0.012-0.571
Yes	138 (87.3)	133 (88.7)	5 (62.5)
No	20 (12.7)	17 (11.3)	3 (37.5)
IPB				0.0151	0.012	9.53	1.960-46.373	0.008a	9.543	1.785-51.004
Yes	12 (7.6)	9 (6.0)	3 (37.5)
No	146 (92.4)	141 (94.0)	5 (62.5)
Time taken for polypectomy (second)	41.5 (32.0, 52.0)	41.0 (32.0, 52.0)	52.0 (43.5, 79.0)	0.0372	0.504	1.01	0.99-1.03	/	/	/
Number of tissue retrieval				0.5671	/	/	/	/	/	/
Yes	152 (96.2)	144 (96.0)	8 (100)
No	6 (3.8)	6 (4.0)	0 (0)
Surgical treatment cost (CNY)	374.9 ± 51.9	372.4 ± 49.6	421.4 ± 73.4	0.0083	/	/	/	/	/	/

¹χ² test.

²Mann-Whitney U test.

³t test.

^aP < 0.05.

The multivariate logistic regression model 1 included variables with P < 0.20 in univariate analyses. The confounding excluded model included size, therapeutic approach, en bloc resection, and immediate procedural bleeding after excluding collinear variables. Besides, the outcome was coded as local recurrence (yes = 1). BBPS: Boston Bowel Preparation Score; CFP: Cold forceps polypectomy; NBI: Narrow-band imaging; CSP: Cold snare polypectomy; IPB: Immediate procedural bleeding.

Table 5 Subgroup analysis of polypectomy outcomes stratified by polyp size between the two groups, n (%)

	Total (n = 170)	≤ 3 mm (n = 97)	> 3 mm (n = 73)	P value
Age (year)				0.022
< 65	127 (74.7)	79 (81.4)	48 (65.8)
> 65	43 (25.3)	18 (18.6)	25 (34.2)
Gender				0.534
Male	94 (55.3)	56 (57.7)	38 (52.1)
Female	76 (44.7)	41 (42.3)	35 (47.9)
Gut preparation score				0.998
6	12 (7.1)	7 (7.2)	5 (6.8)
7	73 (42.9)	41 (42.3)	32 (43.8)
8	78 (45.9)	45 (46.4)	33 (45.2)
9	7 (4.1)	4 (4.1)	3 (4.1)
Polyp location				0.245
Right hemicolon	104 (61.2)	63 (64.9)	41 (56.2)
Left colon	66 (38.8)	34 (35.1)	32 (43.8)

Categorical variables were compared using the χ² test or Fisher’s exact test; continuous variables using Student’s t test or the Mann-Whitney U test.