Published online Aug 27, 2026. doi: 10.4240/wjgs.117626
Revised: February 26, 2026
Accepted: March 27, 2026
Published online: August 27, 2026
Processing time: 201 Days and 17.2 Hours
The most appropriate endoscopic management for small (≤ 5 mm) colorectal adenomas has not yet been well established. Although cold snare polypectomy (CSP) is recommended by the guidelines, cold forceps polypectomy (CFP) re
To assess the performance and safety of the modified CFP-NBI-flush method vs CSP for the management of diminutive colorectal adenomas.
This retrospective study included 124 patients harboring 170 eligible diminutive adenomas (≤ 5 mm) who underwent colonoscopy at the Shaoxing People’s Hospital (Shaoxing, China) between November 2023 and December 2024. Polyps were categorized into CFP-NBI-flush (n = 86) and CSP (n = 84) groups according to the technique documented in the endoscopy report. Polyps were used as the unit of analysis for polyp-level outcomes, including recurrence. The primary endpoint was 6-month local recurrence rate, and the secondary endpoints were en bloc resection rate, procedure duration, cost(s), and complications.
Local recurrence rates were 2.6% (2/78) in the CFP-NBI-flush group and 7.5% (6/80) in the CSP group, with no statistical differences (P = 0.277). Despite a higher en bloc resection rate with CSP (92.9% vs 81.4%, P = 0.038), CFP-NBI-flush resulted in shorter procedural duration (median, 32.0 seconds vs 50.5 seconds; P < 0.001), was less expensive (349.7 ± 30.6 CNY vs 398.3 ± 55.1 CNY; P < 0.001), and yielded 100% specimen retrieval (92.9% for CSP; P = 0.013). Immediate bleeding rates (5.8% vs 8.3%, P = 0.563) and other complications (delayed bleeding, perforation) did not differ significantly between the two groups (both 0%). The use of metal clips between the two groups was also similar (5.8% vs 8.3%; P = 0.563).
The CFP-NBI-flush technique showed a 6-month local recurrence rate comparable to that of CSP, and offered advantages in terms of procedural efficiency, specimen retrieval, and cost.
Core Tip: Results of the present study revealed that the cold forceps polypectomy (CFP)-narrow-band imaging (NBI)-flush technique was efficacious compared with cold snare polypectomy (CSP) for preventing the recurrence of diminutive colorectal adenomas (≤ 5 mm), while also offering additional advantages in procedural efficiency, cost-effectiveness, and specimen retrieval rate. High-pressure waterjet-assisted mucosal lifting and NBI-guided margin assessment optimized the quality of polyp resection making CFP-NBI-flush a feasible alternative to CSP.
- Citation: Wang XM, Xu QW, Bi YZ, Luo Q, Lian B, Dong J, Jiang XT, Zhang J. Refined endoscopic technique combined with cold forceps polypectomy for diminutive colorectal polyps. World J Gastrointest Surg 2026; 18(8): 117626
- URL: https://www.wjgnet.com/1948-9366/full/v18/i8/117626.htm
- DOI: https://dx.doi.org/10.4240/wjgs.117626
Colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer-related mortality worldwide[1,2]. Colonoscopy is the cornerstone of CRC prevention because it decreases the risk of CRC incidence and mortality by approximately 40%-60%[3]. Nevertheless, interval cancers—those detected between colonoscopies and which occur in 7.5%-8.6% of patients who have undergone colonoscopy—remain a troubling issue[4,5]. Residual polyp or missed polyp detection is a major risk factor for interval CRC[6,7].
Management of diminutive colorectal polyps (DCRPs; ≤ 5 mm) using endoscopy has undergone profound trans
Recent developments have aimed at overcoming the shortcomings of conventional CFP. Since 2016, published data suggest that a modified CFP technique using jumbo biopsy forceps, post-resection narrow-band imaging (NBI) evaluation, and submucosal injection can yield en bloc resection rates > 90%[10-13]. However, these modifications require expensive tools and complicated procedures, which render them unfeasible for general use. We present a novel tech
This study aimed to evaluate the feasibility, safety, and cost-effectiveness of the CFP-NBI-flush technique vs CSP for the management of diminutive colorectal adenomas. This study addresses the limitations of conventional CFP and provides a low-cost alternative to the CSP with the potential to contribute to clinical practice and patient care.
This retrospective study included 124 patients (n = 170 polyps) who underwent colonoscopy at the Shaoxing People’s Hospital (Zhejiang Province, China) between November 2023 and December 2024. The patients were categorized into two groups based on the polypectomy technique documented in the endoscopy report: 61 patients with CFP-NBI-flush and 63 patients with CSP. A total of 170 eligible diminutive adenomas were resected, including 86 polyps for the CFP-NBI-flush and 84 polyps for CSP. Polyps were used as the unit of analysis for polyp-level outcomes, including recurrence. The study protocol was reviewed and approved by the Ethics Committee of Shaoxing People’s Hospital (Approval No. 2025-YANLI 088-01) and adhered to the principles of the Declaration of Helsinki. The requirement for informed consent was waived by the Ethics Committee due to the observational and retrospective nature of the study.
The inclusion criteria were as follows: (1) Age, 18-80 years; (2) Adequate bowel preparation, defined as a Boston Bowel Preparation Score (BBPS) ≥ 6; (3) Presence of DCRPs (≤ 5 mm) diagnosed as Japan Expert NBI Team type 2A adenomas on magnifying NBI; (4) Maximum of 3 polyps per patient and no more than 2 polyps in each colonic segment, with adjacent polyps spaced ≥ 5 cm apart; and (5) Availability of clinical data that could be fully reviewed. The polyp was used as the unit of analysis for polyp-level outcomes such as en bloc resection, procedure duration, specimen retrieval, cost, complications, and recurrence.
Patients with depression-type polyps were excluded from the study. The exclusion criteria were as follows: (1) Polyps with suspected malignancy; (2) History of inflammatory bowel disease or familial polyposis; (3) Failure to complete follow-up after biopsy; (4) Inability to cooperate with follow-up for patient-specific reasons; (5) History of other malignancies that could limit eligibility; (6) Coagulation disorders; and (7) Use of anticoagulants or antiplatelet agents within one week before colonoscopy.
As this was a retrospective observational study, no a priori sample size calculation was performed. All consecutive eligible patients were included in this study.
All patients underwent standard bowel preparation consisting of a low-residue diet for 2 days and 4 L dose of poly
Once an eligible polyp was identified, the endoscopists captured white-light (distant, intermediate, and close-up views) and NBI-magnified images. The size, anatomical location, and distance from the anal verge (with the patient in the left lateral decubitus position, using the colonoscope’s natural state) were recorded by a nurse.
In cases of CFP followed by NBI under flush, fully opened endoscopic biopsy forceps were used by the operator to take a single “bite” through the target polyp. Submucosal injection was administered using high-pressure water jet irrigation to achieve better visualization of the resection site. Resection margins were meticulously scrutinized using magnifying NBI. Type I pit patterns were considered indicative of complete resection. If any tissue residue was present, additional bites were obtained using biopsy forceps until the polyps were completely removed. The number of bites required to remove polyps was recorded during the procedure.
For the CSP technique, a single-use snare was opened to encompass 1-2 mm of the normal mucosa surrounding the polyps. Using suction, the snare was tightened slowly during mechanical resection of the polyp tissue. If resistance was encountered while tightening the snare, the snare was loosened and the mucosal layer was gently pushed back before tightening the snare again. If necessary, a piecemeal resection of the polyp fragments was performed. After the first resection, debris was removed by irrigation at the resection site, and the surgeon examined the site visually for residual tissue; if confirmed, snare resection was performed again. A snare-excised polyp specimen was extracted from the colonic lumen using suction.
All excised specimens were fixed in formalin and histopathologically evaluated by two experienced gastrointestinal pathologists, who crosschecked the veracity of the specimens.
All patients underwent repeat colonoscopy at the six-month follow-up by the same endoscopist who performed the initial examination. Six-month surveillance colonoscopy was performed for 158/170 polyps (CSP: 80/84; CFP-NBI-flush: 78/86). The remaining 12 polyps were not evaluated for recurrence because 6-month surveillance colonoscopy data were unavailable in our institutional records. Anatomical location and distance from the anus were used to identify the excision site. To exclude local recurrence, a postpolypectomy scar was suspected based on NBI magnification. If residual polypoid tissue was suspected, biopsy forceps were used for resection, and the tissue was subjected to histopathology. If no suspicious tissue was observed, an additional biopsy was not performed, and recurrence was considered absent. Local recurrence was not confirmed when definite polypoid lesions were detected in the same colonic region.
The primary endpoint was six months local recurrence rate, which was defined as the detection of polypoid tissue at the resection site on follow-up colonoscopy. Secondary outcomes included en bloc resection rate, procedure duration, rate of specimen retrieval, treatment cost(s), and rate of procedure-related adverse events (immediate or delayed bleeding and perforation). The en bloc resection rate was defined based on the number of procedures required to complete the endoscopic resection [1 means 1 bite or snare application; > 1 means > 1 bite(s) or snare application]. Procedural duration (seconds) was recorded for each polyp, defined as the interval between insertion of the tool into the biopsy channel and the appearance of the tool on the endoscopic image. Upon the operator’s “start” command the timer was started and was stopped after resection with specimen retrieval was concluded. If it took > 3 minutes to retrieve the specimen, a “discard” strategy was used. Complications were classified as immediate procedural bleeding (IPB), delayed post-polypectomy bleeding (DPPB), and perforation. IPB was defined as bleeding lasting > 30 seconds at the resection site or requiring endoscopic treatment such as hemoclipping (i.e., endoscopic clipping). DPPB was defined as the presence of he
Comparisons of clinical characteristics between groups were performed using the χ2 test or Fisher’s exact test for categorical data and Student’s t-test or Wilcoxon rank-sum test for continuous data. Univariate and multivariate binary logistic regression analyses were performed to identify significant factors associated local recurrence rates, and the results are expressed as OR with corresponding 95%CI. Differences with P < 0.05 were considered to be statistically significant. All statistical analyses were performed using SPSS version 25.0 (IBM Corp., Armonk, NY, United States).
The demographic and clinical characteristics of the patients are summarized in Table 1. There were no statistically significant differences in age, sex ratio, or quality of bowel preparation between CSP and CFP-NBI-flush groups (all P > 0.05). The overall mean age of all included patients was 57.4 ± 9.1 years. The mean age was 56.1 ± 8.5 years in the CSP group and 58.7 ± 9.5 years in the CFP-NBI-flush group, with no significant difference between the two groups (P = 0.062). For distribution of sexes, 67 patients (54.0%) were male, 34 (54.0%) belonged to the CSP group, and 33 (54.1%) to the CFP-NBI-flush group (P = 0.879). For bowel preparation, the overall mean BBPS was 7.47 ± 0.70 (CSP group: 7.50 ± 0.69 vs CFP-NBI-flush group: 7.44 ± 0.70; P = 0.584), highlighting good bowel preparation (i.e., BBPS ≥ 6) in both groups.
| 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 |
The clinical and pathological characteristics of the 170 resected DCRPs, all of which were low-grade adenomas, are summarized in Table 2. The mean size of the polyps was 3.41 ± 0.78 mm, and there were no significant differences between CSP (3.44 ± 0.78 mm) and CFP-NBI-flush (3.38 ± 0.79 mm) groups. In the size stratification process, the largest percentage of polyps were those measuring 3 mm in size, accounting for 47.1% of the included polyps.
| 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) | |
For location of polyps, most of which were found in the right colon (61.2%), including 27.1% in the cecum and ascending colon and 34.1% in the transverse colon. The remaining tumors were found in the descending colon, sigmoid colon, and rectum. There were no significant differences in the number of polyp sites between the two groups (P = 0.613). There were mostly type 0-IIa polyps (64.7%) according to the Paris classification of polyp morphology, followed by type 0-Is [18.2% (31/170)], type 0-Isp [12.4% (21/170)] and type 0-IIb [4.7% (8/170)]. There was no statistically significant differences in the proportion of polyp morphologies between CSP vs CFP-NBI-flush groups (P = 0.308).
The primary outcome was local recurrence at 6 months, which was defined as visualization of polypoid tissue at the site of the original resection during follow-up colonoscopy. As shown in Table 3, the six-month local recurrence was 7.5% (6/80, 95%CI: 0.028-0.156) in the CSP group and 2.6% (2/78, 95%CI: 0.003-0.090) in the CFP-NBI-flush group, although the difference was not significant (P = 0.277). The rate of local recurrence for both groups combined was 5.1% (8/158, 95%CI: 0.022-0.097).
| 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 |
Secondary outcomes including en bloc resection rate, procedural duration, specimen retrieval rate, treatment cost(s), and complication rates are summarized in Table 3.
The CSP group achieved a significantly higher en bloc resection rate than the CFP-NBI-flush group (92.9% vs 81.4%, P = 0.038). En bloc resection was defined as complete removal of the polyp with a single bite for CFP-NBI-flush or a single snare application for CSP.
Procedural duration was defined as the interval between the insertion of the polypectomy instrument into the biopsy channel and the completion of specimen retrieval. The median procedural time in the CFP-NBI-flush group was significantly shorter [32.0 seconds; interquartile range (IQR) 29.0-37.0 seconds] than that in the CSP group (50.5 seconds, IQR: 44.0-60.8 seconds, P < 0.001). The median duration for the procedure in both groups was 41.5 seconds (IQR: 32.0-52.0 seconds).
The specimen retrieval rates were 100% (86/86) and 92.9% (78/84) in the CFP-NBI-flush and CSP groups, respectively; the difference was statistically significant (P = 0.013). The overall retrieval rate in both groups was 96.5% (164/170).
The mean treatment cost including instrument and consumable expenses, was significantly lower in the CFP-NBI-flush group (349.7 ± 30.6 CNY) than that in the CSP group (398.3 ± 55.1 CNY; P < 0.001). The overall mean treatment cost across both groups was 373.7 ± 50.5 CNY.
No cases of DPPB or perforation were observed in either group. The incidence of IPB or need for endoscopic treatment such as hemoclip application, was 5.8% (5/86) in the CFP-NBI-flush group and 8.3% (7/84) in the CSP group, with no significant differences between the groups (P = 0.563). Consistent with IPB rates, the rate of hemostatic metal clip use was similar between the groups (5.8% vs 8.3%; P = 0.563).
Univariate and multivariate logistic regression analyses were performed to identify the factors associated with six-month local recurrence and the results are summarized in Table 4.
| 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 | / | / | / | / | / | / |
Univariate analysis: Univariate analysis was performed to investigate the relationship between each possible variable and local recurrence (P < 0.05). In the univariate analyses, IPB was significantly associated with local recurrence (P = 0.015). In addition, the procedural time (P = 0.037) and treatment costs (P = 0.008) were associated with recurrence. Besides, three of twelve polyps with IPB (25.0%) experienced local recurrence compared with 5 of 146 polyps without IPB (3.4%) who experienced recurrence.
The other variables were either not significantly correlated with local relapse or were predicted to be non-significantly correlated. For the demographic characteristics, age group (≤ 65 years vs > 65 years; P = 0.680) and sex (male vs female; P = 0.476) were not significantly associated with the risk for recurrence. For the quality of bowel preparation, differences in the BBPS scores between the groups were not significantly associated with local recurrence (P = 0.861). At the level of polyp characteristics, key features including polyp size (≤ 3 mm vs > 3 mm; P = 0.297), anatomical location (right colon vs left colon; P = 0.711), and morphological type (Paris classification; P = 0.209), failed to exhibit statistically significant links with recurrence. Among the treatment-related factors, the choice of therapeutic approach (CFP-NBI-flush vs CSP; P = 0.719) and the occurrence of specimen retrieval failure (yes vs no, P = 0.567) had no significant impact on recurrence, whereas the en bloc resection rate (yes vs no) exhibited a non-significant trend toward an association with recurrence (P = 0.071). Regarding procedural and cost factors, procedural time (P = 0.037) and surgical treatment cost (P = 0.008) were associated with recurrence in univariate analyses.
Multivariate logistic regression analysis: To further explore the independent predictors of local recurrence, two multi
Model without excluding confounders: This model incorporated all factors with P < 0.2 in the univariate analysis, a strategy aimed at avoiding the omission of potential confounding variables. In this model, IPB was the only statistically significant independent predictor of local recurrence (OR = 9.530, 95%CI: 1.960-46.373; P = 0.012), whereas polyp size, treatment modality, and en bloc resection were not significant. However, given the collinearity among the procedural and technical variables in this model, the independent predictive values of these factors should be interpreted with caution.
Model after excluding confounders: After excluding collinear variables such as procedural time and treatment cost, the model retained polyp size, therapeutic approach, en bloc resection, and IPB. Two independent variables were identified in the adjusted model. First, en bloc resection was a strong independent protective factor against local recurrence, with an OR of 0.084 (95%CI: 0.012-0.571; P = 0.012). Among the 138 polyps that underwent en bloc resection, 133 (96.4%) had no local recurrence, only 17 of the 20 (85.0%) polyps that underwent piecemeal resection avoided recurrence of the disease. These results confirm that full-thickness en bloc resection of polyps significantly reduced the risk of local recurrence. Second, the presence of IPB was significantly associated with recurrence (OR = 9.543, 95%CI: 1.785-51.004; P = 0.008). As is shown in Table 4, among the 146 polyps without IPB, only 5 (3.4%) polyps experienced local recurrence, whereas 3 of 12 (25.0%) polyps with IPB had local recurrence. This suggested that the IPB could be a surrogate for uncertain polyp resections such as residual tissue at the resection site causing bleeding, which may be associated with a higher risk of local recurrence. In addition, it is noteworthy that in this adjusted model, neither polyp size (OR = 6.516, 95%CI: 0.677-62.683, P = 0.105) nor treatment method (OR = 0.558, 95%CI: 0.098-3.165, P = 0.510) were statistically significant as independent predictors of local recurrence.
Subgroup analysis was performed to evaluate the differences in characteristics and outcomes of patients with polyp(s) ≤ 3 mm and > 3 mm in size (Table 5).
| 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) | |
The proportion of patients > 65 years of age was significantly greater in the > 3 mm polyp subgroup than that in the ≤ 3 mm subgroup [34.2% (25/73) vs 18.6% (18/97); P = 0.022]. There were no significant differences in sex (P = 0.534), quality of bowel preparation (BBPS, P = 0.998), and location of the polyp (right vs left colon, P = 0.245) between the two size groups.
Polyp size was used as a stratification factor and the resection rate differed between the two approaches. In the CFP-NBI-flush group, the en bloc resection rate for polyps ≤ 3 mm was 100% (43/43) which was numerically higher than that of the CSP group (91.1%, 41/45), but this difference was not statistically significant (P = 0.117). In contrast, the en bloc resection rate of the CSP group was significantly higher [97.1% (34/35)] than that of the CFP-NBI-flush group [57.1% (20/35)] for polyps > 3 mm, and was statistically significantly different (P = 0.001).
Results of the present study indicated that modified CFP-NBI-flush technique yielded clinical efficacy comparable with CSP in the treatment of diminutive colorectal adenomas (≤ 5 mm), and had significant advantages in operational efficiency and cost effectiveness. This study revealed that the six-month recurrence rate in the CFP-NBI-flush group was only 2.6%. This result was consistent with a study by Kuwai et al[14], who reported a one-year recurrence rate of 2.1% for CFP combined with NBI technique. Our research provided an additional comparison with CSP. This study revealed that the local recurrence rate in the CSP group was 7.5% which was slightly higher than that in the CFP-NBI-flush group; however, there were no statistically significant differences between the two groups (P = 0.277). The low recurrence rate associated with the CFP-NBI-flush technique can be attributed to two key technical innovations: High-pressure waterjet-assisted mucosal lifting and NBI-magnified margin assessment. The former replaces traditional submucosal injection with hydrodynamic lifting[14,15], simplifying the procedure and reducing costs, which is consistent with our results demonstrating that the treatment cost of CFP-NBI-flush was significantly lower than that for CSP (349.7 ± 30.6 CNY vs 398.3 ± 55.1 CNY; P < 0.001). Additionally, water pressure may mitigate intraoperative bleeding through a capillary packing effect, although the difference in IPB rates between the two groups was not significant (5.8% vs 8.3%; P = 0.563). NBI-magnified margin assessment[15,16] identified type I pit patterns as a marker of no residual tissue, reducing mis
After excluding confounding factors, multivariate logistic regression confirmed two independent predictors of local recurrence[17,18]. First, en bloc resection emerged as a strong independent protective factor against recurrence (OR = 0.084, P = 0.012), a finding consistent with previous research reporting that CSP achieved a complete resection rate of 93.2%[19], significantly higher than that of traditional CFP. Although the CSP group achieved a significantly higher en bloc resection rate than the CFP-NBI-flush group (92.9% vs 81.4%, P = 0.038), the CFP-NBI-flush group still maintained a low local recurrence rate (2.6%). This favorable outcome is attributable to NBI-guided residual tissue assessment, which effectively compensates for the relatively low en bloc resection rate by enabling real-time identification and removal of any residual polyp(s) tissue at the resection margin. Second, IPB was significantly associated with recurrence (OR = 9.543, P = 0.008)[15-18]. Univariate analysis also revealed associations between IPB and recurrence (P = 0.015) which could be explained by blood obscuring the resection margin, leading to unrecognized residual tissue that increased recurrence risk. Notably, there were no significant difference in IPB rates between the two groups suggesting that technical modifications of the CFP-NBI-flush did not increase the risk of intraoperative bleeding.
The CFP-NBI-flush technique demonstrated clear advantages in terms of operational efficiency and cost-effectiveness. The median procedural time for the CFP-NBI-flush group was significantly shorter than CSP (32.0 seconds vs 50.5 seconds; P < 0.001). This result is consistent with the observations reported by Wei et al[20], who found that CSP required longer operative times. This advantage is particularly valuable for endoscopists working in complex anatomical areas such as the right colon, or endoscopists with less experience who often struggle with snare positioning in the CSP to avoid increasing the procedure time. In terms of specimen retrieval rate, the CFP-NBI-flush group achieved a 100% retrieval rate, whereas the CSP group had a retrieval rate of 92.9% (P = 0.013). Specimen loss in CSP not only extends the operative duration but also limits pathological confirmation of the nature of the polyp(s), increasing uncertainty about the completeness of resection. Both groups demonstrated good safety with respect to complications. IPB occurred in 5.8% (5/86) of the CFP-NBI-flush group and 8.3% (7/84) of the CSP group, with no significant differences (P = 0.563) between the groups; the metal clip usage rates were also comparable (5.8% vs 8.3%; P = 0.563). Univariate analysis linked IPB to recurrence (P = 0.015) possibly because blood obscured the resection margins and impaired edge assessment. Multivariate analysis confirmed that IPB was significantly associated with recurrence. Delayed bleeding or perforations were not observed in either group. From a cost perspective, the CFP-NBI-flush technique was significantly more cost effective (349.7 ± 30.6 CNY vs 398.3 ± 55.1 CNY; P < 0.001), findings which were consistent to previous studies that highlighted the economic advantages of CFP for small polyps[21,22]. Such economies of cost and time are likely to render CFP-NBI-flush a practical alternative for clinics with limited resources, thus narrowing the gap between guideline recommendations and real-world clinical practice where many endoscopists prefer CFP.
Subgroup analysis according to polyp size revealed interesting subgroup differences: The proportion of patients > 65 years of age were significantly higher in the > 3 mm polyp group than that in the ≤ 3 mm group (34.2% vs 18.6%; P = 0.022), and there were no statistically significant differences in sex, quality of bowel preparation, or polyp location. These results suggested that differentiated treatment strategies can be adopted for small polyps of different sizes: CFP-NBI-flush can be given priority for lesions ≤ 3 mm, with the advantage of shorter operative duration and a specimen recovery rate of 100%; for lesions > 3 mm, CSP is generally preferred. If CSP cannot be performed due to a difficult anatomical location, improved CFP-NBI-flush technique can achieve the same resection effect as CSP. Similarly, Kamal et al[23] reported that CFP is not inferior to CSP in removing polyps ≤ 3 mm in size and recommend CFP as an acceptable alternative to CSP. Park et al[16] reported that CFP was not inferior to CSP for polyps > 3 mm. A meta-analysis showed that CFP is comparable with CSP in the removal of polyps with a diameter ≤ 3 mm[23]. However, for DCRPs with a diameter > 3 mm, caution should be exercised because of the low overall resection rate (< 90%). Based on the existing evidence, we proposed the following hierarchical management pathway. For DCRPs with a diameter ≤ 3 mm, we recommend that CFP-NBI-flush could be a practical option. For DCRPs > 3 mm, CSP is generally preferred to CFP-NBI-flush. If this cannot be implemented because of technical limitations, improved CFP-NBI-flush technology can be used as an alternative[23-25].
This study had some limitations. First limitation is that its single-center design and operator bias. All procedures were performed by two senior endoscopists with an annual colonoscopy volume ≥ 2000 cases, which could have overestimated the applicability of the technique among junior endoscopists. Multicenter trials are required to include validation results from operators with different levels of experience. Second, the sample size and follow-up duration were analyzed. The single-center retrospective design and 6-month follow-up duration might limit the generalizability and assessment of long-term recurrence. Future research should focus on conducting multicenter, long-term follow-up studies (≥ 3 years) to further validate long-term efficacy and safety of CFP-NBI-flush technology for resection of small CRPs. In addition, it is necessary to explore the applicability of CFP-NBI-flush in sessile serrated lesions to evaluate its clinical value in different pathological types. A real-time analysis system can be developed using artificial intelligence technology to automatically identify residual lesions in NBI images, reduce human judgment errors, and improve the accuracy of complete resection and postoperative follow-up.
Results of the present study revealed that the CFP-NBI-flush technique yielded efficacy comparable with CSP in pre
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