Best Practices for Resection of Diminutive and Small Polyps in the Colorectum

Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum

BACKGROUND

Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled.

AIM

To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps.

METHODS

Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student's t-tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson's correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators.

RESULTS

The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella, Plesiomonas, and Cronobacter, was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones.

CONCLUSION

These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Clip-assisted endoloop ligation of the mucosal defect after resection of colorectal polyps decreased postprocedural delayed bleeding

BACKGROUND

Postprocedural delayed bleeding (PDB) remains the most common major complication of colorectal polypectomy. Incomplete clip closure of mucosal defect and unclosed injured blood vessels in gaps between clips may be the risk factors for PDB.

OBJECTIVES

To observe whether completely no-gap closure of mucosal defect after polypectomy can reduce PDB occurrence.

DESIGN

Single-center, retrospective case-control study.

METHODS

In this study based on historical comparisons of patients in 2 time periods, only the patients with polyps sized between 6 and 15 mm were included. A new clip-assisted endoloop ligation (CAEL, treatment group) method was used between January 2019 and December 2020, and a traditional simple clip closure (SCC, control) was used Between January 2017 and December 2018 to prevent PDB after polypectomy. The rate of PDB of two groups and risk factors for PDB were evaluated.

RESULTS

Totally 4560 patients were included in the study; 2418 patients belong to CAEL group, and 2142 patients belong to SCC group. The overall rate of PDB was significantly lower in CAEL group compared to SCC group (0.6% versus 1.5%, p < 0.00). On multivariate logistic analysis, CAEL was a significant independent preventive factor for PDB (odds ratio (OR), 0.092; 95% confidence interval (CI), 0.029-0.3335; p = 0.000). Polyps located at rectum (colon versus rectum) represented a significant independent risk factor for PDB (OR, 11.888; 95% CI, 3.343-42.269; p = 0.001).

CONCLUSION

Completely no-gap closure of mucosal defect after polypectomy further reduced the rate of PDB for polyps sized between 6 and 15 mm. CAEL may be a significant independent preventive factor for PDB. Polyps located at the rectum may be a significant independent risk factor for PDB.

Comparison of postpolypectomy bleeding events between cold snare polypectomy and hot snare polypectomy for small colorectal lesions: a large-scale propensity score-matched analysis

BACKGROUND AND AIMS

Cold snare polypectomy (CSP), a safe procedure for removing colon polyps, has a low prevalence of postpolypectomy bleeding (PPB). Previous studies have failed to demonstrate differences in PPB rates between CSP and hot snare polypectomy (HSP), possibly because of their small sample sizes. This study analyzed PPB rates after CSP and HSP.

METHODS

This was a retrospective analysis of colorectal lesions (diameter <10 mm) treated using endoscopic resection at our institution between January 2015 and December 2019. Resections were performed using CSP or HSP, depending on the endoscopist's preference. Endoscopic and histologic findings were recorded in the endoscopic database at our institution. Propensity score (PS) matching was performed to match patient age, lesion size, macroscopic features, location of the lesions, clipping after resection, and antithrombotic agent use. The CSP and HSP groups were compared to determine the adverse event (PPB) rates.

RESULTS

The CSP and HSP groups included 12,928 and 2408 lesions (total of 5371 patients), respectively. Univariate analysis revealed that the overall prevalence of PPB after HSP was higher than that after CSP (odds ratio [OR], 5.39; 95% confidence interval [CI], 2.50-11.60). After PS matching (2135 lesions per group), the prevalence of PPB after HSP remained higher than that after CSP (OR, 6.0; 95% CI, 1.34-26.8).

CONCLUSIONS

For colorectal lesions <10 mm in diameter, the risk of PPB after CSP is significantly lower than that after HSP, after PS matching. CSP for lesions <10 mm could be safely performed compared with HSP.