Underwater endoscopic mucosal resection (uEMR) represents an alternative to conventional EMR for resection of sessile colorectal polyps. We aimed at assessing the efficacy and safety of uEMR for sessile colorectal polyps.

A retrospective analysis of endoscopy database was done for patients who underwent uEMR for sessile colorectal polyps more than 10 mm in size without any features of sub-mucosal invasion from two tertiary care centres in western India between January 2021 and June 2023. Exclusion criteria were other modes of endoscopic resection. Primary outcome was rate of en bloc resection. Secondary outcomes were complete resection rate, adverse events and recurrence rate.

During the study period, 159 patients with 261 lesions met the study inclusion. Mean lesion size was 1.935 ± 0.71 cm with most lesion located in the rectum (75, 28.73%) followed by sigmoid colon (69, 26.43%). Most lesions had a Paris 0-Is morphology (192, 73.56%). Japan NBI Expert Team (JNET) IIa pattern was seen on narrow band imaging (NBI) in 221 (84.67%) lesions. Complete resection was achieved in 98.46% lesions (257/261). En bloc resection was achieved in 91.82% (236/257) lesions. Complications were seen in 6.8%, all of which were managed endoscopically. Recurrence was seen in 3.1% of polyps on follow-up.

uEMR is a safe and efficacious technique for endoscopic resection for sessile colorectal polyps with high rates of en bloc resection for polyps more than 10 mm size.

Conventional endoscopic mucosal resection (CEMR) is the standard modality for removing nonpedunculated colorectal lesions. Underwater endoscopic mucosal resection (UEMR) has emerged as an alternative method. There are few comparative studies between these techniques, especially evaluating recurrence. Therefore, the purpose of this trial was to compare CEMR and UEMR for the resection of colorectal lesions with respect to efficacy, safety, and recurrence rate.

This was a randomized controlled trial of UEMR versus CEMR for naïve and nonpedunculated lesions measuring between 10 and 40 mm. The primary outcome was adenoma recurrence at 6 months after the resection. Secondary outcomes were rates of technical success, en bloc resection, and adverse events. Block randomization was used to assign patients. Tattooing was performed to facilitate localization of the scars and eventual recurrences. Endoscopic follow-up was scheduled at 6 months after the procedure. The sites of resections were examined with white-light imaging, narrow-band imaging (NBI), and conventional chromoscopy with indigo carmine followed by biopsies.

One hundred five patients with 120 lesions were included, with a mean size of 17.5 ± 7.1 (SD) mm. Sixty-one lesions were resected by UEMR and 59 by CEMR. The groups were similar at baseline regarding age, sex, average size, and histologic type. Lesions in the proximal colon in the CEMR group corresponded to 83% and in the UEMR group to 67.8% (P = .073). There was no difference between groups regarding success rate (1 failure in each group) and en bloc resection rate (60.6% UEMR vs 54.2% CEMR, P = .48). Intraprocedural bleeding was observed in 5 CEMRs (8.5%) and 2 UEMRs (3.3%) (P = .27). There was no perforation or delayed hemorrhage in either groups. Recurrence rate was higher in the CEMR arm (15%) than in the UEMR arm (2%) (P = .031). Therefore, the relative risk of 6-month recurrence rate in the CEMR group was 7.5-fold higher (95% CI, 0.98-58.20), with a number needed to treat of 7.7 (95% CI, 40.33-4.22). The higher recurrence rate in the CEMR group persisted only for lesions measuring 21 to 40 mm (35.7% vs 0%; P = .04).

This study demonstrated that UEMR was associated with a lower adenoma recurrence rate than was CEMR. Both endoscopic techniques were effective and had similar rates of adverse events for the treatment of nonpedunculated colorectal lesions.

Underwater endoscopic mucosal resection (UEMR) has emerged as a revolutionary method allowing resection of colorectal lesions without submucosal injection. Brazilian literature about this technique is sparse.

The aim of this study was evaluate the efficacy and safety of UEMR technique for removing non-pedunculated colorectal lesions in two Brazilian tertiary centers.

This prospective study was conducted between June 2016 and May 2017. Naïve and non-pedunculated lesions without signs of submucosal invasion were resected using UEMR technique.

A total of 55 patients with 65 lesions were included. All lesions, except one, were successfully and completely removed by UEMR (success rate 98.5%). During UEMR, two cases of bleeding were observed (3.0%). One patient had abdominal pain on the day after resection without pneumoperitoneum. There was no perforation or delayed bleeding.

This study supports the existing data indicating acceptable rates of technical success, and low incidence of adverse events with UEMR. The results of this Brazilian study were consistent with previous abroad studies.

Cold resection for small colonic polyps, and larger lesions, is being rapidly and widely adopted. Driven by an impressive safety and cost profile compared with conventional polypectomy, these advantages are offset by the limitations of smaller and shallower resection, and absent thermal effects that may permit persistence of residual neoplasia. To overcome this, optimal cold snare technique requires inclusion of a margin of normal mucosa and a piecemeal resection technique for larger polyps. This article examines the fundamentals of cold snare resection and evidence for its application, theorizes on limits to its application, and identifies areas for further research.

The optimal technique for the resection of sessile serrated polyps (SSPs) is unknown, with established limitations and risks with conventional polypectomy. Although cold snare polypectomy is safe, the efficacy of piecemeal resection for large lesions is untested. In this study we evaluate the safety and efficacy of cold EMR for large SSPs.

Patients presenting for elective colonoscopy at an academic endoscopy center with 1 or more SSPs ≥10 mm in size were enrolled, excluding those on anticoagulant or antiplatelet therapy other than aspirin. Lesions were resected with a cold EMR technique comprising submucosal injection of succinylated gelatin and dilute methylene blue before piecemeal cold snare resection of all visible polyp with a margin of normal tissue. Outcomes were the presence of residual serrated neoplasia in biopsy specimens from the defect margin and findings on surveillance colonoscopy.

Cold EMR was performed on 163 SSPs during 105 procedures in 99 patients (97% women; median age, 57 years). The mean size was 17.5 mm: 61 SSPs were ≥20 mm and 13 SSPs ≥30 mm, and 97.5% were in the proximal colon. Cytologic dysplasia was present in 2 (1.2%). Margin biopsy specimens were positive in 2 lesions (1.2%). Surveillance colonoscopy for 82% of lesions (median, 5 months) showed residual serrated tissue in 1, treated with cold snare, but no evidence of recurrence in the remainder. Minor adverse events were seen in 3 patients; no delayed bleeding was observed.

Cold EMR is a safe and effective method for the removal of large SSPs.

To investigate the effect of prophylaxis with antibiotics on clinical adverse events in patients who underwent endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) for colorectal lesions.

From June 2011 to December 2013, a total of 428 patients were enrolled into the study, of which 214 patients admitted to hospital underwent EMR or ESD procedures. These patients were randomized to an antibiotic group, in which patients were given cefuroxime 1.5 g iv half an hour before and 6 h after surgery respectively, and a control group, in which patients were not given any antibiotic. A further 214 outpatients with small polyps treated by polypectomy were compared with controls that were matched by age and gender, and operations were performed as outpatient surgery. Recorded patient parameters were demographics, characteristics of lesions and treatment modality, and the size of the wound area. The primary outcome measures were clinical adverse events, including abdominal pain, diarrhea, hemotachezia, and fever. Secondary outcome measures were white blood cell count, C-reactive protein and blood culture. Additionlly, the relationship between the size of the wound area and clinical adverse events was analyzed.

A total of 409 patients were enrolled in this study, with 107 patients in the control group, 107 patients in the antibiotic group, and another 195 cases in the follow-up outpatient group. The patients' demographic characteristics, including age, gender, characteristics of lesions, treatment modality, and the size of the wound area were similar between the 2 groups. The rates of adverse events in the antibiotic group were significantly lower than in the control group: abdominal pain (2.8% vs 14.9%, P < 0.01), diarrhea (2.0% vs 9.3%, P < 0.05), and fever (0.9% vs 8.4%, P < 0.05) respectively. The levels of inflammatory markers also decreased significantly in the antibiotic group compared with the control group: leukocytosis (2.0% vs 11.2%, P < 0.01), and C-reactive protein (2.0% vs 10.7%, P < 0.05). Additionally, clinical adverse events were related to the size of the surgical wound area. When the surgical wound area was larger than 10 mm × 10 mm, there were more clinical adverse events.

Clinical adverse events are not uncommon after EMR or ESD procedures. Prophylactic antibiotics can reduce the incidence of clinical adverse events. This should be further explored.

There are few randomized studies examining efficacy of snares and agents in EMR.

To compare the use of a combined needle and snare unit with injectate versus a spiral wire and injectate (primary); saline solution versus hydroxypropyl methylcellulose (secondary).

Prospective, randomized, factorial, single center.

Tertiary-care academic medical center.

A total of 140 patients with large (>15 mm), sessile, colorectal polyps.

Polyps randomized to either 1 of 2 snare types and 1 of 2 injectates.

Primary-the Sydney resection quotient (SRQ), defined as the size of the polyp divided by the number of pieces resected and the amount of tissue per snare attempt. Secondary-procedure time, adverse events, residual neoplasia at follow-up.

The SRQ was higher with the combined unit (median 13.8 mm vs 7.1 mm; P = .019); additionally, procedure time was less (median 6 vs 11 minutes; P < .001). Resection was considered complete after the EMR in 62% (42/68) with the combined needle and snare unit versus 51% (37/72; P = .22) with the spiral wire. Rates of adverse events were similar. Residual neoplasia was found at follow-up in 22% (10/46) with the combined needle and snare unit versus 21% (10/48; P = .89) with the spiral wire. There was no evidence of differences in outcomes by lifting agent.

The SRQ is only a surrogate marker.

This study provides evidence that the integrated needle-snare may be superior to the snare alone for the removal of large, flat polyps. Additionally, the type of injectate appears to have no impact on outcome.