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Cold snare polypectomy in the small bowel: Are we ready to turn down the heat?

Published:April 08, 2022DOI:https://doi.org/10.1016/j.gie.2022.02.023

      Abbreviation:

      EMR (endoscopic mucosal resection), RRA (residual or recurrent adenoma)
      Small-bowel adenomas present an endoscopic challenge because of the small bowel’s thin wall and the duodenum’s vascularity. Although they are uncommon and are largely found incidentally, resection is recommended for these precancerous lesions.
      Cautery-based EMR is the mainstay of therapy, although it is not without adverse events. A systematic review of 14 studies using cautery-EMR for 485 nonampullary duodenal polyps 13 to 35 mm reported complete resection of 93%, with 15% recurrence.
      • Navaneethan U.
      • Hasan M.K.
      • Lourdusamy V.
      • et al.
      Efficacy and safety of endoscopic mucosal resection of non-ampullary duodenal polyps: a systematic review.
      The pooled delayed bleeding rate was 5%. There were 3 perforations and 1 hemorrhage requiring surgical intervention. An additional retrospective review of 106 large polyps showed complete resection of 96%, with intraprocedural bleeding in 43% of cases, delayed bleeding in 15%, and recurrence in 14%.
      • Klein A.
      • Nayyar D.
      • Bahin F.F.
      • et al.
      Endoscopic mucosal resection of large and giant lateral spreading lesions of the duodenum: success, adverse events, and long-term outcomes.
      Risk of bleeding was associated with lesion size.
      Advances in colorectal polyp resection have led to increasing use of cold snare resection, now the standard for removal of colorectal polyps <10 mm.
      • Kaltenbach T.
      • Anderson J.C.
      • Burke C.A.
      • et al.
      Endoscopic removal of colorectal lesions: recommendations by the US multi-society task force on colorectal cancer.
      The use of cold polypectomy for larger colorectal lesions has also shown acceptable outcomes with low adverse event rates.
      • Thoguluva Chandrasekar V.
      • Spadaccini M.
      • Aziz M.
      • et al.
      Cold snare endoscopic resection of nonpedunculated colorectal polyps larger than 10 mm: a systematic review and pooled-analysis.
      Given the safety and efficacy of cold snare EMR in the colon, these techniques have been recently adopted for small intestine lesions for similar purposes. However, data regarding cold EMR for small-bowel polyps are sparse. A small prospective study of sporadic nonampullary duodenal polyps <10 mm included 39 polyps removed with either cold snare or cold forceps.
      • Maruoka D.
      • Matsumura T.
      • Kasamatsu S.
      • et al.
      Cold polypectomy for duodenal adenomas: a prospective clinical trial.
      In that study, there were no reported adverse events of perforation or delayed bleeding and no recurrence on follow-up endoscopy. Additionally, a pilot study of cold snare polypectomy in patients with familial adenomatous polyposis showed no adverse events after resection of a total of 126 small polyps in 4 patients.
      • Hamada K.
      • Takeuchi Y.
      • Ishikawa H.
      • et al.
      Feasibility of cold snare polypectomy for multiple duodenal adenomas in patients with familial adenomatous polyposis: a pilot study.
      Data of cold snare EMR in larger duodenal polyps have also been limited.
      In this issue of Gastrointestinal Endoscopy, Dang et al
      • Dang D.T.
      • Suresh S.
      • Vance B.
      • et al.
      Outcomes of cold snare piecemeal EMR for nonampullary small-bowel adenomas larger than 1 cm: a retrospective study.
      present the outcomes of cold snare EMR for large nonampullary small-bowel adenomas. This was a retrospective single-center study of patients with sessile small-bowel polyps >1 cm removed with submucosal lift and subsequent piecemeal cold snare resection. The outcomes including residual or recurrent adenoma (RRA) and adverse events were recorded. Thirty-nine patients undergoing cold snare EMR over a 5-year period were included for analysis. The polyps were stratified by size and circumferential involvement of the lumen. Most were located in the second portion of the duodenum; 2 were jejunal. Advanced histologic features were more likely with increasing size, but no polyp was malignant. RRA was seen in 46% of cases at follow-up endoscopy. RRA was more likely with increasing size: 12.5% of polyps 10 to 19 mm, 55.6% of polyps 20 to 29 mm, and 79% of polyps ≥30 mm. Management of RRA was repeated polypectomy by snare or forceps with or without treatment with argon plasma coagulation. Complete eradication was achieved in 89.4% of polyps; a median of 2 procedures was required. No patient experienced an interval small-bowel cancer. One patient had immediate bleeding requiring endoscopic clips. The same patient had delayed bleeding requiring intervention resulting from supratherapeutic anticoagulation. There were no perforations. Three patients experienced small-bowel strictures, 2 requiring dilation. One patient experienced necrotizing pancreatitis after a follow-up endoscopy and died after a prolonged illness.
      There are crucial factors to consider when interpreting this study and assessing its applicability to the removal of small-bowel polyps in clinical practice. Given the aim of the authors to report the safety and efficacy of cold snare EMR in the small bowel, they astutely set inclusion criteria to capture index polypectomies exclusively, using cold snare techniques without thermal intervention. Whereas this approach may have contributed to the relatively smaller cohort size, the authors are to be commended for their precision, especially considering the inclusion of giant polyps >30 mm in the cohort that are otherwise expected to pose challenges during EMR or confer a higher risk of adverse events necessitating added interventions. However, owing to the retrospective and descriptive nature of the study, it is unknown how many additional patients underwent attempted unsuccessful cold snare resection and required alternative resection techniques. Therefore, how to assess a polyp for feasibility of pure cold snare EMR remains unclear.
      The cohort of 39 patients was composed largely of those with duodenal polyps but only 2 patients with jejunal polyps. This begs the question whether the results can be applied to all proximal small-bowel polyps, assuming similar resection techniques, or whether the optimal management of duodenal polyps and jejunal polyps may differ based on presumed differences in endoscope positioning and risk of perforation and bleeding between the 2 locations.
      Because the authors’ intent was not to examine hot versus cold EMR techniques simultaneously (and thus the study did not include a comparison group in whom cautery-based EMR was used), any comparisons between the 2 modalities should be made with caution. According to the data presented, the first follow-up endoscopy was performed at intervals ranging from 32 to 533 days, mirroring the variability in clinical practice attributable to numerous patient and clinician factors. The authors therefore appropriately termed the presence of adenomatous mucosa found on follow-up endoscopy as “residual or recurrent adenoma (RRA)” rather than differentiating between the 2 conditions. Prior larger retrospective studies examining cautery-based EMR convey recurrence rates of approximately 23% and demonstrate piecemeal resection as a risk factor for incomplete resection and recurrence.
      • Tomizawa Y.
      • Ginsberg G.G.
      Clinical outcome of EMR of sporadic, nonampullary, duodenal adenomas: a 10-year retrospective.
      The present cold snare study showed the presence of RRA in 46% of a considerably smaller cohort. As mentioned by the authors in their discussion, this may be explained at least in part by the larger mean polyp size, and the RRA rate was reassuringly lower in the subgroup of smaller polyps 10 to 20 mm at 12.5%, in spite of piecemeal resection. Regardless, this finding favors en bloc rather than piecemeal resection whenever possible and underscores the need for larger comparative studies regarding the rate of residual and/or recurrent polyp after EMR with various techniques.
      In addition to efficacy, the authors aimed to evaluate the safety of cold snare EMR. In comparison with previously published estimates of bleeding adverse events associated with cautery-based EMR that range as high as 29%,
      • Sohn J.W.
      • Jeon S.W.
      • Cho C.M.
      • et al.
      Endoscopic resection of duodenal neoplasms: a single-center study.
      cold snare EMR in this study demonstrated a much lower rate (2.3%) of intraprocedural/delayed bleeding, occurring in only 1 patient who was taking anticoagulant agents. The authors suggest that cold snare EMR has a lower likelihood of causing deeper mucosal injury in comparison with thermal-assisted EMR
      • Navaneethan U.
      • Hasan M.K.
      • Lourdusamy V.
      • et al.
      Efficacy and safety of endoscopic mucosal resection of non-ampullary duodenal polyps: a systematic review.
      and therefore has a lower risk of both intraprocedural and delayed bleeding. Epinephrine injection and submucosal lift can both aid in controlling immediate intraprocedural venous bleeding if it is not self limited. This is a critical outcome to scrutinize in future prospective comparative studies, inasmuch as the risk of intraprocedural and delayed bleeding has a direct impact on the need for additional interventions required for hemostasis, cost, and time required for the procedure, along with other patient-centered outcomes such as the need for hospitalization. Delayed perforation is also reported after duodenal EMR in approximately 1% of cases
      • Navaneethan U.
      • Hasan M.K.
      • Lourdusamy V.
      • et al.
      Efficacy and safety of endoscopic mucosal resection of non-ampullary duodenal polyps: a systematic review.
      but did not occur in this study of cold snare EMR. Although that finding is reassuring, one must approach it with caution because the small cohort was likely underpowered for rarer, but potentially serious, adverse outcomes. Duodenal strictures were present in 8% of the patients, which occurred in patients with large polyps (≥30 mm) involving >50% of the lumen circumference. Rates of duodenal stricture formation after EMR are poorly reported in the existing literature, but certainly this is a known potential adverse event, particularly for larger polyps. This is a motivating factor to aim for complete resection at the index procedure. The most noteworthy adverse event encountered by the authors was 1 case of fatal necrotizing pancreatitis occurring after the first follow-up endoscopy, during which argon plasma coagulation was performed in addition to residual adenoma resection with cold snare and biopsy forceps. Even though the event was unrelated to the cold snare EMR performed at the index procedure, it emphasizes the need for caution in the performance of resection or thermal interventions adjacent to the pancreatic duct orifice, and to strongly consider placement of a pancreatic duct stent if there is concern for thermal or mechanical injury.
      This study supports the notion that cold snare EMR is overall safe for small-bowel nonampullary polyps. The RRA rate is of concern but appears to be manageable with subsequent follow-up endoscopies to achieve an acceptable complete eradication rate. Resection of small adenomas should be achieved en bloc, but piecemeal cold snare EMR may be a viable option for patients with large polyps, especially those who are poor surgical candidates or at higher risk of delayed hemorrhage. Larger, prospective, and ideally randomized studies are necessary to examine this topic further before widespread extrapolation of the results to different clinical settings, as we keep in mind that a high level of expertise is required. Additionally, future studies should investigate whether there are differences between various resection techniques in the need for prophylactic clip placement, the cost and duration of the procedure, or outcomes based on polyp classification, particularly in the comparison of cold and cautery-assisted modalities. Finally, endoscopists should be vigilant of injury to the biliary and pancreatic orifices when performing therapeutic maneuvers in close proximity.

      Disclosure

      All authors disclosed no financial relationships.

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