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Cold Snare on the Rise?

Stefan Groth, Hamburg

Gut. 2017 Sep 28. [Epub ahead of print]

ORIGINAL ARTICLE
A comparison of the resection rate for cold and hot snare polypectomy for 4–9 mm colorectal polyps: a multicentre randomised controlled trial (CRESCENT study)
Takuji Kawamura1, Yoji Takeuchi2, Satoshi Asai3, Isao Yokota4, Eisuke Akamine3, Minoru Kato2, Takuji Akamatsu5, Kazuhiro Tada6, Yoriaki Komeda7, Mineo Iwatate8, Ken Kawakami9, Michiko Nishikawa10, Daisuke Watanabe11, Atsushi Yamauchi12, Norimasa Fukata13, Masaaki Shimatani13, Makoto Ooi11, Koichi Fujita10, Yasushi Sano8, Hiroshi Kashida7, Satoru Hirose6, Hiroyoshi Iwagami5, Noriya Uedo2, Satoshi Teramukai4, Kiyohito Tanaka1,14

Objective

To investigate the success rate of cold snare polypectomy (CSP) for complete resection of 4–9 mm colorectal adenomatous polyps compared with that of hot snare polypectomy (HSP).

Design

A prospective, multicentre, randomized controlled, parallel, non-inferiority trial conducted in 12 Japanese endoscopy units. Endoscopically diagnosed sessile adenomatous polyps, 4–9 mm in size, were randomly assigned to the CSP or HSP group. After complete removal of the polyp using the allocated technique, biopsy specimens from the resection margin after polypectomy were obtained. The primary endpoint was the complete resection rate, defined as no evidence of adenomatous tissue in the biopsied specimens, among all pathologically confirmed adenomatous polyps.

Results

A total of 796 eligible polyps were detected in 538 of 912 patients screened for eligibility between September 2015 and August 2016. The complete resectionrate for CSP was 98.2% compared with 97.4% for HSP. The non-inferiority of CSP for complete resection compared with HSP was confirmed by the +0.8% (90% CI −1.0 to 0.7) complete resection rate (non-inferiority p<0.0001). Postoperative bleeding requiring endoscopic haemostasis occurred only in the HSP group (0.5%, 2 of 402 polyps).

Conclusions

The complete resection rate for CSP is not inferior to that for HSP. CSP can be one of the standard techniques for 4–9 mm colorectal polyps. (Study registration: UMIN000018328)

What you should know about this paper

Cold snare resection has been established in diminutive polyps (up to 5 mm) as being at least as safe and partially more effective than biopsy removal or hot snare polypectomy. Cold biopsy techniques are very popular, but leave adenomatous tissue behind1. For cold snare removal, a very low post-polypectomy bleeding has been shown 2-4, which was not consistent in randomised trials as compared to hot snare polypectomy5, 6, but was even lower in anticoagulated patients7. 2017 already two meta analyses have been published on cold snare removal of diminutive polyps8, 9, which both show superior efficacy over cold forceps removal.

Is there a size limitation for cold snare polypectomy ? Why would it not work in larger flat polyps ? Four recent smaller retrospective studies suggests good efficacy also in large polyps > 1 cm or even > 2 cm10-13. Interpretation may be hampered by methodological details such as retrospective assessment and patient selection and other biases. Nevertheless, the technique should be studied further. Thus it would be logical to test this hypothesis on the next size level above diminutive polyps, namely of 6-10 mm in diameter. This is the topic of the present paper, a randomized trial from Japan on 4-9 mm adenomas.

 The present study compared cold with hot snare removal of the small polyps in 538 patients and 796 polyps in a multicenter setting. With regards to efficacy, results were similar – complete resection rates were 98.2% for cold versus 97.4% for hot snare removal.  Complete resection was defined by negative marginal biopsies after polypectomy, a methodology well known from the CARE study14. Safety could not really be compared, since the study was not powered for this outcome, and only 2 post-polypectomy bleeding occured (both in the hot group). Results were confirmed by another smaller study from Greece on 155 patients13; safety again appeared comparable, but there were no post-polypectomy bleeding; and the rates of intraprocedural bleedings – it can be debated whether they are a suitable parameter – were numerically different in favour of hot biopsy (3.6% vs 1.2%), but were not statistically significant due to limited case numbers.   

 What would be practical conclusions ? It appears that the days of mandatory hot snare polypectomy for smaller polyps are over. Hot snare polypectomy could be limited to pedunculated polyps or larger flat lesions, but at least in the latter category, randomized studies comparing hot with cold snaring are to be awaited.

 

References

  1. Efthymiou M, Taylor AC, Desmond PV, et al. Biopsy forceps is inadequate for the resection of diminutive polyps. Endoscopy 2011;43:312-6.
  2. Deenadayalu VP, Rex DK. Colon polyp retrieval after cold snaring. Gastrointest Endosc 2005;62:253-6.
  3. Repici A, Hassan C, Vitetta E, et al. Safety of cold polypectomy for <10mm polyps at colonoscopy: a prospective multicenter study. Endoscopy 2012;44:27-31.
  4. Tappero G, Gaia E, De Giuli P, et al. Cold snare excision of small colorectal polyps. Gastrointest Endosc 1992;38:310-3.
  5. Ichise Y, Horiuchi A, Nakayama Y, et al. Prospective randomized comparison of cold snare polypectomy and conventional polypectomy for small colorectal polyps. Digestion 2011;84:78-81.
  6. Paspatis GA, Tribonias G, Konstantinidis K, et al. A prospective randomized comparison of cold vs hot snare polypectomy in the occurrence of postpolypectomy bleeding in small colonic polyps. Colorectal Dis 2011;13:e345-8.
  7. Horiuchi A, Nakayama Y, Kajiyama M, et al. Removal of small colorectal polyps in anticoagulated patients: a prospective randomized comparison of cold snare and conventional polypectomy. Gastrointest Endosc 2014;79:417-23.
  8. Jung YS, Park CH, Nam E, et al. Comparative efficacy of cold polypectomy techniques for diminutive colorectal polyps: a systematic review and network meta-analysis. Surg Endosc 2017.
  9. Raad D, Tripathi P, Cooper G, et al. Role of the cold biopsy technique in diminutive and small colonic polyp removal: a systematic review and meta-analysis. Gastrointest Endosc 2016;83:508-15.
  10. Tutticci NJ, Hewett DG. Cold endoscopic mucosal resection of large sessile serrated polyps at colonoscopy (with video). Gastrointest Endosc 2017.
  11. Tate DJ, Awadie H, Bahin FF, et al. Wide-field piecemeal cold snare polypectomy of large sessile serrated polyps without a submucosal injection is safe. Endoscopy 2017.
  12. Piraka C, Saeed A, Waljee AK, et al. Cold snare polypectomy for non-pedunculated colon polyps greater than 1 cm. Endosc Int Open 2017;5:E184-e189.
  13. Papastergiou V, Paraskeva KD, Fragaki M, et al. Cold versus hot endoscopic mucosal resection for nonpedunculated colorectal polyps sized 6-10 mm: a randomized trial. Endoscopy 2017.
  14. Pohl H, Srivastava A, Bensen SP, et al. Incomplete polyp resection during colonoscopy-results of the complete adenoma resection (CARE) study. Gastroenterology 2013;144:74-80.e1.

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