Cold Snare on the Rise?

Cold Snare on the Rise?

Stefan Groth, Hamburg

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

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


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).


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.


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).


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.



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