Should hot biopsy forceps be abandoned for polypectomy of diminutive colorectal polyps?

Standardized approach to polypectomy of diminutive colorectal polyps (DCPs) is lacking since cold biopsy forceps have been associated with high levels of recurrence, hot biopsy forceps are considered inadequate and risky and cold snaring is currently under investigation for its efficacy and safety. This has led to confusion and a gap in clinical practice. This article discusses the usefulness and contemporary practical applicability of hot biopsy forceps and provides well-intentioned criticism of the new European guidelines for the treatment of DCPs. Diminutive colorectal polyps are a source of frustration for the endoscopist since their small size is accompanied by a considerable risk of premalignant neoplasia and a small but non-negligible risk of advanced neoplasia and even cancer. Since the proportion of diminutive colorectal polyps is substantial and exceeds that of larger polyps, their effective removal poses a considerable workload and a therapeutic challenge. During the last decade, the introduction of cold snaring to routine endoscopy practice has attempted to overcome the use of prior techniques, such as hot biopsy forceps. It is important to recognize that with the exception of endoscopic methods that are obviously unsafe and inadequate to serve their purpose, all other interventional endoscopic methods are operator-dependent in the sense that specific expertise and training are obligatory for the success of any therapeutic intervention. Since relevant publications on hot biopsy forceps are still in favor of its careful use, as it has not yet demonstrated inferiority compared with newer techniques, it would be prudent for any medical practitioner to evaluate the available tools and judge any new proposed technique based on the evidence before it is adopted.

Core tip: Selection of the appropriate endoscopic method for the removal of diminutive colorectal polyps (DCPs), according to the prospective prevention of colorectal cancer, is still a debatable topic. The new recommendation released by ESGE (European Society of Gastrointestinal Endoscopy, 2017) concerning the use of hot biopsy forceps (HBF) is expected to create a shift in daily clinical practice since this technique is still popular and viable for the removal of DCPs. In this letter, the authors request reconsideration of this policy in response to published data referring on the efficacy and safety of HBF and recommend a more cautious approach and transition to prevent the premature acceptance of alternative techniques.

TO THE EDITOR

In a recent article[1], European Society of Gastrointestinal Endoscopy has released guidelines for colorectal polypectomy, which include a strong recommendation against the use of hot biopsy forceps (HBF) based on the GRADE system of clinical evidence. The release of guidelines by professional medical societies is acknowledged by the medical community as policy that functions as a deterrent to specific practices. With respect to that notion, the abandonment of a useful technique such HBF, which for many decades, has contributed to the polypectomy of diminutive colorectal polyps (DCPs), should be considered in an appropriate conscientious and judicious manner.

The reasons for the negative criticism are based on the following: (1) unacceptably high risks of adverse events (AEs); (2) inadequate tissue sampling for histopathology (ITSH); and (3) high incomplete resection rates (IRR). The studies cited in support of the recommendation are 4 human studies (1 RCT non-blinded with a small number of patients[2], one anecdotal report[3] and 2 observational studies[4,5]), 3 of which have already been determined to be of low quality, and 2 animal studies[6,7] (Table 1). The overall quality of evidence was graded as high. Actually, apart from the methodological quality of the individual studies and the questionable generalizability, these studies are heterogeneous in terms of ITSH and IRR. Moreover, all studies are consistent with respect to the absence of perforations, and the few bleeding episodes (0.36%) in one of the studies occured in patients taking antiplatelets[5].

Table 1

List of articles presented in support of European Society of Gastrointestinal Endoscopy guidelines

Ref.	Study design	No of polyps and patients	Level of evidence
	Intervention
Paspatis et al[2], 2005	Randomised trial	38 vs 37 rectal DCPs among 50 patients	High quality
	Bipolar electro-coagulation vs HBF
Peluso et al[3], 1991	Anecdotal report	62 DCPs among 39 patients	Low quality
	HBF
Yasar et al[4], 2015	Observational study	237 DCPs among 179 patients	Low quality
	HBF vs JBF
Weston et al[5], 1995	Observational study	1964 DCPs among 687 patients	Low quality
	HBF vs CBF
Savides et al[6], 1995	Animal study	231 biopsies in 16 right colotomies of 8 mongrel dogs	Not rated in Grade system
	Canine model
Metz et al[7], 2013	Animal study	82 artificial polyps, sized 5-8 mm	Not rated in Grade system
	Porcine model

JBF: Jumbo biopsy forceps; CBF: Cold biopsy forceps; DCPs: Diminutive colorectal polyps; HBF: Hot biopsy forceps.

HBF is considered an alternative method for the removal of DCPs (≤ 5 mm). According to different surveys, it seems that HBF is still a viable option that is preferred by 30%-50% of endoscopists[8-10]. The two studies, with the largest number of patients and polyps[11,12] showed no complications. The study by Wadas et al[13], which reports a 0.38% major bleeding rate and a 0.05% perforation rate, refers to a questionnaire-type survey from an era (1988) when the HBF technique was not standardized. Even this perforation rate is lower than the reported 0.15% for therapeutic colonoscopies[14]. The rate of AEs is also lower compared with that for snare polypectomies (3.3 vs 4.5/1000), and AEs are more likely to occur when low- volume endoscopists use HBF than when high-volume endoscopists (> 300 polypectomies/year) use the technique[15].

HBF has been reported to have a 17% IRR when white coagulum is present[16] and a variable rate of ITSH that ranges from 0.19%-13%-26.7% in studies with different mean polyp sizes[11,17,18]. It is acknowledged that a significant predictor of histological misinterpretation is decreasing polyp size with a cut off limit of 2 mm. It is important to mention that even in studies with high reported rates of cautery artifacts[4], the results showed that histological diagnosis could indeed have been reached in all specimens.

The new rival of HBF, namely, the cold snare polypectomy (CSP), has thus far presented disparate results for IRR at 3.4%-40%, retrieval failure at 1%-13%, and bleeding rates of 1.2%-20% for DCPs[19-24]. In the sole non-blinded RCT, in which HBF and CSP are directly compared, the IRR in the ITT analysis was 29.9% for CSP, which is still unacceptably high. However, the bleeding rates were statistically insignificant at 8.1% vs 8.8% for HBF and CSP, respectively, and no perforations were observed in either study arm[25].

In conclusion, it seems that available evidence is not adequate to exclude hot biopsy forceps from the routine endoscopy practice. We either need more prospective studies exhibiting beneficial comparisons with new techniques or we need to focus on proper utilization of HBF by more experienced endoscopists.