Show me how you remove small polyps and I’ll tell you who you are

Techniques of gastrointestinal endoscopy are not fully standardized. Although recommendations exist they are not always followed for various reasons, and new techniques develop, new ideas occur, and different schools promote their own methods. Furthermore, there are only very few high-quality, randomized controlled trials (RCTs) comparing different endoscopic techniques for defined clinical situations. A good example is a technique for the removal of small polyps (5 – 9 mm); a great degree of “freedom” exists. One may use cold forceps, hot forceps, cold snare, hot snare or even endoscopic mucosal resection. It is usually recommended that polyps of 1 – 3 mm in size are removed using cold biopsy forceps. Polyps of 4 – 5 mm may be removed using cold snare, and for larger polyps (up to 9 mm) a hot snare may be used for pedunculated polyps and a cold snare for flat lesions. The use of hot forceps is generally discouraged. However, many variations and local solutions exist. Other factors that are taken into account before choosing the method of polyp removal include shape, location of the polyp, coagulation status of the patient, and the skill of the endoscopist.

In terms of skills, it is essential to know which ones are important. Gupta et al. [1] have shown that the skill set should include: ability to optimize polyp view and position before removal, ability to adjust distension of the bowel and apply sufficient washing, ability to select the appropriate instrument and appropriately position the snare or forceps on the polyp, and the ability to identify residual polyp tissue in cases where polypectomy is not complete.

Are available methods of polyp removal sufficiently efficacious and are they properly employed? A study by Pohl et al. has shown that even after removing polyps using the proper instrument (snare), the rate of incomplete removal reaches 9.4 % for polyps 8 – 9 mm and 5.8 % for polyps 5 – 7 mm in size [2]. The rate of incomplete removal when an inappropriate removal technique is employed is probably much, much higher.

In this context, the study by Britto-Arias et al. in the current issue of Endoscopy is a good example of the problem [3]. In their study, 46 % of polyps of ≥ 5 mm in size detected within a primary screening colonoscopy program were removed using biopsy forceps. Although the article does not clearly state whether these were hot or cold forceps or both, using any type of forceps for removal of a polyp of this size in nearly 50 % of cases does not seem to be correct. Recent RCTs have shown the clear advantage of snare polypectomy over cold forceps removal of such polyps [4] [5], with differences in the rate of complete removal of about 20 %. Another very important and practical finding from this study is the fact that after publication of European guidelines in 2010 [6], the situation has improved slightly, but only in hospitals and not in private practices. This really makes us wonder what is behind these decisions and how we can bring about change.

It is currently unclear as to why endoscopists choose inappropriate techniques for the removal of small polyps. One may speculate that removal of small polyps by biopsy forceps is preferred because, compared with a snare technique, it is regarded to be safer (cold forceps but not hot ones), because such methods take less time (true), and because retrieval of material for histology is easier (true) and less time consuming (true). Most probably it is also cheaper than snaring. Therefore, endoscopists tend to use biopsy forceps to remove small polyps, particularly in busy, tightly scheduled practices, and in private units, where pressure of time and money is high. However, there is no doubt that this approach is wrong.

What are the consequences of such an approach? Obviously, incomplete removal resulting from an inappropriate removal method may lead to further growth of adenoma and development of larger adenomas and even colorectal cancer. The probability of such outcomes, though, is low. Small and diminutive polyps are regarded as “innocent.” However, malignant polyps of this size can exist, as shown in a recent study from Poland [7]. The authors recorded the withdrawal phase of about 6000 screening colonoscopies. In five cases, small polyps of approximately 5 mm in diameter turned out to be malignant adenomas. Surprisingly, they were not recognized as such during colonoscopy but were diagnosed on subsequent histological analysis. However, re-evaluation of the video recordings revealed that even these small malignant polyps did, in retrospect, show specific malignant features. Fortunately, these polyps were removed completely using a snare. Attempts to remove such polyps with forceps would probably have led to subsequent surgery.

The incomplete removal of even small adenomas is probably one of the reasons for the development of interval cancer [8]. American and Dutch studies have shown that interval cancer may be linked to previous removal of advanced adenoma in the same segment of the large bowel. This was calculated to be responsible for 19 % and 9 % of interval cancers, respectively [9] [10]. Long-term observations are missing for small polyps, but we strongly believe that small adenomas that are incompletely removed may also lead to later development of cancer.

It is not known whether the findings in the study of Britto-Arias et al. are representative of the rest of Europe. The extent of the problem in countries other than Austria should therefore be studied. Available data from England seem to represent the other end of the spectrum. Din et al. [11] extracted data from the English Bowel Cancer Screening Programme, and presented separate data for cold biopsy forceps and hot biopsy forceps. Unfortunately, the polyp size ranges applied were different from those used in the study by Britto-Arias et al. In the Din study, polyps of 4 – 6 mm were removed by cold and hot forceps in 17.2 % and 16.9 % of cases, respectively. Polyps of 7 – 10 mm were rarely removed using forceps (2.2 % and 1.8 % cold and hot forceps, respectively). These data are good and suggest that the English system of training and educating screening colonoscopists developed in recent years plays an important and positive role.

Britto-Arias et al. think that the time has come to introduce a new quality indicator for colonoscopy based on the alarming results of their study. Currently, the most important validated quality measure for colonoscopy as a diagnostic tool is the adenoma detection rate, which has been proven to be associated with colorectal cancer incidence and mortality [12] [13]. Several other quality indicators were recently updated by the American Society for Gastrointestinal Endoscopy/American College of Gastroenterology [14]. They are mainly connected with diagnostic aspects, completeness of evaluation, and complications, but none of them cover the quality of therapy. This is despite the increasing opinion that the polypectomy method may be crucial to colonoscopy efficacy. An indicator such as the appropriate polyp removal technique rate (APRTR) could be proposed. However, this general indicator of appropriateness would be very complicated and difficult to collect. Britto-Arias et al. [3] have suggested the introduction of a simpler indicator called the forceps removal rate (FRR) for polyps ≥ 5 mm, which could be abbreviated to “FRR ≥ 5.” Further studies would be needed to ascertain the values of this measure in other colonoscopy databases. Unfortunately, a subjective element exists, which results mainly from the uncertain methods of assessing polyp size before removal. An FRR ≥ 5 value of 46 % as cited by Britto-Arias et al. is unacceptable; data from the English program are much better but still not perfect. Ideally, we think the value for FRR ≥ 5 should be zero.

We call for data from which to calculate the FRR ≥ 5 for other European countries, and suggest that societies and organizations consider including this indicator into the list of colonoscopy quality measures. In addition, validation of the FRR ≥ 5 is required, and studies are needed to demonstrate whether important outcome data, including the risk of interval cancer, can be associated inversely with the indicator.

• References

• 1 Gupta S, Anderson J, Bhandari P et al. Development and validation of a novel method for assessing competency in polypectomy: direct observation of polypectomy skills. Gastrointest Endosc 2011; 73: 1232-1239
• 2 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
• 3 Britto-Arias M, Waldmann E, Jeschek P et al. Forceps versus snare polypectomies in colorectal cancer screening – Are we adhering to the guidelines?. Endoscopy 2015; 47: 898-902
• 4 Kim JS, Lee B-I, Choi H et al. Cold snare polypectomy versus cold forceps polypectomy for diminutive and small colorectal polyps: a randomized controlled trial. Gastrointest Endosc 2015; 81: 741-747
• 5 Lee CK, Shim JJ, Jang JY. Cold snare polypectomy vs. cold forceps polypectomy using double-biopsy technique for removal of diminutive colorectal polyps: a prospective randomized study. Am J Gastroenterol 2013; 108: 1593-1600
• 6 Steele RJ, Pox C, Kuipers EJ et al. European guidelines for quality assurance in colorectal cancer screening and diagnosis. First edition – Management of lesions detected in colorectal cancer screening. Endoscopy 2012; 44 (Suppl. 03) E140-150
• 7 Bugajski M, Kaminski MF, Orlowska J et al. Suspicious macroscopic features of small malignant colorectal polyps. Scand J Gastroenterol 2015; 50: 1261-1267
• 8 Haug U, Regula J. Interval cancer: nightmare of colonoscopists. Gut 2014; 63: 865-866
• 9 Robertson DJ, Lieberman DA, Winawer SJ et al. Colorectal cancers soon after colonoscopy: a pooled multicohort analysis. Gut 2014; 63: 949-956
• 10 le Clercq CM, Bouwens MW, Rondagh EJ et al. Postcolonoscopy colorectal cancers are preventable: a population-based study. Gut 2014; 63: 957-963
• 11 Din S, Ball AJ, Taylor E et al. Polypectomy practices of sub-centimeter polyps in the English Bowel Cancer Screening Programme. Surg Endosc 2015; In press DOI: 10.1007/s00464-015-4064-6.
• 12 Kaminski MF, Regula J, Kraszewska E et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med 2010; 362: 1795-1803
• 13 Corley DA, Jensen CD, Marks AR et al. Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 2014; 370: 1298-1306
• 14 Rex DK, Schoenfeld PS, Cohen J et al. Quality indicators for colonoscopy. Am J Gastroenterol 2015; 110: 72-90