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The Submucosal Cushion Does Not Improve the Histologic Evaluation of Adenomatous Colon Polyps Resected by Snare Polypectomy
CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2011;9:910 –913
BRIEF COMMUNICATION The Submucosal Cushion Does Not Improve the Histologic Evaluation of Adenomatous Colon Polyps Resected by Snare Polypectomy IVAN JOVANOVIC,*,‡ CARLOS CARO,§ HELMUT NEUMANN,§ ANKE LUX,储 DOERTHE KUESTER,¶ LUCIA C. FRY,¶,# PETER MALFERTHEINER,§ and KLAUS MÖNKEMÜLLER§,# *Clinic for Gastroenterology and Hepatology, Clinical Center of Serbia, Belgrade, Serbia; ‡Faculty of Medicine, University of Belgrade, Belgrade, Serbia; §Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Magdeburg, Germany; 储Institute for Biometry and Medical Informatics, Ottovon-Guericke University, Magdeburg, Germany; ¶Institute of Pathology, Otto-von-Guericke University, Magdeburg, Germany; #Department of Internal Medicine and Gastroenterology, Marienhospital, Bottrop, Germany
See editorial on page 821. BACKGROUND & AIMS: Although the “submucosal cushion” technique or injection-assisted polypectomy (IAP) is often used to resect colon polyps, little is known on the influence of this technique on histologic interpretation. We aimed to evaluate whether the use of a submucosal cushion improves the histologic and margin evaluation of colon polyps. METHODS: Consecutive patients undergoing polypectomy with and without IAP were included. An experienced blinded gastrointestinal pathologist evaluated the specimens using standardized criteria. RESULTS: One hundred eleven sessile colon adenomas were analyzed (IAP, n ⫽ 65, standard, n ⫽ 46). Two-thirds of polyps ranged in size from 10 to 20 mm; the average polyp size was 13.2 mm for IAP and 9.9 mm for standard snare polypectomy (P ⫽ .001). The cautery degree, cautery amount, and margin evaluability, did not differ substantially with regard to the resection technique. For polyps ⱖ10 –20 mm, the overall architecture quality was better in polyps resected with standard technique as compared with IAP. CONCLUSIONS: The utilization of IAP did not result in a better margin evaluability of the resected polyp. Overall, IAP does not result in a better histologic polyp evaluability. Keywords: Colon Polyp; Polypectomy; Mucosectomy; Submucosal Cushion; Histologic Evaluation.
W
hen performing a snare polypectomy the endoscopist essentially performs a “mucosectomy.”1 It is thought that injecting the submucosa with fluid (“submucosal cushion,” inejction-assisted polypectomy; IAP) will raise the polyp and allow for a more complete ensnarement and thus resection of more, deeper seated tissue (ie, submucosa).2– 4 However, whether this increased amount of tissue resection leads to a better histopathological evaluation is not clear. The aim of this study was to compare the diagnostic quality and ability to define the resection margin of adenomatous polyps obtained using standard snare polypectomy as compared with snare polypectomy after the creation of a submucosal cushion (IAP).
Methods The study group consisted of consecutive patients undergoing colonoscopy who underwent snare polypectomy for colon adenomas during a 6-month retrospective study at the Otto-von-Guericke University Hospital, Magdeburg, Germany. Exclusion criteria: polyps ⬎20 mm, nonadenomatous polyps (eg, hyperplastic) or resected using piecemeal technique, coagulation abnormalities (ie, international normalized ratio [INR] ⬎1.2, platelet count ⬍50,000). Patients underwent polypectomy using either standard snare electrocautery with or without submucosal cushion (IAP). The patients were not randomized to either method. All polypectomies were performed by 2 experienced colonoscopists with a minimum experience of 5000 endoscopic procedures. From each patient, the following data were abstracted: demographic variables, pre-existing medical conditions, indication for procedure, type, location, and size of polyps, and pathology report. The collected data were entered into Excel worksheets (Microsoft Corporation, Redmont, WA). Each patient was assigned a coded number. A second worksheet for the blinded pathologist (D.K.) included the coded number for each patient and the previously standardized polyp grading parameters.5–7 The pathologist used this second worksheet to enter her impression of each of the polyps reviewed. Informed consent was obtained from every patient before endoscopic procedure. The study was approved by the institutional review board of our institution and it was conducted according to the ethical guidelines of the declaration of Helsinki. Polypectomy was performed by means of an electrosurgical unit (ERBE, ICC 200, Tübingen, Germany) with use of automatically controlled cutting mode (Endocut). The unit was set for Effect 3 (output limit 120 W) and soft coagulation (output limit 60 W) (ERBE, ICC 200). We used braided, oval shape, 30-mm diameter electrocautery snares (Medwork, GmbH, Höchstadt/Aisch, Germany, Product number: POL1-H3-30-27230-OL). Submucosal injection was performed with a scleroAbbreviation used in this paper: IAP, injection-assisted polypectomy. © 2011 by the AGA Institute 1542-3565/$36.00 doi:10.1016/j.cgh.2011.06.027
October 2011
IAP AND COLON POLYPECTOMY
Table 1. Histologic Evaluation of Polyps Resected Using Submucosal Injection vs Without Submucosal Injection in Polyps 10 –20 mm in Size
n Cautery amount Grade 0 Grade 1 Grade 2 Grade 3 Grade ⱖ2 Cautery degree Grade 0 Grade 1 Grade 2 Grade 3 Grade 4 Grade ⱖ2 Margin evaluability Yes No Architecture Good ⫹ Fair Poor Presence of submucosa Yes No
IAP, n (%)
Without, n (%)
47
29
13 (27.7) 12 (25.5) 12 (25.5) 10 (21.3) 22 (46.8)
8 (27.6) 10 (34.5) 8 (27.6) 3 (10.3) 11 (37.9)
13 (27.7) 8 (17.0) 11 (23.4) 12 (25.5) 3 (6.4) 26 (55.3)
8 (27.6) 7 (24.1) 7 (24.1) 7 (24.1) 0 (0.0) 14 (48.3)
10 (21.3) 37 (78.7)
6 (20.7) 23 (79.3)
35 (74.5) 12 (25.5)
28 (96.6) 1 (3.4)
30 (63.8) 17 (36.2)
17 (58.6) 12 (41.4)
P
.565
.721
.583
.044
911
patients (59% men; mean age 64.4 ⫾ 10 years). Eighty-four polyps (75.7%) were located in the left colon. There were no differences in the demographic characteristics between both groups (P ⫽ .466). The major indications for colonoscopy were screening anemia, lower gastrointestinal bleeding and abdominal pain. The mean polyp size was 12 mm, 68.5% of polyps ranged in size from 11 to 20 mm. Polyps resected using IAP were larger (13.2 mm) than those using standard electrocautery (9.9 mm) (P ⫽ .001) the presence and the degree of dysplasia between both groups was similar (P ⫽ .118 and .296, respectively). There were no significant differences in cautery degree, P ⫽ .838; cautery amount, P ⫽ .068; and margin evaluability P ⫽ .677 did not differ substantially with regard to the resection technique in polyps ⱕ10 mm and those 10 –20 mm in size (Table 1). The overall quality of tissue architecture was almost equal regarding the resection technique (P ⫽ .722) (Table 1). Of interest, an adequate evaluability of the resection margins was not possible in 88.9% of polyps resected using IAP and 88.2% of polyps ⱕ10 mm using standard snare (P ⫽ .677). The submucosa could be observed in about two-thirds of polyps, regardless of their size or use of IAP (Table 1).
Discussion .642
therapy needle (Medwork, GmbH) using a solution of epinephrine diluted 1:10,000 in saline. A total of 2–5 mL of solution was injected for each polyp. Resected polyps were immediately fixed in buffered formalin and submitted for histopathologic study. A minimum of 2 levels each containing 2– 4 tissue sections were stained with H&E. The polyp histopathology grading system was previously designed to categorize polyp histology: cautery damage, margin evaluability, and architecture (overall diagnostic quality).5,7 The amount of cautery damage was determined based on the total area involved. The degree of cautery damage was evaluated based on the cell and tissue response, ie, stringing of nuclei of cells and loss of epithelium. Tissue architecture was considered preserved if more than two-thirds of the specimen could be used for histologic analysis. The diagnostic quality was considered poor if the pathologist was unable to determine the type of tissue examined (Table 1 and Figure 1). The size of the retrieved polyps was measured by a caliper. The size of the resected polyps was estimated by the largest distance between the 2 lateral limits.
Statistical Analysis Descriptive statistics were used to present the demographic, endoscopic, and histologic data. The results are presented in numbers and percentages. Statistical analysis was performed using the 2 (2 ⫻ 2, 3) with Yates’ correction, Fisher, and Student t tests using SPSS, Version 15 (SPSS, Inc, Chicago, IL). A P ⬍ .05 was considered statistically significant.
Results One hundred eleven polypectomies (IAP, n ⫽ 65, standard, n ⫽ 46) of sessile polyps were performed in 64 consecutive
We found that the ability to histologically evaluate the overall tissue morphology was similar for standard snare polypectomy and polypectomy after the creation of a submucosal cushion. In addition, the utilization of a submucosal cushion did not result in the obtention of more submucosa or a better margin evaluability of the resected polyp. The main use of the submucosal cushion has been to prevent the incidence of complications such as bleeding and perforation.2,8 –13 Indeed, a recent survey fund that 82% of American endoscopists use this technique for some polypectomies.14 The criteria for selecting polyps for submucosal saline solution injection are highly variable, although it is commonly used for polyps greater than 10 mm in size and those located in the right colon. Based on preliminary animal studies and occasional clinical observations showing that the submucosa could be well seen in specimens resected using the submucosal cushion technique, we hypothesized that the utilization of this technique would result in a more complete oncological resection and thus a better histopathological and margin evaluability of the resected colon polyp.3 However, our results do not support our hypothesis. There are several potential reasons that might explain our findings. First, the amount of injected volume may have resulted in swelling and tension of the underlying submucosa, thus making it more difficult for the endoscopist to ensnare enough tissue to include the muscularis mucosa and submucosa. Nevertheless, the endoscopists performing the procedure were highly experienced in advanced therapeutic endoscopy. Thus, it is unlikely that technical factors impeded the creation of adequate submucosal cushions. Second, the distribution of heat and hence the level of tissue resection might have been influenced by increased tissue resistance. When performing an electrocautery snare resection the depth of heat penetration into the tissue is determined by the distribution of electric field (ie, source of heating) and by thermal diffusion, the latter which can be increased by the presence of a liquid substance (ie, submucosal cushion). Indeed, it is possible that by having a
912
JOVANOVIC ET AL
CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Vol. 9, No. 10
Figure 1. Degree of cautery damage. (A) Grade 1, mild tissue damage with stringing of nuclei. (B) Grade 2, stringing of the nuclei with minimal epithelial loss. (C) Grade 3, stringing of the nuclei with significant epithelial loss. (D) Grade 4, significant epithelial loss. All photos: H&E stain, original magnification ⫻100.
larger volume to cut, the electrocautery unit increases its output and more damage results in the resected specimen.15 Nevertheless, some may argue that this is not important as the thermally injured, adenomatous tissue rests will “fall-off” anyway. However, this assumption can be potentially risky as some experts hypothesize that polyps and cancers found during surveillance colonoscopy may have originated form nonresected, “left-over” adenomas.16,17 Third, we used a computerized blended type current.17 Whether pure cutting currents result in better tissue evaluability is the matter of further studies. Our study has some potential limitations. The study was retrospective and nonrandomized. It was left at the discretion of the endoscopist to use submucosal injection and somehow, logically, polyps where IAP was used were larger in size. However, this does not limit the validity of our results as it reflects real-life practice. Indeed, this might even be an advantage as the possibility of bias was decreased as none of the involved endoscopists knew that the polypectomy technique was going to be evaluated by a pathologist. Therefore, there was no special “motivation” to show that the submucosal resection technique was better. Furthermore, the data collection was thorough, and the primary end point of the study, ie, having both the endoscopists and pathologist blinded to the main objective to the study was accomplished. Second, the number of polyps analyzed maybe relatively small. However, the study was powered to detect a 30% difference in margin evaluability. Furthermore, only adenomatous polyps were evaluated. Finally, the specimens were all read by 1 pathologist. Nonetheless, the histologic criteria used in this study are standardized and have been employed in several other studies evaluating polyp histology.5–7
In summary, in this study we were unable to confirm the hypothesis that snare polypectomy with the use of a submucosal cushion results in an improved ability to histologically evaluate the margins and overall tissue histology of endoscopically resected polyps. Our study adds to the scarce literature on histologic evaluability of resected polyps using various endoscopic resection techniques.5–7 More studies in this area are warranted. References 1. Mönkemüller K, Neumann H, Malfertheiner P, et al. Advanced colon polypectomy. Clin Gastroenterol Hepatol. 2009;7:641– 652. 2. Gostout CJ. Ode to the submucosal fluid cushion. Endoscopy 2004;36:638 – 639. 3. Norton ID, Wang L, Levine SA, et al. Efficacy of colonic submucosal saline solution injection for the reduction of iatrogenic thermal injury. Gastrointest Endosc 2002;56:95–99. 4. Varadarajulu S, Tamhane A, Slaughter RL. Evaluation of dextrose 50% as a medium for injection-assisted polypectomy. Endoscopy 2006;38:907–912. 5. Fry LC, Lazenby AJ, Mikolaenko I, et al. Diagnostic quality of polyps resected by snare polypectomy: does the type of electrosurgical current used matter? Am J Gastroenterol 2006;101:2123–2127. 6. Fantin AC, Neuweiler J, Binek JS, et al. Diagnostic quality of biopsy specimens: comparison between a conventional biopsy forceps and multibite forceps. Gastrointest Endosc 2001;54:600 – 604. 7. Mönkemüller KE, Fry LC, Jones BH, et al. Histological quality of polyps resected using the cold versus hot biopsy technique. Endoscopy 2004;36:432– 436. 8. Hsieh YH, Lin HJ, Tseng GY, et al. Is submucosal epinephrine injection necessary before polypectomy? A prospective, comparative study. Hepatogastroenterology 2001;48:1379 –1382.
October 2011
ERRATUM
9. Dobrowolski S, Dobosz M, Babicki A, et al. Prophylactic submucosal saline-adrenaline injection in colonoscopic polypectomy: prospective randomized study. Surg Endosc 2004;18:990 – 993. 10. Heldwein W, Dollhopf M, Rösch T, et al. The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies. Endoscopy 2005;37:1116–1122. 11. Macrae FA, Tan KG, Williams CB. Towards safer colonoscopy: a report on the complications of 5000 diagnostic or therapeutic colonoscopies. Gut 1983;24:376 –383. 12. Mönkemüller K, Neumann H, Fry LC, et al. Polypectomy techniques for difficult colon polyps. Dig Dis 2008;26:342–346. 13. Di Giorgio P, De Luca L, Calcagno G, et al. Detachable snare versus epinephrine injection in the prevention of postpolypectomy bleeding: a randomized and controlled study. Endoscopy 2004;36:860 – 863. 14. Singh N, Harrison M, Rex DK. A survey of colonoscopic polypectomy practices among clinical gastroenterologists. Gastrointest Endosc 2004;60:414 – 418. 15. Morris ML, Tucker RD, Baron TH, et al. Electrosurgery in gastrointestinal endoscopy: principles to practice. Am J Gastroenterol 2009;104:1563–1574.
913
16. Butterly LF, Chase MP, Pohl H, et al. Prevalence of clinically important histology in small adenomas. Clin Gastroenterol Hepatol 2006;4:343–348. 17. Pohl H, Robertson DJ. Colorectal cancers detected after colonoscopy frequently result from missed lesions. Clin Gastroenterol Hepatol 2010;8:858 – 864.
Reprint requests Address requests for reprints to: Klaus Mönkemüller, MD, PhD, FASGE, Marienhospital, Bottrop, Josef-Albers Straße 70, 46236 Bottrop, Germany. e-mail: [email protected]; fax: ⴙ49 (0) 241106-1009. Acknowledgments IJ and CC contributed equally to this report. Ivan Jovanovic, MD, PhD, is a recipient of the American Society for Gastrointestinal Endoscopy (ASGE) Cook Don Wilson Award 2010. This work was performed in part during his award period at the Marienhospital Bottrop, Germany. Conflicts of interest The authors disclose no conflicts.
Correction Calabrese C, Liguori G. Acute esophageal necrosis. Clin Gastroenterol Hepatol 2011;9:A30. In the above article, the following text was not properly cited from another published work (Gurvits GE, Shapsis A, Lau N, et al. Acute esophageal necrosis: a rare syndrome. J Gastroenterol 2007;42:29 –38). Any future citations based on the following sentences should cite the Gurvits et al article instead of the Calabrese et al article: “Several theories have been proposed to explain the pathogenesis of AEN. An ischemic phenomenon is viewed by some as the major factor in rapid development of esophageal lesions. Associated duodenal lesions might also suggest vascular compromise as the inciting event. Lowflow states or shock, atherosclerosis, thromboembolic disease, cardiac arrhythmias, and hypoperfusion as a result of severe lactic acidosis have been implied as possible etiologies.2 The blood supply to the proximal esophagus is derived from the superior and inferior thyroid arteries, whereas the rest of the organ receives blood flow from the esophageal branches of the descending aorta and splenic and left gastric arteries. An association between AEN and malnutrition, debilitated state, and malignancy suggests an overall reduction in the mucosal defense mechanism. Blood supply is an important component of the postepithelial defense as well as maintenance of the intrinsic repair mechanism. In combination with atherosclerosis, lowflow states, and thromboembolic phenomena, this can directly cause mucosal necrosis. The prognosis is typically poor, and mortality depends on the underlying illness.”
BRIEF COMMUNICATION The Submucosal Cushion Does Not Improve the Histologic Evaluation of Adenomatous Colon Polyps Resected by Snare Polypectomy IVAN JOVANOVIC,*,‡ CARLOS CARO,§ HELMUT NEUMANN,§ ANKE LUX,储 DOERTHE KUESTER,¶ LUCIA C. FRY,¶,# PETER MALFERTHEINER,§ and KLAUS MÖNKEMÜLLER§,# *Clinic for Gastroenterology and Hepatology, Clinical Center of Serbia, Belgrade, Serbia; ‡Faculty of Medicine, University of Belgrade, Belgrade, Serbia; §Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Magdeburg, Germany; 储Institute for Biometry and Medical Informatics, Ottovon-Guericke University, Magdeburg, Germany; ¶Institute of Pathology, Otto-von-Guericke University, Magdeburg, Germany; #Department of Internal Medicine and Gastroenterology, Marienhospital, Bottrop, Germany
See editorial on page 821. BACKGROUND & AIMS: Although the “submucosal cushion” technique or injection-assisted polypectomy (IAP) is often used to resect colon polyps, little is known on the influence of this technique on histologic interpretation. We aimed to evaluate whether the use of a submucosal cushion improves the histologic and margin evaluation of colon polyps. METHODS: Consecutive patients undergoing polypectomy with and without IAP were included. An experienced blinded gastrointestinal pathologist evaluated the specimens using standardized criteria. RESULTS: One hundred eleven sessile colon adenomas were analyzed (IAP, n ⫽ 65, standard, n ⫽ 46). Two-thirds of polyps ranged in size from 10 to 20 mm; the average polyp size was 13.2 mm for IAP and 9.9 mm for standard snare polypectomy (P ⫽ .001). The cautery degree, cautery amount, and margin evaluability, did not differ substantially with regard to the resection technique. For polyps ⱖ10 –20 mm, the overall architecture quality was better in polyps resected with standard technique as compared with IAP. CONCLUSIONS: The utilization of IAP did not result in a better margin evaluability of the resected polyp. Overall, IAP does not result in a better histologic polyp evaluability. Keywords: Colon Polyp; Polypectomy; Mucosectomy; Submucosal Cushion; Histologic Evaluation.
W
hen performing a snare polypectomy the endoscopist essentially performs a “mucosectomy.”1 It is thought that injecting the submucosa with fluid (“submucosal cushion,” inejction-assisted polypectomy; IAP) will raise the polyp and allow for a more complete ensnarement and thus resection of more, deeper seated tissue (ie, submucosa).2– 4 However, whether this increased amount of tissue resection leads to a better histopathological evaluation is not clear. The aim of this study was to compare the diagnostic quality and ability to define the resection margin of adenomatous polyps obtained using standard snare polypectomy as compared with snare polypectomy after the creation of a submucosal cushion (IAP).
Methods The study group consisted of consecutive patients undergoing colonoscopy who underwent snare polypectomy for colon adenomas during a 6-month retrospective study at the Otto-von-Guericke University Hospital, Magdeburg, Germany. Exclusion criteria: polyps ⬎20 mm, nonadenomatous polyps (eg, hyperplastic) or resected using piecemeal technique, coagulation abnormalities (ie, international normalized ratio [INR] ⬎1.2, platelet count ⬍50,000). Patients underwent polypectomy using either standard snare electrocautery with or without submucosal cushion (IAP). The patients were not randomized to either method. All polypectomies were performed by 2 experienced colonoscopists with a minimum experience of 5000 endoscopic procedures. From each patient, the following data were abstracted: demographic variables, pre-existing medical conditions, indication for procedure, type, location, and size of polyps, and pathology report. The collected data were entered into Excel worksheets (Microsoft Corporation, Redmont, WA). Each patient was assigned a coded number. A second worksheet for the blinded pathologist (D.K.) included the coded number for each patient and the previously standardized polyp grading parameters.5–7 The pathologist used this second worksheet to enter her impression of each of the polyps reviewed. Informed consent was obtained from every patient before endoscopic procedure. The study was approved by the institutional review board of our institution and it was conducted according to the ethical guidelines of the declaration of Helsinki. Polypectomy was performed by means of an electrosurgical unit (ERBE, ICC 200, Tübingen, Germany) with use of automatically controlled cutting mode (Endocut). The unit was set for Effect 3 (output limit 120 W) and soft coagulation (output limit 60 W) (ERBE, ICC 200). We used braided, oval shape, 30-mm diameter electrocautery snares (Medwork, GmbH, Höchstadt/Aisch, Germany, Product number: POL1-H3-30-27230-OL). Submucosal injection was performed with a scleroAbbreviation used in this paper: IAP, injection-assisted polypectomy. © 2011 by the AGA Institute 1542-3565/$36.00 doi:10.1016/j.cgh.2011.06.027
October 2011
IAP AND COLON POLYPECTOMY
Table 1. Histologic Evaluation of Polyps Resected Using Submucosal Injection vs Without Submucosal Injection in Polyps 10 –20 mm in Size
n Cautery amount Grade 0 Grade 1 Grade 2 Grade 3 Grade ⱖ2 Cautery degree Grade 0 Grade 1 Grade 2 Grade 3 Grade 4 Grade ⱖ2 Margin evaluability Yes No Architecture Good ⫹ Fair Poor Presence of submucosa Yes No
IAP, n (%)
Without, n (%)
47
29
13 (27.7) 12 (25.5) 12 (25.5) 10 (21.3) 22 (46.8)
8 (27.6) 10 (34.5) 8 (27.6) 3 (10.3) 11 (37.9)
13 (27.7) 8 (17.0) 11 (23.4) 12 (25.5) 3 (6.4) 26 (55.3)
8 (27.6) 7 (24.1) 7 (24.1) 7 (24.1) 0 (0.0) 14 (48.3)
10 (21.3) 37 (78.7)
6 (20.7) 23 (79.3)
35 (74.5) 12 (25.5)
28 (96.6) 1 (3.4)
30 (63.8) 17 (36.2)
17 (58.6) 12 (41.4)
P
.565
.721
.583
.044
911
patients (59% men; mean age 64.4 ⫾ 10 years). Eighty-four polyps (75.7%) were located in the left colon. There were no differences in the demographic characteristics between both groups (P ⫽ .466). The major indications for colonoscopy were screening anemia, lower gastrointestinal bleeding and abdominal pain. The mean polyp size was 12 mm, 68.5% of polyps ranged in size from 11 to 20 mm. Polyps resected using IAP were larger (13.2 mm) than those using standard electrocautery (9.9 mm) (P ⫽ .001) the presence and the degree of dysplasia between both groups was similar (P ⫽ .118 and .296, respectively). There were no significant differences in cautery degree, P ⫽ .838; cautery amount, P ⫽ .068; and margin evaluability P ⫽ .677 did not differ substantially with regard to the resection technique in polyps ⱕ10 mm and those 10 –20 mm in size (Table 1). The overall quality of tissue architecture was almost equal regarding the resection technique (P ⫽ .722) (Table 1). Of interest, an adequate evaluability of the resection margins was not possible in 88.9% of polyps resected using IAP and 88.2% of polyps ⱕ10 mm using standard snare (P ⫽ .677). The submucosa could be observed in about two-thirds of polyps, regardless of their size or use of IAP (Table 1).
Discussion .642
therapy needle (Medwork, GmbH) using a solution of epinephrine diluted 1:10,000 in saline. A total of 2–5 mL of solution was injected for each polyp. Resected polyps were immediately fixed in buffered formalin and submitted for histopathologic study. A minimum of 2 levels each containing 2– 4 tissue sections were stained with H&E. The polyp histopathology grading system was previously designed to categorize polyp histology: cautery damage, margin evaluability, and architecture (overall diagnostic quality).5,7 The amount of cautery damage was determined based on the total area involved. The degree of cautery damage was evaluated based on the cell and tissue response, ie, stringing of nuclei of cells and loss of epithelium. Tissue architecture was considered preserved if more than two-thirds of the specimen could be used for histologic analysis. The diagnostic quality was considered poor if the pathologist was unable to determine the type of tissue examined (Table 1 and Figure 1). The size of the retrieved polyps was measured by a caliper. The size of the resected polyps was estimated by the largest distance between the 2 lateral limits.
Statistical Analysis Descriptive statistics were used to present the demographic, endoscopic, and histologic data. The results are presented in numbers and percentages. Statistical analysis was performed using the 2 (2 ⫻ 2, 3) with Yates’ correction, Fisher, and Student t tests using SPSS, Version 15 (SPSS, Inc, Chicago, IL). A P ⬍ .05 was considered statistically significant.
Results One hundred eleven polypectomies (IAP, n ⫽ 65, standard, n ⫽ 46) of sessile polyps were performed in 64 consecutive
We found that the ability to histologically evaluate the overall tissue morphology was similar for standard snare polypectomy and polypectomy after the creation of a submucosal cushion. In addition, the utilization of a submucosal cushion did not result in the obtention of more submucosa or a better margin evaluability of the resected polyp. The main use of the submucosal cushion has been to prevent the incidence of complications such as bleeding and perforation.2,8 –13 Indeed, a recent survey fund that 82% of American endoscopists use this technique for some polypectomies.14 The criteria for selecting polyps for submucosal saline solution injection are highly variable, although it is commonly used for polyps greater than 10 mm in size and those located in the right colon. Based on preliminary animal studies and occasional clinical observations showing that the submucosa could be well seen in specimens resected using the submucosal cushion technique, we hypothesized that the utilization of this technique would result in a more complete oncological resection and thus a better histopathological and margin evaluability of the resected colon polyp.3 However, our results do not support our hypothesis. There are several potential reasons that might explain our findings. First, the amount of injected volume may have resulted in swelling and tension of the underlying submucosa, thus making it more difficult for the endoscopist to ensnare enough tissue to include the muscularis mucosa and submucosa. Nevertheless, the endoscopists performing the procedure were highly experienced in advanced therapeutic endoscopy. Thus, it is unlikely that technical factors impeded the creation of adequate submucosal cushions. Second, the distribution of heat and hence the level of tissue resection might have been influenced by increased tissue resistance. When performing an electrocautery snare resection the depth of heat penetration into the tissue is determined by the distribution of electric field (ie, source of heating) and by thermal diffusion, the latter which can be increased by the presence of a liquid substance (ie, submucosal cushion). Indeed, it is possible that by having a
912
JOVANOVIC ET AL
CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Vol. 9, No. 10
Figure 1. Degree of cautery damage. (A) Grade 1, mild tissue damage with stringing of nuclei. (B) Grade 2, stringing of the nuclei with minimal epithelial loss. (C) Grade 3, stringing of the nuclei with significant epithelial loss. (D) Grade 4, significant epithelial loss. All photos: H&E stain, original magnification ⫻100.
larger volume to cut, the electrocautery unit increases its output and more damage results in the resected specimen.15 Nevertheless, some may argue that this is not important as the thermally injured, adenomatous tissue rests will “fall-off” anyway. However, this assumption can be potentially risky as some experts hypothesize that polyps and cancers found during surveillance colonoscopy may have originated form nonresected, “left-over” adenomas.16,17 Third, we used a computerized blended type current.17 Whether pure cutting currents result in better tissue evaluability is the matter of further studies. Our study has some potential limitations. The study was retrospective and nonrandomized. It was left at the discretion of the endoscopist to use submucosal injection and somehow, logically, polyps where IAP was used were larger in size. However, this does not limit the validity of our results as it reflects real-life practice. Indeed, this might even be an advantage as the possibility of bias was decreased as none of the involved endoscopists knew that the polypectomy technique was going to be evaluated by a pathologist. Therefore, there was no special “motivation” to show that the submucosal resection technique was better. Furthermore, the data collection was thorough, and the primary end point of the study, ie, having both the endoscopists and pathologist blinded to the main objective to the study was accomplished. Second, the number of polyps analyzed maybe relatively small. However, the study was powered to detect a 30% difference in margin evaluability. Furthermore, only adenomatous polyps were evaluated. Finally, the specimens were all read by 1 pathologist. Nonetheless, the histologic criteria used in this study are standardized and have been employed in several other studies evaluating polyp histology.5–7
In summary, in this study we were unable to confirm the hypothesis that snare polypectomy with the use of a submucosal cushion results in an improved ability to histologically evaluate the margins and overall tissue histology of endoscopically resected polyps. Our study adds to the scarce literature on histologic evaluability of resected polyps using various endoscopic resection techniques.5–7 More studies in this area are warranted. References 1. Mönkemüller K, Neumann H, Malfertheiner P, et al. Advanced colon polypectomy. Clin Gastroenterol Hepatol. 2009;7:641– 652. 2. Gostout CJ. Ode to the submucosal fluid cushion. Endoscopy 2004;36:638 – 639. 3. Norton ID, Wang L, Levine SA, et al. Efficacy of colonic submucosal saline solution injection for the reduction of iatrogenic thermal injury. Gastrointest Endosc 2002;56:95–99. 4. Varadarajulu S, Tamhane A, Slaughter RL. Evaluation of dextrose 50% as a medium for injection-assisted polypectomy. Endoscopy 2006;38:907–912. 5. Fry LC, Lazenby AJ, Mikolaenko I, et al. Diagnostic quality of polyps resected by snare polypectomy: does the type of electrosurgical current used matter? Am J Gastroenterol 2006;101:2123–2127. 6. Fantin AC, Neuweiler J, Binek JS, et al. Diagnostic quality of biopsy specimens: comparison between a conventional biopsy forceps and multibite forceps. Gastrointest Endosc 2001;54:600 – 604. 7. Mönkemüller KE, Fry LC, Jones BH, et al. Histological quality of polyps resected using the cold versus hot biopsy technique. Endoscopy 2004;36:432– 436. 8. Hsieh YH, Lin HJ, Tseng GY, et al. Is submucosal epinephrine injection necessary before polypectomy? A prospective, comparative study. Hepatogastroenterology 2001;48:1379 –1382.
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9. Dobrowolski S, Dobosz M, Babicki A, et al. Prophylactic submucosal saline-adrenaline injection in colonoscopic polypectomy: prospective randomized study. Surg Endosc 2004;18:990 – 993. 10. Heldwein W, Dollhopf M, Rösch T, et al. The Munich Polypectomy Study (MUPS): prospective analysis of complications and risk factors in 4000 colonic snare polypectomies. Endoscopy 2005;37:1116–1122. 11. Macrae FA, Tan KG, Williams CB. Towards safer colonoscopy: a report on the complications of 5000 diagnostic or therapeutic colonoscopies. Gut 1983;24:376 –383. 12. Mönkemüller K, Neumann H, Fry LC, et al. Polypectomy techniques for difficult colon polyps. Dig Dis 2008;26:342–346. 13. Di Giorgio P, De Luca L, Calcagno G, et al. Detachable snare versus epinephrine injection in the prevention of postpolypectomy bleeding: a randomized and controlled study. Endoscopy 2004;36:860 – 863. 14. Singh N, Harrison M, Rex DK. A survey of colonoscopic polypectomy practices among clinical gastroenterologists. Gastrointest Endosc 2004;60:414 – 418. 15. Morris ML, Tucker RD, Baron TH, et al. Electrosurgery in gastrointestinal endoscopy: principles to practice. Am J Gastroenterol 2009;104:1563–1574.
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16. Butterly LF, Chase MP, Pohl H, et al. Prevalence of clinically important histology in small adenomas. Clin Gastroenterol Hepatol 2006;4:343–348. 17. Pohl H, Robertson DJ. Colorectal cancers detected after colonoscopy frequently result from missed lesions. Clin Gastroenterol Hepatol 2010;8:858 – 864.
Reprint requests Address requests for reprints to: Klaus Mönkemüller, MD, PhD, FASGE, Marienhospital, Bottrop, Josef-Albers Straße 70, 46236 Bottrop, Germany. e-mail: [email protected]; fax: ⴙ49 (0) 241106-1009. Acknowledgments IJ and CC contributed equally to this report. Ivan Jovanovic, MD, PhD, is a recipient of the American Society for Gastrointestinal Endoscopy (ASGE) Cook Don Wilson Award 2010. This work was performed in part during his award period at the Marienhospital Bottrop, Germany. Conflicts of interest The authors disclose no conflicts.
Correction Calabrese C, Liguori G. Acute esophageal necrosis. Clin Gastroenterol Hepatol 2011;9:A30. In the above article, the following text was not properly cited from another published work (Gurvits GE, Shapsis A, Lau N, et al. Acute esophageal necrosis: a rare syndrome. J Gastroenterol 2007;42:29 –38). Any future citations based on the following sentences should cite the Gurvits et al article instead of the Calabrese et al article: “Several theories have been proposed to explain the pathogenesis of AEN. An ischemic phenomenon is viewed by some as the major factor in rapid development of esophageal lesions. Associated duodenal lesions might also suggest vascular compromise as the inciting event. Lowflow states or shock, atherosclerosis, thromboembolic disease, cardiac arrhythmias, and hypoperfusion as a result of severe lactic acidosis have been implied as possible etiologies.2 The blood supply to the proximal esophagus is derived from the superior and inferior thyroid arteries, whereas the rest of the organ receives blood flow from the esophageal branches of the descending aorta and splenic and left gastric arteries. An association between AEN and malnutrition, debilitated state, and malignancy suggests an overall reduction in the mucosal defense mechanism. Blood supply is an important component of the postepithelial defense as well as maintenance of the intrinsic repair mechanism. In combination with atherosclerosis, lowflow states, and thromboembolic phenomena, this can directly cause mucosal necrosis. The prognosis is typically poor, and mortality depends on the underlying illness.”