EMR: A More Practical Move For 3 CM Polyp Removal

Endoscopic mucosal resection (EMR) uses adjunctive techniques to achieve curative resection of neoplastic lesions limited to the mucosal layers that are not amenable to cure using standard snare resection techniques alone.1 A flat, 3 centimeter, rectal lesion is well suited for EMR by initial injection of a submucosal fluid cushion, followed by confluent, wide-area, piecemeal snare resection. This saline-assisted EMR technique is safe, effective, fast, uses off-the- shelf routine accessories and has been part of the GI endoscopist’s armamentarium for close to 20 years, winning broad adoption.

By contrast, endoscopic submucosal dissection (ESD) is a technique that was initially developed and refined in Asia for the en bloc resection of early mucosal gastric cancer. Although ESD has been demonstrated to be an effective technique for resection of large mucosal lesions, it has not been widely adopted in Western countries for the following reasons: lower incidence of early gastric malignancies, increased technical challenge of the procedure, lack of training and expertise, longer procedure duration, inadequate reimbursement and higher risk of complications. Even in Japan, colorectal ESD is performed only by a small, dedicated group of practitioners.

Wide-area EMR is extremely safe for laterally spreading rectal adenomas. Perforation and transmural burn syndrome are negated by the location distal to the retroperitoneal reflection. Acute bleeding is uncommon. When it occurs, it is readily treated with routine hemostatic techniques and should not interfere with completion resection. We previously reported a delayed bleeding rate as high as 7 percent following resection of colonic neoplasms greater than or equal to 2 centimeters in diameter.2However, virtually all the delayed bleeding cases occurred with right colon lesions. Clinically significant bleeding with ESD for a rectal lesion occurs at comparable rates. Massive air extravasation of insufflation gas with pneumoretroperitoneum, pneumomediastinum and subcutaneous emphysema has been described during rectal ESD, and so the procedure should only be undertaken with the use of CO2 gas to mitigate this potential complication.3 In expert hands, both EMR and ESD have comparable safety levels for the curative resection of a flat, 3 centimeter rectal lesion.

Both EMR and ESD also achieve effective curative resection of laterally spreading rectal adenomas limited to the mucosa, including those with intramucosal carcinoma (T1a). However, lesions with early invasive carcinoma into the submucosal layer (T1b) pose challenges to management. Depth of submucosal invasion is associated with an incrementally increased risk for concurrent lymph node metastases in the context of the other histopathological prognosticators of depth of invasion, tumor grade and presence of lymphovascular invasion. Fortunately, these make up only a very small percentage of flat, 3 centimeter rectal lesions. En bloc EMR is generally relegated to lesions less than or equal to 2 centimeters. Piecemeal resection is typically required for a 3 centimeter lesion. ESD offers the potential to provide an intact resection specimen with minimal thermal injury, and thus preserves the architecture for staging. However, published series of ESD for rectal lesions report intact margins in as low as 67 percent of cases.4

There is a higher rate of local residual/recurrent adenoma observed at follow-up surveillance endoscopy following EMR versus ESD. However, surveillance endoscopy is necessary after both procedures, the focal residual/recurrence is readily recognizable, and is readily eradicated with additional resection/ablation. In our large series on EMR for defiant colorectal neoplasia (not limited to the rectum) we identified local residual/recurrent adenoma in 27 percent of lesions at six to 18 months follow-up colonoscopies in addition to metachronous lesions.2 However, in all cases, complete eradication was achieved during follow-up endoscopy. Other series have reported similar findings and promote the importance of conceptualizing curative EMR of large, laterally spreading colorectal neoplasia as a two-step procedure” initial and follow-up.5,6

As such,EMR and ESD are equivalent in achieving curative resection of a flat, 3 centimeter rectal lesion. Local residual/recurrent adenoma may be more common after EMR versus ESD but is readily eradicated at follow-up exams. Lastly, EMR is substantially more practical than ESD. EMR of a flat, 3 centimeter rectal lesion will take a fraction of the time needed to perform ESD. EMR will utilize a standard injection needle, normal saline solution, a standard snare and an ordinary electrosurgical generator. ESD will require a large bore injection needle to accommodate a hybrid injection solution (mucopolysaccaride, hyaluronic acid,hetastarch or other), one or more specialty ESD knives (around $250-$500 each), a transparent cap, CO2 insufflation gas and a microprocessor equipped electrosurgical generator. While the cost in time and accessories approaches a 10- fold increase, the reimbursement (technical and professional) is equivalent.


ESD is a more elegant means of endoscopic resection compared to EMR. However, ESD for colorectal neoplasms remains a largely virtuous undertaking because the potential value of ESD over EMR for the vast majority of colorectal neoplasms cannot be reconciled
with the marked increases in procedure cost and duration.


ESD is a more elegant means of endoscopic resection compared to EMR. However, ESD for colorectal neoplasms remains a largely virtuous undertaking because the potential value of ESD over EMR for the vast majority of colorectal neoplasms cannot be reconciled
with the marked increases in procedure cost and duration.7

Dr. Ginsberg has served as a consultant for Olympus, Boston Scientic, Fractyl and Microinterventions.

References

1.Chandrasekhara V. Ginsberg G. Endoscopic Mucosal Resection: Not Your Father’s Polypectomy Anymore. Gastroenterology , 2011;141(1):4249.
2. Buchner AM, Guarner-Argente C, Ginsberg GG.
Outcomes of EMR of de ant colorectal lesions directed to an endoscopy referral center. Gastrointest Endosc 2012;76:255-63.

3. Koichiro Sato, Sayo Itoh, Fukimo Shigiyama,
Tomoyuki Kitagawa, and Iruru Maetani. Pneumoretroperitoneum, pneumomediastinum and subcutaneous emphysema after colorectal endoscopic submucosal dissection (ESD) with air insuf ation. J Interv Gastroenterol. 2011 Jul-Sep; 1(3): 136138

4. J Gastroenterol Hepatol. 2011 Jun;26(6):1028-33. doi: 10.1111/j.1440-1746.2011.06684.x. Comparing endoscopic submucosal dissection with transanal resection for non-invasive rectal tumor: study. Kiriyama S1, Saito Y, Matsuda Mashimo Y, Joeng HK, Moriya Y, Kuwano
a retrospective T, Nakajima T, H.

5. Woodward TA, Heckman MG, Cleveland P, De Melo S, Raimondo M, Wallace M. Predictors of Complete Endoscopic Mucosal Resection of Flat and Depressed Gastrointestinal Neoplasia of the Colon. Am J Gastroenterol 2012;107:650654.
6. Moss A, Bourke MJ, Williams SJ, Hourigan LF, Brown G, Tam W, Singh R, Zanati S, Chen RY, Byth K. Endoscopic mucosal resection outcomes and prediction of submucosal cancer from advanced colonic mucosal neoplasia. Gastroenterology. 2011;140(7):1909-18.
7. Chandrasekhara V, Ginsberg GG. ESD for colorectal neoplasms: dissecting value from virtue. Gastrointest Endosc 2011;74:1084-6.

Join the discussion

Your email address will not be published. Required fields are marked *