Outcomes for Underwater Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection of 21-30-mm Colorectal Polyps: A Feasible Study

BACKGROUND AND AIMS

This randomized controlled trial (RCT) was designed to evaluate the short-term outcomes of underwater endoscopic mucosal resection (UEMR) and endoscopic submucosal dissection (ESD) of 21-30 mm colonic polyps.

METHOD

We conducted a single-center RCT. Patients diagnosed with suspected colorectal intramucosal carcinoma (21-30 mm and adaptable for both UEMR and ESD) were randomly assigned to the UEMR and ESD groups at a 1:1 ratio. The primary endpoint was the R0 resection rate. We independently performed one-sample tests against the set threshold for each treatment. The significance level was set at p = 0.224.

RESULT

Eleven polyps each in the UEMR and ESD groups, respectively, were analyzed. The R0 resection rate (%) was 36 (95% confidence interval 11-69) and 100 (72-100) for UEMR and ESD, respectively, with a significant difference between the two groups (p = 0.002). The p-value against the set threshold for UEMR was 0.743, whereas that for ESD was < 0.001 (one-sample binomial test). The en bloc resection rates (%) were 82 (48-97) and 100 (72-100) for UEMR and ESD, respectively; however, no significant difference was observed (p = 0.167). The mean treatment time (min) was significantly shorter in the UEMR group (8 ± 6) than in the ESD group (48 ± 29) (p = 0.001).

CONCLUSION

ESD could achieve a high R0 resection rate, while the en bloc resection rate was comparable between the two treatment techniques with less burden on patients undergoing UEMR for 21-30-mm colorectal polyps.

CLINICAL TRIAL REGISTRATION

The study was registered at the Japan Registry of Clinical Trial as jRCT1030210015 and jRCT1030210177.

Underwater Endoscopic Mucosal Resection

Although an established standard, conventional endoscopic mucosal resection (EMR) has disseminated despite an absence of studies demonstrating the value of submucosal injection. Several consequences of poorly executed submucosal injection may increase the difficulty and risk of EMR. Underwater EMR (UEMR), an alternative resection method for colonic neoplasms, avoids the need for submucosal injections. In comparison with reported outcomes of EMR, UEMR achieves similar rates of complete resection with comparable safety, with lower rates of recurrence and fewer repeat procedures. UEMR also compares favorably with endoscopic submucosal dissection in terms of procedure time and rates of complete resection, recurrence, and complications.

Underwater endoscopic mucosal resection: The third way for en bloc resection of colonic lesions?

BACKGROUND

Underwater endoscopic mucosal resection without submucosal injection has been described for removing large flat colorectal lesions.

OBJECTIVE

We aim to evaluate the reproducibility of this technique in terms of ease of implementation, safety and efficacy.

METHODS

A prospective observational study of consecutive underwater endoscopic mucosal resection in a community hospital was performed.

RESULTS

From September 2014 to April 2015, 25 flat or sessile colorectal lesions (median size 22.8 mm, range 10-50 mm; 18 placed in the right colon) were removed in 25 patients. Two of the lesions were adenomatous recurrences on scar of prior resection and one was a recurrence on a surgical anastomosis. The resection was performed en bloc in 76% of the cases. At the pathological examination, 14 lesions (56%) had advanced histology and seven (28%) were sessile serrated adenomas (two with high-grade dysplasia). Complete resection was observed in all the lesions removed en bloc. Intra-procedural bleeding was observed in two cases; both were managed endoscopically and were uneventful. No major adverse events occurred.

CONCLUSION

Underwater endoscopic mucosal resection appears to be an easy, safe and effective technique in a community setting. Further studies evaluating the efficacy of the technique (early and late recurrence), as well as comparing it with traditional mucosal resection, are warranted.

"Underwater" EMR of sporadic laterally spreading nonampullary duodenal adenomas (with video)

BACKGROUND

EMR for the treatment of duodenal adenomas is challenging due to a thin wall and rich vascularity.

OBJECTIVE

To evaluate a novel technique of "underwater" EMR without prior submucosal injection for the removal of large (≥2 cm) laterally spreading nonampullary duodenal adenomas.

DESIGN

Prospective, observational study.

SETTING

Tertiary academic referral center.

PATIENTS

Twelve patients (median age, 60 years) meeting the inclusion criteria.

INTERVENTIONS

Piecemeal EMR technique after sterile water submersion when using a double-channel endoscope.

MAIN OUTCOME MEASUREMENTS

Technical success, adverse events, completeness of resection on follow-up endoscopy.

RESULTS

Median adenoma size was 35 mm (25% greater than one-half circumference, 50% equal to one-third to one-half circumference, and 25% less than one-third circumference). Median procedure time was 65 minutes (range, 32-151). Final histology was tubular adenoma (7), tubulovillous adenoma (1), villous adenoma (3), and high-grade dysplasia (1). Eleven patients (92%) met the primary endpoint (technical success) and all patients met the secondary endpoint (completeness of resection). Median interval until follow-up endoscopy was 16 weeks (range, 11-56). Adverse events were as follows: delayed bleeding (3 patients, of whom 2 required transfusions), water intoxication syndrome manifested by altered mental status and hyponatremia (1), and stricture formation (1) that responded to balloon dilation. No perforation or postresection abdominal pain was found.

LIMITATIONS

Single operator, single center, small sample size, limited follow-up.

CONCLUSION

Underwater EMR for large sessile duodenal adenomas has high success rates for complete removal. The risk of delayed bleeding is significant, and precautions are needed when infusing a large volume of fluid into the GI tract.