Underwater Endoscopic Mucosal Resection for Colorectal Lesions: A Bridge Between Conventional Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection

Underwater vs conventional endoscopic mucosal resection for nonpedunculated colorectal neoplasms: A randomized controlled trial

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) has been shown to be a good treatment option for the management of nonpedunculated polyps ≥ 10 mm since its introduction. However, there is a paucity of randomized controlled trials (RCTs) in Asia.

AIM

To compare the efficacy and safety of UEMR with those of conventional EMR (CEMR) in treating nonpedunculated colorectal lesions.

METHODS

We carried out this RCT at a tertiary hospital from October 2022 to July 2024. Patients with nonpedunculated colorectal neoplasms ranging from 10 mm to 30 mm in size were randomly assigned to either the UEMR or CEMR group. The primary outcome was the curative resection (R0) rate. The secondary outcomes included en bloc resection, procedure time, adverse events, and the number of clips used for defect closure.

RESULTS

A total of 260 patients with 260 lesions (130 in each UEMR and CEMR group) were recruited. The median age was 58 (27-85) years, the male/female ratio was 1.74, and the median lesion size was 20 (10-30 mm) mm. Compared with CEMR, UEMR was associated with a significantly greater curative resection (R0) rate (98.4% vs 90.3%; P = 0.007), greater en bloc resection rate (100% vs 94.6%; P = 0.014), shorter procedure time (65 vs 185 seconds; P < 0.001), lower rate of bleeding complications (1.5% vs 10%; P = 0.003), and fewer clips used (2 vs 3; P < 0.001). No perforations were observed in either group.

CONCLUSION

Compared with CEMR, UEMR has a higher R0 rate, greater en bloc resection rate, shorter procedure time, fewer bleeding complications, and clips used in the management of nonpedunculated colorectal neoplasms.

Underwater Versus Conventional Endoscopic Mucosal Resection for Colorectal Laterally Spreading Tumors: A Post Hoc Analysis of Efficacy

BACKGROUND AND AIMS

Underwater endoscopic mucosal resection (UEMR) has emerged as a promising alternative to conventional endoscopic mucosal resection (CEMR) for the treatment of colorectal laterally spreading tumors (LSTs). This study aimed to compare the efficacy and safety of UEMR and CEMR in managing LSTs measuring 10-30 mm.

METHODS

A post hoc analysis was performed on 88 patients with 88 colorectal LSTs, who were randomly assigned to two treatment groups: 42 with CEMR and 46 with UEMR. The primary outcome was the rate of R0 resection, defined as the absence of neoplastic cells at the resection margin. The secondary outcomes included en bloc resection rates, procedure times, and postprocedural complications. The data were analyzed via chi-square tests, t tests, and the Mann-Whitney U test where appropriate.

RESULTS

No significant difference was found in the R0 resection rate between UEMR and CEMR. However, UEMR achieved a significantly higher en bloc resection rate, particularly for LSTs ranging from 20 to 30 mm (42.9% for CEMR vs. 100% for UEMR; p = 0.009). Additionally, UEMR resulted in a shorter median procedure time (85.0 s for UEMR vs. 207.5 s for CEMR; p < 0.001). There was no significant difference in bleeding complications or the number of clips used between the two groups.

CONCLUSIONS

Compared with CEMR, UEMR offers a higher en bloc resection rate and a shorter procedure time, particularly for larger lesions, without increasing the risk of complications. UEMR should be considered a preferred option for managing colorectal LSTs, especially those measuring 20-30 mm.

Treatment for T1 colorectal cancers substratified by site and size: "horses for courses"

Background

Owing to advances in diagnostic technology, the diagnosis of T1 colorectal cancers (CRCs) continues to increase. However, the optimal management of T1 CRCs in the Western Hemisphere remains unclear due to limited population-based data directly comparing the efficacy of endoscopic therapy (ET) and surgical resection (SR). The purpose of this study was to report outcome data from a large Western cohort of patients who underwent ET or SR for early CRCs.

Methods

The SEER-18 database was used to identify patients with T1 CRCs diagnosed from 2004 to 2018 treated with ET or SR. Multivariable logistic regression models were employed to identify variables related to lymph node metastasis (LNM). Rates of ET and 1-year relative survival were calculated for each year. Effect of ET or SR on overall survival and cancer-specific survival was compared using Kaplan-Meier method stratified by tumor size and site.

Results

A total of 28,430 T1 CRCs patients were identified from 2004 to 2018 in US, with 22.7% undergoing ET and 77.3% undergoing SR. The incidence of T1 CRCs was 6.15 per 100,000 person-years, with male patients having a higher incidence. Left-sided colon was the most frequent location of tumors. The utilization of ET increased significantly from 2004 to 2018, with no significant change in 1-year relative survival rate. Predictors of LNM were age at diagnosis, sex, race, tumor size, histology, grade, and location. The 5-year relative survival rates were 91.4 and 95.4% for ET and SR, respectively. Subgroup analysis showed that OS and CSS were similar between ET and SR in T1N0M0 left-sided colon cancers with tumors 2 cm or less and in rectal cancers with tumors 1 cm or less.

Conclusion

Our study showed that ET was feasible and safe for patients with left-sided T1N0M0 colon cancers and tumors of 2 cm or less, as well as T1N0M0 rectal cancers and tumors of 1 cm or less. Therefore, the over- and under-use of ET should be avoided by carefully selecting patients based on tumor size and site.