Underwater Endoscopic Mucosal Resection Vs Conventional Endoscopic Mucosal Resection for Superficial Nonampullary Duodenal Epithelial Tumors in the Western Setting.

BACKGROUND & AIMS: Conventional endoscopic mucosal resection (C-EMR) is established as the primary treatment modality for superficial nonampullary duodenal epithelial tumors (SNADETs), but recently underwater endoscopic mucosal resection (U-EMR) has emerged as a potential alternative. The majority of previous studies focused on Asian populations and small lesions (≤20 mm). We aimed to compare the efficacy and outcomes of U-EMR vs C-EMR for SNADETs in a Western setting. METHODS: This was a retrospective multinational study from 10 European centers that performed both C-EMR and U-EMR between January 2013 and July 2023. The main outcomes were the technical success, procedure-related adverse events (AEs), and the residual/recurrent adenoma (RRA) rate, evaluated on a per-lesion basis. We assessed the association between the type of endoscopic mucosal resection and the occurrence of AEs or RRAs using mixed-effects logistic regression models (propensity scores). Sensitivity analyses were performed for lesions ≤20 mm or >20 mm. RESULTS: A total of 290 SNADETs submitted to endoscopic resection during the study period met the inclusion criteria and were analyzed (C-EMR: n = 201, 69.3%; U-EMR: n = 89, 30.7%). The overall technical success rate was 95.5% and comparable between groups. In logistic regression models, compared with U-EMR, C-EMR was associated with a significantly higher frequency of overall delayed AEs (odds ratio [OR], 4.95; 95% CI, 2.87-8.53), postprocedural bleeding (OR, 7.92; 95% CI, 3.95-15.89), and RRAs (OR, 3.66; 95% CI, 2.49-5.37). Sensitivity analyses confirmed these results when solely considering either small (≤20 mm) or large (>20 mm) lesions. CONCLUSIONS: Compared with C-EMR, U-EMR was associated with a lower rate of overall AEs and RRAs, regardless of lesion size. Our results confirm the possible role of U-EMR as an effective and safe technique in the management of SNADETs.

Conventional versus underwater endoscopic resection for superficial non-ampullary duodenal epithelial tumours.

BACKGROUND AND OBJECTIVE: Several endoscopic resection methods have been developed as less invasive treatments for superficial non-ampullary duodenal epithelial tumours. This study aimed to compare outcomes of conventional endoscopic mucosal resection and underwater endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumours, including resection depth and rate of the muscularis mucosa contained under the lesion. METHODS: This single-centre retrospective cohort study conducted from January 2009 to December 2021 enrolled patients who underwent conventional endoscopic mucosal resection and underwater endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumours and investigated their clinicopathological outcomes using propensity score matching. RESULTS: Of the 285 superficial non-ampullary duodenal epithelial tumours, 98 conventional endoscopic mucosal resections and 187 underwater endoscopic mucosal resections were included. After propensity score matching, 64 conventional endoscopic mucosal resections and 64 underwater endoscopic mucosal resections were analysed. The R0 resection rate was significantly higher in underwater endoscopic mucosal resection cases than in conventional endoscopic mucosal resection cases (70.3% vs. 50.0%; P = 0.030). In the multivariate analysis, a lesion diameter > 10 mm (odds ratio 7.246; P = 0.001), being in the 1st-50th treatment period (odds ratio 3.405; P = 0.008), and undergoing conventional endoscopic mucosal resection (odds ratio 3.617; P = 0.016) were associated with RX/R1 resection. Furthermore, in underwater endoscopic mucosal resection cases, the R0 rate was significantly higher for lesions diameter ≤10 mm than >10 mm, and was significantly higher in the 51st-treatment period than in the 1st-50th period. Conventional endoscopic mucosal resection and underwater endoscopic mucosal resection cases showed no significant difference in resection depth and muscularis mucosa containing rate. CONCLUSIONS: Underwater endoscopic mucosal resection may be more acceptable than conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumours ≤ 10 mm. A steep early learning curve may be acquired for underwater endoscopic mucosal resection. Large multicentre prospective studies need to be conducted to confirm the effectiveness of underwater endoscopic mucosal resection.

Underwater versus conventional endoscopic mucosal resection for colorectal lesions: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND & AIMS: Conventional endoscopic mucosal resection (CEMR) is the established method for the resection of non-pedunculated colorectal lesions (NPCRL) ≥ 10 mm. In the last decade, underwater endoscopic mucosal resection (UEMR) has been introduced as a potential alternative. The aim of this systematic review with meta-analysis is to compare the recurrence and safety of UEMR and CEMR by analyzing only randomized controlled trials (RCTs). METHODS: We systematically searched PubMed, Cochrane Library and EMBASE until April 2023. Studies met the following inclusion criteria: (1) RCTs, (2) comparing UEMR with CEMR, (3) NPCRL ≥ 10 mm, and (4) reporting the outcomes of interest. Primary outcomes were recurrence and safety. Secondary outcomes were en bloc, R0, complete resection, clipping and adverse events per type. RESULTS: Five RCTs were included. UEMR was associated with a lower recurrence rate (OR: 0.56; 95% CI: 0.32-0.97). Thus, the RR of recurrence was 1.7 times higher in the CEMR group (95% CI, 1.04-2.77). There was no significant difference in the pooled safety analysis. UEMR showed better en bloc resection rates (OR: 1.54; 95% CI: 1.15-2.07), but subgroup analysis showed comparable rates in lesions ≥ 20 mm. R0 resection was higher in UEMR (OR: 1.72; 95% CI: 1.23-2.41). Other outcomes were not different between the 2 groups. CONCLUSIONS: UEMR is as safe as CEMR, with a higher overall R0 rate and a higher en bloc resection rate for lesions < 20 mm, leading to a lower overall recurrence rate. The results of this meta-analysis support the widespread use of UEMR.

Feasibility of underwater endoscopic mucosal resection for endoscopic management of gastric neoplasms in patients with familial adenomatous polyposis.

BACKGROUND: Underwater endoscopic mucosal resection (UEMR) has been developed as an effective endoscopic intervention for colon, rectum, and duodenum neoplasms. However, there are no comprehensive reports regarding the stomach, and its safety and efficacy are unknown. We aimed to examine the feasibility of UEMR for gastric neoplasms in patients with familial adenomatous polyposis (FAP). METHODS: We retrospectively extracted data of patients with FAP who underwent endoscopic resection (ER) for gastric neoplasms at Osaka International Cancer Institute from February 2009 to December 2018. Elevated gastric neoplasms of ≤ 20 mm in diameter were extracted, and conventional endoscopic mucosal resection (CEMR) and UEMR were compared. Furthermore, outcomes after ER until March 2020 were examined. RESULTS: 91 endoscopically resected gastric neoplasms were extracted from 31 patients with 26 pedigrees, and 12 neoplasms underwent CEMR and 25 neoplasms underwent UEMR was compared. The procedure time was shorter for UEMR than for CEMR. There was no significant difference between en bloc resection and R0 resection rates by EMR methods. CEMR and UEMR showed postoperative hemorrhage rates of 8% and 0%, respectively. Residual/local recurrent neoplasms were identified in four lesions (4%), but additional endoscopic intervention (three UEMR and one cauterization) resulted in a local cure. CONCLUSION: UEMR was feasible in gastric neoplasms of FAP patients, especially in elevated lesions and those of ≤ 20 mm in diameter.

Underwater EMR for the diagnosis of diffuse infiltrative gastric cancer.

Video 1Underwater EMR for establishing diagnosis of diffuse infiltrative gastric cancer.

'Underwater endoscopic mucosal resection with submucosal injection and marking' for superficial non-ampullary duodenal epithelial tumors to achieve R0 resection: a single-center case series.

OBJECTIVES: To describe an endoscopic technique named 'underwater endoscopic mucosal resection (UEMR) with submucosal injection and marking (UEMR-SIM)' and to evaluate the therapeutic characteristics of superficial non-ampullary duodenal epithelial tumors (SNADETs) < 20 mm vis-a-vis classical EMR (CEMR) and UEMR techniques. MATERIALS AND METHODS: This retrospective study included 103 consecutive SNADET patients (103 lesions) who underwent CEMR, UEMR, or UEMR-SIM. The UEMR-SIM procedure included (1) marking and submucosal injection, (2) filling of the duodenal lumen with 0.9% saline, (3) snaring of the lesion, and (4) electrosurgical removal. The procedural outcomes were compared between the UEMR-SIM and other-procedure groups. RESULTS: The en bloc resection rate was significantly higher in the UEMR-SIM group (100%) than in the CEMR group (76.8%) (p = 0.015) but was not statistically different between the UEMR-SIM and UEMR groups (88.0%) (p = 0.236). The R0 resection rate was significantly higher in the UEMR-SIM group (90.9%) than in the UEMR group (48.0%) (p = 0.001) but was not statistically different between the UEMR-SIM and CEMR groups (76.8%) (p = 0.209). CONCLUSIONS: Our study indicates that the proposed method, UEMR-SIM for SNADETs, is feasible to achieve a high R0 resection rate and a potentially low local recurrence rate.

Issues and Prospects of Current Endoscopic Treatment Strategy for Superficial Non-Ampullary Duodenal Epithelial Tumors.

An increasing number of duodenal tumors are being diagnosed over the years, leading to increased confusion regarding the choice of treatment options. Small-to-large tumors and histological types vary from adenoma to carcinoma, and treatment methods may need to be selected according to lesion characteristics. Because of its anatomic characteristics, complications are more likely to occur in the duodenum than in other gastrointestinal organs. Several reports have described the outcomes of conventional endoscopic mucosal resection, endoscopic submucosal dissection, cold snare polypectomy, underwater endoscopic mucosal resection, endoscopic full-thickness resection, and laparoscopic and endoscopic cooperative surgery for duodenal tumors. However, even in the guidelines set out by various countries, only the treatment methods are listed, and no clear treatment strategies are provided. Although there are few reports with a sufficiently high level of evidence, considering the currently available treatment options is essential. In this report, we reviewed previous reports on each treatment strategy, discussed the current issues and prospects, and proposed the best possible treatment strategy.

Underwater endoscopic mucosal resection for rectal neuroendocrine tumors (with videos): a single center retrospective study.

BACKGROUND: Underwater endoscopic mucosal resection (UMER) is a new method of endoscopic resection to completely remove the lesion without submucosal injection. But few attempts have been carried out for rectal neuroendocrine tumors (rectal NETs). METHODS: We retrospectively investigated data on the tumor characteristics and outcomes of patients with ≤ 10 mm rectal NETs who underwent UEMR or endoscopic submucosal dissection (ESD) from January 2019 to June 2021 in our institute. RESULTS: The endoscopic resection rate was 100% in both UEMR and ESD groups. The histological complete resection rate of the UEMR group (95.5%) was lower than that of the ESD group (96.4%) with no significant difference. The average operation time, hospitalization time and operation cost of UEMR group were less than those of ESD group (P < 0.05). The incidence of postoperative abdominal pain and abdominal distention in the UEMR group was lower than that in the ESD group (P < 0.05). There was no significant difference in the incidence of delayed bleeding and perforation between the two groups. There was no local recurrence or distant metastasis in the two groups during the follow-up period. CONCLUSIONS: Both the UEMR and ESD can effectively treat ≤ 10 mm rectal NETs with invasion depth confined to the mucosa and submucosa. UEMR is superior to ESD in operation time, hospitalization time, operation cost, postoperative abdominal pain and abdominal distention.

Underwater Endoscopic Mucosal Resection of Small Rectal Neuroendocrine Tumors.

Background and Study Aims: The resection strategy for rectal neuroendocrine tumors (NET) < 10 mm is not uniform. We compared the utility of underwater endoscopic mucosal resection (UEMR) to endoscopic submucosal resection with a ligation device (ESMR-L) to resect rectal NETs. Patients and Methods: Patients with rectal NET < 10 mm treated with UEMR or ESMR-L were included. Their medical records were retrospectively reviewed. Results: Thirty-two patients were divided into a UEMR group (n = 7) and an ESMR-L group (n = 25). Histopathological diagnosis of NET by biopsy was known before resection in 43% (3/7) in the UEMR group and 68% (17/25) in the ESMR-L group, (p = 0.379). UEMR was performed on an outpatient basis for all patients, and 92% of ESMR-L (23/25) were performed as inpatient procedures (p < 0.001). The procedure time was significantly shorter in the UEMR group than in the ESMR-L group [median (IQR), min, 6 (5-8) vs. 12 (9-14), p = 0.002]. En bloc resection and R0 resection rates were 100% in both groups. Pathological evaluations were predominantly NET G1 in both groups (UEMR: 7/7, 100% and ESMR-L: 23/25, 92%). Two patients in the ESMR-L group developed delayed bleeding, controlled by endoscopic hemostasis. Device costs were significantly higher in the ESMR-L group than the UEMR group by approximately US$180 [median (IQR), $90.45 (83.64-108.41) vs. $274.73 (265.86-292.45), P < 0.001]. Conclusion: UEMR results in similar resection quality with shorter procedure time and lower costs compared to ESMR-L. We recommend UEMR for the resection of rectal NET < 10 mm.

Endoscopic management of difficult laterally spreading tumors in colorectum.

Due to the advent of the screening programs for colorectal cancer and the era of quality assurance colonoscopy the number the polyps that can be considered difficult, including large (> 20 mm) laterally spreading tumors (LSTs), has increased in the last decade. All LSTs should be assessed carefully, looking for suspicious areas of submucosal invasion (SMI), such as nodules or depressed areas, describing the morphology according to the Paris classification, the pit pattern, and vascular pattern. The simplest, most appropriate and safest endoscopic treatment with curative intent should be selected. For LST-granular homogeneous type, piecemeal endoscopic mucosal resection should be the first option due to its biological low risk of SMI. LST-nongranular pseudodepressed type has an increased risk of SMI, and en bloc resection should be mandatory. Underwater endoscopic mucosal resection is useful in situations where submucosal injection alters the operative field, e.g., for the resection of scar lesions, with no lifting, adjacent tattoo, incomplete resection attempts, lesions into a colonic diverticulum, in ileocecal valve and lesions with intra-appendicular involvement. Endoscopic full thickness resection is very useful for the treatment of difficult to resect lesions of less than 20 up to 25 mm. Among the indications, we highlight the treatment of polyps with suspected malignancy because the acquired tissue allows an exact histologic risk stratification to assign patients individually to the best treatment and avoid surgery for low-risk lesions. Endoscopic submucosal dissection is the only endoscopic procedure that allows completes en bloc resection regardless of the size of the lesion. It should therefore be indicated in the treatment of lesions with risk of SMI.

Depth of the cutting plane with underwater and conventional endoscopic mucosal resection: Post-hoc analysis of a randomized study.

BACKGROUND AND AIM: A multicenter randomized controlled trial reported a better R0 resection rate for intermediate-sized (10-20 mm) colorectal polyps with underwater endoscopic mucosal resection (UEMR) than conventional endoscopic mucosal resection (CEMR). To clarify whether UEMR removes enough submucosal tissue in the removal of unpredictable invasive cancers, we investigated the cutting plane depth with UEMR versus CEMR. METHODS: This was a post-hoc analysis of a randomized controlled trial in which 210 intermediate-sized colorectal polyps were removed in five Japanese hospitals. One pathologist and two gastroenterologists independently reviewed all resected specimens and measured the cutting plane depth. The cutting plane depth was evaluated as (i) maximum depth of submucosal layer and (ii) mean depth of submucosal layer, calculated using a virtual pathology system. RESULTS: We identified 168 appropriate specimens for the evaluation of the cutting plane depth, resected by UEMR (n = 88) and CEMR (n = 80). The median resection depth was not significantly different between UEMR and CEMR specimens, regardless of the measurement method ([i] 1317 vs 1290 µm, P = 0.52; [ii] 619 vs 545 µm, P = 0.32). All specimens in the UEMR and CEMR groups contained substantial submucosa and no muscularis propria. CONCLUSIONS: The cutting plane depth with UEMR was comparable with that with CEMR. UEMR can be a viable alternative method that adequately resects the submucosal layer for the histopathological assessment of unpredictable submucosal invasive cancers.

Feasibility Study of Partial Submucosal Injection Technique Combining Underwater EMR for Superficial Duodenal Epithelial Tumors.

BACKGROUND AND AIMS: Endoscopic mucosal resection (EMR) and Underwater EMR have been reported as effective endoscopic treatment for superficial duodenal tumor (SDET). However, a notable problem of EMR for SDET is technical difficulty for the lesion with non-lifting sign, and it of UEMR is that en bloc resection rate is relatively low. Therefore, we performed partial submucosal injection combining UEMR (PI-UEMR). The aim of this study is to evaluate feasibility and safety of this technique for duodenal tumor. METHODS: This is a prospective observational study from tertiary care hospital. We performed PI-UEMR in patients with SDET that is 13-20 mm in diameter, or less than 13 mm with technical difficulty for EMR and UEMR from January 2019 to March 2020. Primary outcome was en bloc resection rate. Secondary outcomes were R0 resection rate, mean total procedure time, intra- and post-procedure complication. RESULTS: Thirty patients were included in this study. Mean age was 62 ± 12 years old. Three fourths lesions were located at anal side from major papilla. Median lesion size was 12 mm [IQR 10-16 mm]. Twenty-four cases were taken endoscopic biopsy in prior hospital and observed biopsy scar. En bloc resection rate was 97%. Ro resection rate was 83%. Mean total procedure time was 17 ± 12 min. And there was an only one case of complication, intra-procedure bleeding that was controllable endoscopically. CONCLUSIONS: PI-UEMR might be very useful and safe technique of endoscopic resection for SDET including relatively large lesions.

Current Treatment Strategy for Superficial Nonampullary Duodenal Epithelial Tumors.

Endoscopic submucosal dissection (ESD) is the standard treatment method for esophageal, gastric, and colorectal cancers. However, it has not been standardized for duodenal lesions because of its high complication rates. Recently, minimally invasive and simple methods such as cold snare polypectomy and underwater endoscopic mucosal resection have been utilized more for superficial nonampullary duodenal epithelial tumors (SNADETs). Although the rate of complications associated with duodenal ESD has been gradually decreasing because of technical advancements, performing ESD for all SNADETs is unnecessary. As such, the appropriate treatment plan for SNADETs should be chosen according to the lesion type, patient condition, and endoscopist's skill.

Nonrecurrence Rate of Underwater EMR for ≤20-mm Nonampullary Duodenal Adenomas: A Multicenter Prospective Study (D-UEMR Study).

BACKGROUND AND AIMS: Endoscopic resection of nonampullary duodenal adenoma is often challenging, and its technique has not yet been standardized. To overcome the practical difficulty of conventional endoscopic mucosal resection, underwater endoscopic mucosal resection (UEMR) was recently developed; therefore, we investigated the effectiveness and safety of UEMR for nonampullary duodenal adenoma. METHODS: A multicenter, prospective cohort study was conducted at 21 institutions in Japan. We enrolled patients with no more than 2 nonampullary duodenal adenomas ≤20 mm in size, who were planned to undergo UEMR. After UEMR, follow-up endoscopies were scheduled at 2 and 12 months after the procedure, and biopsy specimens were taken from the post-UEMR scars. The primary endpoint was the proportion of patients with histologically proven nonrecurrence at follow-up endoscopy and biopsy. RESULTS: A total of 155 patients with 166 lesions underwent UEMR. One patient with a non-neoplastic lesion in the resected specimen and 10 patients with 10 lesions who were lost to follow-up were excluded. Finally, 144 patients with 155 lesions who received all follow-up endoscopies were analyzed for the primary endpoint. The proportion of patients with proven nonrecurrence was 97.2% (n = 140 of 144; 95% confidence interval, 92.8%-99.1%) which exceeded the predefined threshold value (92%). Two cases of delayed bleeding (1.2%) occurred and they were successfully managed by clips. All recurrences were successfully treated by additional endoscopic treatment. CONCLUSIONS: This multicenter, prospective cohort study demonstrated effectiveness and safety of UEMR for nonampullary duodenal adenomas ≤20 mm in size. (University Hospital Medical Network Clinical Trials Registry, Number: UMIN000030414).

Efficacy and safety of underwater endoscopic mucosal resection for ≤20 mm superficial non-ampullary duodenal epithelial tumors: Systematic review and meta-analysis.

Background and aims: Superficial non-ampullary duodenal epithelial tumors (SNADETs) as a rare disease have gradually increased in recent years. Underwater endoscopic mucosal resection (UEMR) has emerged as a newly available option for the endoscopic resection of SNADETs. This study aimed to evaluate the efficacy and safety of UEMR for ≤20 mm SNADETs. Methods: A literature search was performed across multiple databases, including PubMed, Embase, Scopus, and Clinical trials for studies containing tumors ≤20 mm published from January 1, 2012, to August 8, 2022. Outcomes examined were the pooled rates of en bloc resection, R0 resection, adverse events, and recurrence. Subgroup analyses of the resection rate were conducted stratified by sample size and polyp size. Results: A total of 10 studies with UEMR performed in a total of 648 tumors were included for analysis. The pooled rate of en bloc resection and R0 resection was 88.2% (95% confidence interval (CI): 82.1-93.2) and 69.1% (95% CI: 62.2-76.1), respectively. The results showed pooled rate of intraoperative bleeding rate was 2.9% (95% CI: 0-9.0), delayed bleeding rate was 0.9% (95% CI: 0.1-2), recurrence rate was 1.5% (95% CI: 0-4.9). In the subgroup analysis, R0 and en-bloc resection rates were significantly higher in <10 mm than 10-20 mm SNADETs subgroups (R0 resection rate 83.1 vs. 48.6%; en bloc resection rate 100.0 vs. 84.0%, P < 0.05). Conclusion: Underwater endoscopic mucosal resection was an effective and safe technique for the optional treatment for ≤20 mm SNADETs, especially of <10 mm. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022340578.

Gel immersion endoscopy-facilitated endoscopic mucosal resection of a superficial nonampullary duodenal epithelial tumor: a novel approach.

Video 1Gel immersion endoscopy-facilitated endoscopic mucosal resection of a superficial nonampullary duodenal epithelial tumor.

Avaliação de ressecção de mucosa endoscópica sob imersão d'água de pólipos colorretais em um centro ambulatorial no Brasil / Evaluation of underwater endoscopic mucosal resection for colorectal polyps in an outpatient clinic in brazil

ABSTRACT BACKGROUND: Since 2012, a new technique for resection of large polyps has been described, the underwater endoscopic mucosal resection (UEMR). Some advantages that emerge from it is the needless of injection in submucosal layer and a greater chance of complete capture of the polyp. OBJECTIVE: There are few studies of UEMR in Brazil. The aim of this study is to evaluate the safety and efficacy of this technique in one Brazilian center. METHODS: This case series was conducted from February to December of 2020. Colorectal polyps greater than 9 mm without features of deep submucosal invasion were resected using UEMR. RESULTS: Twenty-four large polyps were resected with the UEMR approach from 24 patients. The mean size of the polys was 19 mm, ranging from 12 to 35 mm. All lesions were successful resected and 66% (16/24) were resected en bloc. In histologic analyses, most of them were adenomas (70.8%) and only one had deep submucosal invasion. There were no cases of acute complications, such perforation or acute bleeding. CONCLUSION: The UEMR is a safe and feasible procedure. With the emerging data on the procedure, it seems to be a wonderful tool in preventing colorectal cancer and its applicability and scope should be encourage to surpass reference centers.

RESUMO CONTEXTO: Desde 2012, uma nova técnica para ressecção de pólipos grandes tem sido descrita, a ressecção da mucosa endoscópica sob imersão d'água (REMS). Algumas vantagens que surgem desta técnica são evitar a injeção na camada submucosa e a maior chance de captura completa do pólipo. Objetivo - Há poucos estudos com REMS no Brasil. Nosso objetivo é avaliar a segurança e a eficácia da técnica em um centro brasileiro. MÉTODOS: Esta série de casos foi conduzida de fevereiro a dezembro de 2020. Pólipos colorretais maiores que 9 mm sem sinais endoscópicos de invasão de submucosa foram ressecados utilizando RMES. RESULTADOS: Vinte e quatro pólipos foram ressecados com RMES em 24 pacientes diferentes. O tamanho médio dos pólipos era de 19 mm, variando de 12 a 35 mm. Todas as lesões foram ressecadas e 66% (16/24) foram ressecadas em monobloco. Na análise histológica, a maioria era adenoma (70.8%) e apenas uma havia invasão profunda da submucosa. CONCLUSÃO: O uso de REMS é um procedimento seguro e factível. Com o aumento de dados relativos ao procedimento, esta parece ser uma excelente ferramenta na prevenção do câncer colorretal e sua aplicabilidade deve ser encorajada para fora dos centros de referência.

Underwater endoscopic mucosal resection of adenomas and colorectal serrated lesions: a prospective clinical study.

BACKGROUND: Underwater endoscopic mucosal resection (UEMR) without submucosal injection has been described as an alternative technique to the endoscopic resection of adenomas and colorectal serrated lesions. We aimed to assess the feasibility, safety, and efficacy of UEMR in a Brazilian setting. METHODS: This was a prospective observational study of consecutive patients who underwent UEMR between January and July 2019, in a single tertiary care center. Inclusion criteria were lesions without endoscopic stigmata of deep submucosal invasion in patients referred for endoscopic resection of colorectal adenomas, and serrated lesions detected in a previous colonoscopy. The following features were assessed: complete resection rate, en bloc resection rate, resection time, adverse events, and resection infeasibility. RESULTS: A total of 36 patients underwent UEMR for 51 colorectal lesions. The mean/median lesion size was 16.24/13 mm and the mean/median resection time was 16.97/9.19 min. Histopathology revealed the following: tubular adenoma (43.1%), tubulovillous adenoma (13.7%), serrated lesions (41.2%), and intramucosal adenocarcinoma (2%). Complete resection was achieved in 86.3% of cases; 52.9% of the lesions were removed en bloc, while 47.1% were resected in a piecemeal fashion. UEMR was feasible in 96.1% of cases and failed on 2 occasions, requiring conversion to standard endoscopic mucosal resection. Minor intraoperative bleeding occurred in 5 patients (9.8%) and only 1 presented with delayed bleeding (2%), all controlled endoscopically. CONCLUSION: UEMR for removal of adenomas and colorectal serrated lesions was demonstrated to be feasible, safe and effective.