Flat gastric polyps: results of forceps biopsy, endoscopic mucosal resection, and long-term follow-up

OBJECTIVE: Histological examination of specimens obtained by forceps biopsy sampling of gastric polyps is of limited accuracy, and their management on this basis is therefore controversial. The aim of this prospective study was to assess the value of forceps biopsy sampling in establishing the correct diagnosis revealed by endoscopic mucosal resection (EMR). The complication rate of EMR was also determined. MATERIAL AND METHODS: Subjects with gastric polyps of epithelial origin, of at least 0.5 cm in diameter, and not associated with polyposis syndromes, were included in the study. Between 1994 and 2004, 56 gastric polyps in 44 patients (30 F, 14 M, mean age 67 years) met the inclusion criteria. Indigo carmine dye staining and electronic magnification were used in all cases. Following forceps biopsy sampling, 56 EMRs were performed. The histological results of the forceps biopsy and the resected specimens were analyzed. RESULTS: The initial forceps biopsies identified in situ carcinoma in 3 cases, adenoma with no dysplasia in 19, adenoma with low-grade dysplasia in 2, adenoma with moderate-grade dysplasia in 6, adenoma with high-grade dysplasia in 7, and hyperplastic lesions in 19 cases. The histological examination of the resected polyps revealed in situ carcinoma in 5 cases, carcinoid in 1, gastrointestinal stromal tumor in 1, adenoma with no dysplasia in 14, adenoma with low-grade dysplasia in 3, adenoma with moderate-grade dysplasia in 9, adenoma with high-grade dysplasia in 1, hyperplastic lesions in 21, and no diagnosis in 1 case. Complete agreement between the histological results on the forceps biopsy sample and on the ectomized polyp was seen in only 31 (55.3%) polyps. There were important disagreements in 12 cases. In 14 neoplastic and 1 hyperplastic polyps, the degree of dysplasia seen on histological examination of the forceps biopsy specimens differed from that observed for the resected specimens. Post-mucosectomy bleeding was observed in 3 patients, all of whom were successfully treated endoscopically. CONCLUSIONS: Forceps biopsy is not sufficiently reliable for the identification of gastric polyps. These lesions should be fully resected by EMR for a final diagnosis and (depending on the lesion size and type) possibly definitive treatment.     

The utility of endoscopic ultrasonography and endoscopy in the endoscopic mucosal resection of early gastric cancer

OBJECTIVE: To clarify the usefulness of endoscopic ultrasonography (EUS) and endoscopy in the endoscopic mucosal resection (EMR) of early gastric cancer. Patients/Methods-EMR was performed in 61 patients with early gastric cancer over the past five years. The accuracy of the assessment of the depth of cancerous invasion was studied in 49 patients who had EUS before EMR. Forty eight patients were treated with endoscopy alone; in these patients, EUS and endoscopic findings correlated with the clinical course. RESULTS: Forty six patients showed no changes in the submucosal layer or deeper structures on EUS. Pathologically these included 37 patients with mucosal cancer and nine with submucosal cancer showing very slight submucosal infiltration. Three patients showed diffuse low echo changes in the submucosal layer on EUS; pathologically, these included two with submucosal cancer and one with mucosal cancer with a peptic ulcer scar within the tumour focus. Of 48 patients receiving endoscopic treatment alone, 45 showed no tumour recurrence or evidence of metastases on EUS and endoscopy. Three cases of recurrence were observed. Two of these patients had a surgical gastrectomy, and one was re-treated endoscopically. In the former cases, the surgical results correlated well with assessment by EUS and endoscopy. In addition, the latter patient who was re-treated endoscopically after evaluation with EUS and endoscopy has so far had no recurrence. CONCLUSION: The combined use of EUS and endoscopy is effective in diagnosing the depth of cancerous invasion in patients undergoing EMR as well as in clarifying changes both within and between anatomic levels during follow up.     

Factors affecting complete resection of gastric tumors by the endoscopic mucosal resection procedure

BACKGROUND: In Japan, endoscopic mucosal resection (EMR) has been widely used as a treatment option for small early gastric cancer (EGC). The present study reviewed 178 cases for the 10-year period 1987-1997 in order to clarify the factors affecting the successful outcome of EMR. METHODS: Logistic regression analysis was used to examine whether complete resection of EGC correlated with the patient's age, gender, the characteristics of the tumor (location, macroscopic form, and size), the duration of the procedure and the experience of the doctor. RESULTS: The location of the tumor and the duration of the procedure correlated with the completeness of the resection (P < 0.01 and P < 0.05, respectively). Endoscopic mucosal resection was more difficult to perform for tumors in the gastric body than in the antrum or incisura region, and the longer the procedure the less complete the resection. CONCLUSION: The outcome of EMR is affected significantly by the location of the EGC.     

Endoscopic mucosal resection for treatment of early gastric cancer

BACKGROUND: In Japan, endoscopic mucosal resection (EMR) is accepted as a treatment option for cases of early gastric cancer (EGC) where the probability of lymph node metastasis is low. The results of EMR for EGC at the National Cancer Center Hospital, Tokyo, over a 11 year period are presented. METHODS: EMR was applied to patients with early cancers up to 30 mm in diameter that were of a well or moderately histologically differentiated type, and were superficially elevated and/or depressed (types I, IIa, and IIc) but without ulceration or definite signs of submucosal invasion. The resected specimens were carefully examined by serial sections at 2 mm intervals, and if histopathology revealed submucosal invasion and/or vessel involvement or if the resection margin was not clear, surgery was recommended. RESULTS: Four hundred and seventy nine cancers in 445 patients were treated by EMR from 1987 to 1998 but submucosal invasion was found on subsequent pathological examination in 74 tumours. Sixty nine percent of intramucosal cancers (278/405) were resected with a clear margin. Of 127 cancers without "complete resection", 14 underwent an additional operation and nine were treated endoscopically; the remainder had intensive follow up. Local recurrence in the stomach occurred in 17 lesions followed conservatively, in one lesion treated endoscopically, and in five lesions with complete resection. All tumours were diagnosed by follow up endoscopy and subsequently treated by surgery. There were no gastric cancer related deaths during a median follow up period of 38 months (3-120 months). Bleeding and perforation (5%) were two major complications of EMR but there were no treatment related deaths. CONCLUSION: In our experience, EMR allows us to perform less invasive treatment without sacrificing the possibility of cure.     

《早期胃癌内镜黏膜下剥离术和内镜黏膜切除术治疗指南(第二版)》的更新与解读

2014年日本胃肠内镜学会与日本胃癌学会联合发布了基于循证医学原则的《早期胃癌内镜黏膜下剥离术和内镜黏膜切除术治疗指南》。然而由于当时该领域的许多证据级别较低,部分准则只能通过专家共识来建立。近年来,设计规范的临床研究数量激增。基于这些新的证据,日本胃肠内镜学会发布了上述治疗指南的修订第二版。本文将基于新版指南中更新和...     

内镜下黏膜切除术治疗老年及老年前期胃肠道息肉的临床研究

目的探讨内镜下黏膜切除术（endoscopic mucosal resection,EMR）对老年及老年前期胃及大肠息肉的治疗效果,并对其临床病理特征、适应证、并发症等进行讨论。方法 2003年10月至2009年10月共完成老年及非老年胃息肉及大肠息肉EMR手术1076例;对切除标本进行病理检查,记录术中及术后发生的并发症及处理情况,术后定期内镜随访1-60月。结果 348处胃息肉经首次或再次EMR治疗病变均完整清除,病理示炎性息肉、增生性息肉、腺瘤性息肉分别占62.6%（218/348）,27.9%（97/348）,9.5%（33/348）。935处大肠息肉中892处病变经首次或再次EMR治疗病变完整清除,治愈率为95.4%;23处病变（2.5%）术后病理示浸润癌再追加外科开腹手术。病理示炎性息肉、增生性息肉、腺瘤性息肉、腺瘤癌变分别占29.1%（272/935）,20.9%（195/935）,46.2%（432/935）,3.9%（36/935）,随年龄的增加,腺瘤性息肉的比例逐渐升高（P〈0.01）。术中出血52例（4.8%）,均内镜下止血;术后迟发出血（〉24 h）21例（2.0%）,其中15例经内镜下止血,6例经输血及内科保守治疗后止血。无穿孔、感染等并发症发生。随访期间所有病例均无复发。结论 EMR是一种安全和微创的内镜治疗手段,对老年及老年前期胃及大肠息肉治疗的疗效优于传统的内镜下治疗方法。     

Benefits of endoscopic submucosal dissection according to size and location of gastric neoplasm, compared with conventional mucosal resection

Background and Aims:  To clarify optimal therapeutic strategies for early gastric cancers without vestigial remnant or recurrence, we evaluated the benefits of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) according to tumor size and location.
Methods:  From January 2000 to December 2007, a total of 328 gastric lesions were treated using conventional EMR, while 572 lesions were treated by ESD. Patients who underwent surgery on the upper gastrointestinal tract before EMR or ESD were excluded from the study. We compared tumor size, location and rates of complete resection, curative resection, postoperative bleeding, perforation and local recurrence between EMR and ESD according to tumor situation.
Results:  Overall local complete resection rate (EMR, 64.2%; ESD, 95.1%) and overall curative resection rate (EMR, 59.5%; ESD, 82.7%) were significantly higher in ESD than in EMR. No significant differences were seen in complication rates between EMR and ESD. Local recurrence was detected in 13 lesions (4.0%) of the EMR group during follow up. In contrast, no local recurrence was detected in the ESD group. For lesions 5 mm or less in diameter, complete resection rate in the EMR group was not significantly inferior to that in the ESD group at any location. However, rates were overwhelmingly better in the ESD group than in the EMR group for lesions more than 5 mm in diameter, regardless of location.
Conclusion:  We concluded that lesions exceeding 5 mm in diameter should be treated by ESD, although a high resection rate is obtained also with EMR for lesions of 5 mm or less in diameter.     

Guidelines for endoscopic submucosal dissection and endoscopic mucosal resection for early gastric cancer (second edition)

In response to the rapid and wide acceptance and use of endoscopic treatments for early gastric cancer, the Japan Gastroenterological Endoscopy Society, in collaboration with the Japanese Gastric Cancer Association, produced “Guidelines for Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection for Early Gastric Cancer” in 2014, as a set of basic guidelines in accordance with the principles of evidence‐based medicine. At the time, a number of statements had to be established by consensus (the lowest evidence level), as evidence levels remained low for many specific areas in this field. However, in recent years, the number of well‐designed clinical studies has been increasing. Based on new findings, we have issued the revised second edition of the above guidelines that cover the present state of knowledge. These guidelines are divided into the following seven categories: indications, preoperative diagnosis, techniques, evaluation of curability, complications, long‐term postoperative surveillance, and histology.     

Endoscopic submucosal dissection vs endoscopic mucosal resection for early gastric cancer: A meta-analysis

AIM: To compare endoscopic submucosal dissection(ESD) and endoscopic mucosal resection(EMR) for early gastric cancer(EGC).METHODS: Computerized bibliographic search was performed on PubMed/Medline, Embase, Google Schol-ar and Cochrane library databases. Quality of each included study was assessed according to current Co-chrane guidelines. Primary endpoints were en bloc re-section rate and histologically complete resection rate. Secondary endpoints were length of procedure, post-treatment bleeding, post-procedural perforation and re-currence rate. Comparisons between the two treatment groups across all the included studies were performed by using Mantel-Haenszel test for fixed-effects mod-els(in case of low heterogeneity) or DerSimonian and Laird test for random-effects models(in case of high heterogeneity).RESULTS: Ten retrospective studies(8 full text and 2 abstracts) were included in the meta-analysis. Overall data on 4328 lesions, 1916 in the ESD and 2412 in the EMR group were pooled and analyzed. The mean operation time was longer for ESD than for EMR(stan-dardized mean difference 1.73, 95%CI: 0.52-2.95, P =0.005) and the "en bloc " and histological complete re-section rates were significantly higher in the ESD group [OR = 9.69(95%CI: 7.74-12.13), P 0.001 and OR = 5.66,(95%CI: 2.92-10.96), P 0.001, respectively]. As a consequence of its greater radicality, ESD provided lower recurrence rate [OR = 0.09,(95%CI: 0.05-0.17), P 0.001]. Among complications, perforation rate was significantly higher after ESD [OR = 4.67,(95%CI, 2.77-7.87), P 0.001] whereas the bleeding incidences did not differ between the two techniques [OR = 1.49(0.6-3.71), P = 0.39].CONCLUSION: In the endoscopic therapy of EGC, ESD showed a superior efficacy but higher complication rate with respect to EMR.     

Endoscopic mucosal resection of non-ampullary sporadic duodenal adenomas: a retrospective analysis with long-term follow-up

Objective: We investigate the efficiency of endoscopic mucosal resection (EMR) of non-ampullary sporadic duodenal adenomas (NASDA) in a retrospective analysis with long-term follow-up.

Methods: Consecutive patients undergoing EMR of NASDA between May 2002 and December 2016 were retrospectively identified from an electronic database. Endoscopic follow-up was scheduled after 3, 6 and 12 months for the first year, then yearly for up to five years.

Results: EMR of 75 NASDA was performed in 68 patients (56% en-bloc, 44% piecemeal). Retroperitoneal perforations occurred in 3/68 (4.4%) patients, were treated by surgical (n?=?2) or percutaneous (n?=?1) drainage; delayed bleeding was reported in 13/75 (17.3%) resections and was successfully managed by endoscopy (n?=?12) or radiologic embolization (n?=?1). There was no procedure-related mortality. Follow-up was available in 61/68 patients (89.7%) after a median time of 59 months from resection. Residual and recurrent adenoma were diagnosed in 9 (14.5%) and 6 (10.9%) cases, respectively; all but one were successfully retreated endoscopically.

Conclusions: EMR for NASDA is effective with a favorable long-term outcome. Local recurrences can be retreated endoscopically. A recall system, patient’s compliance to endoscopic follow-up are mandatory to detect recurrences and their prompt treatment.     

Gastric vascular ectasia treated by endoscopic mucosal resection

An 80‐year‐old woman consulted our hospital complaining of general weakness. She had iron deficiency anemia, and upper gastrointestinal endoscopy revealed a small lesion accompanying a small amount of fresh bleeding in the stomach. Close observation of the lesion revealed that it was composed of a local assembly of dilated microvessels. The diagnosis of this patient was gastric vascular ectasia causing anemia. Endoscopic ultrasonography demonstrated that the lesion involved the mucosal and submucosal layers of the stomach, and that there were no large vessels inflowing to or outflowing from the lesion. In the present case, we attempted endoscopic mucosal resection (EMR). The lesion was completely resected by only one procedure of EMR without complications such as bleeding. After the endoscopic treatment, iron deficiency anemia improved. Follow‐up endoscopy performed 1 year later revealed that there was no residual or recurrent lesion. Although there have not been any published reports describing the use of EMR for gastric vascular ectasia, EMR may be a useful endoscopic treatment for this condition.     

A study of metachronous cancer after endoscopic resection of early gastric cancer

Abstract

Objective. Endoscopic resection is commonly used for early gastric cancer (EGC) in Korea and Japan. There are only a few reports of metachronous cancer after endoscopic resection. The aim of this study was to identify clinical factors associated with metachronous gastric cancer after endoscopic resection. Methods. A total of 176 patients with EGC who had underwent endoscopic submucosal dissection (ESD) were periodically followed-up with endoscopic examinations from January 2004 to December 2007. The incidence and variable factors of metachronous gastric cancer were investigated in a retrospective study. Results. The median interval between the diagnosis of primary cancer and the diagnosis of the first metachronous cancer was 30 months (range 18–42 months). Metachronous gastric cancer had developed in nine patients (5.1%) during follow-up period and seven patients (4.0%) had synchronous gastric cancer lesions within 1 year of the initial endoscopic treatment. Annual incidence rate of metachronous cancer was approximately 3.3%. Antrum atrophy and old age were significantly associated with the incidence of metachronous cancer. The status of Helicobacter pylori, size, location and gross finding of lesion had no significant relationship with metachronous occurrence. Conclusions. We should examine more carefully older patients who have atrophic gastritis because secondary cancer including metachronous cancer might occur in remnant stomach after initial successful endoscopic resection. And prospective study will be needed for the optimal endoscopic surveillance interval.     

Safety and efficacy of cold polypectomy compared to endoscopic mucosal resection and hot biopsy polypectomy

Backgrounds: Recently, several studies have demonstrated the usefulness of cold polypectomy (CP), a safe and simple method for the removal of small polyps. We investigated the safety and efficacy of CP compared to that of endoscopic mucosal resection (EMR) and hot biopsy polypectomy (HB).

Methods: We retrospectively examined 1713 colorectal polyps (size 1–9?mm) in 731 patients. CP, EMR, and HB were performed on 476, 997, and 240 lesions, respectively. We compared the region, size, morphology, the presence of delayed bleeding as overt bleeding 24?h after operation, number of clips, pathology, the presence of antithrombotic therapy, procedure time from detection of a polyp to resection and hemostasis, device cost including device and clips, and polyp remnants.

Results: The delayed bleeding in the CP group (0/476) was significantly lower compared to that in the HB group (3/240) and EMR group (7/997). There were no cases of perforations. The procedure time was significantly shorter in the CP group than in the EMR group (91.3sec vs 290.1sec, p?<?.0001). The CP group had a significantly lower device cost than the HB and EMR groups (49.2USD vs 58.0?USD vs 91.3?USD, p?<?.0001) was not inferior in terms of polyp remnants to the EMR and HB groups. (1.4% vs 0.6% vs 6.1%, p?=?.1599)

Conclusions: CP is a safe treatment that achieves less delayed bleeding. Moreover, CP is not inferior to other groups in terms of polyp remnants and offers a cost benefit. CP can be considered useful for colonic polypectomy.     

Esophageal and multiple gastric cancers treated by endoscopic mucosal resections

A case of successful endoscopic therapy of superficial esophageal and multiple gastric cancers in an 87‐year‐old man is reported. A slightly elevated superficial cancer 10 mm in diameter in the proximal stomach (type 0‐IIa) was detected by esophagogastroduodenoscopy (EGD) and treated by endoscopic mucosal resection (EMR) in September 1999. Four months later, in January 2000, a slightly depressed superficial cancer 10 mm in diameter in the proximal esophagus (type 0‐IIc) was found in follow‐up EGD and treated by EMR. Further, in August 2000, a slightly elevated superficial cancer 10 mm in diameter in the distal stomach (type 0‐IIa) was found in follow‐up EGD and treated by EMR. Microscopic examination of these resected specimens showed that invasion was limited to the mucosal layer, and confirmed that no lymphatic or vascular permeation had occurred. No endoscopic or histological recurrence was detected for 33 months after the most recent EMR for gastric cancer. As multiple primary cancers in the upper gastrointestinal tract are not rare in Japan, periodic endoscopic follow up is important for early detection of recurrence of new primary cancers.     

Is endoscopic one‐piece mucosal resection essential for early gastric cancer?

Background: Endoscopic mucosal resection (EMR) is widely accepted as a minimally invasive treatment for early gastric cancer (EGC) in Japan. However, the criteria for EMR must be strictly adhered to otherwise patients will miss the chance for additional therapy. We assess the important factor in expanding the indication of EMR. Methods: We investigated 1101 EGCs that had been resected by EMR at the National Cancer Center Hospital (NCCH), Tokyo, Japan, according to the indication recommended by Japanese Gastric Cancer Association (JGCA) and the expanded indication proposed by NCCH. Curability and local recurrence of the EMRs were assessed related to the applied indication and the number of resected specimens. Results: The recurrence rate of non‐evaluable resection was higher than that of evaluable resection (P < 0.0001). Eighty‐three lesions among 772 lesions in the JGCA group were non‐evaluable. Thirty‐seven leisons among 329 lesions in the NCCH group were non‐evaluable. There was no difference in the rate of non‐evaluable resection between JGCA and NCCH groups (P = 0.8329). However, the rate of curative resection was lower in the NCCH group than in the JGCA group (P = 0.0009). In piecemeal resection, there was no difference in the rate of non‐evaluable resection between JGCA and NCCH groups (P = 0.0527). In one‐piece resection, the rate of non‐evaluable resection was lower in the NCCH group than the JGCA group (P = 0.0137). Conclusion: Based on our series of cases, we propose one‐piece resection as a gold standard for EMR because it enables accurate histological evaluation, even in the EMR, according to the expanded indication.     

内镜黏膜下剥离术和内镜下黏膜切除术治疗早期胃癌的术后出血影响因素分析

目的：分析影响早期胃癌内镜黏膜下剥离术和内镜下黏膜切除术(ESD/EMR)术后出血的可能影响因素,以便降低出血风险,对术后出血高危人群进行特殊关注。方法：回顾性收集2012年6月至2018年5月于北京友谊医院内镜中心因诊断早期胃癌而行ESD/EMR治疗患者的临床资料,包括病人基本信息(年龄、性别、疾病史)、临床特征(病变大小、部位、形态)及术后病理信息(病理类型、浸润深度)等,分析上述因素对ESD/EMR术后发生出血的影响。结果：共有255例早期胃癌患者纳入研究,其中11例发生术后出血(4.3%)。术后出血病例与未出血病例相比,心脑血管疾病史、氯吡格雷服药史、多发病变在两组间分布有统计学差异 (P=0.004, P=0.017及P=0.042)。多因素分析显示心脑血管疾病史(OR=5.151, 95% CI：1.242-21.356, P=0.024)、多发病变(OR=7.245, 95% CI：1.471-35.684, P=0.015)及主要病变≥2cm (OR=4.713, 95%CI：1.011-21.982, P=0.048)是术后发生出血的可能危险因素。生存分析结果显示：有心脑血管疾病史(P<0.001)、多发病变(P=0.013)、主要病变≥2cm的患者(P=0.031),ESD/EMR术后发生出血的风险明显增高。结论：ESD/EMR术后应重点关注具有心脑血管疾病史、病变部位多发、病变较大的患者的出血风险。     

Endoscopic mucosal resection: not only therapeutic, but a diagnostic procedure for sessile gastric polyps

Background and Aims: Histological examination of specimens obtained by forceps biopsy sampling of gastric lesions is of limited accuracy, and their management on this basis is therefore controversial. Endoscopic mucosal resection (EMR) was initially developed in Japan for the resection of early gastric cancer (EGC). The potential use of EMR as a diagnostic tool has been suggested. The aims of the present study were to assess the value of forceps biopsy sampling in establishing the correct diagnosis revealed by EMR and to evaluate the efficacy of EMR. Methods: Fifty‐six subjects with sessile gastric polyps of epithelial origin, at least 0.5 cm in diameter, and not associated with polyposis syndromes, were included. Following forceps biopsy sampling, EMR was performed with an inject‐and‐cut technique or with cap‐fitted methods. The histological results on the forceps biopsy and the resected specimens were analyzed. Results: Histology on the resected specimens revealed neoplastic lesions in 34 cases, including seven EGC, and there were hyperplastic‐inflammatory lesions in 21 cases. Complete agreement between the previous histological results of the forceps biopsy samples and the resected specimens was seen in only 76.7% of the lesions. Altogether, the sensitivity and specificity of the forceps biopsy procedure for diagnosing neoplastic lesions were 87.5% (95% confidence interval [CI] = 76.0–98.9%) and 65.2% (95% CI = 45.7–84.7), respectively. A clinically relevant discrimination between neoplastic and non‐neoplastic lesions was not achieved in seven cases. No complications, such as perforation or massive bleeding necessitating surgical treatment, were encountered. EMR was considered complete in five patients. None of the EGC recurred during the mean 38‐month (6–72) follow up. Conclusions: Forceps biopsy is not fully representative of the entire lesion, and a simple biopsy may therefore lead to a faulty differentiation between neoplastic and non‐neoplastic lesions. EMR proposes diagnostic and staging advantage in assessing patients with EGC as compared to forceps biopsy, because it provides more intact mucosa and submucosa for histological analysis. Sessile gastric polyps should be fully resected by EMR for a final diagnosis and (depending on the lesion size and type) possibly definitive treatment.     

Endoscopic mucosal resection of early gastric cancer： Experiences in Korea

Endoscopic mucosal resection （EMR） has been established as one of the treatment options for early gastric cancer （EGC）. However, there are many uncertain areas such as indications of EIR, best treatment methods, management of complications and follow-up methods after the procedure. Host studies on this topic have been carried out by researchers in Japan. In Korea, gastric cancer is the most common malignant disease, and the second leading cause of cancer death. In these days, EIR for EGC is widely performed in many centers in Korea. In this review, we will provide an overview of the bechniques and outcomes of EIR in Korea.     

Endoscopic mucosal resection with 0.13% hyaluronic acid solution for colorectal polyps less than 20 mm: a randomized controlled trial

Background and Aim: Adequate mucosal elevation by submucosal injection is important for definitive en bloc resection and prevention of perforation during endoscopic mucosal resection (EMR). The objective of this study is to determine the efficacy of 0.13% hyaluronic acid (HA) solution for high and sustained mucosal elevation during colorectal EMR. Methods: The study was a prospective randomized controlled trial; a total of 196 patients with colon polyps of < 20 mm diameter were enrolled and randomized in a 1:1 ratio to undergo EMR using either 0.13% HA or normal saline (NS). The primary outcome of the study was histopathologically confirmed complete resection. The secondary outcomes such as maintenance of high mucosal elevation and development of complications were also evaluated. Moreover, the relationship between complete resection and the experience of the endoscopist (veteran vs less experienced) was analyzed. Results: Compete resection was achieved in 74 of 93 polyps (79.5%) in the 0.13% HA group and 63 of 96 polyps (65.6%) in the NS group (P < 0.05). High mucosal elevation was maintained in 83.9% of procedures in the 0.13% HA group and 54.1% in the NS group (P < 0.01). The frequency of complete resection achieved by less‐experienced endoscopists was higher in the 0.13% HA group (79.3%) than in the NS group (62.1%; P < 0.05). Conclusions: Endoscopic mucosal resection using 0.13% HA to colon polyps of less than 20 mm diameter is more effective than NS for complete resection and maintenance of mucosal elevation.