Conventional Endoscopic Mucosal Resection Group Research Articles

Tip-in Versus Conventional Endoscopic Mucosal Resection for Colorectal Neoplasia: A Systematic Review and Meta-analysis.

Early-stage gastrointestinal neoplasms are frequently treated with conventional endoscopic mucosal resection (C-EMR). However, C-EMR frequently leads to incomplete resection of large colorectal lesions. Tip-in endoscopic mucosal resection (EMR), which was recently introduced for en bloc resection of colorectal neoplasms, minimizes slippage during the procedure. We conducted a systematic review and meta-analysis of published studies that compared Tip-in EMR with conventional EMR. We searched several electronic databases and included studies that reported on the primary outcomes of en bloc resection rate and complete resection rate, as well as secondary outcomes such as procedure time and procedure-related complications (including perforation and delayed bleeding rate). We used a random effects model to calculate odds ratios (ORs) with 95% CIs for dichotomous data and weighted mean differences with 95% CIs for continuous data. We also conducted several sensitivity analyses to assess the robustness of our findings. A total of 11 studies involving 1244 lesions (684 in the Tip-in EMR group and 560 in C-EMR group) were included in the meta-analysis. Our meta-analysis showed that compared with conventional EMR, Tip-in EMR significantly increased the en bloc resection rate in patients with colorectal neoplasia (OR=3.61; 95% CI, 2.09-6.23; P <0.00001; I2 =0%) and had a higher complete resection rate (OR=2.49; 95% CI, 1.65-3.76; P <0.0001; I2 =0%). However, the procedure time and rates of procedure-related complications did not differ significantly between the 2 groups. Tip-in EMR outperformed C-EMR for both the en bloc and complete resection of colorectal lesions with similar rates of procedural complications.

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

Conventional endoscopic mucosal resection (CEMR) is the established method for the resection of non-pedunculated colorectal lesions (NPCRL) ≥ 10mm. 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). 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 ≥ 10mm, 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. 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 ≥ 20mm. R0 resection was higher in UEMR (OR: 1.72; 95% CI: 1.23-2.41). Other outcomes were not different between the 2 groups. UEMR is as safe as CEMR, with a higher overall R0 rate and a higher en bloc resection rate for lesions < 20mm, leading to a lower overall recurrence rate. The results of this meta-analysis support the widespread use of UEMR.

Conventional endoscopic mucosal resection versus modified endoscopic mucosal resection for duodenal neuroendocrine tumor.

As the incidence of duodenal neuroendocrine tumors (DNET) is steadily increasing, the role of endoscopic treatment for appropriate lesions is becoming more significant. We aimed to compare the outcomes according to lesion size and endoscopic mucosal resection (EMR) techniques for DNET treatment. Patients who underwent endoscopic treatment for DNET between June 2000 and December 2019 were included. The clinicopathologic features and treatment outcomes were investigated by reviewing medical records. Overall, 104 cases underwent endoscopic resection for nonampullary DNET, including conventional EMR (n = 57), cap-assisted EMR (EMR-C, n = 19), and precut EMR (EMR-P, n = 28). The en bloc resection rates (100% vs. 94.7% vs. 96.4%) and histologic complete resection rates (45.6% vs. 52.6% vs. 57.1%) were not significantly different between the EMR, EMR-C, and EMR-P groups. The histologic complete resection rates were significantly higher in lesions < 10mm than in lesions ≥ 10mm (69.8% vs. 38.9%, P = 0.013). In lesions < 10mm, perforation occurred more frequently in the modified EMR group than in the conventional EMR group (13.2% vs. 0.0%, P = 0.007). During the median follow-up period of 88.0months, the recurrence-free survival (92.2% vs. 94.4% vs. 92.1%) and overall survival (98.0% vs. 88.1% vs. 100.0%) rates did not show significant differences between the EMR, EMR-C, and EMR-P groups. Conventional EMR and modified EMR are feasible and effective for the treatment of nonampullary DNET sized < 10mm and limited to mucosal and submucosal layer. Additionally, endoscopists should be aware of the high risk of perforation in modified EMR.

Underwater versus conventional EMR for nonpedunculated colorectal lesions: a randomized clinical trial

Conventional endoscopic mucosal resection (CEMR) is the standard modality for removing nonpedunculated colorectal lesions. Underwater endoscopic mucosal resection (UEMR) has emerged as an alternative method. There are few comparative studies between these techniques, especially evaluating recurrence. Therefore, the purpose of this trial was to compare CEMR and UEMR for the resection of colorectal lesions with respect to efficacy, safety, and recurrence rate. This was a randomized controlled trial of UEMR versus CEMR for naïve and nonpedunculated lesions measuring between 10 and 40mm. The primary outcome was adenoma recurrence at 6 months after the resection. Secondary outcomes were rates of technical success, en bloc resection, and adverse events. Block randomization was used to assign patients. Tattooing was performed to facilitate localization of the scars and eventual recurrences. Endoscopic follow-up was scheduled at 6 months after the procedure. The sites of resections were examined with white-light imaging, narrow-band imaging (NBI), and conventional chromoscopy with indigo carmine followed by biopsies. One hundred five patients with 120 lesions were included, with a mean size of 17.5 ± 7.1 (SD)mm. Sixty-one lesions were resected by UEMR and 59 by CEMR. The groups were similar at baseline regarding age, sex, average size, and histologic type. Lesions in the proximal colon in the CEMR group corresponded to 83% and in the UEMR group to 67.8% (P= .073). There was no difference between groups regarding success rate (1 failure in each group) and en bloc resection rate (60.6% UEMR vs 54.2% CEMR, P= .48). Intraprocedural bleeding was observed in 5 CEMRs (8.5%) and 2 UEMRs (3.3%) (P= .27). There was no perforation or delayed hemorrhage in either groups. Recurrence rate was higher in the CEMR arm (15%) than in the UEMR arm (2%) (P= .031). Therefore, the relative risk of 6-month recurrence rate in the CEMR group was 7.5-fold higher (95% CI, 0.98-58.20), with a number needed to treat of 7.7 (95% CI, 40.33-4.22). The higher recurrence rate in the CEMR group persisted only for lesions measuring 21 to 40mm (35.7% vs 0%; P= .04). This study demonstrated that UEMR was associated with a lower adenoma recurrence rate than was CEMR. Both endoscopic techniques were effective and had similar rates of adverse events for the treatment of nonpedunculated colorectal lesions.

Resection depth and layer of underwater versus conventional endoscopic mucosal resection of intermediate-sized colorectal polyps: A pilot study.

Background and study aims Curability of colorectal tumors is associated with resection depth and layer in endoscopic resection. Underwater endoscopic mucosal resection (UEMR) has not undergone sufficient histopathological evaluation. We conducted a pilot study to compare the effectiveness, including resection depth and layer, of UEMR and conventional endoscopic mucosal resection (CEMR). Patients and methods This study was a single-center, retrospective study. Patients with colorectal lesions were treated by UEMR or CEMR between January 2018 and March 2020. Eligible patients were selected from included patients in a 1:1 ratio using propensity score matching. We compared the resection depth and layer and treatment results between the UEMR and CEMR groups. Results We evaluated 55 patients undergoing UEMR and 291 patients undergoing CEMR. Using propensity score matching, we analyzed 54 lesions in each group. The proportion of specimens containing submucosal tissue was 100 % in both groups. The median thickness of the submucosal tissue was significantly greater in the CEMR group than in the UEMR group [1235 µm (95 % confidence interval [CI], 1020–1530 µm) vs. 950 µm (95 % CI, 830–1090 µm), respectively]. However, vertical margins were negative in all lesions in both groups. Conclusions Our findings suggest that the median thickness of submucosal tissue in the UEMR group was about 1,000 μm. Even though the resection depth achieved with UEMR was more superficial than that achieved with CEMR, UEMR may be a treatment option, especially for colorectal lesions ≤ 20 mm in diameter without suspicious findings of submucosal deeply invasive cancer.

S1042 Efficacy and Safety of Underwater versus Conventional Endoscopic Mucosal Resection for Colorectal Polyps: A Systematic Review and Meta-Analysis

Introduction: Endoscopic mucosal resection (EMR) is a commonly used endoscopic technique for removing colorectal polyps. Underwater EMR (UEMR) has recently been introduced as a potential alternative for conventional EMR (CEMR). However, its clinical outcomes compared to CEMR remains uncertain. Therefore, we conducted this meta-analysis to evaluate the efficacy and safety outcomes of UEMR compared to CEMR. Methods: We performed a comprehensive literature search using MEDLINE and EMBASE databases from inception through January 2021 for all the studies that compared UEMR with CEMR in the removal of colorectal polyps. The assessed outcomes were en bloc resection, residual/recurrent polyps on follow-up, piecemeal resection, complete macroscopic resection, complete histological resection, and overall adverse events (intraprocedural and post-procedural bleeding and perforation). Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using the random-effects model. Heterogeneity was assessed by I2 statistic. Results: A total of 13 studies including 2046 patients with 2517 polyps were included (1213 in UEMR group, 1304 in CEMR group); four were Randomized controlled studies, eight were retrospective cohort studies, and one study was prospective cohort. Seven were full-text publications and 6 were abstracts. All the results are summarized in Table 1. UEMR showed significantly better rates of en bloc resection (OR 1.51, 95% CI 1.01, 2.18, P = 0.03, I2 = 52%) (Figure 1), residual/recurrent polyps on follow-up (OR 0.35, 95% CI 0.20, 0.62, P = 0.0003, I2 = 26%), piecemeal resection (OR 0.68, 95% CI 0.49, 0.94, P = 0.02, I2 = 0%), complete macroscopic resection (OR 12.56, 95% CI 4.88, 32.33, P < 0.00001, I2 = 0%). There was no significant difference in complete histological resection (OR 1.11, 95% CI 0.63, 1.98, P = 0.71, I2 = 62%), and overall adverse events (OR 0.92, 95% CI 0.52, 1.62, P = 0.76, I2 = 61%) between the two groups. Conclusion: Compared to Conventional EMR, Underwater EMR demonstrated better rates of en bloc resection and complete macroscopic resection with lower risks of piecemeal resection and residual/recurrent polyps. However, there was no difference in terms of complete histological resection and overall adverse events between the two approaches.Table 1Figure 1.: Flowchart.

Underwater vs Conventional Endoscopic Mucosal Resection of Large Sessile or Flat Colorectal Polyps: A Prospective Randomized Controlled Trial

Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, nonmalignant colorectal polyps. We investigated whether underwater endoscopic mucosal resection (UEMR) is superior to CEMR for large (20-40mm) sessile or flat colorectal polyps. In this prospective randomized controlled study, patients with sessile or flat colorectal polyps between 20 and 40 mm in size were randomly assigned to UEMR or CEMR. The primary outcome was the recurrence rate after 6 months. Secondary outcomes included en bloc and R0 resection rates, number of resected pieces, procedure time, and adverse events. En bloc resection rates were 33.3% in the UEMR group and 18.4% in the CEMR group (P= .045); R0 resection rates were 32.1% and 15.8% for UEMR vs CEMR, respectively (P= .025). UEMR was performed with significantly fewer pieces compared to CEMR (2 pieces: 45.5% UEMR vs 17.7% CEMR; P= .001). The overall recurrence rate did not differ between both groups (P= .253); however, subgroup analysis showed a significant difference in favor of UEMR for lesions of >30 mm to ≤40 mm in size (P= .031). The resection time was significantly shorter in the UEMR group (8 vs 14 minutes; P< .001). Adverse events did not differ between both groups (P= .611). UEMR is superior to CEMR regarding en bloc resection, R0 resection, and procedure time for large colorectal lesions and shows significantly lower recurrence rates for lesions >30 mm to ≤40 mm in size. UEMR should be considered for the endoscopic resection of large colorectal polyps.

Efficacy of Underwater Endoscopic Mucosal Resection for Superficial Non-Ampullary Duodenal Epithelial Tumor.

Background/AimsEndoscopic resection (ER) for superficial non-ampullary duodenal epithelial tumors (SNADETs) is challenging. Conventional endoscopic mucosal resection (CEMR) is also problematic due to the anatomical features of the duodenum. We compared the safety and efficacy of underwater endoscopic mucosal resection (UEMR) with those of CEMR through a retrospective analysis. MethodsAltogether, 44 consecutive patients with 46 SNADETs underwent ER (18 CEMR cases and 28 UEMR cases) between January 2016 and October 2019. We investigated the proportions of en bloc resection, R0 resection, complications, resection time, and total procedure time and compared the outcomes of patients from the CEMR group with those of patients from the UEMR group. ResultsThe median tumor size was 8.0 mm (range, 2.0–20.0 mm). The UEMR group showed a higher proportion of en bloc resection (96.4% vs. 72.2%, p<0.05) and significantly lower median resection time and total procedure time (4 min vs. 9.5 min, p<0.05 and 13 min vs. 19 min, p<0.05; respectively) than the CEMR group. No complications were observed. However, two patients treated with piecemeal resection in the CEMR group had residual tumors. ConclusionsUEMR is a feasible therapeutic option for SNADETs. It can be recommended as a standard treatment.

Underwater versus conventional endoscopic mucosal resection for small size non-pedunculated colorectal polyps: a randomized controlled trial

BackgroundUnderwater endoscopic mucosal resection (UEMR) is a recently developed technique and can be performed during water-aided or ordinary colonoscopy for the treatment of colorectal polyps. The objective of this clinical trial was to evaluate the efficacy and safety of UEMR in comparison with conventional endoscopic mucosal resection (CEMR) of small non-pedunculated colorectal polyps.MethodsPatients with small size, non-pedunculated colorectal polyps (4–9 mm in size) who underwent colonoscopic polypectomy were enrolled in this multicenter randomized controlled clinical trial. The patients were randomly allocated to two groups, an UEMR group and a CEMR group. Efficacy and safety were compared between groups.ResultsIn the intention-to-treat (ITT) analysis, the complete resection rate was 83.1% (59/71) in the UEMR group and 87.3% (62/71) in the CEMR group. The en-bloc resection rate was 94.4% (67/71) in the UEMR group and 91.5% (65/71) in the CEMR group (difference 2.9%; 90% CI − 4.2 to 9.9%), showed noninferiority (noninferiority margin − 5.7% < − 4.2%). No significant difference in procedure time (81 s vs. 72 s, P = 0.183) was observed. Early bleeding was observed in 1.4% of patients in the CEMR group (1/71) and 1.4% of patients in the UEMR group (1/71). None of the patients in the UEMR group complained of postprocedural bloody stool, whereas two patients in the CEMR group (2/64) reported this adverse event.ConclusionOur results indicate that UEMR is safer and just as effective as CEMR in En-bloc resection for the treatment of small colorectal polyps as such, UEMR is recommended as an alternative approach to excising small and non-pedunculated colorectal adenomatous polyps.Trial registrationClinical Trials.gov, NCT03833492. Retrospectively registered on February 7, 2019.

Water immersion-assisted endoscopic en bloc resection for colorectal sessile tumors

Objective To compare the feasibility and efficacy of attempted underwater endoscopic mucosal resection(EMR) with conventional EMR for colorectal sessile or flat tumors. Methods A total of 120 colorectal tumors of 5 to 30 mm in size were removed using underwater EMR or conventional EMR. En bloc resection rates of the two groups were retrospectively analyzed. Results Underwater EMR was performed on 53 colorectal sessile/flat tumors with the median size of 22 mm, and conventional EMR was performed on 67 tumors of the same median size. The overall en bloc resection rate of the underwater EMR group was higher than that of the conventional EMR group(81.1% VS 59.7%, P=0.012). The subgroup analysis showed en bloc resection rates of Paris 0-Ⅱa tumor (76.7% VS 50.0%, P=0.035) and those located at the inaccessible regions (100.0% VS 42.9%, P=0.004) were higher than that of conventional EMR. Neither postoperative bleeding nor perforation occurred in the two groups. Residual adenoma was found in 1 patient in underwater EMR group and 2 in the conventional EMR group, respectively(P=0.712). Conclusion Underwater EMR with prior submucosal injection appears superior to conventional EMR for the removal of colorectal sessile or flat Paris 0-Ⅰs/Ⅱa tumors of less than 3 cm in size in the rate of complete endoscopic resection and defect closure. Key words: Intestinal neoplasms; Endoscopes; Endoscopic mucosal resection; Water-immersion

Endoscopic resection therapies for rectal neuroendocrine tumors: A systematic review and meta‐analysis

Among various endoscopic resection therapies, including conventional endoscopic mucosal resection (EMR) only with a snare after submucosal injection, modified EMR (m-EMR) with other assistant devices such as a ligation band or a suction cap, and endoscopic submucosal dissection (ESD), we aimed to study which is the best choice for rectal neuroendocrine tumors. A broad literature research was performed, and a systematic review and meta-analysis were conducted. Ten retrospective studies with 650 patients were included. Complete resection rates were significantly higher in the ESD group compared with the EMR group (relative risk [RR] 0.89, 95% confidence interval [CI] [0.79, 0.99]), in the m-EMR group compared with the conventional EMR group (RR 0.72, 95% CI [0.60, 0.86]), and was comparable between the ESD group and the m-EMR group (RR 1.03, 95% CI [0.95, 1.11]). Procedure time was significantly longer in the ESD group than in the EMR group (standard mean differences -1.37, 95% CI [-1.99, -0.75]), but there was no significant difference between that of the m-EMR group and ESD group (standard mean differences -1.50, 95% CI [-3.14, 0.14]). Local recurrence occurred in five cases in the EMR group (5/328) and did not occur in the ESD group (0/209). ESD or m-EMR techniques could be applied to rectal neuroendocrine tumors with indications for endoscopic treatment. m-EMR procedures appear to be comparable with ESD in the treatment of rectal neuroendocrine tumors. However, the findings have to be carefully interpreted due to the lower level of evidence.

Tips and Tricks for Better Endoscopic Treatment of Colorectal Tumors: Usefulness of Cap and Band in Colorectal Endoscopic Mucosal Resection

Endoscopic mucosal resection (EMR) is an endoscopic alternative to surgical resection of mucosal and submucosal neoplastic lesions. Prior to the development of knives, EMR could be performed with accessories to elevate the lesion. After the development of various knives, en bloc resection was possible without other accessories. So, recently, simple snaring without suction or endoscopic submucosal dissection using knife in the epithelial lesions such as adenoma or early mucosal cancer has been performed. However, for easy and complete resection of subepithelial lesions such as carcinoid tumor, a few accessories are needed. Complete resection of rectal carcinoid tumors is difficult to achieve with conventional endoscopic resection techniques because these tumors often extend into the submucosa. The rate of positive resection margin for tumor is lower in the group of EMR using a cap (EMR-C) or EMR with a ligation device (EMR-L) than conventional EMR group. EMR-C and EMR-L (or endoscopic submucosal resection with a ligation device) may be a superior method to conventional EMR for removing small rectal carcinoid tumors.

A Comparative Study on Endoscopy Treatment in Rectal Carcinoid Tumors

To investigate the advantages and disadvantages of various endoscopic resection methods for rectal carcinoid tumors. A retrospective analysis of 3 types of endoscopic resection techniques for rectal carcinoid tumors was performed. The surgical time and the complication rate were compared between 30 patients who underwent conventional endoscopic mucosal resection (EMR), cap-assisted endoscopic mucosal resection (EMR-C), or endoscopic submucosal dissection (ESD). All rectal carcinoid tumors were under 1 cm and were treated in our center between January 2002 and January 2008. Ten patients underwent each surgical approach. All cases were pathologically diagnosed as rectal carcinoid tumors. One-time complete resection rates using the conventional EMR, EMR-C, and ESD were 80%, 100%, and 100%, respectively. The operation time ranged from 5 to 53 minutes for the conventional EMR group, from 4 to 7 minutes for the EMR-C group, and from 16 to 35 minutes for the ESD group. The average follow-up time for the 30 patients was 18.43 ± 9.76 months. There were no recurrent or metastatic cases. Endoscopic resection for rectal carcinoid tumors below 1 cm was safe. Considering the clinical efficacy, surgical time, and intraoperative complication rate, EMR-C may be the best endoscopic excision method.

Usefulness of Endoscopic Submucosal Dissection (esd) Versus Conventional EMR for Superficial Gastric Lesions

Usefulness of Endoscopic Submucosal Dissection (esd) Versus Conventional EMR for Superficial Gastric Lesions Manabu Nakagawa, Souichi Nakagawa, Yuichi Shimizu, Mototsugu Kato, Yuji Ono, Takehiko Katsurada, Shoko Ono, Yosuke Miura, Yasuaki Mori, Jyunji Yamamoto, Toshifumi Hayakawa, Yoshito Komatsu, Hiroshi Takeda, Masahiro Asaka Background and Aim: En-bloc resection is desirable for accurate pathological assessment of tissue specimens obtained by endoscopic mucosal resection (EMR). Using a new EMR method, endoscopic submucosal dissection (ESD) method, enbloc resections can be successfully carried out on large superficial gastric lesions greater than 20 mm in diameter. However the rate of complications in patients undergoing ESD is high, and a safe ESD method is therefore needed. To prevent complications, we performed ESD using an injection of sodium hyarulonate with a small-caliber-tip transparent hood (ST hood) attached to the end of the endoscope. This method enables easier submucosal incision. The aim of this study was to evaluate the therapeutic quality of ESD by comparison with the conventional EMR method. Patients and Methods: ESD was performed as follows: 1) placement of markings for the incision line, 2) submucosal injections of sodium hyaluronate under and around the lesion, 3) circumferential mucosal incision around the tumor with an insulated-tip knife (IT knife), and 4) submucosal incision with the needleknife (flat type) through the ST hood. A total of 140 patients with early gastric carcinoma or gastric adenoma were enrolled in this study during the period from 2002 to 2004. They were divided into two groups: a conventional EMR (doublechannel method and endoscopic aspiration mucosectomy) group and an ESD group. Rates of en-bloc resection, curative resection, and complications in the two groups were compared. Results: Seventy-eight cases in the conventional EMR group and 58 cases in the ESD group were finally investigated. There was no significant difference between the two groups in age or sex, but significant differences were found in mean size of the tumor (12.4 G 6.9 cm vs. 26.3 G 13.4 cm; p ! 0.01) and pathological findings (adenoma/carcinoma: 27/51 vs. 6/52; p ! 0.01). The rates of en-bloc resection, curative resection and complications were 52.6% (41/78), 51.3% (40/78) and 9.0% (7/78; bleeding, 5; perforation, 2) in the conventional EMR group and 94.8% (55/58), 93.1% (54/58) and 1.7% (1/58; bleeding, 1) in the ESD group, respectively. The rates of en-bloc resection and curative resection were significantly higher in the ESD group (p ! 0.01), but there was no significant difference between the rates of complications (p Z 0.07) in the two groups. Conclusion: The ESD method for superficial gastric tumors is safe and enables high-quality resection.

Endoscopic Submucosal Dissection May Become a Standard Treatment for Intramucosal Gastric Tumors with Differentiated Type

Background: Endoscopic resection has been accepted as the standard treatments for intramucosal gastric tumors with differentiated type. These days, we have developed endoscopic submucosal dissection (ESD) as a new endoscopic resection technique. In this study, we investigated the feasibility of ESD in comparison with conventional endoscopic mucosal resection (EMR) such as strip biopsy and cap-technique. Methods: We retrospectively analyzed the data of 360 intramucosal gastric tumors with differentiated type in final histology with endoscopic resection at the University Hospital from July 1991 to September 2004. From the data, we investigated an en bloc resection rate, a complete resection rate, and a cumulative local recurrent rate. Complete resection was defined as tumor-free resected margins in lateral and vertical directions even if the lesion was resected with multiple fragments. Statistical analysis was performed by chi-square analysis. Results: Among 360 lesions, 100 and 260 lesions were resected with conventional EMR and ESD, respectively. En bloc resection rates were 55% (55/100) and 92.7% (241/260) in the conventional EMR group and the ESD group, respectively (p < 0.05). Complete resection rates were 68% (68/100) and 91.9% (239/260) in the conventional EMR group and the ESD group, respectively (p < 0.05). Furthermore, 13 lesions recurred locally, not in metastatic area, in the conventional EMR group and, on the contrary, none recurred in the ESD group. Conclusions: ESD results in far excellent en bloc and complete resection rates in comparison with conventional EMR. Background: Endoscopic resection has been accepted as the standard treatments for intramucosal gastric tumors with differentiated type. These days, we have developed endoscopic submucosal dissection (ESD) as a new endoscopic resection technique. In this study, we investigated the feasibility of ESD in comparison with conventional endoscopic mucosal resection (EMR) such as strip biopsy and cap-technique. Methods: We retrospectively analyzed the data of 360 intramucosal gastric tumors with differentiated type in final histology with endoscopic resection at the University Hospital from July 1991 to September 2004. From the data, we investigated an en bloc resection rate, a complete resection rate, and a cumulative local recurrent rate. Complete resection was defined as tumor-free resected margins in lateral and vertical directions even if the lesion was resected with multiple fragments. Statistical analysis was performed by chi-square analysis. Results: Among 360 lesions, 100 and 260 lesions were resected with conventional EMR and ESD, respectively. En bloc resection rates were 55% (55/100) and 92.7% (241/260) in the conventional EMR group and the ESD group, respectively (p < 0.05). Complete resection rates were 68% (68/100) and 91.9% (239/260) in the conventional EMR group and the ESD group, respectively (p < 0.05). Furthermore, 13 lesions recurred locally, not in metastatic area, in the conventional EMR group and, on the contrary, none recurred in the ESD group. Conclusions: ESD results in far excellent en bloc and complete resection rates in comparison with conventional EMR.