A novel method of endoscopic mucosal resection using sodium hyaluronate

A prospective randomized trial of lafutidine vs rabeprazole on post-ESD gastric ulcers

AIM: To compare the effects of rabeprazole and lafutidine on post-endoscopic submucosal dissection (ESD) gastric ulcers.

METHODS: Patients with gastric tumors indicated for ESD were prospectively studied. After ESD, all patients were treated with intravenous omeprazole for the first 3 d. Patients were then randomly assigned to oral lafutidine or rabeprazole. Ulcer size, ulcer size reduction rate, and ulcer stage were evaluated 4 wk later. Occurrence of complication was monitored throughout the 4-wk period.

RESULTS: Sixty five patients were enrolled in the study, and 60 patients were subjected to the final analysis. In the lafutidine group (30 lesions in 29 patients), initial and 4-wk post-ESD ulcer sizes were 33.3 ± 9.2 and 10.5 ± 4.8 mm, respectively. In the rabeprazole group (34 lesions in 31 patients), the values were 34.7 ± 11.3 and 11.8 ± 6.7 mm, respectively. Ulcer size reduction rates in lafutidine and rabeprazole groups were 32.3% and 33.5%, respectively (P = 0.974). Ulcer stage 4 wk post-ESD did not differ significantly between the two groups (P = 0.868). Two cases in the rabeprazole group and no cases in the lafutidine group developed ulcer bleeding during the oral dose period, although the difference of bleeding rate between the two groups was not statistically significant (P = 0.157).

CONCLUSION: Lafutidine and rabeprazole have equivalent therapeutic effects on post-ESD gastric ulcers.

A comparison of outcomes of endoscopic submucosal dissection (ESD) For early gastric neoplasms between high-volume and low-volume centers: multi-center retrospective questionnaire study conducted by the Nagano ESD Study Group

OBJECTIVE

Outcomes of endoscopic submucosal dissection (ESD) for early gastric neoplasms at low-volume centers have been unknown, because all previous reports have studied in advanced single centers. The aim of this study was to compare ESD outcomes between high- and low-volume centers.

METHODS

A retrospective questionnaire survey was conducted and 30 centers (96.8%) responded. The complete en-bloc resection rate (CERR) and the incidence of complications were analyzed. Early gastric cancer (EGC) was divided into three categories on the basis of pathological diagnosis-standard indication (SI), expanded indication (EI) and out-of-indication (OI).

RESULTS

A total of 703 early gastric neoplasms (586 EGCs, 117 gastric adenomas) were treated with ESD from January to December 2005. The institutions that treated more than 30 cases a year were classified as high-volume centers, and those with less than 30 cases, low-volume centers. In SI, the CERRs at high- and low-volume centers were 92.1% and 91.1%, in EI, CERRs were 86.2% and 82.6% and in OI, CERRs were 80.3% and 88.0%. The perforation rates at high- and low-volume centers were 3.6% and 4.7%. The intra-operative bleeding rates at high- and low-volume centers were 0.26% and 0%, while the delayed bleeding rates were 0% and 0.63%.

CONCLUSION

There were no significant difference in the outcomes of ESD for early gastric neoplasms between high- and low volume centers.

Endoscopic mucosal resection and endoscopic submucosal dissection for esophageal dysplasia and carcinoma

Advanced cancer in the esophagus is a serious and fatal disease that invades locally to deeper layers of the esophageal wall with significant risk of nodal metastasis and invasion of adjacent organs. One reliable method of avoiding this is to detect lesions at an early stage of esophageal cancer and then to resect them locally. A major advantage of endoscopic local resection is to recover a specimen for histopathologic analysis, which helps to make a clinical decision for further therapy. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have already been established as the techniques of endoscopic local resection. EMR includes strip-off biopsy, double-channel techniques, cap technique, EMR using a ligating device, and so on. ESD is a newly developed technique in which submucosal dissection is carried out using an electrocautery knife to acquire a single-piece specimen.

Endoscopic mucosal resection and endoscopic submucosal dissection for early gastric cancer: Current and original devices

Compared with endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR) is easier to perform and requires less time for treatment. However, EMR has been replaced by ESD, because achieving en bloc resection of specimens > 20 mm in diameter is difficult with EMR. The technique of ESD was introduced to resect large specimens of early gastric cancer in a single piece. ESD can provide precise histological diagnosis and can also reduce the rate of recurrence, but has a high level of technical difficulty, and is consequently associated with a high rate of complications, a need for advanced endoscopic techniques, and a lengthy procedure time. To overcome disadvantages in both EMR and ESD, various advances have been made in submucosal injections, knives, other accessories, and in electrocoagulation systems.

Endoscopic submucosal dissection for superficial duodenal neoplasms

Endoscopic submucosal dissection (ESD) has emerged as a novel technique for achieving en bloc resection for superficial neoplasms limited to the mucosa. ESD was originally developed in Japan as a method of endoscopic resection of superficial gastric cancers. In our hospital, ESD has been used concurrently in other parts of the gastrointestinal tract, including the esophagus and colorectum from the beginning of its development. However, ESD in the duodenum is considered more challenging than other parts. From August 2005 to March 2008, a total of 15 superficial duodenal neoplastic lesions in 14 patients were treated with endoscopic resection. Of these, nine underwent ESD. We report our experience with duodenal ESD with a combination of ST hood and hook knife.

Endoscopic submucosal dissection for colorectal tumors

BACKGROUND

Endoscopic submucosal dissection (ESD) is a state-of-the-art method that enables resection of larger tumors than those resectable by conventional endoscopic mucosal resection (EMR). However, the individual role of each method in the treatment of colorectal tumors remains undetermined.

OBJECTIVE AND METHODS

To consider the respective indications of ESD and EMR for colorectal tumors, we analyzed the results of the two treatments retrospectively.

RESULTS

Tumors treated by ESD (44 tumors) were significantly larger, more often located in the rectum and more often coexistent with cancer than those treated by EMR (512 tumors). EMR was used in the majority of adenomas, and showed high rates of both one-piece resection (OPR) and complete resection (CR) for adenomas less than 20 mm. However, for adenomas and cancers greater or equal to 20 mm, the CR rate for EMR was significantly lower than that for ESD because of the incidence of OPR with a positive lateral margin (16% vs 0% with ESD vs EMR). Histopathology (cancer), size (> or =20 mm) and macroscopic type (laterally spreading tumors) were shown to be significant risk factors for that incidence. For tumors with these factors, ESD showed a higher CR rate than did EMR. However, ESD required longer operating times and tended to have a higher rate of perforation compared with EMR. ESD was aborted halfway in seven cases due to technical difficulties and perforation.

CONCLUSION

ESD and EMR have different characteristics as treatment for colorectal tumors. Careful evaluation of the lesion and of the balance between benefits and risks are mandatory before selecting either of these treatments for colorectal tumors.

Endoscopic submucosal dissection with a combination of small-caliber-tip transparent hood and flex knife is a safe and effective treatment for superficial esophageal neoplasias

BACKGROUND

Superficial esophageal neoplasias resected in piecemeal manner with endoscopic mucosal resection (EMR) sometimes recur locally, and additional treatments need to be developed. Efficacy and safety of endoscopic submucosal dissection (ESD) for esophageal neoplasias are not sufficiently demonstrated, so we conducted a retrospective study to evaluate the efficacy and safety of ESD for superficial esophageal neoplasias.

METHODS

Thirty-seven superficial esophageal neoplasias consisted of 34 squamous cell neoplasias and 3 columnar neoplasias in 35 patients were treated with ESD from May 2006 to July 2008. Patients were regularly followed up with endoscopy every 6 months, and with echoendoscope and computed tomography every year. Therapeutic efficacy, complications, and follow-up results were evaluated.

RESULTS

The mean size of the resected neoplasias and that of the resected specimens were 22 mm (range 10-83 mm) and 41 mm (range 18-90 mm), respectively. The mean duration of the ESD procedures was 117 min (range 40-235 min). The overall rates of en bloc resection and of free margin resection were 100% (37/37) and 95% (35/37), respectively. The mean follow-up period of 19 months (range 7-32 months) revealed no local or distant recurrence. There were no complications such as bleeding or perforation in any case. In all nine cases, the strictures were successfully managed with prophylactic endoscopic balloon dilation.

CONCLUSIONS

ESD with a combination of small-caliber-tip transparent hood and flex knife is a safe endoscopic treatment for superficial esophageal neoplasias and enables large en bloc resection.

Endoscopic submucosal dissection with a combination of small-caliber-tip transparent hood and flex knife is a safe and effective treatment for superficial esophageal neoplasias

BACKGROUND

Superficial esophageal neoplasias resected in piecemeal manner with endoscopic mucosal resection (EMR) sometimes recur locally, and additional treatments need to be developed. Efficacy and safety of endoscopic submucosal dissection (ESD) for esophageal neoplasias are not sufficiently demonstrated, so we conducted a retrospective study to evaluate the efficacy and safety of ESD for superficial esophageal neoplasias.

METHODS

Thirty-seven superficial esophageal neoplasias consisted of 34 squamous cell neoplasias and 3 columnar neoplasias in 35 patients were treated with ESD from May 2006 to July 2008. Patients were regularly followed up with endoscopy every 6 months, and with echoendoscope and computed tomography every year. Therapeutic efficacy, complications, and follow-up results were evaluated.

RESULTS

The mean size of the resected neoplasias and that of the resected specimens were 22 mm (range 10-83 mm) and 41 mm (range 18-90 mm), respectively. The mean duration of the ESD procedures was 117 min (range 40-235 min). The overall rates of en bloc resection and of free margin resection were 100% (37/37) and 95% (35/37), respectively. The mean follow-up period of 19 months (range 7-32 months) revealed no local or distant recurrence. There were no complications such as bleeding or perforation in any case. In all nine cases, the strictures were successfully managed with prophylactic endoscopic balloon dilation.

CONCLUSIONS

ESD with a combination of small-caliber-tip transparent hood and flex knife is a safe endoscopic treatment for superficial esophageal neoplasias and enables large en bloc resection.

Efficacy of a reverse-phase polymer as a submucosal injection solution for EMR: a comparative study (with video)

INTRODUCTION

Reverse-phase polymers undergo a temperature-dependent liquid-to-gel transition that may provide a more durable cushion for EMR and could yield improvements in safety and efficacy.

OBJECTIVE

Our purpose was to assess the efficacy of poloxamer solution PS137-25 as a submucosal injection.

DESIGN

Comparative study among 3 different solutions for EMR using ex vivo and in vivo porcine models.

INTERVENTIONS

A total of 120 gastric submucosal cushions were performed in fresh ex vivo porcine stomachs with saline solution 0.9% (n = 40), hydroxypropyl methylcellulose (HPMC) (n = 40), and PS137-25 (n = 40). Five in vivo porcine colon EMRs were then performed.

MAIN OUTCOME MEASUREMENTS

Height and duration of submucosal cushions were measured in the ex vivo model, and the usefulness of reverse-phase polymers was assessed by in vivo en bloc resection.

RESULTS

Ex vivo: The height of mucosal elevation was greater with PS137-25 (10.3 +/- 2.2 mm) than with saline solution (8.3 +/- 2.6 mm) or HPMC (9.05 +/- 2.3 mm, not significant). All submucosal elevations with PS137-25 lasted longer (more than 20 minutes) than with saline solution (20.9 +/- 11 minutes, P < .01) or HPMC (89 +/- 32 minutes, P < .01). After 120 minutes, the elevations obtained with PS137-25 showed no differences in size, shape, or consistency from initial measurements. In vivo: All 5 EMRs were successfully performed after 1 injection of PS137-25. No repeat injections were needed. During resection, a large gel cushion was noted.

CONCLUSIONS

Mucosal elevation with PS137-25 is more durable than with other substances, with no changes in size or consistency observed over 120 minutes. Additionally, reverse-phase polymers performed well in in vivo colon EMRs. These results suggest that reverse-phase polymers may provide increased safety and efficacy for EMR procedures.

Technical feasibility of endoscopic submucosal dissection of gastrointestinal epithelial neoplasms with a splash-needle

Endoscopic submucosal dissection (ESD) permits the resection of large gastrointestinal epithelial neoplasms and neoplasms with submucosal fibrosis in an en bloc manner. However, the high frequency of complications accompanying ESD and its complex processes suggests that the process requires improvement. A total of 22 consecutive patients with gastrointestinal epithelial neoplasms were enrolled during a 6-month period to evaluate a novel endosurgical knife for ESD. This novel knife is known as the "splash-needle," and it is thin, short needle with a water-irrigation function. The technical results revealed that the rates of bloc resection and en bloc resection with tumor-free lateral/basal margins (R0 resection) were 91% (20/22) and 82% (18/22), respectively. There was no significant bleeding or perforation during or after ESD. The median operation time was 60 minutes (range, 20 to 210). The splash-needle is a promising novel endosurgical knife that is useful for less complicated ESD. The accumulation of knowledge and cases verifying its usefulness is necessary, and a study comparing the knife with first-generation endosurgical knives is also warranted.

Double-balloon endoscopy: past, present, and future

Double-balloon endoscopy (DBE) was developed as a new technique for visualization of and intervention in the entire small intestine. In DBE, the intestinal walls are held apart by a balloon attached to the distal end of a soft overtube. DBE has been reported worldwide to be very useful for not only diagnosis but also endoscopic therapy. Biopsy samples of small intestinal tumors can be obtained using DBE, and the appropriate treatment can be selected before a surgical procedure. For inflammatory diseases, DBE can reveal the localization of ulcers in the lumen (on the mesenteric or antimesenteric side), which is important for differential diagnosis. Some endoscopic therapies such as hemostatic procedures, polypectomy, and dilation therapy for benign strictures can be performed in the same manner as in the large intestine. DBE may also be suitable for colonoscopy for difficult insertion cases and therapeutic procedures such as endoscopic submucosal dissection. Furthermore, a double-balloon endoscope can be selectively inserted into the afferent loop to perform endoscopic retrograde cholangiopancreatography in patients with Roux-en-Y anastomosis, allowing various kinds of endoscopic treatments for biliary diseases to be successfully performed. Endoscopic therapy in the small intestine, whose wall is very thin, should be performed with special care to avoid complications such as bleeding and perforation. In the future, improvement is expected in terms of maneuverability, therapeutic capability, and imaging technology such as the addition of a magnifying function and flexible spectral imaging color enhancement. We anticipate that DBE will contribute to the establishment of medical science of the small intestine and to research elucidating the mechanisms of small intestinal diseases.

Submucosal injection solution for gastrointestinal tract endoscopic mucosal resection and endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have provided new alternatives for minimally invasive treatment of gastrointestinal adenomas and early-stage cancers that involve a minimum risk of lymph-node metastasis. The use of submucosal injections is essential to the success of these endoscopic resection techniques. The “ideal” submucosal injection solution should provide a sufficiently high submucosal fluid cushion for safe and effective EMRs and ESDs while also preserving lesion tissue for accurate histopathological assessment. In the past, normal saline (NS) solution was commonly used for this purpose, but it is difficult to achieve the proper submucosal elevation and maintain the desired height with NS. Therefore, other safe and effective facilitative submucosal injection solutions have been developed that also take into account relevant cost-benefit considerations. This review examines recent advances in the development of effective submucosal injection solutions for use during endoscopic resections.

A comparative study of 50% dextrose and normal saline solution on their ability to create submucosal fluid cushions for endoscopic resection of sessile rectosigmoid polyps

BACKGROUND

EMR traditionally performed by using normal saline solution (NS) plus epinephrine (E) as a submucosal fluid cushion does not maintain the submucosal elevation for a prolonged time. It was hypothesized that 50% dextrose (D(50)) plus E as a hypertonic, inexpensive, and easily available solution might be an ideal alternative for producing and maintaining more-prolonged mucosal elevation.

OBJECTIVE

To evaluate D(50)+E versus NS+E during an EMR of sessile rectosigmoid polyps (> 10 mm).

DESIGN

A prospective, double-blind, randomized study that compared EMR by using either D(50)+E or NS+E submucosal fluid cushions.

SETTING

Four tertiary endoscopic referral centers with 1370 polypectomies in 2006, performed by 5 experienced endoscopists.

PATIENTS

Patients treated for sessile rectosigmoid polyps (> 10 mm).

INTERVENTIONS

Polypectomy with D(50)+E or NS+E submucosal fluid cushions.

MAIN OUTCOME MEASUREMENTS

The duration of submucosal elevation, volume of solution, number of required injections to maintain the elevation, and observations for complications.

RESULTS

Ninety-two sessile rectosigmoid polyps were removed. Injected solution volumes and the number of injections to maintain submucosal elevation were lower in the D(50)+E group than in the NS+E group (P = .033 and P = .028, respectively). Submucosal elevation had a longer duration in the D(50)+E group (P = .043). This difference mainly included large (> or = 20 mm) and giant (> 40 mm) polyps. There were 6 and 1 cases of postpolypectomy syndrome in the D(50)+E and NS+E groups, respectively (P = .01).

LIMITATIONS

May be limited by inexperienced endoscopist's lack of injection and polypectomy skills.

CONCLUSIONS

D(50)+E is superior to NS+E for an EMR, particularly in large and giant sessile polyps, but the risk of thermal tissue injury should be considered.

Chromoendoscopy with indigo carmine dye added to acetic acid in the diagnosis of gastric neoplasia: a prospective comparative study

BACKGROUND

Conventional endoscopy and chromoendoscopy with indigo carmine dye are usually performed for recognizing adequate tumor-negative lateral margins for successful endoscopic resection of gastric neoplasia. However, chromoendoscopy with indigo carmine dye added to acetic acid has not been used for this purpose.

OBJECTIVE

Our purpose was to compare the diagnostic performance of chromoendoscopy with indigo carmine dye added to acetic acid with that of conventional endoscopy and chromoendoscopy with indigo carmine dye or acetic acid alone.

DESIGN

Prospective study.

SETTING

Social Insurance Funabashi Central Hospital.

PATIENTS

Forty-seven consecutive patients (53 lesions) with early gastric cancer and gastric adenomas who underwent endoscopic submucosal dissection (ESD) from April 2006 to July 2007 were studied.

INTERVENTIONS

All the lesions were examined by the endoscopic modalities before ESD, and the resected specimens were analyzed histopathologically.

MAIN OUTCOME MEASUREMENTS

Two endoscopists independently evaluated the diagnostic performance of each image in terms of recognition of tumor borders with reference to macroscopic and histopathologic findings of resected specimens. We also conducted a substudy to assess interobserver variability.

RESULTS

There was good interobserver agreement between the 2 endoscopists in this study (kappa index = 0.764). The diagnostic performance of chromoendoscopy with indigo carmine dye added to acetic acid was significantly greater than that of any of the other modalities (vs each: P < .005).

CONCLUSIONS

The diagnostic performance of chromoendoscopy with indigo carmine dye added to acetic acid was better compared with conventional endoscopy and chromoendoscopy by using only indigo carmine dye or acetic acid. The applicability of this method for gastric neoplasia merits further investigation.

Does hyaluronic acid stimulate tumor growth after endoscopic mucosal resection?

BACKGROUND AND AIM

A submucosal injection of sodium hyaluronate is widely used for mucosal elevation in endoscopic mucosal resection (EMR) or endoscopic submucosal dissection procedures; however, the oncologic safety of sodium hyaluronate remains unknown. Hyaluronate is the main ligand for CD44 and this interaction was reported to promote tumor progression in in vitro or animal studies. This study aimed to evaluate the effects of sodium hyaluronate on tumor growth after EMR for gastrointestinal cancers.

METHODS

The study included 18 consecutive patients who underwent surgery for locally-recurrent or remnant gastrointestinal cancers after EMR from January 2001 to December 2006. The immunohistochemical expression levels of Ki-67, CD44, ErbB2, and epidermal growth factor receptor (EGFR) were evaluated in the primary tumor tissue and the recurrent tumor. The protein expression in recurrent or remnant lesions was also compared between the sodium hyaluronate group and non-sodium hyaluronate group.

RESULTS

Sodium hyaluronate was used in nine of 14 cases with EMR for gastric cancers and in one of four cases for colon cancers. The time to operation after EMR was 133 days (5-687 days). An analysis of the immunohistochemical expression levels between primary and recurrent or remnant tumors showed no significant differences in the expression levels of Ki-67, CD44, ErbB2, and EGFR with or without sodium hyaluronate.

CONCLUSIONS

We found no evidence that sodium hyaluronate stimulates the growth of remnant tumors after EMR.

Electrical characteristics of various submucosal injection fluids for endoscopic mucosal resection

Submucosal fluid injection, prerequisite to endoscopic mucosal resection, necessitates detailed evaluation for proper selection. We aimed to compare height of gastric tissues after submucosal injection, and to verify electrical implications of injectants. Porcine stomach pieces were cut out, and eight solutions were used: normal saline, 0.5% sodium hyaluronate (SH), 0.25% SH, hydroxypropyl methylcellulose, 10% glycerin, fibrinogen, 1% sodium alginate (SA), and 2.5% SA. Elevated heights were measured after submucosal injection of the eight fluids, and electrical impedance was measured for fluids plus a reference solution (0.01 N KCl) with a potentiostat electroimpedance spectrometry and an insulation-tipped knife. Resistivity was calculated thereafter. Normal saline and 10% glycerin solution showed greater height diminution. Resistivity were in the range of 80-110 Omega cm, except for 309.7 Omega cm for fibrinogen. Higher resistivity may improve performance of electrosurgery, probably by strengthening impedance and heat dissipation. Further studies are required to back up this basic experiment for clinical application.

Endoscopic submucosal dissection for gastrointestinal neoplasms

Endoscopic submucosal dissection (ESD) is an advanced technique of therapeutic endoscopy for superficial gastrointestinal neoplasms. Three steps characterize it: injecting fluid into the submucosa to elevate the lesion, cutting the surrounding mucosa of the lesion, and dissecting the submucosa beneath the lesion. The ESD technique has rapidly permeated in Japan for treatment of early gastric cancer, due to its excellent results of en-bloc resection compared to endoscopic mucosal resection (EMR). Although there is still room for improvement to lessen its technical difficulty, ESD has recently been applied to esophageal and colorectal neoplasms. Favorable short-term results have been reported, but the application of ESD should be well considered by three aspects: (1) the possibility of nodal metastases of the lesion, (2) technical difficulty such as location, ulceration and operator’s skill, and (3) organ characteristics.

Usefulness and safety of 0.4% sodium hyaluronate solution as a submucosal fluid "cushion" in endoscopic resection for gastric neoplasms: a prospective multicenter trial

BACKGROUND

Sodium hyaluronate (SH) solution has been used for submucosal injection in endoscopic resection to create a long-lasting submucosal fluid "cushion."

OBJECTIVES

Our purpose was to assess the usefulness and safety of 0.4% SH solution in endoscopic resection.

DESIGN

A prospective multicenter randomized controlled trial.

SETTING

Six referral hospitals in Japan.

PATIENTS

One hundred forty patients with 5- to 20-mm gastric intramucosal neoplastic lesions.

INTERVENTIONS

Patients were randomized into 0.4% SH and control groups. Endoscopic resection was performed with 0.4% SH or normal saline solution for submucosal injection.

PRIMARY OUTCOME MEASURE

The usefulness of 0.4% SH solution was assessed by en bloc complete resection and the formation and maintenance of mucosal lesion-lifting during endoscopic resection.

SECONDARY OUTCOME MEASURES

(1) steepness of mucosal lesion lifting, (2) complications, (3) time required for mucosal resection, (4) volume of submucosal injection solution, and (5) ease of mucosal resection. Safety was assessed by analyzing adverse events during the study period.

RESULTS

The usefulness rate was significantly higher for the 0.4% SH group (88.4%, 61/69) than for the control group (58.6%, 41/70). As secondary outcome measures, significant intergroup differences (P < .001) were noted for (1) steepness of mucosal lesion lifting, (2) volume of submucosal injection solution, and (3) ease of mucosal resection. No serious adverse events were encountered in either group.

LIMITATIONS

Lack of blinding. Safety was not a powered outcome measure.

CONCLUSIONS

Using 0.4% SH as a submucosal injection solution in endoscopic resection enabled the formation and maintenance of sufficient mucosal lesion lifting for gastric intramucosal lesions, reducing the need for additional injections and simplifying mucosal resection. Use of 0.4% SH thus simplifies the complicated procedures involved in endoscopic resection.

Endoscopic mucosal resection of colonic lesions: current applications and future prospects

The introduction of submucosal fluid injection has remarkably extended the range of endoscopically resectable polyps. The limiting factor for endoscopic resection is not polyp size, but polyp depth. Endoscopic ultrasound is a useful adjunctive diagnostic tool to assess the depth of invasion. The success of are section ultimately depends on pathologic confirmation of a benign nature of this lesion or of a cancer limited to the mucosa. Selected well-differentiated cancers without lymphovascular invasion of the superficial submucosa can be successfully resected endoscopically.

Treatment of gastric remnant cancer post distal gastrectomy by endoscopic submucosal dissection using an insulation-tipped diathermic knife

AIM: To evaluate the effectiveness of endoscopic submucosal dissection using an insulation-tipped diathermic knife (IT-ESD) for the treatment of patients with gastric remnant cancer.

METHODS: Thirty-two patients with early gastric cancer in the remnant stomach, who underwent distal gastrectomy due to gastric carcinoma, were treated with endoscopic mucosal resection (EMR) or ESD at Sumitomo Besshi Hospital and Shikoku Cancer Center in the 10-year period from January 1998 to December 2007, including 17 patients treated with IT-ESD. Retrospectively, patient backgrounds, the one-piece resection rate, complete resection (CR) rate, operation time, bleeding rate, and perforation rate were compared between patients treated with conventional EMR and those treated with IT-ESD.

RESULTS: The CR rate (40% in the EMR group vs 82% in the IT-ESD group) was significantly higher in the IT-ESD group than in the EMR group; however, the operation time was significantly longer for the IT-ESD group (57.6 ± 31.9 min vs 21.1 ± 12.2 min). No significant differences were found in the rate of underlying cardiopulmonary disease (IT-ESD group, 12% vs EMR group, 13%), one-piece resection rate (100% vs 73%), bleeding rate (18% vs 6.7%), and perforation rate (0% vs 0%) between the two groups.

CONCLUSION: IT-ESD appears to be an effective treatment for gastric remnant cancer post distal gastrectomy because of its high CR rate. It is useful for histological confirmation of successful treatment. The long-term outcome needs to be evaluated in the future.

Endoscopic mucosal resection in the upper gastrointestinal tract

Endoscopic mucosal resection (EMR) is a technique used to locally excise lesions confined to the mucosa. Its main role is the treatment of advanced dysplasia and early gastrointestinal cancers. EMR was originally described as a therapy for early gastric cancer. Recently its use has expanded as a therapeutic option for ampullary masses, colorectal cancer, and large colorectal polyps. In the Western world, the predominant indication for EMR in the upper gastrointestinal tract is the staging and treatment of advance dysplasia and early neoplasia in Barrett’s esophagus. This review will describe the basis, indications, techniques, and complications of EMR, and its role in the management of Barrett’s esophagus.

Submucosal cushioning with water jet before endoscopic mucosal resection : Which fluids are effective?

BACKGROUND

Several new techniques have recently been described that allow the endoscopic mucosal resection even of broad-based flat lesions in the gastrointestinal tract. The technique recently described by us of using a water jet dissector (Helix HydroJet) for a selective deposition of liquid in the submucosal lamina has now been combined with different substances, and their effects have been compared.

MATERIAL AND METHODS

Gastroscopies were carried out in 8 pigs under intubation anesthesia, and 2 submucosal cushions each were created in the stomach using one out of 4 test substances (gelatin, glucose 50, hydroxyethyl starch [HES] 10%, dextran 40), as well as one cushion of isotonic saline solution placed in each area via the Helix HydroJet). The height of the submucosal cushions was intermittently measured over a period of 40 or 20 min, respectively, by miniprobe endosonography. In 7 of the animals the stomach was subsequently subjected to mucosal resection. The specimens and the gastric wall were histologically assessed to evaluate the localization of the liquid cushion and the effect on adjacent layers of the gastric wall.

RESULTS

All test substances produced strictly selective liquid cushions in the submucosa. With HES 10% and dextran the maximum height of the cushions initially increased and then decreased during the further course to an average of 90% of the initial height within 40 min. Isotonic saline solution showed the most rapid decrease in height (72% after 20 min). The histological assessment confirmed the selective nature of the liquid deposit in the submucosa.

DISCUSSION

Plasma expanders produced cushions that initially increased in height but then remained constant for a longer period than cushions produced using glucose 50, gelatin, or isotonic saline solution. The combination of transmucosal jet application for elevation of the mucosa with plasma expanders is therefore an interesting approach to optimize endoscopic mucosal resections.

A prospective randomized trial of either famotidine or pantoprazole for the prevention of bleeding after endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) has been reported to have a higher bleeding rate than conventional methods. However, there are few reports on whether a proton pump inhibitor or a histamine2-receptor antagonist is the more effective treatment for preventing bleeding after ESD. In a prospective trial, patients undergoing ESD due to gastric adenoma or adenocarcinoma were randomly assigned to pantoprazole or famotidine. Both drugs were given intravenously for the first 2 days, thereafter by mouth. Eighty-five in the pantoprazole group and 79 in the famotidine group were included for analysis. Primary outcome measure was the delayed bleeding rate. Clinical characteristics were not different between the two groups. The delayed bleeding rate was significantly lower in the pantoprazole group compared with the famotidine group (3.5% vs. 12.7%, p=0.031). On multivariate analysis, the preventive use of pantoprazole (relative hazard: 0.220, 95% CI: 0.051- 0.827, p=0.026) and the specimen size (> or =34 mm, relative hazard: 4.178, 95% CI: 1.229-14.197, p=0.022) were two independent factors predictive of delayed bleeding. There were no significant differences in en bloc and complete resection rate between the two groups. In conclusion, pantoprazole is more effective than famotidine for the prevention of delayed bleeding after ESD.

Submucosal glycerol injection-assisted laser surgical treatment of oral lesions

Recently, we modified laser surgery for superficial lesions in the oral cavity by using submucosal glycerol injection. This procedure was based on a technique for endoscopic mucosal resection (EMR) in the gastrointestinal tract. The aim of this study was to evaluate the effectiveness of the modified laser surgery assisted by a submucosal glycerol injection. Eleven superficial oral lesions in ten patients were treated with diode laser (continuous wave mode, 3 W) after a submucosal injection of glycerol solution. Injection of glycerol solution created mucosal expansion, which enabled the procedures to be done without bleeding, over cutting, over coagulation and unintended irradiation. The surface of the wounds showed little carbonization, resulting in good healing. Submucosal glycerol injection for laser treatment in the oral cavity is a promising technique for treating superficial oral lesions by virtue of less invasion and good results.

Autologous blood as a submucosal fluid cushion for endoscopic mucosal therapies: results of an ex vivo study

OBJECTIVE

Submucosal injection of fluid is used to elevate lesions in order to prevent perforation, which is the most calamitous complication during endoscopic resection therapies. There are several injection options when performing mucosal elevation (normal saline (NS), sodium hyaluronate (SH), etc.). Submucosal injection of fresh, autologous blood offers some advantages because of its specific properties: corpuscular components ensure prolonged elevation and procoagulatory constituents prevent post-interventional bleeding. The purpose of this study was to compare the ex vivo performance of autologous blood as a submucosal fluid cushion (SFC) with that of NS, SH and DW (dextrose water).

MATERIAL AND METHODS

The proximal third of a resected porcine stomach was cut into squares. One millilitre NS, DW, SH and fresh porcine blood was injected into the submucosa. The height and duration of the submucosal injections were objectively measured during 1 h. Mucosal elevations were resected using an electro snare.

RESULTS

The initial height and width of the mucosal elevations were comparable for SH and blood, and significantly higher compared with NS and DW. Mucosal elevation after injecting autologous blood persisted significantly longer compared with NS (p <0.05), but did not differ from hyaluronate. Histopathological examination of the resected specimen confirmed the appropriate submucosal injection of these substances.

CONCLUSIONS

Submucosal injection of autologous blood with a standard endoscopic injection needle is possible and generates adequate mucosal elevation for the resection of high-quality specimens. This procedure could offer a "gratis" option for SFC as opposed to the expensive SH. Further clinical studies are needed to substantiate its use.

Technology insight: endoscopic submucosal dissection of gastrointestinal neoplasms

Gastrointestinal neoplasms can be cured by local resection as long as the lesions are in the early stage and have not metastasized. Endoscopic resection is a minimally invasive treatment for early-stage gastrointestinal neoplasms, and endoscopic submucosal dissection (ESD) is one type of endoscopic resection that has been developed in the past 10 years. For ESD to be a reliable, curative treatment for gastrointestinal neoplasms, it is necessary for the endoscopist to detect the lesion early, make a precise pretreatment diagnosis, ensure that the patient has the correct indication for endoscopic resection, and have the skill to perform ESD. For early lesion detection, endoscopists should pay attention to subtle changes in the surface structure, the color of the mucosa and the visibility of underlying submucosal vessels. Chromoendoscopy and magnifying endoscopy are useful for determining the margin of the lesions for pretreatment diagnosis, and endoscopic ultrasonography and magnifying endoscopy are useful for determining the depth of invasion. For ESD to be successful, local injection of sodium hyaluronate helps maintain mucosal elevation during dissection. Selecting the appropriate knife, using transparent hoods wisely, employing a good strategy that uses gravity, and having good control of bleeding are all needed to make ESD reliable.

State of the art on endoscopic mucosal resection and endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) provide new alternatives for minimally invasive treatment of superficial gastrointestinal malignancies. Evidence suggests that these techniques can be performed safely and have comparable outcomes to surgery with less morbidity and better quality of life due to their tissue-sparing nature when compared with conventional surgery. Although the techniques and accessories have become standardized, there is room for improvement, and further research and development are required. Current challenges facing American gastroenterologists or endoscopic surgeons include access to training and lack of appropriate reimbursement for these heavy-weighted and technically demanding procedures. Nevertheless, EMR and ESD are here to stay and are only the first steps toward true radical endoluminal resection of GI malignancies.

Novel techniques and instrumentation for EMR, ESD, and full-thickness endoscopic luminal resection

Endoscopic intervention is evolving into an established therapeutic alternative for small superficial lesions, and an eventual application for en bloc resection of large lesions, deeper layers, and a reliable access to lesions outside of the gastrointestinal wall. Although further developmental and clinical evaluation is necessary, we believe endoscopic resection by the submucosal route and by full-thickness approaches will replace standard surgical procedures in the next several years.

Effectiveness of sodium alginate as a submucosal injection material for endoscopic mucosal resection in animal

BACKGROUND/AIMS

Although various solutions are being tested for submucosal injection during endoscopic resection, ideal solution has not been established yet. We performed an animal study to evaluate the possibility of sodium alginate as an ideal submucosal injection solution for endoscopic mucosal resection (EMR).

METHODS

To compare the lesion-lifting properties of different solutions, injection was done to the submucosal layer of porcine stomach. Then the height of mucosal elevation was measured. In addition, EMR was performed after submucosal injection of sodium alginate solution in six dogs. Two were euthanized after 30 minutes of endoscopic observation while the others were euthanized after 1-4 weeks. Retrieved stomachs were examined microscopically.

RESULTS

Sodium alginate and sodium hyaluronate solutions maintained longer elevation of the submucosal layer than other solutions. There was no significant difference in the height between two solutions. A clear separation of the mucosal layer from the proper muscle layer was achieved by injecting sodium alginate solution. Histological examination of EMR-induced artificial ulcers revealed no apparent tissue damage and showed normal healing process.

CONCLUSIONS

Sodium alginate solution creates a sufficient submucosal fluid cushion without apparent tissue damage. It can be considered as an effective submucosal injection material.

Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection

BACKGROUND/AIM

Numerous new techniques have recently been reported and described for the endoscopic mucosal resection of large superficial lesions of the gastrointestinal tract. We present here for the first time the application of a water jet dissector for mucosa elevation.

MATERIALS AND METHODS

In an ex vivo study, the effectiveness of a water jet dissector (Helix Hydro-Jet) placed directly on the stomach walls of 8 pigs was examined to create a mucosal elevation. After having determined optimal pressures, angle of application, and application times, 13 submucosal fluid cushions were produced in different areas of the stomach walls of 8 pigs in vivo, and the sizes of the resulting submucosal cushions were measured.

RESULTS

Using pressures between 30 and 70 bar, it was routinely possible to create submucosal fluid cushions in the stomach wall ex vivo as well as in vivo. Histological examination showed a selective edema in the submucosa without damage to the deeper mucosal layers of the gastric wall.

CONCLUSIONS

The capacity of a targeted high-pressure water jet to penetrate the mucosa and selectively create a fluid cushion in the submucosa facilitates endoscopic resection of the mucosa. This new method could contribute to ameliorate the endoscopic treatment of mucosal tumors which previously could not be resected endoscopically due to their size, extent, or location.

Endoscopic submucosal dissection for stomach neoplasms

Recent advances in techniques of therapeutic endoscopy for stomach neoplasms are rapidly achieved. One of the major topics in this field is endoscopic submucosal dissection (ESD). ESD is a new endoscopic technique using cutting devices to remove the tumor by the following three steps: injecting fluid into the submucosa to elevate the tumor from the muscle layer, pre-cutting the surrounding mucosa of the tumor, and dissecting the connective tissue of the submucosa beneath the tumor. So the tumors are resectable in an en bloc fashion, regardless of the size, shape, coexisting ulcer, and location. Indication for ESD is strictly confined by two aspects: the possibility of nodal metastases and technical difficulty, which depends on the operators. Although long-term outcome data are still lacking, short-term outcomes of ESD are extremely favourable and laparotomy with gastrectomy is replaced with ESD in some parts of therapeutic strategy for early gastric cancer.

Advantage of endoscopic submucosal dissection compared with EMR for early gastric cancer

BACKGROUND

In EMR of early gastric cancer (EGC), en bloc resection reduces the risk of residual cancer. Endoscopic submucosal dissection (ESD) now allows en bloc resection of large EGCs.

OBJECTIVE

To retrospectively determine whether ESD is more advantageous than EMR for EGCs.

DESIGN

EMR (825 lesions, 711 patients) or ESD (195 lesions, 185 patients) was performed. The en bloc resection rate, histologically complete resection rate, operation time, complications, and local recurrence rate were studied in relation to ulceration.

SETTING

Hiroshima University Hospital.

PATIENTS

Subjects comprised 896 patients in whom 1020 EGCs were resected endoscopically from 1990 to 2004.

RESULTS

In cases without ulceration, en bloc and histologically complete resection rates were significantly higher with ESD than with EMR, regardless of tumor size. The frequency of ulceration did not differ significantly between groups. Average operation time was significantly longer for ESD than for EMR, regardless of tumor size. Also, regardless of ulceration, the incidence of intraoperative bleeding was significantly higher with ESD (22.6%) than with EMR (7.6%). Delayed bleeding did not differ. In cases with ulceration, the incidence of perforation was significantly higher with ESD (53.8%) than with EMR (2.9%). Local recurrences were treated by incomplete EMR (en bloc, 2.9%; piecemeal, 4.4%). No patient experienced recurrence after ESD.

CONCLUSIONS

ESD increased en bloc and histologically complete resection rates and may reduce the local recurrence rate. Increased operation time and complication risks with ESD in comparison with EMR remain problematic. Special measures are necessary for ESD of ulcerated lesions to reduce the rates of perforation and incomplete resection.

A novel method of endoscopic submucosal dissection with blunt abrasion by submucosal injection of sodium carboxymethylcellulose: an animal preliminary study

BACKGROUND

Endoscopic submucosal dissection (ESD), particularly the process of submucosal incision with a knife, is technically difficult and carries a high risk of perforation. Submucosal injection of a viscous substance, eg, jelly, obviates the need of submucosal incision with a knife. Sodium carboxymethylcellulose (SCMC), known as cellulose gum, is highly viscous when dissolved in water.

OBJECTIVE

To evaluate the efficacy and the safety of ESD by submucosal injection of SCMC solution in a porcine stomach.

DESIGN AND SETTING

A prospective, single-center study.

INTERVENTIONS

The viscosity of various concentrations (0.5%-3.5%) of SCMC was measured by a viscometry. First, we injected 10 mL of various concentrations of SCMC solution into the submucosal layer of resected porcine stomachs in vitro and examined whether the submucosal injection dissected the mucosal layer from the muscular layer by EUS. Second, we performed ESD by injecting, with an 18-gauge needle, the SCMC solution into the submucosal layer of the stomach in white domestic pigs in vivo to evaluate the efficacy and the safety of SCMC for ESD.

MAIN OUTCOME MEASUREMENTS AND RESULTS

Submucosal injection of the SCMC solution dissected most of the mucosal layer from the muscular layer at the concentration above 2.0%. We, therefore, decided to use 2.5% SCMC for ESD with a 18-gauge needle to ensure dissection. Submucosal injection of 2.5% SCMC dissected the mucosal layer from the muscular layer without complications, such as massive bleeding or perforation, in white domestic pigs. Histologically, injection of 2.5% SCMC revealed no damage to the muscular layer and surrounding tissue.

LIMITATIONS

Our novel injection technique was evaluated in an animal model with a normal stomach; it was relatively easy to approach the target mucosa.

CONCLUSIONS

ESD by submucosal injection of viscous SCMC solution appeared to be an easy, safe, and technically efficient method for dissection of gastric lesions.

Clinical efficacy of EMR with submucosal injection of a fibrinogen mixture: a prospective randomized trial

BACKGROUND

Submucosal injection is essential to performing EMR easily, and various solutions have been proposed to create a long-lasting submucosal fluid cushion.

OBJECTIVE

To assess the efficacy of a fibrinogen mixture (FM) as a submucosal injection solution.

DESIGN

A prospective, randomized, controlled trial.

SETTING

At a tertiary care, academic medical center.

PATIENTS

A total of 72 patients with early gastric neoplasm were randomly assigned to receive EMR with submucosal injection of normal saline solution (NS) or an FM.

INTERVENTION

We performed EMR only with a conventional method.

MAIN OUTCOME MEASUREMENTS

En bloc resection rate, complete resection rate, complications, and other procedure-related outcomes.

RESULTS

No significant differences were observed between the 2 groups (the FM group vs the NS group) in the rates of en bloc resection (80.6% vs 88.9%), complete resection rate (86.1% vs 80.6%), and recurrence rate (3% vs 6.1%). Mean procedure time was significantly shorter in the FM group vs the NS group (11.39 +/- 3.07 minutes vs 13.93 +/- 3.26 minutes; P < .05). Mean submucosal injection volume of the FM group was significantly less than that of the NS group (9.81 +/- 2.26 mL vs 14.32 +/- 2.35 mL; P < .05). Also, additional submucosal injection to maintain elevation of the lesion was less frequently required in the FM group than in the NS group (5.6% vs 33.3%; P < .05).

LIMITATIONS

The main limitations were the method of EMR (only included the conventional method) and the size of lesions (<30 mm), because a long-lasting submucosal fluid cushion was more important in the dissection method and larger tumors.

CONCLUSIONS

The FM is a reliable submucosal injection solution for conventional EMR.

A novel method of endoscopic mucosal resection assisted by submucosal injection of autologous blood (blood patch EMR)

PURPOSE

Endoscopic mucosal resection assisted by submucosal injection of saline is a widely used procedure; however, it has three limitations: 1) it often is difficult to maintain a desirable level of tissue elevation after the injection; 2) the saline has no efficacy in preventing hemorrhage; 3) nothing can protect the site of mucosal defect after endoscopic mucosal resection to prevent perforation. Blood, as a new medium for use in submucosal injection, may remedy these drawbacks. This is the first report of this technique.

METHODS

From May to October 2004, 28 outpatients (8 females; median, 64 years) with 35 colorectal polyps (median, 5 mm in diameter; range, 1-30 mm) were enrolled in this study. Technique of the blood patch endoscopic mucosal resection: after autologous blood was injected into the submucosa under the lesion using a disposable 23-gauge needle, the lifted mucosa with the lesion was removed using a conventional snaring technique. The outcomes were prospectively studied.

RESULTS

Although one lesion was not lifted by the submucosal injection because of the submucosal invasion of carcinoma, 33 of the other 34 lesions (97.1 percent) were successfully completed using the blood patch endoscopic mucosal resection. The clot covered the raw surface after the endoscopic mucosal resection without bleeding. No complications (including hemorrhage and perforation) were observed. The blood patch endoscopic mucosal resection did not disturb pathologic examination.

CONCLUSIONS

Endoscopic mucosal resection assisted by submucosal injection of autologous blood can be performed safely, easily, and economically. Autologous blood is a promising medium for submucosal injection on endoscopic mucosal resection.

Endoscopic submucosal dissection for stomach neoplasms

Recent advances in techniques of therapeutic endoscopy for stomach neoplasms are rapidly achieved. One of the major topics in this field is endoscopic submucosal dissection (ESD). ESD is a new endoscopic technique using cutting devices to remove the tumor by the following three steps: injecting fluid into the submucosa to elevate the tumor from the muscle layer, pre-cutting the surrounding mucosa of the tumor, and dissecting the connective tissue of the submucosa beneath the tumor. So the tumors are resectable in an en bloc fashion, regardless of the size, shape, coexisting ulcer, and location. Indication for ESD is strictly confined by two aspects: the possibility of nodal metastases and technical difficulty, which depends on the operators. Although long-term outcome data are still lacking, short-term outcomes of ESD are extremely favourable and laparotomy with gastrectomy is replaced with ESD in some parts of therapeutic strategy for early gastric cancer.

Endoscopic submucosal dissection for stomach neoplasms

Recent advances in techniques of therapeutic endoscopy for stomach neoplasms are rapidly achieved. One of the major topics in this field is endoscopic submucosal dissection (ESD). ESD is a new endoscopic technique using cutting devices to remove the tumor by the following three steps: injecting fluid into the submucosa to elevate the tumor from the muscle layer, pre-cutting the surrounding mucosa of the tumor, and dissecting the connective tissue of the submucosa beneath the tumor. So the tumors are resectable in an en bloc fashion, regardless of the size, shape, coexisting ulcer, and location. Indication for ESD is strictly confined by two aspects: the possibility of nodal metastases and technical difficulty, which depends on the operators. Although long-term outcome data are still lacking, short-term outcomes of ESD are extremely favourable and laparotomy with gastrectomy is replaced with ESD in some parts of therapeutic strategy for early gastric cancer.

Endoscopic submucosal dissection allows curative resection of locally recurrent early gastric cancer after prior endoscopic mucosal resection

BACKGROUND

Repeat endoscopic mucosal resection (EMR) to cure locally recurrent early gastric cancer (EGC) is difficult to perform because the initial EMR causes submucosal fibrosis; however, ESD allows submucosal dissection through the fibrosis and provides an en bloc specimen.

OBJECTIVE

The objective was to determine the safety and efficacy of ESD and compare the results to historical controls.

DESIGN

This was a retrospective, case-control study.

PATIENTS

We used our prospectively entered database (1993-2003) to identify 64 patients who had locally recurrent EGC after EMR.

MAIN OUTCOME MEASUREMENTS

We defined the resections as curative when the lateral and vertical margins were free of cancer and repeat endoscopy showed no recurrent disease.

RESULTS

Among 46 patients who underwent ESD, 41 (89.1%) en bloc resections were achieved compared to none in 18 conventional procedures (P < .0001). The specimen of 1 lesion (2.4%) out of 41 en bloc resections was histologically nonevaluable, compared with 10 lesions (43.4%) in 23 piecemeal resections (P < .0001). Three residual tumors (27.3%) were found in the 11 nonevaluable specimens. Three perforations occurred during ESD; all were successfully treated endoscopically with endoclips.

LIMITATIONS

The limitation of the study was retrospective design.

CONCLUSIONS

ESD provides high en bloc resection rate for locally recurrent EGC after previous EMR. In turn, en bloc resections allow precise histological staging to be assessed and prevent residual disease and recurrence.

Clinical outcomes of EMR for gastric tumors: historical pilot evaluation between endoscopic submucosal dissection and conventional mucosal resection

BACKGROUND

EMR is currently a standard treatment for mucosal gastric tumors. Endoscopic submucosal dissection (ESD) has been developed for en bloc resection.

OBJECTIVE

We evaluated the clinical outcomes of ESD compared with conventional EMR.

DESIGN

Not applicable.

SETTING

A historical control study was performed between EMR and ESD.

PATIENTS

EMR of 245 gastric tumors was performed in 229 patients. Lesions were divided into two groups. Conventional EMR was performed in group A from February 1999 to June 2001, and ESD was performed in group B from July 2001 to March 2004. Group B was divided into subgroups: subgroup B-1 underwent ESD from July 2001 to March 2003 and subgroup B-2 from April 2003 to March 2004.

INTERVENTIONS

All lesions were resected with conventional EMR or with ESD.

MAIN OUTCOME MEASUREMENTS

En bloc resection rate, rate in completeness of resection, required time, remnant ratio, and complications were evaluated.

RESULTS

With regard to lesions >10 mm in size, the en bloc resection rate and the rate in completeness of resection of group B was significantly higher than that of group A (p < 0.01). Although the required time was longer in group B than A (p < 0.01), it was shorter in subgroup B-2 compared with B-1 (p < 0.05) with lesions < or =10 mm in size. The remnant ratio and perforation rate were not different between groups.

LIMITATIONS

Not applicable.

CONCLUSIONS

The en bloc resection rate was better with ESD than with conventional EMR. The required time was longer in ESD, but this disadvantage might be improved with experience.