ENDOSCOPIC SUBMUCOSAL DISSECTION FOR GASTRIC SUBMUCOSAL TUMOR,ENDOSCOPIC SUB‐TUMORAL DISSECTION

Gastric submucosal tumor (SMT) is frequently found during screening endoscopy, but definitive diagnosis based on histological confirmation is relatively difficult. Even without accurate diagnosis before treatment, open or laparoscopic surgery is currently carried out to remove SMT. The purpose of this study was to demonstrate the feasibility of endoscopic submucosal dissection (ESD) in diagnostic treatment for submucosal tumor (SMT) of the stomach. Subjects in this case study comprised nine patients who had undergone ESD for gastric SMT. Before treatment, endoscopic ultrasonography was carried out in all cases to evaluate depth and origin of the SMT. Then ESD was only indicated for tumors of submucosal layer or muscularis mucosa origin. Using an endoscopic sub‐tumoral dissection technique with a hook knife and a flex knife, local complete resections were achieved in all patients without severe complications. These results suggest the clinical benefits of ESD avoiding oversurgery for the diagnostic treatment of gastric SMT of the submucosal layer and muscularis mucosa origin.     

IS IT DIFFICULT FOR ENDOSCOPISTS WHO HAVE DONE CONVENTIONAL ENDOSCOPIC MUCOSAL RESECTION TO PERFORM SUBMUCOSAL DISSECTION?

Submucosal resection is a very useful method of endoscopic mucosal resection (EMR) for en bloc resection. We began using this method in March 2003 and have resected lesions in 16 patients with gastric cancer. We describe the procedure times and complications associated with submucosal resection from a beginner's point of view. Our first five patients experienced bleeding and perforation. With the aid of a range of instruments and the advice of expert endoscopists, our complication rate became very low and the procedure time much shorter. Endoscopists who seek to perform submucosal dissections easily and safely should avail themselves of training and education from experts in the method. A program for training endoscopists in submucosal dissection is essential.     

ENDOSCOPIC MUCOSAL RESECTION AND SUBMUCOSAL DISSECTION METHOD FOR LARGE COLORECTAL TUMORS

The goal of endoscopic mucosal resection (EMR) is to allow the endoscopist to obtain tissue or resect lesions not previously amenable to standard biopsy or excisional techniques and to remove malignant lesions without open surgery. In this article, we describe the results of conventional EMR and EMR using an insulation‐tipped (IT) electrosurgical knife (submucosal dissection method) for large colorectal mucosal neoplasms and discuss the problems and future prospects of these procedures. At present, conventional EMR is much more feasible than EMR using IT‐knife from the perspectives of time, money, complication, and organ preservation. However, larger lesions tend to be resected in a piecemeal fashion; and it is difficult to confirm whether EMR has been complete. For accurate histopathological assessment of the resected specimen en bloc EMR is desirable although further experience is needed to establish its safety and efficacy. Further improvements of in EMR with special knife techniques are required to simply and safely remove large colorectal neoplasms.     

FEASIBILITY OF ENDOSCOPIC SUBMUCOSAL DISSECTION FOR ELDERLY PATIENTS WITH EARLY GASTRIC CANCERS AND ADENOMAS

Background: Endoscopic submucosal dissection (ESD) has the advantage of permitting en bloc and histologically complete resection for early gastric cancer. Elderly patients often have surgical operative risks due to disease, and the feasibility of this treatment for such patients will improve the quality of life. The aim of the present study is to evaluate the efficacy and safety of ESD in elderly patients. Methods: We reviewed patients who underwent ESD for gastric lesions at Maebashi Red Cross Hospital. Among 251 gastric lesions treated by ESD from 2002 to 2006, 110 lesions were discovered in 93 elderly patients who were 75 years of age or older. The one‐piece resection with tumor‐free margin rate and the complications were assessed in comparison with younger patients under 75 years old. Results: The average age of the elderly patients was 79.8 years (range 75–92 years). The one‐piece resection with tumor‐free margin rate was 96.4% (106/110). Immediate bleeding occurred in one lesion (0.9%) and delayed bleeding requiring emergency endoscopy occurred in five lesions (4.5%). Perforation during ESD occurred in two patients (1.8%), and was immediately closed with endoclips and managed by conservative medical treatment. One case (0.9%) complicated with delayed perforation was managed by conservative medical treatment. The one‐piece resection with tumor‐free margin rate and the complication rate in elderly patients were not significantly different from those of younger patients. Conclusion: The present study shows the technical feasibility of ESD for gastric neoplasms in elderly patients.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR THE RELIABLE EN BLOC RESECTION OF COLORECTAL MUCOSAL TUMORS

Scheduled piecemeal resection has been actively conducted for granular type laterally spreading tumor (LST‐G) in Japan, as long as a definite preoperative diagnosis is made. However, en bloc resection is desirable for depressed lesions (e.g. IIc lesion) as well as non‐granular type laterally spreading tumor (LST‐NG) since they have considerable high risk for submucoasl invasion and require precise histopathological evaluation. Endoscopic submucosal dissection (ESD) has been developed for the en bloc resection of mucosal tumors of gastrointestinal tract and widely applied especially in gastric lesions. Although the large intestine involves structural and technical difficulties, we conducted en bloc resection by ESD while exercising sorts of ingenuity for preparation; endoscopes, instruments, local injections, and others. ESD is a reliable technique that allows en bloc resection of gastrointestinal mucosal lesions, and even has a splendid possibility for the treatment of early stage colorectal cancer.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR RECURRENT GASTRIC TUMORS

Endoscopic resection has been accepted as the standard treatment for intramucosal gastric tumors of differentiated type. However, the indication was limited to small tumors to achieve en bloc resection and prevent local recurrence in cases of conventional endoscopic mucosal resection (EMR) such as the strip biopsy and the cap technique. To avoid multi‐fragmental resection, we have developed endoscopic submucosal dissection (ESD) as a new endoscopic resection technique. ESD is a remarkable technique, because we make it possible to remove the lesions en bloc regardless of size, shape, coexisting ulcer, and location. However, it is difficult or impossible to resect recurrent tumors en bloc in conventional EMR owing to hard fibrosis, and some patients need laparotomy. Using ESD, we can dissect the submucosal layer as we directly look at the submucosa, and remove the lesion safely and reliably even in cases of hard fibrosis. The key to treatment of recurrent tumors in ESD are as follows: (i) using enough submucosal injection solution (we use a mixture of Glyceol and 1% 1900 kDa hyaluronic acid preparation); (ii) incising the mucosa without fibrosis; (iii) understanding characteristics of various cutting devices, and changing other devices in difficult situations. In these ways we can remove the majority of the recurrent tumors en bloc. Hence, we consider that ESD is a very effective treatment which achieves excellent en bloc and complete resection rates and enables patients with intramucosal gastric tumors to a recurrent‐free survival even in recurrent tumors.     

STRICTURE AFTER ENDOSCOPIC SUBMUCOSAL DISSECTION FOR EARLY GASTRIC CANCERS AND ADENOMAS

Background and Aim: Stricture is a complication that may occur after endoscopic submucosal dissection (ESD) of gastric neoplasms. The goal of the present study was to investigate the incidence, risk factors and management of gastric stricture after ESD. Methods: The medical records of 308 patients who underwent ESD for gastric neoplasms were reviewed. Stricture is defined as having symptoms caused by an obstruction through which a 1‐cm diameter endoscopic fiber cannot be passed. Results: Stricture was identified in six of 308 patients (1.9%). Three of the six lesions were located in the prepylorus, two cases in the antrum and one in the cardia. The mean longitudinal distance and the mean area of the resected specimens in the six cases with stricture (7.8 ± 2.0 cm, 34.0 ± 15.8 cm², respectively) was significantly larger than in those without stricture (4.5 ± 1.4 cm, 12.7 ± 8.3 cm², respectively, P < 0.01). The ratio of the resected circumference/whole circumference was 83.3 ± 7.5% in those with stricture in comparison to 25.4 ± 16.3% in those without stricture (P < 0.01). All six patients underwent endoscopic balloon dilations, and obtained relief from stricture. However, one patient experienced a gastric perforation and recovered following conservative therapy. Conclusion: Sub‐circumferential resection over 75% of the circumference by ESD in the prepylorus, antrum and cardia is a risk factor for the occurrence of stricture. Early intervention might be considered for this high‐risk group to avoid a perforation during balloon dilation.     

SUCCESSFUL ENDOSCOPIC CLOSURES OF COLONIC PERFORATIONS REQUIRING ABDOMINAL DECOMPRESSION AFTER ENDOSCOPIC MUCOSAL RESECTION AND ENDOSCOPIC SUBMUCOSAL DISSECTION FOR EARLY COLON CANCER

Endoscopic submucosal dissection (ESD) for colorectal cancer is not widely accepted because of its technical difficulty and the risk of perforation. In addition, the risk of peritonitis cannot be completely eliminated even if a perforation is closed successfully. Reported here are two cases of early colon cancer in which the patients sustained iatrogenic perforations of the ascending colon during conventional endoscopic mucosal resection and of the sigmoid colon during ESD, respectively, requiring abdominal decompression with an 18 G Medicut needle. Both of these perforations were successfully treated by endoscopic clipping. In conclusion, conservative medical management may be possible in patients who have undergone successful closure of colonic perforations using endoscopic clipping. In order to perform immediate endoscopic closure, abdominal decompression has been useful to decrease patient discomfort and colonic lumen collapse. Now, CO₂ insufflation is being used effectively for the prevention of pneumoperitoneum.     

SUCCESSFUL ENDOSCOPIC SUBMUCOSAL DISSECTION FOR MUCOSAL CANCER OF THE DUODENUM

We report a case of mucosal duodenal cancer in a 62‐year‐old woman, which was successfully removed en bloc by endoscopic submucosal dissection (ESD). The patient underwent an upper gastrointestinal endoscopy at our hospital, which revealed an elevated flat mucosal lesion (type IIa) measuring 10 mm in diameter in the second portion of the duodenum. Histopathological examination of a biopsy specimen revealed features suggestive of a tubulovillous adenoma with severe atypia. As the findings suggested that the lesion had an adenocarcinoma component but was confined to the mucosal layer, we decided to carry out ESD and successfully removed the tumor in one piece. The resected tumor was 20 × 15 mm in size. Histopathological examination revealed that the lesion was a well‐differentiated mucosal adenocarcinoma with no lymphovascular invasion. Mucosal duodenal cancer is extremely rare, and ESD of a lesion in the duodenum requires a high level of skill. To the best of our knowledge, this case is the first report of successful ESD carried out in a case of mucosal duodenal cancer.     

ENDOSCOPIC MUCOSAL RESECTION OF A SOLITARY GASTRIC PLASMACYTOMA

Gastrointestinal plasmacytoma typically occurs in the setting of a systemic plasma cell neoplasm such as multiple myeloma or plasma cell leukemia. Rarely, a solitary plasmacytoma is identified. Surgical excision of early, isolated plasmacytomas is usually curative. We report on endoscopic excision of a solitary gastrointestinal plasmacytoma.     

ENDOSCOPIC SUBMUCOSAL DISSECTION WITH SHEATH‐ASSISTED COUNTER TRACTION FOR EARLY GASTRIC CANCERS

Aim: Endoscopic submucosal dissection (ESD) is associated with frequent complications, such as bleeding and perforation. The procedure is technically difficult, requires considerable skill and is longer than conventional endoscopic mucosal resection (EMR). Thus, non‐invasive tools and methods are needed to facilitate direct visualization of the submucosal layer during ESD. Methods: An insulation‐tipped (IT) knife was inserted into one channel, and a conventional injection sheath was inserted to the other channel of a double‐channel fiberscope. The submucosal layer was lifted via a circumferential incision using the conventional injection sheath for visualizing cutting lines, and the submucosal layer under the lesion was directly dissected from the underlying muscularis propria. Results: Sheath‐assisted traction resulted in successful ESD with en bloc resection in all 25 patients. Hemostasis and manipulation of blood vessels were uncomplicated and dissection was completed safely, without either bleeding or perforation. The movement of the sheath was not suppressed while lifting the submucosal layer and the IT knife could be moved freely, which allowed submucosal dissection independently of the sheath movement. Conclusion: Sheath‐assisted traction ESD, using simple materials and methods, has several advantages over other standard traction methods. Our procedure is straightforward, safe, non‐invasive, cost‐effective and uses readily available instruments to enhance visualization of cutting lines.     

THE HEALING PROCESS OF GASTRIC ARTIFICIAL ULCERS AFTER ENDOSCOPIC SUBMUCOSAL DISSECTION

Background: Due to the remarkable progress of endoscopic resection techniques, endoscopic submucosal dissection (ESD) has been widely performed for larger mucosal tumors that would result in large arti?cial ulcers. The healing process of peptic ulcers has been previously studied in detail; however, no precise investigation for arti?cial ulcers after ESD has been reported. To con?rm the validity of the treatment from the aspect of wound healing, we aimed to clarify the healing process of large gastric arti?cial ulcers after ESD. Methods: Seventy patients with gastric mucosal tumors treated by ESD were enrolled. The size, location and time of scar formation of the ulcers were reviewed using endoscopic pictures taken from the same view and angle. Follow‐up endoscopy was performed at 1, 4, 8 and 12 weeks after ESD. For postoperative medication, all patients received normal doses of proton pump inhibitors and sucralfate for 8 weeks. Results: The average size of the resected specimen was 34.7 mm (20–90 mm). Irrespective of ulcer size and location, all of the cases healed up to scarring stages within 8 weeks. Conclusions: Gastric arti?cial ulcers after ESD healed within 8 weeks regardless of size and location using normal doses of medication as peptic ulcers. The fact that even giant ulcers after ESD heal within 8 weeks could be helpful information for candidates for ESD and for postoperative management of patients after ESD.     

PRESENT STATUS and PERSPECTIVES OF SUBMUCOSAL DISSECTING METHOD OF ENDOSCOPIC MUCOSAL RESECTION IN THE COLORECTUM IN JAPAN

Endoscopic mucosal resection (EMR) is one of the endoscopic procedures for treatment of intramucosal cancer of the gastrointestinal tract. This method enables complete resection of a lesion, however, the size of lesions which can be resected en bloc has a limit. For lesions which can not be resected en bloc, endoscopic piecemeal mucosal resection (EPMR) are employed. However, it is often difficult to determine cancer invasion at holizontal and vertical cut end on pathological examination of resected specimens. Therefore, for the purpose of en bloc resection submucosal dissecting method of endoscopic mucosal resection (SDEMR) that is a method by which mucosa is dissected using some special devices after circumferential mucosal incision around the lesion was proposed. It enables us to resect large lesions which cannot be removed en bloc by EMR. Therefore, it is possible that this procedure is able to prevent residual cancer. Furthermore, sufficient pathological examination of resected specimens is possible, and it helps to determine a therapeutic plan after resection. It is now widely accepted as one of the endoscopic procedures for treatment of early gastric cancer, however, there have been few reports on its experience in the colorectum. Then, in order to consider the perspectives of SDEMR in the colorectum, the present status of it in Japan in August 2003 was analyzed and reviewed in this paper.     

NEW ENDOSCOPIC TECHNIQUE TO CLOSE LARGE MUCOSAL DEFECTS AFTER ENDOSCOPIC MUCOSAL RESECTION IN PATIENTS WITH GASTRIC MUCOSAL TUMORS

Endoscopic mucosal resection has been recognized as a standard method for treating mucosal tumors of the stomach in Japan. In our department, we have treated mucosal defects after this procedure by using metallic clips to prevent and manage complications related to endoscopic mucosal resection. In the present study, we explain the new technique, the ‘loop‐and‐clips’ method, which uses clips and a detachable snare to close large mucosal defects after endoscopic mucosal resection.     

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR SUBMUCOSAL INVASIVE GASTRIC CANCER AND CURABILITY CRITERIA

Aims: The aims of the present study were to evaluate the feasibility of endoscopic submucosal dissection (ESD) as curative treatment for node‐negative submucosal invasive early gastric cancer (EGC) and to consider further expansion of the curability criteria for submucosal invasive EGC. Methods: A total of 977 EGC in 855 patients treated by ESD were enrolled. They were divided into intramucosal cancer (M); minimally submucosal invasive cancer (<500 µm from the muscularis mucosa) (SM1); and deeper submucosal invasive cancer (>500 µm from the muscularis mucosa) (SM2). The technical feasibility of ESD for SM1 and M were compared, and the clinical prognosis of SM1 was evaluated. Furthermore, the volume of carcinoma invading to the submucosal layer, which we called the SM volume index, was calculated virtually to analyze its correlation with lymphatic‐vascular invasion. Results: There were no statistical differences in technical outcomes and complications between M and SM1. Curative resection rates were significantly better in M than in SM1 (M, 92.6%; SM1, 63.8%). No local recurrences and distant metastases were found in 48 SM1 patients declared to have undergone curative resections. Most cases (72.0%) with successful ESD but non‐curative resection exceeded 30 mm in maximum size, and no local recurrences and metastases were found in these patients. The SM volume index of these cases was comparatively small. Conclusion: The technical and theoretical validity of ESD for SM1 was validated. The possibility of further expansion of the curability criteria for submucosal invasive cancers was suggested by the evaluation of the SM volume index.     

ENDOSCOPIC SUBMUCOSAL DISSECTION OF COLORECTAL LESION

Endoscopic submucosal dissection (ESD) has been developed for en‐bloc resection of mucosal lesions of the gastrointestinal tract. It enables us to resect almost all mucosal and slightly submucosal invasive tumors, regardless of size and shape, even in the colon. Therefore, preoperative diagnosis, especially for the depth of invasion, is very important to determine the treatment strategy. The shape of the lesion, its pit pattern and also EUS findings are very useful in estimating the depth of invasion. We use an EndoEcho system with ultrasonic probe, which gives us both radial and linear image of the lesions. Remodeled three‐dimensional (3D) images are also very useful in evaluating the size and the expansion of the lesion when it is located on a fold. Although the large intestine involves structural and technical difficulties, we conduct en‐bloc resection by ESD while exercising various ingeunities in preparation, endoscopes, use of instruments and local injections. ESD is the reliable technique, which allows en‐bloc resection of gastrointestinal mucosal lesions, and has a excellent chance of success in the treatment of early stage colorectal cancer.     

SELF‐LIMITING RISK OF METACHRONOUS GASTRIC CANCERS AFTER ENDOSCOPIC RESECTION

Background: Since endoscopic resection (ER) has been established as a treatment for early gastric cancer, metachronous multiple cancers have become a problem. It is unclear whether the risk of metachronous cancer is self‐limiting or permanent. The aim of this study was to evaluate the incidence of multiple cancers after ER during a long‐term follow‐up study. Patients and Methods: A total of 234 patients who received initial ER for early gastric cancers were evaluated retrospectively. ER included endoscopic mucosal resection and endoscopic submucosal dissection. Patients were followed up with endoscopy for 3.0–19.6 years (median, 5.0 years), including 40 patients surveyed for more than 10 years. Accessory cancers detected after ER, but which could be retrospectively viewed in pre‐ER pictures, were evaluated in the metachronous group. Results: Thirty patients (12.8%) developed 36 metachronous multiple cancers. The median interval between the discovery of metachronous cancer and the initial ER was 3.2 years; the longest interval was 9.7 years. Eight (22.2%) of the 36 metachronous cancers could be detected retrospectively in the picture record from pre‐ER. The Kaplan–Meier curve of cumulative incidence of metachronous cancers stopped increasing after 10 years of follow up. Conclusions: Although the residual gastric mucosa after ER is thought to be a high‐risk environment, the high risk may only be the result of occult synchronous cancers. It is probable that the high risk of metachronous cancers is not continuous after 10 years.     

EN BLOC REMOVAL OF A GASTRIC CARCINOID TUMOR USING ENDOSCOPIC SUBMUCOSAL DISSECTION TECHNIQUES

Endoscopic submucosal dissection (ESD) has recently been applied to the resection of gastric submucosal tumors other than carcinoid tumors. We describe a case of gastric carcinoid tumor enucleated with ESD. An 82‐year‐old woman was referred for treatment of a gastric tumor. Upper gastrointestinal endoscopy revealed a solitary submucosal tumor in the greater curvature of the gastric body. We diagnosed a carcinoid tumor by histological examination of biopsy specimens. Endoscopic ultrasound revealed a hypoechoic mass in the submucosal layer. Neither lymph node nor liver metastasis was recognized. The serum gastrin level was normal, and this tumor was classified as a type III (sporadic) carcinoid tumor. Endoscopic resection was decided on considering her age, general status, and wishes. We used ESD techniques, because the tumor was too large to be resected by conventional endoscopic mucosal resection. En bloc resection was performed. Histological examination of the 13 × 19 × 11 mm resected specimen showed that the cut end was free of tumor cells. Type III carcinoid tumor is usually treated by surgical resection with lymph node dissection. However, in high‐risk elderly patients we consider ESD to be a therapeutic option for local control of gastric carcinoid tumors.     

LEARNING CURVE FOR ENDOSCOPIC SUBMUCOSAL DISSECTION OF LARGE COLORECTAL TUMORS

Background and Aim: No studies have previously described the learning curve for colonic endoscopic submucosal dissection (ESD). The aim of the present study was to describe the learning curve for ESD of large colorectal tumors based on a single colonoscopist's experience. Methods: ESD was carried out for 120 colorectal tumors in 115 patients (68 males, median age 70 years). All procedures were carried out by a single experienced colonoscopist. The cases were grouped chronologically into three periods: (1st): cases 1–40; (2nd): cases 41–80; and (3rd): cases 81–120. Results: The learning curve was the changes in proficiency over time. Proficiency was expressed as procedure time per unit area of specimen. In the 1st, 2nd and 3rd periods, the proficiencies were 18.9, 12.6 and 12.9 (min/cm²), respectively. The proficiencies in the 2nd and 3rd periods were significantly shorter than in the 1st period (t‐test, P < 0.05). The en‐bloc resection rates of the 1st, 2nd and 3rd periods were 92.5% (37/40), 90% (36/40) and 97.5% (39/40), respectively. The en‐bloc and R0 resection rates of the 1st, 2nd and 3rd periods were 85% (34/40), 77.5% (31/40) and 92.5% (37/40), respectively. The perforation rates of the 1st, 2nd and 3rd periods were 12.5% (5/40), 5% (2/40) and 5% (2/40), respectively. Conclusion: Based on our analysis of the learning curve, approximately 80 procedures must be carried out to acquire skill with ESD for large colorectal tumors. However, approximately 40 procedures were sufficient to acquire skill in avoiding perforations during the ESD procedure.     

ENDOSCOPIC SUBMUCOSAL DISSECTION USING A GRASPING‐TYPE SCISSORS FORCEPS FOR EARLY GASTRIC CANCERS AND ADENOMAS

Aim: To reduce the risk of complications related to endoscopic submucosal dissection (ESD) using knives, we developed a new grasping‐type scissors forceps (GSF) that can grasp and incise the target tissue using electrosurgical current. The aim of the present study was to evaluate the efficacy and safety of ESD using GSF for the removal of early gastric cancers and adenomas. Methods: ESD using GSF was carried out on 35 consecutive patients with early gastric cancers or adenomas who had preoperative EUS diagnoses of mucosal tumor without lymph node involvement. Therapeutic efficacy and safety were assessed. Results: All lesions were treated easily and safely without unexpected incision. The mean size of epithelial tumors and resected specimens was 15.6 mm and 32.7 mm, respectively. Curative en‐bloc resection rates according to tumor size and location were 96% (26/27) in tumors ≤20 mm, 100% (8/8) in tumors >20 mm, 100% (18/18) of tumors in the lower portion, 100% (8/8) of tumors in the middle portion, 89% (8/9) of tumors in the upper portion, and 97% (34/35) overall. The mean operating time according to tumor size and location was 93.4 min in tumors ≤20 mm, 140 min in tumors >20 mm, 77.6 min for tumors in the lower portion, 113.4 min for tumors in the middle portion, 148.6 min for tumors in the upper portion, and 104.1 min overall. No intraoperative complication occurred, and postoperative bleeding was seen in 3% (1/35). Conclusions: ESD using GSF allows simple and safe en‐bloc resection of early gastric cancer or adenoma irrespective of tumor size and location.