Endoscopic resection for premalignant and malignant lesions of the gastrointestinal tract from the esophagus to the colon

Indications and outcomes of endoscopic resection for non-pedunculated colorectal lesions: A narrative review

In the last years, endoscopic techniques gained a crucial role in the treatment of colorectal flat lesions. At the same time, the importance of a reliable assessment of such lesions to predict the malignancy and the depth of invasion of the colonic wall emerged. The current unsolved dilemma about the endoscopic excision techniques concerns the necessity of a reliable submucosal invasive cancer assessment system that can stratify the risk of the post-procedural need for surgery. Accordingly, this narrative literature review aims to compare the available diagnostic strategies in predicting malignancy and to give a guide about the best techniques to employ. We performed a literature search using electronic databases (MEDLINE/PubMed, EMBASE, and Cochrane Library). We collected all articles about endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) registering the outcomes. Moreover, we analyzed all meta-analyses comparing EMR vs ESD outcomes for colorectal sessile or non-polypoid lesions of any size, preoperatively estimated as non-invasive. Seven meta-analysis studies, mainly Eastern, were included in the analysis comparing 124 studies and overall 22954 patients who underwent EMR and ESD procedures. Of these, eighty-two were retrospective, twenty-four perspective, nine case-control, and six cohorts, while three were randomized clinical trials. A total of 18118 EMR and 10379 ESD were completed for a whole of 28497 colorectal sessile or non-polypoid lesions > 5-10 mm in size. In conclusion, it is crucial to enhance the preoperative diagnostic workup, especially in deciding the most suitable endoscopic method for radical resection of flat colorectal lesions at risk of underlying malignancy. Additionally, the ESD necessitates further improvement because of the excessively time-consuming as well as the intraprocedural technical hindrances and related complications. We found a higher rate of en bloc resections and R0 for ESD than EMR for non-pedunculated colorectal lesions. Nevertheless, despite the lower local recurrence rates, ESD had greater perforation rates and needed lengthier procedural times. The prevailing risk for additional surgery in ESD rather than EMR for complications or oncologic reasons is still uncertain.

Two histologic compartments in nonpolypoid conventional colon adenomas

Two intertwined compartments coexisting in nonpolypoid conventional (i.e. tubular or villous) adenomas are highlighted in this review: one built of dysplastic tissue on top and the other portraying crypts with irregular, corrupted shapes, albeit lined with normal epithelium, below. The latter compartment has remained unattended in the literature. Recently, however, the histologic characteristics of the nondysplastic compartment in nonpolypoid conventional adenomas were closely examined, and some of its biological attributes were unveiled. Studies with the proliferation marker ki67 showed that the crypts with irregular, corrupted shapes in the nondysplastic compartment displayed haphazardly distributed proliferating cell-domains. Given that the proliferating cells are generated by stem cells, the relocation of proliferating cell-domains in those crypts seems to be the result of a reorganization of the stem cells within the crypts. The abnormal distribution of proliferating cells, the finding of p53-upregulated cells, and of crypts in asymmetric fission suggest that the crypts in that compartment are histo-biologically altered, probably somatically mutated. This new information might contribute to unravel the riddle of crypto-histogenesis of nonpolypoid conventional adenomas of the colon. More research along these lines is necessary, before the biology of the crypts in the nondysplastic compartment can be fully translated into molecular terms.

An evaluation of the feasibility of an expanded indication of endoscopic submucosal dissection for ulcer positive early gastric cancer: a case-control study from two medical centers

Background

Endoscopic submucosal dissection (ESD) has increasingly gained broad application in the treatment of early gastric cancer (EGC). This study aimed at evaluating the clinical significance of lymph node metastasis (LNM) in patients with ulcer positive [UL (+)] EGC and assessing the feasibility of expanded indications of ESD for such cases.

Methods

Patients with UL (+) EGC undergoing radical surgical resection between January 2012 and December 2018 were retrospectively reviewed. Associations between clinicopathological factors and the incidence of LNM were investigated by univariate and multivariate linear regression analysis.

Results

Retrospective statistical analysis was performed on 653 EGC patients. The multivariate linear regression analysis showed that the presence of LNM was significantly associated with depth of invasion (P<0.0001) and lymphatic invasion (P<0.001). The proportion of EGC patients met absolute and expanded indication of ESD with positive LNM who were subject to the criteria of curative resection was 0.75% (4/532) and 6.67% (8/120), respectively. LNM between patients, which were subject to the absolute and expanded ESD indication, is significantly different (P=0.000274).

Conclusions

Our study revealed that 6.67% (8/120) of EGC patients who did not meet all criteria of curative resection were present with LNM. EGC patients with UL (+), differentiated adenocarcinoma, tumor invasion pathologically diagnosed as T1a, and tumor diameter ≤3 cm showed for ESD are suggested for a carefully weighed treatment.

Endoscopic submucosal dissection for Barrett's early neoplasia: a multicenter study in the United States

BACKGROUND AND AIMS

The role of endoscopic submucosal dissection (ESD) in Barrett's early neoplasia is not well defined, with most studies originating from Asia and Europe. We aimed to assess the efficacy, safety, and results of ESD in Barrett's esophagus (BE) with high-grade dysplasia (HGD) and early adenocarcinoma (EAC) across centers in the United States.

METHODS

Multicenter retrospective analysis on 46 patients with BE who underwent ESD for BE-HGD or EAC, or both, between January 2010 and April 2015. The primary endpoint was the rate of en bloc resection. Secondary aims included rate of R0 (complete) and curative resection, a comparison of pre- and post-ESD histology, procedure-related adverse events, and rate of remission at follow-up.

RESULTS

Median age was 69 years (range, 42-82 years). The median resected specimen size was 45 mm (range, 13-125 mm). En bloc and curative resection rates were 96% (44/46) and 70% (32/46), respectively. Most lesions (11/20; 55%) diagnosed as BE-HGD on biopsy were upstaged to intramucosal or invasive EAC on post-ESD histopathology. There were 4 early (<48 hours) adverse events (3 bleeding and 1 perforation), and all were treated endoscopically. Seven patients (15%) developed esophageal strictures that were managed endoscopically. Complete remission of BE neoplasia was found in 100% (32/32) of patients with curative resection at median follow-up of 11 months (range, 2-25 months).

CONCLUSIONS

This is the largest multicenter series of ESD for early neoplastic BE from the United States. ESD appears to be safe and effective, with high en bloc and curative resection rates in the treatment of early BE neoplasia.

Endoscopic submucosal dissection versus surgical resection for early gastric cancer: a retrospective multicenter study on immediate and long-term outcome over 5 years

BACKGROUND

Endoscopic submucosal dissection (ESD) is an alternative to surgical resection for treating early gastric cancer (EGC). However, there have been limited reports on the long-term outcome of ESD compared to that of surgical resection. The aim of this study was to evaluate the immediate and long-term clinical and oncologic outcomes of ESD compared to surgical resection.

METHOD

We retrospectively reviewed data of patients in five centers who were treated with ESD or surgical resection for EGC within expanded criteria for ESD from 2006 to 2008.

RESULT

ESD group had significantly shorter procedure times, shorter fasting period, and shorter hospital stay than the surgical resection group. Immediate complications in the surgical resection group were more common compared to those in the ESD group. Five-year cancer recurrence rate of the ESD group was 12.3 % and significantly higher than 2.1 % of the surgical resection group (P = 0.001). Five-year disease-free survival rate of the surgical resection group was 97 %, which was significantly higher than 85 % of the ESD group (P = 0.001). Metachronous lesions were equally found every year during the follow-up period in the ESD group. Five-year overall survival rates were 100 % for both groups.

CONCLUSION

ESD might be an acceptable and effective treatment for EGC considering overall survival rates with fewer early complication rates and shorter duration of hospital stay compared to surgical resection. However, intensive and persistent endoscopic surveillance should be performed after ESD for early detection of metachronous lesions.

Risk factors and management for pyloric stenosis occurred after endoscopic submucosal dissection adjacent to pylorus

Endoscopic submucosal dissection (ESD) has been widely accepted as a curative treatment for gastric neoplasm. Pyloric stenosis is a chronic complication that can be caused by ESD. The aim of this study is to clarify the risk factors and management for pyloric stenosis. From January 2004 to January 2014, a total of 126 patients who underwent ESD adjacent to pylorus were reviewed retrospectively. Pyloric mucosal defect was defined as when any resection margin of ESD was involved in the pyloric ring. Pyloric stenosis was defined as when a conventional endoscope could not be passed to the duodenum. Among the 126 patients, pyloric stenosis was identified in 9. In a univariate analysis, pyloric stenosis was more common in older patients (P < 0.05) and in lesions with resections over 75% of the pyloric ring circumference (P < 0.001). In a multivariate analysis, the factor that was associated with pyloric stenosis was the extent of the pyloric ring dissection (P < 0.001). Four of the 9 patients with pyloric stenosis had mild dyspepsia, and the others had gastric outlet obstruction symptoms. The 5 symptomatic patients underwent endoscopic balloon dilation (EBD), and the frequency of EBD was 1 to 8 times. The asymptomatic patients were treated conservatively. The incidence of pyloric stenosis was higher in lesions with resections over 75% of the pyloric ring circumference. Although EBD was an effective treatment for pyloric stenosis, conservative management was also helpful in patients who had mild symptoms.

Prospective evaluation of the clinical utility of endoscopic submucosal dissection (ESD) in patients with Barrett's esophagus: a Western center experience

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) carries significant advantages over endoscopic mucosal resection. As such, ESD is an established therapy for esophageal squamous cell carcinoma but there are only limited data on ESD as therapy for Barrett's esophagus (BE). Thus, we prospectively evaluated the outcomes of ESD in patients with BE with high-grade dysplasia (HGD) and early esophageal adenocarcinoma (EAC) performed in a Western center.

PATIENTS AND METHODS

This is a prospective cohort study. Indications for ESD included: (1) early EAC defined as lesions with intramucosal cancer or superficial submucosal invasion; (2) early EAC with positive lateral margin after EMR; and (3) nodularity with HGD that could not be removed en-bloc with EMR Results: From October 2013 to July 2015, 36 consecutive patients (median age 69, 32 males) underwent ESD at our center. Median procedure time was 88 minutes, with median maximal diameter of resected specimens of 49 mm. En-bloc, R0, and curative resection rates were 100 %, 81 %, and 69 %, respectively. Intramucosal EAC was found in 13 patients (36 %), and submucosal invasion in 13 patients (36 %). In 59 % of the cases, there was discrepancy in the pre- and post-ESD histopathologic diagnosis. Adverse events occurred in 8 patients (22 %), including one episode of bleeding treated with endoscopy and seven esophageal strictures, which were successfully managed with dilations.

CONCLUSIONS

ESD for BE with HGD/early EAC is feasible and safe with resulting very high en-bloc and R0 resection rates. ESD provided for more accurate pathologic evaluation and significant discrepancy between the pre- and post-ESD histopathological diagnosis was noted.

Endoscopic resection of gastric and esophageal cancer

Endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) techniques have reduced the need for surgery in early esophageal and gastric cancers and thus has lessened morbidity and mortality in these diseases. ESD is a relatively new technique in western countries and requires rigorous training to reproduce the proficiency of Asian countries, such as Korea and Japan, which have very high complete (en bloc) resection rates and low complication rates. EMR plays a valuable role in early esophageal cancers. ESD has shown better en bloc resection rates but it is easier to master and maintain proficiency in EMR; it also requires less procedural time. For early esophageal adenocarcinoma arising from Barrett’s, ESD and EMR techniques are usually combined with other ablative modalities, the most common being radiofrequency ablation because it has the largest dataset to prove its success. The EMR techniques have been used with some success in early gastric cancers but ESD is currently preferred for most of these lesions. ESD has the added advantage of resecting into the submucosa and thus allowing for endoscopic resection of more aggressive (deeper) early gastric cancer.

Expanding indications for ESD: mucosal disease (upper and lower gastrointestinal tract)

Endoscopic resection is now considered a curative procedure for early gastric cancer. In Japan, it has increasingly replaced surgical resection for this indication, although in the West it has not been universally accepted as a first-line treatment. Recently, endoscopic submucosal dissection has been increasingly applied to colorectal disease, although it has not become a standard therapeutic procedure for early colorectal carcinoma because of its technical difficulty, the relatively long procedure time required, and the risk of complications, such as perforation and bleeding.

Gastric endoscopic submucosal dissection: From animal model to patient

AIM: To assess whether the use of porcine models is useful for learning endoscopic submucosal dissection (ESD), thus contributing to its subsequent application in human patients.

METHODS: This study/learning process was carried out in 3 phases: Phase I: Ex vivo animal; Phase II: In vivo animal; Phase III: Humans. One endoscopist performed 30 gastric ESDs in porcine models, and later 5 gastric ESDs in 5 patients. The ESD was done following the method practiced at the National Cancer Center in Tokyo, Japan. Technical aspects, size, time and speed of ESD, as well as complications were registered. In patients, their clinical, endoscopic and histologic evolution was additionally added.

RESULTS: Thirty en bloc ESDs were carried out in animal models. The mean ± SD size of the pieces was of 28.4 ± 1.2 mm, and the time of ESD was 41.7 ± 2.4 min. The time of ESD in the first 15 procedures was 43.0 ± 3.0 min whereas in the next 15 procedures, the time was 40.3 ± 3.9 min, P = 0.588. The speed in the first 15 ESDs was 1.25 ± 0.11 cm²/min vs 2.12 ± 0.36 cm²/min in the remaining 15, P = 0.028. There were no complications. In patients, 5 lesions were resected en bloc. The size of the pieces was 25.2 ± 5.1 mm and the time was 85.0 ± 25.6 min. Endoscopic and histological controls did not show evidence of residual neoplastic tissue.

CONCLUSION: A sequential ESD training program of a unique endoscopist, based on the practice in porcine models, contributed to learning ESD for its subsequent application in humans, yielding good results in efficacy and safety.

Endoscopic resection (endoscopic submucosal dissection/endoscopic mucosal resection) for superficial Barrett's esophageal cancer

Recently developed endoscopic resection (endoscopic submucosal dissection [ESD]/ endoscopic mucosal resection) has dramatically changed the therapeutic approach for Barrett's esophageal cancer. The rationale for endoscopic resection is that lesions confined to the mucosal layer have negligible risk for developing lymph node metastasis and can be successfully eradicated by endoscopic treatment as a curative treatment with minimal invasiveness. According to some reports that analyzed the rate of lymph-node involvement relative to the depth of mucosal or submucosal tumor infiltration, endoscopic resection is clearly indicated for intramucosal carcinoma and might be extended to lesions with invasion into the submucosa (<200 μm, sm1) because of the low risk for lymph node metastasis. Most Japanese experts recommend ESD for Barrett's esophageal cancer after accurate diagnosis of the margin of cancer using narrow band imaging with magnifying endoscopy because of its high curative rate. However, few studies have evaluated the long-term outcomes of endoscopic resection for Barrett's esophageal cancer in Japan. Further investigations should be conducted to establish endoscopic resection for Barrett's esophageal cancer.

Surgical approaches to gastric cancer

While the incidence of gastric cancer has declined substantially, it remains a major cause of morbidity and mortality. Surgical resection offers the best chance for curative treatment. Despite numerous studies, surgical controversies persist including endoscopic resection, extent of gastric resection, degree of lymphadenectomy, and laparoscopic resection. Balancing the benefits with the risks of surgical morbidity and mortality is essential. This review examines these controversies and provides insight into the surgical management of gastric cancer.

[Endoscopic submucosal dissection: only for expert endoscopists?]

Endoscopic submucosal dissection (ESD) can be applied to early gastrointestinal cancers. This technique was developed to achieve radical curative resection and to reduce unnecessary surgical interventions. ESD was designed in eastern countries and is not widely used in the West. Although ESD represents a major therapeutic advance in endoscopy and is performed with curative intent, the complication rate (hemorrhage, perforation) is higher than reported in other techniques, requiring from endoscopists the acquirement of technical skill and experience through a structured and progressive training program to reduce the morbidity associated with this technique and increase its potential benefits. Although there is substantial published evidence on the applications and results of ESD, there are few publications on training in this technique and a standardized training program is lacking. The current article aims to describe the various proposals for training, as well as the basic principles of the technique, its indications, and the results obtained, since theoretical knowledge that would guide endoscopists during the clinical application of ESD is advisable before training begins. Training in an endoscopic technique has a little value without knowledge of the technique's aims, the situations in which it should be applied, and the results that can be expected.

Endoscopic resection techniques and ablative therapies for Barrett’s neoplasia

Esophageal adenocarcinoma is the most rapidly increasing cancer in western countries. High-grade dysplasia (HGD) arising from Barrett’s esophagus (BE) is the most important risk factor for its development, and when it is present the reported incidence is up to 10% per patient-year. Adenocarcinoma in the setting of BE develops through a well known histological sequence, from non-dysplastic Barrett’s to low grade dysplasia and then HGD and cancer. Endoscopic surveillance programs have been established to detect the presence of neoplasia at a potentially curative stage. Newly developed endoscopic treatments have dramatically changed the therapeutic approach of BE. When neoplasia is confined to the mucosal layer the risk for developing lymph node metastasis is negligible and can be successfully eradicated by an endoscopic approach, offering a curative intention treatment with minimal invasiveness. Endoscopic therapies include resection techniques, also known as tissue-acquiring modalities, and ablation therapies or non-tissue acquiring modalities. The aim of endoscopic treatment is to eradicate the whole Barrett’s segment, since the risk of developing synchronous and metachronous lesions due to the persistence of molecular aberrations in the residual epithelium is well established.

Full-thickness laparoendoscopic excision in the stomach: the FLEx technique

BACKGROUND

The authors describe the initial validation of a novel full-thickness laparoendoscopic excision (FLEx) technique for the stomach.

METHODS

The technique was studied in seven 50-kg pigs. Secure full-thickness excision was ensured by inversion excision target with a 1-cm circumferential margin using laparoendoscopically placed brace bars passed intraluminally from the outside of the stomach, laparoscopic oversewing of the site of inversion, and endoscopic full-thickness excision using a dual scope approach. Pigs were sacrificed either immediately (n = 3) or between 7 and 10 days after surgery (n = 4).

RESULTS

The procedure achieved uncomplicated full-thickness excision in every case. Median procedure duration was 227 minutes (range = 210-245 minutes). Median specimen diameter was 5.5 cm (range = 2.5-8 cm). Investigative autopsy confirmed technical sufficiency in all animals. Median site bursting pressure was 130 mm Hg (range = 120-160 mm Hg).

CONCLUSIONS

The FLEx technique proved useful for excision of small localized lesions of the stomach in this animal study.

Do we have enough evidence for expanding the indications of ESD for EGC?

Endoscopic submucosal dissection (ESD) is the most advanced and representative technique in the field of therapeutic endoscopy and has been used for the treatment of gastrointestinal neoplasms, including early gastric cancer. The major difference and advantage of ESD compared to existing endoscopic resection techniques, such as endoscopic mucosal resection (EMR) and polypectomy, are the width and depth of the resection. Newly developed cutting devices, distal attachable endoscopic accessories, and an advanced electrosurgical unit have helped to overcome the limitations of therapeutic endoscopy in terms of lesion size, location, presence of fibrotic scarring, and accompanying ulcers. As a result, the indications for ESD have been expanded from the classical indication for EMR and polypectomy, and there is now support for a further expansion of ESD indications. At present, the most critical factor to consider in the decision of whether to perform ESD is the probability of unexpected lymph node metastasis. The guidelines for ESD are continually being updated and debated. In this review, we discuss the strengths and weaknesses of the expanded guidelines, based on evidence found in the literature.

Endoscopic submucosal dissection for premalignant lesions and noninvasive early gastrointestinal cancers

AIM: To investigate the indication, feasibility, safety, and clinical utility of endoscopic submucosal dissection (ESD) in the management of various gastrointestinal pathologies.

METHODS: The medical records of 60 consecutive patients (34 female, 26 male) who underwent ESD at the gastroenterology department of Kocaeli University from 2006-2010 were examined. Patients selected for ESD had premalignant lesions or non-invasive early cancers of the gastrointestinal tract and had endoscopic and histological diagnoses. Early cancers were considered to be confined to the submucosa, with no lymph node involvement by means of computed tomography and endosonography.

RESULTS: Sixty ESD procedures were performed. The indications were epithelial lesions (n = 39) (33/39 adenoma with high grade dysplasia, 6/39 adenoma with low grade dysplasia), neuroendocrine tumor (n = 7), cancer (n = 7) (5/7 early colorectal cancer, 2/7 early gastric cancer), granular cell tumor (n = 3), gastrointestinal stromal tumor (n = 2), and leiomyoma (n = 2). En bloc and piecemeal resection rates were 91.6% (55/60) and 8.3% (5/60), respectively. Complete and incomplete resection rates were 96.6% (58/60) and 3.3% (2/60), respectively. Complications were major bleeding [n = 3 (5%)] and perforations [n = 5 (8.3%)] (4 colon, 1 stomach). Two patients with colonic perforations and two patients with submucosal lymphatic and microvasculature invasion (1 gastric carcinoid tumor, 1 colonic adenocarcinoma) were referred to surgery. During a mean follow-up of 12 mo, 1 patient with adenoma with high grade dysplasia underwent a second ESD procedure to resect a local recurrence.

CONCLUSION: ESD is a feasible and safe method for treatment of premalignant lesions and early malignant gastrointestinal epithelial and subepithelial lesions. Successful en bloc and complete resection of lesions yield high cure rates with low recurrence.

A new serrated snare for improved tissue capture during endoscopic snare resection

Endoscopic snare resection of gastrointestinal polyps and neoplasm is a standard procedure in interventional endoscopy. Due to technical and procedural improvements the removal of large sessile polyps can be achieved by endoscopic mucosal resection either in one single specimen or by piecemeal resection. In this experimental study a new snare with special teeth attached to the distal part of the wire loop was evaluated and compared to a conventional snare. Seventy artificial sessile tumors were created in a standardized manner in a porcine ex vivo colon. Thirty-five polyps were resected with the new serrated snare, whilst the other 35 polyps were removed using an identical snare without teeth. The weight measurement of the resected polyps showed that when using the new serrated snare 31% more tissue could be removed with a single snare resection in comparison with the conventional snare without teeth (mean 454 mg vs. 347 mg, +/-202 mg vs. +/-165 mg). The teeth obviously increased the effectiveness of snare resection by avoiding the accidental loss of entrapped tissue from the loop. The new snare hopes to faciliate the removal of flat polyps and to reduce the number of specimens during piecemeal resection to a minimum, allowing a better histopathological assessment.

Endoscopic submucosal dissection training with pig models in a Western country

AIM: To test a strategy for endoscopic submucosal dissection (ESD) training in animal models designed to overcome the initial learning curve.

METHODS: ESD was attempted in ex vivo and in vivo pig models. Thirty ESD procedures were attempted in the esophagus (n = 9) or the stomach (n = 21). The ex vivo model was used until initial competence was achieved. In the in vivo model, several ESD procedures were performed in up to 3 sessions. The following variables were analyzed: specimen size, complete and en bloc resection rate, time for circumferential incision, time for submucosal dissection, total ESD duration, and complications.

RESULTS: Complete resection was achieved in 28 cases (en bloc 27); 2 could not be completed (one perforation, one technical difficulty). The mean ± SD time for circumferential incision was 36.2 ± 16.8 min (range: 8-87 min), and the mean ± SD time for submucosal dissection was 45.1 ± 35.7 min (range: 9-196 min). The mean ± SD size of the resected specimens was 45.2 ± 17.8 mm. The mean ± SD total resection time was significantly increased for the gastric cases performed in the first half of the study (n = 13) than in the second half (n = 8) (98.9 ± 62.4 min vs 61.7 ± 17.6 min, P = 0.04), although the specimen size did not differ.

CONCLUSION: Training in animal models could help endoscopists overcome the learning curve before starting ESD in humans.

Endoscopic mucosal resection for staging and therapy of adenocarcinoma of the esophagus, gastric cardia, and upper gastric third

Minamally invasive endoscopic resection techniques allow definitive histological staging for dysplasia and early cancer and in many cases curative treatment. In Barrett's esophagus with High Grade Dysplasia (HGD) or early mucosal cancer, endoscopic mucosal resection (EMR) should be considered both as diagnostic and therapeutic first line procedure, with the possibility to repeat the procedure in case of residual Barrett's dysplasia or mucosal cancer. In early cancer of the the submucosa, surgical resection should be discussed. Endoscopic submucosal dissection (ESD) is a useful therapeutic option for HGD or early cancer in the squamous epithelium of the esophagus or in the stomach when en bloc resection is needed in large lesions.

Gastric oncology: an update

PURPOSE OF REVIEW

As the field of endoscopy progresses, new tools and techniques continue to be developed for gastroenterology in general and gastrointestinal oncology in particular. Some of these include enhancements in diagnostic optics such as chromoendoscopy, magnification endoscopy, and confocal laser endomicroscopy. Others include advanced therapeutics such as endoscopic mucosal resection and endoscopic submucosal dissection. In this review, we will update the reader on these latest of technologies, their benefits and risks, as well as their role in evaluating, staging, and treating gastric neoplasms, especially gastric adenocarcinoma, gastrointestinal stromal tumors, and primary gastric lymphoma.

RECENT FINDINGS

Noteworthy studies in this review indicate that in properly selected patients with gastric adenocarcinoma, endoscopic submucosal dissection is a viable alternative to gastric resection with 100% 5-year survival rates; in patients with metastatic gastrointestinal stromal tumors, imatinib can provide effective treatment with reasonable outcome; and in patients with low grade mucosa-associated lymphoid tissue lymphoma, eradication therapy with antibiotics is curative with a very low recurrence rate.

SUMMARY

The advances discussed in this review have significantly improved the care we can offer our patients in gastric oncology. With continued advancement in the field, it will be crucial to continue to study outcomes and safety of these techniques and to develop structured training for those looking to perform these procedures.

Diet synergistically affects helicobacter pylori-induced gastric carcinogenesis in nonhuman primates

BACKGROUND & AIMS

Gastric cancer results from a combination of Helicobacter pylori (H pylori) infection, exposure to dietary carcinogens, and predisposing genetic make-up. Because the role of these factors in gastric carcinogenesis cannot be determined readily in human beings, the present study examined the role of an oral carcinogen and H pylori infection in rhesus monkeys.

METHODS

Gastroscopies were performed in 23 monkeys assigned to 4 groups: controls; nitrosating carcinogen ethyl-nitro-nitrosoguanidine administration alone; inoculation of a virulent H pylori strain alone (H); and ethyl-nitro-nitrosoguanidine in combination with H pylori (EH). Follow-up gastroscopies and biopsies were performed at 3-month intervals for 5 years for pathologic and molecular studies.

RESULTS

Postinoculation, H and EH groups showed persistent infection and antral gastritis. Starting at 2 and 5 years, respectively, gastric intestinal metaplasia and intraepithelial neoplasia developed in 3 EH monkeys but in no other groups. Transcriptional analysis of biopsy specimens at 5 years revealed group-specific expression profiles, with striking changes in EH monkeys, plus a neoplasia-specific expression profile characterized by changes in multiple cancer-associated genes. Importantly, this neoplastic profile was evident in nonneoplastic mucosa, suggesting that the identified genes may represent markers preceding cancer.

CONCLUSIONS

Gastric intraglandular neoplasia is induced in primates when H pylori infection is associated with consumption of a carcinogen similar to the nitrosamines found in pickled vegetables, suggesting that H pylori and the carcinogen synergistically induce gastric neoplasia in primates.

Squamous intraepithelial neoplasia of the esophagus: past, present, and future

With regard to the esophagus, the term "squamous dysplasia" has been used in European countries, the United States, and China, while its use is controversial in Japan. Recently, "low-grade intraepithelial neoplasia" and "high-grade intraepithelial neoplasia" have been used as inclusive terms for dysplasia and carcinoma in situ in the World Health Organization classification. Endoscopically, it is often difficult to identify squamous intraepithelial neoplasia by conventional endoscopy, but application of iodine is useful for the diagnosis of such a lesion. In addition, new types of endoscopic techniques, including magnifying endoscopy, narrow-band imaging (NBI), and endocytoscopy are helpful to detect squamous intraepithelial neoplasia. NBI is very useful for identifying the intrapapillary capillary loop pattern. Regarding the pathological criteria of squamous dysplasia and squamous cell carcinoma, the views of Japanese and Western pathologists have differed significantly. Before the term "intraepithelial neoplasia" was introduced, severe dysplasia as diagnosed by Western pathologists was in fact the same as squamous cell carcinoma in situ or noninvasive carcinoma as diagnosed by Japanese pathologists. This problem has been solved by the introduction of the Vienna classification; however, there are still some issues that need to be resolved. One of them is the presence of basal layer type squamous cell carcinoma in situ, which is often underdiagnosed as lowgrade intraepithelial neoplasia by Western pathologists. Endoscopic treatments such as endoscopic mucosal resection and endoscopic submucosal dissection have recently become possible choices for squamous intraepithelial neoplasia; however, these techniques are not in widespread use in the West. We believe that a consensus meeting between Japanese and Western pathologists as well as endoscopists should be held promptly to reach a common ground for the nomenclature.