Prediction of invasion depth for submucosal differentiated gastric cancer by magnifying endoscopy with narrow-band imaging

Management of high risk T1 gastric adenocarcinoma following endoscopic resection

Endoscopic submucosal dissection has revolutionized the treatment of early gastric cancer. However, cases that do not meet the curability criteria have a higher risk of lymph node metastasis and salvage surgery is still considered the next treatment approach to increase the chance of cure. Nevertheless, not all high-risk resections entail the same level of risk, emphasizing the utmost importance of individualized stratification for further treatment. In this review, we aim to examine the current evidence concerning the management following a high-risk non-curative resection, highlighting the existing approaches, while also presenting upcoming strategies that attempt to improve patient outcomes, minimize adverse events, and provide a tailored management.

Risk of lymph node metastasis and feasibility of endoscopic submucosal dissection in undifferentiated-type early gastric cancer

BACKGROUND

Whether endoscopic submucosal dissection (ESD) applies to undifferentiated-type early gastric cancer (UEGC) remains controversial. We aimed to analyze the risk factors for lymph node metastasis (LNM) in UEGC and evaluate the feasibility of ESD.

METHODS

This study included 346 patients with UEGC who underwent curative gastrectomy between January 2014 and December 2021. Univariate and multivariate analyses of the correlation between clinicopathological features and LNM were conducted, and the risk factors for exceeding the expanded ESD indications were evaluated.

RESULTS

The overall LNM rate in UEGC was 19.94%. Among the preoperatively assessable factors, submucosal invasion (odds ratio [OR] = 4.77, 95% confidence interval [CI]: 2.14-10.66) and > 2 cm(OR = 2.49, 95% CI: 1.20-5.15) were independent risk factors for LNM, while postoperative independent risk factors were > 2 cm (OR = 3.35, 95% CI: 1.02-5.40) and lymphovascular invasion(OR = 13.21, 95% CI: 5.18-33.70). Patients who met the expanded indications had a low LNM risk (4.1%). Additionally, tumors located in the cardia (P = 0.03), non-elevated type (P < 0.01) were independent risk factors for exceeding the expanded indications in UEGC.

CONCLUSIONS

ESD may be applicable for UEGC meeting the expanded indications, and preoperative evaluation should be cautious when the lesion is non-elevated type or located in the cardia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (12/05/2022 ChiCTR2200059841 ).

Endoscopic submucosal dissection for superficial gastrointestinal lesions: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022

ESGE recommends that the evaluation of superficial gastrointestinal (GI) lesions should be made by an experienced endoscopist, using high definition white-light and chromoendoscopy (virtual or dye-based).ESGE does not recommend routine performance of endoscopic ultrasonography (EUS), computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET)-CT prior to endoscopic resection.ESGE recommends endoscopic submucosal dissection (ESD) as the treatment of choice for most superficial esophageal squamous cell and superficial gastric lesions.For Barrett's esophagus (BE)-associated lesions, ESGE suggests the use of ESD for lesions suspicious of submucosal invasion (Paris type 0-Is, 0-IIc), for malignant lesions > 20 mm, and for lesions in scarred/fibrotic areas.ESGE does not recommend routine use of ESD for duodenal or small-bowel lesions.ESGE suggests that ESD should be considered for en bloc resection of colorectal (but particularly rectal) lesions with suspicion of limited submucosal invasion (demarcated depressed area with irregular surface pattern or a large protruding or bulky component, particularly if the lesions are larger than 20 mm) or for lesions that otherwise cannot be completely removed by snare-based techniques.ESGE recommends that an en bloc R0 resection of a superficial GI lesion with histology no more advanced than intramucosal cancer (no more than m2 in esophageal squamous cell carcinoma), well to moderately differentiated, with no lymphovascular invasion or ulceration, should be considered a very low risk (curative) resection, and no further staging procedure or treatment is generally recommended.ESGE recommends that the following should be considered to be a low risk (curative) resection and no further treatment is generally recommended: an en bloc R0 resection of a superficial GI lesion with superficial submucosal invasion (sm1), that is well to moderately differentiated, with no lymphovascular invasion, of size ≤ 20 mm for an esophageal squamous cell carcinoma or ≤ 30 mm for a stomach lesion or of any size for a BE-related or colorectal lesion, and with no lymphovascular invasion, and no budding grade 2 or 3 for colorectal lesions.ESGE recommends that, after an endoscopically complete resection, if there is a positive horizontal margin or if resection is piecemeal, but there is no submucosal invasion and no other high risk criteria are met, this should be considered a local-risk resection and endoscopic surveillance or re-treatment is recommended rather than surgery or other additional treatment.ESGE recommends that when there is a diagnosis of lymphovascular invasion, or deeper infiltration than sm1, or positive vertical margins, or undifferentiated tumor, or, for colorectal lesions, budding grade 2 or 3, this should be considered a high risk (noncurative) resection, and complete staging and strong consideration for additional treatments should be considered on an individual basis in a multidisciplinary discussion.ESGE recommends scheduled endoscopic surveillance with high definition white-light and chromoendoscopy (virtual or dye-based) with biopsies of only the suspicious areas after a curative ESD.

Enlarged folds on endoscopic gastritis as a predictor for submucosal invasion of gastric cancers

BACKGROUND

Accurate diagnosis of the depth of gastric cancer invasion is crucial in clinical practice. The diagnosis of gastric cancer depth is often made using endoscopic characteristics of the tumor and its margins; however, evaluating invasion depth based on endoscopic background gastritis remains unclear.

AIM

To investigate predicting submucosal invasion using the endoscopy-based Kyoto classification of gastritis.

METHODS

Patients with gastric cancer detected on esophagogastroduodenoscopy at Toyoshima Endoscopy Clinic were enrolled. We analyzed the effects of patient and tumor characteristics, including age, sex, body mass index, surveillance endoscopy within 2 years, current Helicobacter pylori infection, the Kyoto classification, and Lauren’s tumor type, on submucosal tumor invasion and curative endoscopic resection. The Kyoto classification included atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness. Atrophy was characterized by non-reddish and low mucosa. Intestinal metaplasia was detected as patchy whitish or grayish-white flat elevations, forming an irregular uneven surface. An enlarged fold referred to a fold width ≥ 5 mm in the greater curvature of the corpus. Nodularity was characterized by goosebump-like multiple nodules in the antrum. Diffuse redness was characterized by uniform reddish non-atrophic mucosa in the greater curvature of the corpus.

RESULTS

A total of 266 gastric cancer patients (mean age, 66.7 years; male sex, 58.6%; mean body mass index, 22.8 kg/m²) were enrolled. Ninety-three patients underwent esophagogastroduodenoscopy for surveillance within 2 years, and 140 had current Helicobacter pylori infection. The mean Kyoto score was 4.54. Fifty-eight cancers were diffuse-type, and 87 cancers had invaded the submucosa. Multivariate analysis revealed that low body mass index (odds ratio 0.88, P = 0.02), no surveillance esophagogastroduodenoscopy within 2 years (odds ratio 0.15, P < 0.001), endoscopic enlarged folds of gastritis (odds ratio 3.39, P = 0.001), and Lauren’s diffuse-type (odds ratio 5.09, P < 0.001) were independently associated with submucosal invasion. Similar results were obtained with curative endoscopic resection. Among cancer patients with enlarged folds, severely enlarged folds (width ≥ 10 mm) were more related to submucosal invasion than mildly enlarged folds (width 5-9 mm, P < 0.001).

CONCLUSION

Enlarged folds of gastritis were associated with submucosal invasion. Endoscopic observation of background gastritis as well as the lesion itself may help diagnose the depth of cancer invasion.

Unified magnifying endoscopic classification for esophageal, gastric and colonic lesions: a feasibility pilot study

Background and study aims  Image-enhanced magnifying endoscopy allows optimization of the detection and diagnosis of lesions found in the gastrointestinal tract. Current organ-specific classifications are well-accepted by specialized endoscopists but may pose confusion for general gastroenterologists. To address this, our group proposed the Unified Magnifying Endoscopic Classification (UMEC) which can be applied either in esophagus, stomach, or colon. The aim of this study was to evaluate the diagnostic performance and clinical applicability of UMEC. Patients and methods  A single-center, feasibility pilot study was conducted. Two endoscopists with experience in magnifying narrow band imaging (NBI), blinded to white-light and non-magnifying NBI findings as well as histopathological diagnosis, independently reviewed and diagnosed all images based on UMEC. In brief, UMEC is divided into three categories: non-neoplasia, intramucosal neoplasia, and deep submucosal invasive cancer. The diagnostic performance of UMEC was assessed while using the gold standard histopathology as a reference. Results  A total of 303 gastrointestinal lesions (88 esophageal squamous lesions, 90 gastric lesions, 125 colonic lesions) were assessed. The overall accuracy for both endoscopists in the diagnosis of esophageal squamous cell cancer, gastric cancer, and colorectal cancer were 84.7 %, 89.5 %, and 83.2 %, respectively. The interobserver agreement for each organ, Kappa statistics of 0.51, 0.73, and 0.63, was good. Conclusions  UMEC appears to be a simple and practically acceptable classification, particularly to general gastroenterologists, due to its good diagnostic accuracy, and deserves further evaluation in future studies.

A comprehensive update on early gastric cancer: defining terms, etiology, and alarming risk factors

INTRODUCTION

Early gastric cancer (EGC) is a well-defined gastric malignancy that is limited to the mucosa or submucosa, irrespective of lymph node metastasis. At an early stage, gastric cancer often does not cause symptoms until it becomes advanced, and it is a heterogeneous disease and usually encountered in its late stages.

AREA COVERED

This comprehensive review will provide a novel insight into the evaluation of EGC epidemiology, defining terms, extensive etiology and risk factors, and timely diagnosis since prevention is an essential approach for controlling this cancer and reducing its morbidity and mortality.

EXPERT OPINION

The causative manner of EGC is complex and multifactorial. In recent years, researchers have made significant contributions to understanding the etiology and pathogenesis of EGC, and standardization in the evaluation of disease activity. Though the incidence of this cancer is steadily declining in some advanced societies owing to appropriate interventions, there remains a serious threat to health in developing nations. Early detection of resectable gastric cancer is crucial for better patient outcomes.

Quality in diagnostic upper gastrointestinal endoscopy for the detection and surveillance of gastric cancer precursor lesions: Position paper of AEG, SEED and SEAP

This position paper, sponsored by the Asociación Española de Gastroenterología [Spanish Association of Gastroenterology], the Sociedad Española de Endoscopia Digestiva [Spanish Gastrointestinal Endoscopy Society] and the Sociedad Española de Anatomía Patológica [Spanish Anatomical Pathology Society], aims to establish recommendations for performing an high quality upper gastrointestinal endoscopy for the screening of gastric cancer precursor lesions (GCPL) in low-incidence populations, such as the Spanish population. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates different measures to improve the quality of upper gastrointestinal endoscopy in this setting and makes recommendations on how to evaluate and treat the identified lesions. We recommend that upper gastrointestinal endoscopy for surveillance of GCPL should be performed by endoscopists with adequate training, administering oral premedication and use of sedation. To improve the identification of GCPL, we recommend the use of high definition endoscopes and conventional or digital chromoendoscopy and, for biopsies, NBI should be used to target the most suspicious areas of intestinal metaplasia. Regarding the evaluation of visible lesions, the risk of submucosal invasion should be evaluated with magnifying endoscopes and endoscopic ultrasound should be reserved for those with suspected deep invasion. In lesions amenable to endoscopic resection, submucosal endoscopic dissection is considered the technique of choice.

Endoscopic Indication of Endoscopic Submucosal Dissection for Early Gastric Cancer Is Not Compatible with Pathologic Criteria in Clinical Practice

BACKGROUND

The inappropriate selection of patients with early gastric cancer (EGC) for endoscopic submucosal dissection (ESD) may lead to additional surgery because of a non-curative resection. This study was performed to assess the accuracy of clinical decisions in ESD for EGC.

METHODS

A total of 607 cases of EGC treated by ESD were prospectively enrolled from January 2011 to June 2014 at a single academic hospital. The 607 EGCs were divided into three groups (overestimated, same-estimated, and underestimated) based on pre-procedure endoscopic findings (indication) and pathological diagnosis after ESD (criteria). We evaluated the discrepancy rates between pre-procedure indication and pathological criteria, and then analyzed the pre-procedure factors that could influence the occurrence of the discrepancies.

RESULTS

The absolute, expanded, and beyond the expanded indication has its accuracy on curability criteria in 87%, 77.6%, and 55.6% of cases, respectively. The ratio of overall indication-criteria discrepancies was 250/607 (41.2%). The curability was significantly lower in the underestimated group compared to the overestimated and same-estimated groups (41.6% vs. 94.6%, 94.4%, p < 0.001). In multivariate analysis examining the predictive factors for discrepancies in the 598 EGCs with absolute/expanded indications, the endoscopic size ≥ 20 mm [odds ratio (OR) 2.493, confidence interval (CI) 1.546-4.022, p < 0.001], presence of ulcers (OR 1.712, CI 1.070-2.738, p = 0.025), patient age < 60 years (OR 1.689, CI 1.044-2.733, p = 0.033), and undifferentiated type EGC on forceps biopsy (OR 5.397, CI 2.027-14.369, p = 0.001) were all associated with discrepancies.

CONCLUSIONS

Indication judged by pre-procedural endoscopy is not sufficiently accurate to be used as a good measurement for post-procedural criteria.

Usefulness of Narrow-Band Imaging in Endoscopic Submucosal Dissection of the Stomach

There have been many advances in endoscopic imaging technologies. Magnifying endoscopy with narrow-band imaging is an innovative optical technology that enables the precise discrimination of structural changes on the mucosal surface. Several studies have demonstrated its usefulness and superiority for tumor detection and differential diagnosis in the stomach as compared with conventional endoscopy. Furthermore, magnifying endoscopy with narrow-band imaging has the potential to predict the invasion depth and tumor margins during gastric endoscopic submucosal dissection. Classifications of the findings of magnifying endoscopy with narrow-band imaging based on microvascular and pit patterns have been proposed and have shown excellent correlations with invasion depth confirmed by microscopy. In terms of tumor margin prediction, magnifying endoscopy with narrow-band imaging offers superior delineation of gastric tumor margins compared with traditional chromoendoscopy with indigo carmine. The limitations of narrow-band imaging, such as the need for considerable training, long procedure time, and lack of studies about its usefulness in undifferentiated cancer, should be resolved to confirm its value as a complementary method to endoscopic submucosal dissection. However, the role of magnifying endoscopy with narrow-band imaging is expected to increase steadily with the increasing use of endoscopic submucosal dissection for the treatment of gastric tumors.

Magnifying Endoscopy with Narrow Band Imaging of Early Gastric Cancer: Correlation with Histopathology and Mucin Phenotype

Background/Aims

Magnifying endoscopy with narrow band imaging (ME-NBI) is a useful modality for the detailed visualization of microsurface (MS) and microvascular (MV) structures in the gastrointestinal tract. This study aimed to determine whether the MS and MV patterns in ME-NBI differ according to the histologic type, invasion depth, and mucin phenotype of early gastric cancers (EGCs).

Methods

The MS and MV patterns of 160 lesions in 160 patients with EGC who underwent ME-NBI before endoscopic or surgical resection were prospectively collected and analyzed. EGCs were categorized as either differentiated or undifferentiated and as either mucosal or submucosal, and their mucin phenotypes were determined via immunohistochemistry of the tumor specimens.

Results

Differentiated tumors mainly displayed an oval and/or tubular MS pattern and a fine network or loop MV pattern, whereas undifferentiated tumors mainly displayed an absent MS pattern and a corkscrew MV pattern. The destructive MS pattern was associated with submucosal invasion, and this association was more prominent in the differentiated tumors than in the undifferentiated tumors. MUC5AC expression was increased in lesions with either a papillary or absent MS pattern and a corkscrew MV pattern, whereas MUC6 expression was increased in lesions with a papillary MS pattern and a loop MV pattern. CD10 expression was more frequent in lesions with a fine network MV pattern.

Conclusions

ME-NBI can be useful for predicting the histopathology and mucin phenotype of EGCs.

Evidence based review of the impact of image enhanced endoscopy in the diagnosis of gastric disorders

Gastric cancer is the third most common cause of cancer-related death. Advanced stages of gastric cancers generally have grim prognosis. But, good prognosis can be achieved if such cancers are detected, diagnosed and resected at early stages. However, early gastric cancers and its precursors often produce only subtle mucosal changes and therefore quite commonly remain elusive at the conventional examination with white light endoscopy. Image-enhanced endoscopy makes mucosal lesions more conspicuous and can therefore potentially yield earlier and more accurate diagnoses. Recent years have seen growing work of research in support of various types of image enhanced endoscopy (IEE) techniques (e.g., dye-chromoendoscopy; magnification endoscopy; narrow-band imaging; flexible spectral imaging color enhancement; and I-SCAN) for a variety of gastric pathologies. In this review, we will examine the evidence for the utilization of various IEE techniques in the diagnosis of gastric disorders.

What types of early gastric cancer are indicated for endoscopic ultrasonography staging of invasion depth?

AIM

To clarify the diagnostic efficacy and limitations of endoscopic ultrasonography (EUS) and the characteristics of early gastric cancers (EGCs) that are indications for EUS-based assessment of cancer invasion depth.

METHODS

We retrospectively investigated the cases of 153 EGC patients who underwent conventional endoscopy (CE) and EUS (20 MHz) before treatment.

RESULTS

We found that 13.7% were “inconclusive” cases with low-quality EUS images, including all nine of the cases with protruded (0-I)-type EGCs. There was no significant difference in the diagnostic accuracy between CE and EUS. Two significant independent risk factors for misdiagnosis by EUS were identified-ulcer scarring [UL(+); odds ratio (OR) = 4.49, P = 0.003] and non-indication criteria for endoscopic resection (ER) (OR = 3.02, P = 0.03). In the subgroup analysis, 23.1% of the differentiated-type cancers exhibiting SM massive invasion (SM2) invasion (submucosal invasion ≥ 500 μm) by CE were correctly diagnosed by EUS, and 23.1% of the undifferentiated-type EGCs meeting the expanded-indication criteria for ER were correctly diagnosed by EUS.

CONCLUSION

There is no need to perform EUS for UL(+) EGCs or 0-I-type EGCs, but EUS may enhance the pretreatment staging of differentiated-type EGCs with SM2 invasion without UL or undifferentiated-type EGCs revealed by CE as meeting the expanded-indication criteria for ER.

Magnifying endoscopy simple diagnostic algorithm for early gastric cancer (MESDA-G)

Gastric cancer is the third leading cause of cancer death worldwide. Early detection and accurate diagnosis of mucosal cancer is desirable in order to achieve decreased mortality; cause-specific survival of patients with early gastric cancer is reported to exceed 95%. Endoscopy is the functional modality to detect early cancer; however, the procedure is not definitive when using conventional white-light imaging. In contrast, magnifying narrow-band imaging (M-NBI), a novel endoscopic technology, is a powerful tool for characterizing gastric mucosal lesions because it can visualize the microvascular architecture and microsurface structure. To date, many reports on the diagnosis of early gastric cancer by M-NBI, including multicenter prospective randomized studies conducted in Japan, have been published in peer-reviewed international journals. Based on these published data, we devised a proposal for a diagnostic strategy for gastric mucosal cancer using M-NBI to simplify the process of diagnosis and improve accuracy. Herein, we recommend a diagnostic algorithm for early gastric cancer using magnifying endoscopy.

Detection and Management of Early Gastric Cancer

OPINION STATEMENT

Early gastric cancer (EGC), defined as being confined to the submucosa, is a curable condition. In recent years, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been widely applied to subgroups of mucosal cancers, thereby avoiding the burden of operation while preserving gastric function. However, it can be difficult to identify mucosal cancers, which often evade detection due to their flat shapes without ulceration. Proper preparation to clean the mucosal surface, detailed systematic observation of the entire stomach, and the use of high-resolution systems for both endoscopies equipped with image-enhanced modality and monitors would facilitate the detection of such lesions. It is also critical to evaluate the resected specimen to confirm completeness of resection (tumor-free lateral and vertical margins as well as the absence of lymphatic and vascular invasion). If the resection is incomplete, further treatment is usually recommended-further endoscopic resection for patients with positive lateral margins or surgery for patients with positive vertical margins or with lymphatic or vascular involvement. The five-year survival for endoscopically resected EGC is excellent-and comparable to that of surgical therapy. Since most gastric cancers are caused by Helicobacter pylori, this infection should be tested for routinely. If a patient is H. pylori-positive, eradication is recommended, as heterotopic, metachronous recurrence of EGC is subsequently reduced. Importantly, basic principles for early diagnosis and endoscopic treatment of EGC can be applied to neoplasms arising in other parts of the gut, such as the esophagus and colon, and would be beneficial for patients through preserving organ function and minimizing operative intervention.

Early Gastric Cancer: Current Advances of Endoscopic Diagnosis and Treatment

Endoscopy is a major method for early gastric cancer screening because of its high detection rate, but its diagnostic accuracy depends heavily on the availability of endoscopic instruments. Many novel endoscopic techniques have been shown to increase the diagnostic yield of early gastric cancer. With the improved detection rate of EGC, the endoscopic treatment has become widespread due to advances in the instruments available and endoscopist's experience. The aim of this review is to summarize frequently-used endoscopic diagnosis and treatment in early gastric cancer (EGC).

Endoscopic prediction of tumor margin and invasive depth in early gastric cancer

Gastric cancer (GC) is the fifth most common cancer and the third leading cause of cancer-related deaths in the world. The prognosis of GC is clearly associated with the tumor stage, with a 5-year overall survival rate for early gastric cancer (EGC) exceeding 90%, which is significantly higher than that of advanced gastric cancer. Endoscopic resection, including endoscopic mucosal resection and endoscopic submucosal dissection, has been adopted in recent decades as the first treatment option of EGC in many countries for its minimal invasion and high curative rate. However, the horizontal and vertical margins are related to the curative resection of EGC and the prognosis of patients. Thus the accurate prediction of the tumor boundary and its invasive depth before treatment counts for much in planning the most appropriate treatment strategy and promising curative resection. To date, various endoscopic techniques have been identified to play a role in pretreatment evaluation, such as white light endoscopy, chromoendoscopy, narrow band imaging and endoscopic ultrasonography. This article aimed to summarize the diagnostic methods, applications and limitations of these different endoscopic techniques for identifying tumor horizontal and vertical margins in EGC, helping to increase preoperative evaluation of capabilities and to improve the curative resection rate of EGC.

Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: do we have enough data to support this?

Although endoscopic submucosal dissection (ESD) is now accepted for treatment of early gastric cancers (EGC) with negligible risk of lymph node (LN) metastasis, ESD for intramucosal undifferentiated type EGC without ulceration and with diameter ≤ 2 cm is regarded as an investigational treatment according to the Japanese gastric cancer treatment guidelines. This consideration was largely based on the analysis of surgically resected EGCs that contained undifferentiated type EGCs; however, results from several institutes showed some discrepancies in sample size and incidence of LN metastasis. Recently, some reports about the safety and efficacy of ESD for undifferentiated type EGC meeting the expanded criteria have been published. Nonetheless, only limited data are available regarding long-term outcomes of ESD for EGC with undifferentiated histology so far. At the same time, endoscopists cannot ignore the patients' desire to guarantee quality of life after the relatively non-invasive endoscopic treatment when compared to conventional surgery. To satisfy the needs of patients and provide solid evidence to support ESD for undifferentiated EGC, we need more delicate tools to predict undetected LN metastasis and more data that can reveal predictive factors for LN metastasis.

Diagnostic efficacy of magnifying endoscopy with narrow-band imaging for gastric neoplasms: a meta-analysis

Background

Magnifying endoscopy with narrow-band imaging (ME-NBI) is a novel, image-enhanced endoscopic technique for differentiating gastrointestinal neoplasms and potentially enabling pathological diagnosis.

Objectives

The aim of this analysis was to assess the diagnostic performance of ME-NBI for gastric neoplasms.

Methods

We performed a systematic search of the PubMed, EMbase, Web of Science, and Cochrane Library databases for relevant studies. Meta-DiSc (version 1.4) and STATA (version 11.0) software were used for the data analysis. Random effects models were used to assess diagnostic efficacy. Heterogeneity was tested by the Q statistic and I² statistic. Meta-regression was used to analyze the sources of heterogeneity.

Results

A total of 10 studies, with 2151 lesions, were included. The pooled characteristics of these studies were as follows: sensitivity 0.85 (95% confidence interval [CI]: 0.81–0.89), specificity 0.96 (95% confidence interval [CI]: 0.95–0.97), and area under the curve (AUC) 0.9647. In the subgroup analysis, which compared the diagnostic efficacy of ME-NBI and white light imaging (WLI), the pooled sensitivity and specificity of ME-NBI were 0.87 (95% CI: 0.80–0.92) and 0.93 (95% CI: 0.90–0.95), respectively, and the area under the curve (AUC) was 0.9556. In contrast, the pooled sensitivity and specificity of WLI were 0.61 (95% CI: 0.53–0.69) and 0.65 (95% CI: 0.60–0.69), respectively, and the area under the curve (AUC) was 0.6772.

Conclusions

ME-NBI presents a high diagnostic value for gastric neoplasms and has a high specificity.

New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and ¹⁸F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years.

Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: Do we have enough data to support this?

Although endoscopic submucosal dissection (ESD) is now accepted for treatment of early gastric cancers (EGC) with negligible risk of lymph node (LN) metastasis, ESD for intramucosal undifferentiated type EGC without ulceration and with diameter ≤ 2 cm is regarded as an investigational treatment according to the Japanese gastric cancer treatment guidelines. This consideration was largely based on the analysis of surgically resected EGCs that contained undifferentiated type EGCs; however, results from several institutes showed some discrepancies in sample size and incidence of LN metastasis. Recently, some reports about the safety and efficacy of ESD for undifferentiated type EGC meeting the expanded criteria have been published. Nonetheless, only limited data are available regarding long-term outcomes of ESD for EGC with undifferentiated histology so far. At the same time, endoscopists cannot ignore the patients’ desire to guarantee quality of life after the relatively non-invasive endoscopic treatment when compared to conventional surgery. To satisfy the needs of patients and provide solid evidence to support ESD for undifferentiated EGC, we need more delicate tools to predict undetected LN metastasis and more data that can reveal predictive factors for LN metastasis.

The Usefulness of Magnifying Endoscopy and Narrow-Band Imaging in Measuring the Depth of Invasion before Endoscopic Submucosal Dissection

With the widespread application of endoscopic submucosal dissection for the treatment of gastrointestinal neoplasms, accurate determination of the invasion depth prior to intervention has become an indispensable part of treatment planning. Narrow-band imaging (NBI) is a novel endoscopic technique that may enhance the accuracy of diagnosis. Magnifying endoscopy with NBI has been shown to be effective for determining invasion depth for intrapapillary capillary loop classification of esophageal cancer and microvascular pattern of stomach cancer. Such precise pre-treatment staging of early neoplastic lesions in the gastrointestinal tract warrants timely initiation of disease-tailored treatment and, ultimately, better quality of life and improved patient survival.