Endoscopic submucosal dissection of early gastric cancer

Diagnostic Endoscopic Ultrasound (EUS) of the Luminal Gastrointestinal Tract

The purpose of this review is to focus on the diagnostic endoscopic ultrasound of the gastrointestinal tract. In the last decades, EUS has gained a central role in the staging of epithelial and sub-epithelial lesions of the gastrointestinal tract. With the evolution of imaging, the position of EUS in the diagnostic work-up and the staging flow-chart has continuously changed with two extreme positions: some gastroenterologists think that EUS is absolutely indispensable, and some think it is utterly useless. The truth is, as always, somewhere in between the two extremes. Analyzing the most up-to-date and strong evidence, we will try to give EUS the correct position in our daily practice.

Endoscopic Ultrasound in Cancer Staging

The authors review the role of endoscopic ultrasound (EUS) in the staging of cancers throughout the gastrointestinal tract. EUS offers an advantage over cross-sectional imaging in locoregional tumor staging but is less sensitive in identifying distant metastasis. The addition of FNA increases diagnostic accuracy and provides a tissue diagnosis. EUS combined with cross-sectional imaging is important in accurately staging GI tumors and thereby reducing unnecessary procedures and health care costs.

Usefulness of a new polyvinyl alcohol hydrogel (PVA-H)-based simulator for endoscopic submucosal dissection training: a pilot study

BACKGROUND/AIMS

We developed a new endoscopic submucosal dissection (ESD) simulator and evaluated its efficacy and realism for use training endoscopists.

METHODS

An ESD simulator was constructed using polyvinyl alcohol hydrogel sheets and compared to a previous ESD simulator. Between March 1, 2020, and December 30, 2021, eight expert endoscopists from three different centers analyzed the procedure-related factors of the simulator. Five trainees performed gastric ESD exercises under the guidance of these experts.

RESULTS

Although the two ESD simulators provided overall favorable outcomes in terms of ESD-related factors, the new simulator had several benefits, including better marking of the target lesion's limits (p<0.001) and overall handling (p<0.001). Trainees tested the usefulness of the new ESD simulator. The complete resection rate improved after 3 ESD training sessions (9 procedures), and the perforation rate decreased after 4 sessions (12 procedures).

CONCLUSION

We have developed a new ESD simulator that can help beginners achieve a high level of technical experience before performing real-time ESD procedures in patients.

Simple and Reliable Method for Gastric Subepithelial Tumor Localization Using Endoscopic Tattooing before Totally Laparoscopic Resection

Background: Totally laparoscopic surgery for early gastric cancer and subepithelial tumors has been popularized worldwide, yet localization of early or small-sized tumors is a persistent challenge due to difficulty being identified with the lack of manual tactile sensation. Thus, accurate localization with tattooing before the surgery would help improve efficiency during surgery. There are multiple methods to localize tumors before laparoscopy, each with varying advantages and disadvantages. The use of endoscopic tattooing with dye has been carried out for several decades due to its safety, lower cost, and convenience. However, there is a lack of studies on endoscopic tattooing before totally laparoscopic resection. Aims: To evaluate the effect of endoscopic tattooing with dye for gastric subepithelial tumors localization before laparoscopic resection and to evaluate the tattooing effect on different locations of tumors in stomach. Method: We retrospectively collected data of patients with gastric subepithelial tumors who underwent endoscopic tattooing before totally laparoscopic resection from 2017 to 2020 in a university affiliated medical center. All patients were analyzed for preoperative characteristics and then categorized into two groups based on tumor locations concerning the difficulty of laparoscopic surgery. The independent t test and Chi-square test were performed to compare perioperative outcome and complications between these two groups. Result: A total of 19 patients were included retrospectively at our center. The individuals were 5 male and 14 female patients with a mean age of 58.2 years old. Most patients had no symptoms, and the tumors were found incidentally in 12 patients (63%). All tumors were identified clearly during laparoscopic resection. The mean tumor size was 2.3 cm. The surgeries took an average of 111 min and a mean of 7 mL blood loss was found. All tumors had negative resection margins with no recurrence during follow-up. Gastrointestinal stromal tumor was the major pathologic diagnosis, found in 12 patients (63%), followed by the leiomyoma in 5 patients (26%). Only three patients had mild adverse effects after surgery and the symptoms were self-limited. Our analysis found no significant difference in preoperative patient characteristics and perioperative outcomes between patients with differing tumor locations. Conclusion: This study is the first and largest report on endoscopic tattooing with dye before laparoscopic resection of gastric subepithelial tumor resection. Our results emphasize that endoscopic tattooing with dye is a safe and reliable method for localizing subepithelial tumors in the stomach prior to totally laparoscopic resection, with no correlation to where the tumor is located.

Analysis of lymph node metastasis in early gastric cancer: a single institutional experience from China

BACKGROUND

Lymph node metastasis (LNM) has a strong influence on the prognosis of patients with early gastric cancer (EGC). The aim of this study was to reveal the incidence of LNM and evaluate risk factors for LNM to determine the appropriate treatment for EGC in a Chinese population.

METHODS

Patients who underwent radical gastrectomy with lymph node dissection for EGC between 2012 and 2017 were retrospectively analyzed. Univariate and multivariate analyses were conducted to identify clinicopathological features that were risk factors for LNM.

RESULTS

A total of 1033 patients with EGC were enrolled. Of these patients, 668 (64.7%) were men, and 365 (35.3%) were women, ranging in age from 19 to 82 years (mean 56.9 ± 10.9 years). LNM was detected in 173(16.7%) patients with EGC. Among 508 patients with mucosal cancer, 44 (8.7%) patients had LNM. In 525 patients with submucosal cancer, the incidence of LNM was 24.6% (129/525). The age, gender, tumor size, type of differentiation, Lauren classification, and lymphovascular and perineural invasion showed a significant correlation with the rate of LNM in EGC by univariate and multivariate analyses. Patients with submucosal gastric cancer had an older age, a higher proportion of proximal lesion, larger tumor size, more frequent lymphovascular invasion, perineural invasion, and more LNM than patients with mucosal gastric cancer.

CONCLUSIONS

Our study revealed a relatively high incidence of LNM in EGC, compared with Japanese and Korean cohorts. Female sex, large tumor size, undifferentiated-type, and lymphovascular invasion were independent risk factors for LNM in EGC. Radical gastrectomy with lymphadenectomy should be performed in EGC patients with a high risk of LNM.

Deployable, Variable Stiffness, Cable Driven Robot for Minimally Invasive Surgery

Minimally Invasive Surgery (MIS) imposes a trade-off between non-invasive access and surgical capability. Treatment of early gastric cancers over 20 mm in diameter can be achieved by performing Endoscopic Submucosal Dissection (ESD) with a flexible endoscope; however, this procedure is technically challenging, suffers from extended operation times and requires extensive training. To facilitate the ESD procedure, we have created a deployable cable driven robot that increases the surgical capabilities of the flexible endoscope while attempting to minimize the impact on the access that they offer. Using a low-profile inflatable support structure in the shape of a hollow hexagonal prism, our robot can fold around the flexible endoscope and, when the target site has been reached, achieve a 73.16% increase in volume and increase its radial stiffness. A sheath around the variable stiffness structure delivers a series of force transmission cables that connect to two independent tubular end-effectors through which standard flexible endoscopic instruments can pass and be anchored. Using a simple control scheme based on the length of each cable, the pose of the two instruments can be controlled by haptic controllers in each hand of the user. The forces exerted by a single instrument were measured, and a maximum magnitude of 8.29 N observed along a single axis. The working channels and tip control of the flexible endoscope remain in use in conjunction with our robot and were used during a procedure imitating the demands of ESD was successfully carried out by a novice user. Not only does this robot facilitate difficult surgical techniques, but it can be easily customized and rapidly produced at low cost due to a programmatic design approach.

More Frequent Follow-up CT Scans in Postsurgical Resection Patients Than in Postendoscopic Resection Patients of Early Gastric Cancers: Impracticality of CTs for Mucosal Cancer

RATIONALE AND OBJECTIVES

The aim of this study was to compare the utility and timing of computed tomography (CT) in the detection of recurrent tumors between patients after surgical and endoscopic resections for early gastric cancer (EGC).

MATERIALS AND METHODS

A total of 670 patients after surgical (n = 535) and endoscopic (n = 135) resections for EGC between 2007 and 2009 were enrolled. The mean numbers of CT and endoscopy between both treatment groups were compared. The mean and cumulative dose length products of CT examinations were calculated. The modality that detected recurrence was compared between the two groups using the Pearson chi-square test.

RESULTS

The mean interval of CT was significantly shorter and the mean number of CTs was significantly larger in the surgical resection group than in the endoscopic resection group. All 34 gastric recurrences were diagnosed by endoscopy. All seven extragastric recurrences occurred in patients treated for EGC with submucosal invasion. Six extragastric recurrences were detected by CT out of a total of 5417 CT scans. The average cumulative dose length product was significantly higher in the surgical group than in the endoscopic resection group (P = 0.004).

CONCLUSION

Follow-up CTs were performed more frequently in patients after surgical resection than in patients after endoscopic resection of EGCs. However, CT scans were not effective in detecting recurrent tumors after either treatment methods, especially for patients treated for mucosal gastric cancer.

Mixed Histology Is a Risk Factor for Lymph Node Metastasis in Early Gastric Cancer

BACKGROUND

The risk factors of lymph node (LN) metastasis are important factors to consider in endoscopic submucosal dissection in early gastric cancer (EGC). The aim of the study was to identify the correlation between mixed histology and LN metastasis in EGC.

METHODS

A total of 1645 patients who underwent curative radical gastrectomy for EGC were divided into three groups (pure differentiated [pure D], mixed, and pure undifferentiated [pure UD]) according to histologic type. They were subsequently analyzed retrospectively for LN metastasis. The patients who had mixed histology between differentiated and undifferentiated tubular adenocarcinoma were defined as mixed group.

RESULTS

The pure UD group was significantly younger than the other groups. Tumor size was larger in the mixed group. LN metastasis occurred more frequently in the mixed group and the pure UD group than in the pure D group (pure D, mixed, and pure UD, 7.7%, 23.2%, and 10.8%, respectively; P < 0.001). A logistic regression analysis revealed that the independent risk factors for LN metastasis were large tumor size (odd ratio [OR], 1.308), submucosal invasion (OR, 3.565), lymphovascular invasion (OR, 9.755), and histologic types of mixed (OR, 2.360) and pure UD (OR, 1.657).

CONCLUSIONS

Mixed histology is an important risk factor for LN metastasis in EGC. Thus, radical gastrectomy should be considered in the cases of mixed-type histology after endoscopic resection.

Risk assessment of lymph node metastases in early gastric adenocarcinoma fulfilling expanded endoscopic resection criteria

BACKGROUND AND AIMS

Early gastric cancer (EGC) is known to present a low rate of lymph node metastases (LNMs). Gastrectomy with D2 lymphadenectomy is usually curative for EGC. Endoscopic submucosal dissection (ESD) is a well-accepted treatment modality for lesions that meet the classic criteria: those mucosal differentiated adenocarcinoma measuring 20 mm or less, without ulceration. Expanded criteria for ESD have been proposed based on a null LNM rate from large gastrectomy series from Japan. Patients with LNM have been reported in Western centers, heightening the need for validation of expanded criteria. Our aim was to assess the risk of LNM in gastrectomy specimens of patients with EGC who met the expanded criteria for ESD.

METHODS

We conducted an evaluation of gastrectomy specimens including LNM staging of patients submitted to gastrectomy for EGC in a 39-year retrospective cohort.

RESULTS

A total of 389 surgical specimens were included. From them, 135 fulfilled criteria for endoscopic resection. None of the 31 patients with classic criteria had LNM. From the 104 patients with expanded criteria, 3 had LNM (n = 104 [2.9%], 95% confidence interval, .7%-8.6%), all of them with undifferentiated tumors without ulceration, measuring less than 20 mm.

CONCLUSIONS

There is a small risk of LNM in EGC when expanded criteria for ESD are met. Refinement of the expanded criteria for the risk of LNM may be desirable in a Brazilian cohort. Meanwhile, the decision to complement the endoscopic treatment with gastrectomy will have to take into consideration the individual risk of perioperative morbidity and mortality.

Efficacy of second-look endoscopy in preventing delayed bleeding after endoscopic submucosal dissection of early gastric cancer

The present study aimed to evaluate whether second-look endoscopy (SLE) is able to prevent delayed bleeding after endoscopic submucosal dissection (ESD) of gastric carcinoma and to identify which types of lesion require SLE. ESD of gastric cancer at the early stage was performed on 210 patients between October 2014 and September 2016. Mucosal damage-associated bleeding within 24 h after ESD was considered as delayed bleeding. The association of the characteristics of patients and lesions, as well as surgical factors, with the incidence of bleeding as a measure of outcome was analyzed. A total of 110 patients with melena and/or hematemesis underwent SLE on the second day following gastric ESD. Within the entire cohort (n=210), late delayed bleeding (LDB) was defined as hematemesis or melena occurring following second-look endoscopy. Early delayed bleeding (EDB) was defined as hematemesis or melena occurring from the end of ESD to second-look endoscopy, or as active or possible bleeding at the time of the second-look endoscopy was reported in 17 (8.1%) and 20 patients(9.5%), respectively. The median interval between late delayed bleeding and ESD was one day (range, 1–10 days). The incidence of late delayed bleeding was significantly decreased in the SLE group compared with that in the non-SLE group (4.5 vs. 12%, P=0.028). Multivariate analyses revealed that ulcer, flat gross type, lesion diameter (>2 cm), the resected tumor size of >40 mm and Helicobacter pylori infection were independently associated with late delayed bleeding after ESD, while flat gross type, ulcer, the resected tumor size of >40 mm and artificial ulcer diameter >3 cm were independently associated with early delayed bleeding. Thus, the data of the present study indicates that second-look endoscopy following gastric ESD may be useful in preventing post-ESD delayed bleeding and should be performed on the second day.

CT volumetry for gastric adenocarcinoma: association with lymphovascular invasion and T-stages

Purpose

To determine whether gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict presence of lymphovascular invasion and T-stages.

Results

Gross tumor volume increased with the lymphovascular invasion (r = 0.426, P < 0.0001) and T stage (r = 0.656, P < 0.0001). Univariate analysis showed gross tumor volume could predict lymphovascular invasion (P < 0.0001). Multivariate analyses indicated gross tumor volume as an independent risk factor of lymphovascular invasion (P = 0.026, odds ratio = 2.284). The Mann-Whitney U test showed gross tumor volume could distinguish T2 from T3, T1 from T2–T4a, T1–T2 from T3–T4a and T1–T3 from T4a (P = 0.000). In the development cohort, gross tumor volume could predict lymphovascular invasion (cutoff, 15.92 cm³; AUC, 0.760), and distinguish T2 from T3 (cutoff, 10.09 cm³; AUC, 0.828), T1 from T2-T4a (cutoff, 8.20 cm³; AUC, 0.860), T1-T2 from T3-T4a (cutoff, 15.88 cm³; AUC, 0.883), and T1-T3 from T4a (cutoff, 21.53 cm³; AUC, 0.834). In validation cohort, gross tumor volume could predict presence of lymphovascular invasion (AUC, 0.742), and distinguish T2 from T3 (AUC, 0.861), T1 from T2-T4a (AUC, 0.859), T1–T2 from T3–T4a (AUC, 0.875), and T1–T3 from T4a (AUC, 0.773).

Materials and Methods

360 consecutive patients with gastric adenocarcinoma were retrospectively identified. Gross tumor volume was evaluated on multidetector computed tomography images. Statistical analysis was performed to determine whether gross tumor volume could predict presence of lymphovascular invasion and T-stages. Cutoffs of gross tumor volume were first investigated in 212 patients and then validated in an independent 148 patients using area under the receiver operating characteristic curve (AUC) for predicting lymphovascular invasion and T-stages.

Conclusions

Gross tumor volume of resectable gastric adenocarcinoma at multidetector computed tomography demonstrated capability in predicting lymphovascular invasion and distinguishing T-stages.

Optimal duration of fasting period after endoscopic submucosal dissection for gastric epithelial neoplasia: A prospective evaluation

OBJECTIVE

There are currently no standardized guidelines for adequately determining the fasting period following gastric endoscopic submucosal dissection (ESD). The aim of this study was to determine the appropriate fasting period.

METHODS

The enrolled patients were randomized into a short and a long-fasting group. In the short-fasting group, patients had fasted until the day after the ESD. In the long-fasting group, patients had fasted until 2 days after the ESD. A second-look endoscopy was performed immediately prior to starting to eat meals. The primary end-point was the measurement of discomfort-related ESD after starting meals such as epigastric pain, heartburn, regurgitation, nausea and vomiting. Secondary end-points included the bleeding rate after starting meals, hospital stay, patient satisfaction and hemostasis upon second-look endoscopy.

RESULTS

We analyzed data from 101 of 110 randomized patients. Both groups demonstrated similar baseline characteristics. There were no significant differences in reports of epigastric pain, heartburn, regurgitation, nausea and vomiting after starting meals. Both groups demonstrated similar hemostasis rates upon second-look endoscopy (26% vs 31.4%, P = 0.551) and bleeding rate (4% vs 0%, P = 0.149). The duration of hospital stay was significantly shorter in the short-fasting group (4.3 days vs 5.1 days, P < 0.001), and patient satisfaction was greater (P = 0.003) than in the long-fasting group.

CONCLUSIONS

A short fasting protocol does not cause discomfort related to ESD or influence post-ESD bleeding. Moreover, the short fasting protocol results in shorter hospital stays and greater patient satisfaction.

Endoscopic ultrasound in oncology: An update of clinical applications in the gastrointestinal tract

An accurate staging is necessary to select the best treatment and evaluate prognosis in oncology. Staging usually begins with noninvasive imaging such as computed tomography, magnetic resonance imaging or positron emission tomography. In the absence of distant metastases, endoscopic ultrasound plays an important role in the diagnosis and staging of gastrointestinal tumors, being the most accurate modality for local-regional staging. Its use for tumor and nodal involvement in pre-surgical evaluation has proven to reduce unnecessary surgeries. The aim of this article is to review the current role of endoscopic ultrasound in the diagnosis and staging of esophageal, gastric and colorectal cancer.

Feasibility study on expanded indication for endoscopic submucosal dissection of intramucosal poorly differentiated early gastric cancer

AIM: To identify clinicopathological factors predictive of lymph node metastasis (LNM) in intramucosal poorly differentiated early gastric cancer (EGC), and further to expand the possibility of using endoscopic submucosal dissection (ESD) for the treatment of intramucosal poorly differentiated EGC.

METHODS: Data for 81 surgically treated patients with intramucosal poorly differentiated EGC were collected, and the association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Several clinicopathologic factors were investigated to identify predictive factors for lymph nodes metastasis, including gender, age, family history of gastric cancer, number of tumors, tumor location, ulceration, tumor size, macroscopic type, lymphatic vessel involvement, and signet-ring-cell component.

RESULTS: Tumor size (OR = 7.273, 95%CI: 1.246-29.918, P = 0.042), lymphatic vessel involvement (OR = 42.219, 95%CI: 1.923-97.052, P = 0.018) and signet-ring-cell component (OR = 17.513, 95%CI: 1.647-77.469, P = 0.034) that were significantly associated with LNM by univariate analysis, were found to be significant and independent risk factors for LNM by multivariate analysis. However, gender, age, family history of gastric cancer, number, location, ulceration and macroscopic type of tumor were found not to be associated with LNM. Of these 81 patients diagnosed with intramucosal poorly differentiated EGC, 7 (8.6%) had LNM. The LNM rates were 9.1%, 22.2% and 57.1%, respectively, in cases with one, two and three of the risk factors. There was no LNM in 54 patients without the three risk clinicopathological factors.

CONCLUSION: Tumor size, lymphatic vessel involvement and signet-ring-cell component are independently associated with the presence of LNM in intramucosal poorly differentiated EGC. Thus, these three risk factors may be used as a simple criterion to expand the possibility of using ESD for the treatment of intramucosal poorly differentiated EGC.

Clinicopathologic Similarities of the Main and Minor Lesions of Synchronous Multiple Early Gastric Cancer

The detection rate of early gastric cancer (EGC) is increasing due to improvements in diagnostic methods, but synchronous multiple EGC (SMEGC) remains a major problem. Therefore, we investigated the characteristics of and the correlation between the main and minor lesions of SMEGC. We retrospectively reviewed the medical records of patients with EGC between April 2008 and May 2013. The main lesion was defined as the one with the greatest invasion depth. If lesions had the same invasion depth, the tumor diameter was used to define the main lesion. Of 963 patients who had treatment for EGC, 37 patients with SMEGC were analyzed. The main and minor lesions showed a significant positive correlation of size (r = 0.533, P = 0.001). The main and minor lesions of SMEGC showed the same vertical and horizontal locations at 70.3% and 64.9%, respectively (P = 0.002 and P = 0.002). Macroscopic types were identical in 67.6% (P < 0.001), and 32.4% had identical macroscopic type and location. The main and minor lesions had identical characteristics of invasion depth, presence of lymphovascular invasion (LVI), and differentiation in 78.4%, 83.8%, and 83.8%, respectively. Differentiation, LVI, and invasion depth (microscopic characteristics) were simultaneously the same in 62.2%. The location, macroscopic type, and 3 microscopic characteristics were matched in 27%. The main and minor lesions of SMEGC have similar clinicopathologic characteristics. Therefore, the possibility of SMEGC should not be neglected in cases of EGC, considering an understanding of the characteristics and association of lesions.

Identification of Serum Biomarkers for Gastric Cancer Diagnosis Using a Human Proteome Microarray

We aimed to globally discover serum biomarkers for diagnosis of gastric cancer (GC). GC serum autoantibodies were discovered and validated using serum samples from independent patient cohorts encompassing 1,401 participants divided into three groups, i.e. healthy, GC patients, and GC-related disease group. To discover biomarkers for GC, the human proteome microarray was first applied to screen specific autoantibodies in a total of 87 serum samples from GC patients and healthy controls. Potential biomarkers were identified via a statistical analysis protocol. Targeted protein microarrays with only the potential biomarkers were constructed and used to validate the candidate biomarkers using 914 samples. To provide further validation, the abundance of autoantibodies specific to the biomarker candidates was analyzed using enzyme-linked immunosorbent assays. Receiver operating characteristic curves were generated to evaluate the diagnostic accuracy of the serum biomarkers. Finally, the efficacy of prognosis efficacy of the final four biomarkers was evaluated by analyzing the clinical records. The final panel of biomarkers consisting of COPS2, CTSF, NT5E, and TERF1 provides high diagnostic power, with 95% sensitivity and 92% specificity to differentiate GC patients from healthy individuals. Prognosis analysis showed that the panel could also serve as independent predictors of the overall GC patient survival. The panel of four serum biomarkers (COPS2, CTSF, NT5E, and TERF1) could serve as a noninvasive diagnostic index for GC, and the combination of them could potentially be used as a predictor of the overall GC survival rate.

Cost comparison between surgical treatments and endoscopic submucosal dissection in patients with early gastric cancer in Korea

BACKGROUND/AIMS

This study was conducted to evaluate whether medical costs can be reduced using endoscopic submucosal dissection (ESD) instead of conventional surger-ies in patients with early gastric cancer (EGC).

METHODS

Pa-tients who underwent open gastrectomy (OG), laparoscopy-assisted gastrectomy (LAG), and ESD for EGC were recruited from three medical institutions in 2009. For macro-costing, the medical costs for each patient were derived from the ex-penses incurred during the patient's hospital stay and 1-year follow-up. The overall costs in micro-costing were determined by multiplying the unit cost with the resources used during the patients' hospitalization.

RESULTS

A total of 194 patients were included in this study. The hospital stay for ESD was 5 to 8 days and was significantly shorter than the 12-day hospital stay for OG or the 11- to 17-day stay for LAG. Using macro-costing, the average medical costs for ESD during the hospital stay ranged from 2.1 to 3.4 million Korean Won (KRW) per patient, and the medical costs for conventional surgeries were estimated to be between 5.1 million and 8.2 million KRW. There were no significant differences in the 1-year follow-up costs between ESD and conventional surger-ies.

CONCLUSIONS

ESD patients had lower medical costs than those patients who had conventional surgeries for EGC with conservative indications. (Gut Liver, 2015;9174-180).

Usefulness of Ready-to-Use 0.4% Sodium Hyaluronate (Endo-Ease) in the Endoscopic Resection of Gastrointestinal Neoplasms

BACKGROUND/AIMS

Commercially available sodium hyaluronate solutions are usually too thick to inject through catheters and need dilution with normal saline (NS) before use, which increases the risk of contamination. We evaluated the usefulness of ready-to-use 0.4% sodium hyaluronate, Endo-Ease (EE; UNIMED Pharm. Inc., Seoul, Korea).

METHODS

We performed a prospective multicenter randomized study from May 2011 to September 2012. Patients requiring endoscopic resection (ER) for gastric or colorectal neoplasm at two referral hospitals were enrolled.

RESULTS

One hundred fifty-four patients (72 with a gastric neoplasm and 82 with a colorectal neoplasm) were included in intention-to-treat analysis. Thirty-seven gastric neoplasms and 43 colorectal neoplasms were enrolled in the EE group. The usefulness rate was significantly higher in the EE group than in the NS group (89.2% vs. 60.0% for gastric neoplasms and 95.3% vs. 67.7% for colorectal neoplasms, p<0.001). In the EE group, the ease of mucosal resection was significantly higher than in the NS group (p<0.001). The injected volume was smaller in the EE group than in the NS group (p<0.05).

CONCLUSIONS

The use of EE reduced the need for additional injections and improved the ease of ER. A submucosal injection of EE is useful for the ER of both gastric and colorectal neoplasms.

Diagnostic accuracy of endoscopic ultrasonography (EUS) for the preoperative locoregional staging of primary gastric cancer

BACKGROUND

Endoscopic ultrasound (EUS) is proposed as an accurate diagnostic device for the locoregional staging of gastric cancer, which is crucial to developing a correct therapeutic strategy and ultimately to providing patients with the best chance of cure. However, despite a number of studies addressing this issue, there is no consensus on the role of EUS in routine clinical practice.

OBJECTIVES

To provide both a comprehensive overview and a quantitative analysis of the published data regarding the ability of EUS to preoperatively define the locoregional disease spread (i.e., primary tumor depth (T-stage) and regional lymph node status (N-stage)) in people with primary gastric carcinoma.

SEARCH METHODS

We performed a systematic search to identify articles that examined the diagnostic accuracy of EUS (the index test) in the evaluation of primary gastric cancer depth of invasion (T-stage, according to the AJCC/UICC TNM staging system categories T1, T2, T3 and T4) and regional lymph node status (N-stage, disease-free (N0) versus metastatic (N+)) using histopathology as the reference standard. To this end, we searched the following databases: the Cochrane Library (the Cochrane Central Register of Controlled Trials (CENTRAL)), MEDLINE, EMBASE, NIHR Prospero Register, MEDION, Aggressive Research Intelligence Facility (ARIF), ClinicalTrials.gov, Current Controlled Trials MetaRegister, and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), from 1988 to January 2015.

SELECTION CRITERIA

We included studies that met the following main inclusion criteria: 1) a minimum sample size of 10 patients with histologically-proven primary carcinoma of the stomach (target condition); 2) comparison of EUS (index test) with pathology evaluation (reference standard) in terms of primary tumor (T-stage) and regional lymph nodes (N-stage). We excluded reports with possible overlap with the selected studies.

DATA COLLECTION AND ANALYSIS

For each study, two review authors extracted a standard set of data, using a dedicated data extraction form. We assessed data quality using a standard procedure according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. We performed diagnostic accuracy meta-analysis using the hierarchical bivariate method.

MAIN RESULTS

We identified 66 articles (published between 1988 and 2012) that were eligible according to the inclusion criteria. We collected the data on 7747 patients with gastric cancer who were staged with EUS. Overall the quality of the included studies was good: in particular, only five studies presented a high risk of index test interpretation bias and two studies presented a high risk of selection bias.For primary tumor (T) stage, results were stratified according to the depth of invasion of the gastric wall. The meta-analysis of 50 studies (n = 4397) showed that the summary sensitivity and specificity of EUS in discriminating T1 to T2 (superficial) versus T3 to T4 (advanced) gastric carcinomas were 0.86 (95% confidence interval (CI) 0.81 to 0.90) and 0.90 (95% CI 0.87 to 0.93) respectively. For the diagnostic capacity of EUS to distinguish T1 (early gastric cancer, EGC) versus T2 (muscle-infiltrating) tumors, the meta-analysis of 46 studies (n = 2742) showed that the summary sensitivity and specificity were 0.85 (95% CI 0.78 to 0.91) and 0.90 (95% CI 0.85 to 0.93) respectively. When we addressed the capacity of EUS to distinguish between T1a (mucosal) versus T1b (submucosal) cancers the meta-analysis of 20 studies (n = 3321) showed that the summary sensitivity and specificity were 0.87 (95% CI 0.81 to 0.92) and 0.75 (95% CI 0.62 to 0.84) respectively. Finally, for the metastatic involvement of lymph nodes (N-stage), the meta-analysis of 44 studies (n = 3573) showed that the summary sensitivity and specificity were 0.83 (95% CI 0.79 to 0.87) and 0.67 (95% CI 0.61 to 0.72), respectively.Overall, as demonstrated also by the Bayesian nomograms, which enable readers to calculate post-test probabilities for any target condition prevalence, the EUS accuracy can be considered clinically useful to guide physicians in the locoregional staging of people with gastric cancer. However, it should be noted that between-study heterogeneity was not negligible: unfortunately, we could not identify any consistent source of the observed heterogeneity. Therefore, all accuracy measures reported in the present work and summarizing the available evidence should be interpreted cautiously. Moreover, we must emphasize that the analysis of positive and negative likelihood values revealed that EUS diagnostic performance cannot be considered optimal either for disease confirmation or for exclusion, especially for the ability of EUS to distinguish T1a (mucosal) versus T1b (submucosal) cancers and positive versus negative lymph node status.

AUTHORS' CONCLUSIONS

By analyzing the data from the largest series ever considered, we found that the diagnostic accuracy of EUS might be considered clinically useful to guide physicians in the locoregional staging of people with gastric carcinoma. However, the heterogeneity of the results warrants special caution, as well as further investigation for the identification of factors influencing the outcome of this diagnostic tool. Moreover, physicians should be warned that EUS performance is lower in diagnosing superficial tumors (T1a versus T1b) and lymph node status (positive versus negative). Overall, we observed large heterogeneity and its source needs to be understood before any definitive conclusion can be drawn about the use of EUS can be proposed in routine clinical settings.

Endoscopic treatment for early gastric cancer

Gastric cancer remains one of the most common causes of cancer death. However the proportion of early gastric cancer (EGC) at diagnosis is increasing. Endoscopic treatment for EGC is actively performed worldwide in cases meeting specific criteria. Endoscopic mucosal resection can treat EGC with comparable results to surgery for selected cases. Endoscopic submucosal dissection (ESD) increases the en bloc and complete resection rates and reduces the local recurrence rate. ESD has been performed with expanded indication and is expected to be more widely used in the treatment of EGC through the technological advances in the near future. This review will describe the techniques, indications and outcomes of endoscopic treatment for EGC.

Early gastric cancer: an update on endoscopic management

PURPOSE OF REVIEW

The review focuses on the latest endoscopic techniques that are emerging in the management of early gastric cancer.

RECENT FINDINGS

Improved sensitivity and specificity in the diagnosis of early gastric cancers has been demonstrated in a number of studies by narrow band imaging (92.7 and 94.5%), confocal laser endomicroscopy (90.2 and 98.5%), and magnification chromoendoscopy (88.6 and 93.2%), respectively. In early gastric cancer, endoscopic submucosal dissection (ESD) has been shown to be superior to endoscopic mucosal resection (EMR) with curative resection rate at 79.5% for ESD vs. 59% for EMR, and a lower local recurrence rate at 0.82% for ESD vs. 5.03% for EMR.

SUMMARY

Advanced diagnostic and therapeutic endoscopic techniques are changing the paradigm of care in patients with early gastric cancers.

Argon plasma coagulation is safe and effective for treating smaller gastric lesions with low-grade dysplasia: a comparison with endoscopic submucosal dissection

BACKGROUND AND AIMS

The best therapeutic modality has not been established for gastric low-grade adenomas or dysplasia (LGD), which can progress to invasive carcinoma despite a low risk. This study aims to investigate the clinical efficacy, safety, and local recurrence after argon plasma coagulation (APC) treatment of gastric LGD compared with endoscopic submucosal dissection (ESD).

PATIENTS AND METHODS

A total of 320 patients with gastric LGD ≤ 2.0 cm treated with APC or ESD between 2004 and 2011 were retrospectively analyzed. We compared local recurrence rate, complication rate, procedure time, and admission to hospital between APC and ESD groups.

RESULTS

Of the 320 patients, 116 patients were treated with APC and 204 with ESD. During follow-up, local recurrence was more common in the APC group (3.8 %, 4/106) than the ESD group (0.5 %, 1/188; log-rank test P = 0.036). However, all patients with local recurrence (n = 5) were treated by additional APC, and followed up without further recurrences. ESD was complicated by two perforations (1.0 %, 2/204) compared with no perforations in the APC group (0 %, 0/116). Bleeding complications were not different between the APC (1.7 %, 2/116) and ESD (2.0 %, 4/204) groups. Procedure time was shorter in the APC (7.8 ± 5.1 min) than the ESD (53.1 ± 38.1 min) group (P < 0.001). The proportion of hospitalization was less in the APC group (31.0 %, 36/116) than the ESD group (100.0 %, 204/204) (P < 0.001).

CONCLUSIONS

APC can be a good treatment option for patients with LGD ≤ 2.0 cm.

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.

Benign regional lymph nodes in gastric cancer on multidetector row CT

BACKGROUND

Benign regional lymph nodes (LNs) are sometimes enlarged in gastric cancer patients due to reactive or inflammatory changes. Frequently these enlarged LNs can mimic LN metastasis and lead to overstaging.

PURPOSE

To assess frequency of benign regional LNs in gastric cancer patients compared with that in a healthy population and to assess the frequency of benign regional LNs in gastric cancer according to T-staging.

MATERIAL AND METHODS

Between August 2005 and June 2009, 177 patients with surgically proven gastric cancer without LN metastasis (TanyN0M0) who had previously undergone preoperative multidetector row CT (MDCT) and 168 healthy patients who visited the healthcare center and underwent an abdominal MDCT were included in this retrospective study. An abdominal radiologist evaluated the distribution of regional LNs and measured the short diameter of LNs ≥6 mm, ≥8 mm, and ≥10 mm. The number of enlarged benign LNs was compared between the two groups, and the distribution of LN with regard to T-stage of gastric cancer was also evaluated.

RESULTS

At least one LN ≥6 mm, ≥8 mm, and ≥10 mm was detected in 64.4% (114/177), 22.0% (39/177), and 4.0% (7/177) of patients in the gastric cancer group, respectively, compared to 29.8% (50/168), 4.2% (7/168), and 0% of patients in the healthy group, respectively. The difference between the two groups was statistically significant (P <0.0001). The LN ≥8 mm was found in 14.9% (20/134) in early gastric cancer (T1), and 44.2% (19/43) in advanced cancer (T2 or higher); the difference was statistically significant (P = 0.0002). However, the frequency of LN ≥6 mm in mucosal cancer (T1a) and submucosal cancer (T2b) was not significantly different, regardless of its size.

CONCLUSION

Benign regional LNs ≥6 mm are more frequently detected in gastric cancer patients than in a healthy population and in advanced gastric cancer than in early cancer.