Role of endoscopic ultrasound in the characterization of solid pseudopapillary neoplasm of the pancreas.

BACKGROUND: Solid pseudopapillary neoplasm (SPN) is an uncommon pathology of the pancreas with unpredictable malignant potential. Endoscopic ultrasound (EUS) assessment plays a vital role in lesion characterization and confirmation of the tissue diagnosis. However, there is a paucity of data regarding the imaging assessment of these lesions. AIM: To determine the characteristic EUS features of SPN and define its role in preoperative assessment. METHODS: This was an international, multicenter, retrospective, observational study of prospective cohorts from 7 large hepatopancreaticobiliary centers. All cases with postoperative histology of SPN were included in the study. Data collected included clinical, biochemical, histological and EUS characteristics. RESULTS: One hundred and six patients with the diagnosis of SPN were included. The mean age was 26 years (range 9 to 70 years), with female predominance (89.6%). The most frequent clinical presentation was abdominal pain (80/106; 75.5%). The mean diameter of the lesion was 53.7 mm (range 15 to 130 mm), with the slight predominant location in the head of the pancreas (44/106; 41.5%). The majority of lesions presented with solid imaging features (59/106; 55.7%) although 33.0% (35/106) had mixed solid/cystic characteristics and 11.3% (12/106) had cystic morphology. Calcification was observed in only 4 (3.8%) cases. Main pancreatic duct dilation was uncommon, evident in only 2 cases (1.9%), whilst common bile duct dilation was observed in 5 (11.3%) cases. One patient demonstrated a double duct sign at presentation. Elastography and Doppler evaluation demonstrated inconsistent appearances with no emergence of a predictable pattern. EUS guided biopsy was performed using three different types of needles: Fine needle aspiration (67/106; 63.2%), fine needle biopsy (37/106; 34.9%), and Sonar Trucut (2/106; 1.9%). The diagnosis was conclusive in 103 (97.2%) cases. Ninety-seven patients were treated surgically (91.5%) and the post-surgical SPN diagnosis was confirmed in all cases. During the 2-year follow-up period, no recurrence was observed. CONCLUSION: SPN presented primarily as a solid lesion on endosonographic assessment. The lesion tended to be located in the head or body of the pancreas. There was no consistent characteristic pattern apparent on either elastography or Doppler assessment. Similarly SPN did not frequently cause stricture of the pancreatic duct or common bile duct. Importantly, we confirmed that EUS-guided biopsy was an efficient and safe diagnostic tool. The needle type used does not appear to have a significant impact on the diagnostic yield. Overall SPN remains a challenging diagnosis based on EUS imaging with no pathognomonic features. EUS guided biopsy remains the gold standard in establishing the diagnosis.

Scoring system assessing mucosal visibility of upper gastrointestinal tract: The POLPREP scale.

BACKGROUND AND AIM: The proper visibility of mucosa during esophagogastroduodenoscopy (EGD) is crucial for the detection of early upper gastrointestinal tract lesions. In contrast to colonoscopy, no validated scoring system for the assessment of upper gastrointestinal mucosal cleanliness has been developed so far. The aim of the study was to create and validate standardized grading system (POLPREP) to assess the mucosal cleanliness during EGD. METHODS: To assess the visibility of mucosa during EGD, 4-point scale was developed (0-3). Twelve operators assessed 18 images of esophagus, stomach, and duodenum twice (in 2 weeks interval). In validation round, the images and endoscopy reports of 443 EGDs performed in six centers were assessed. RESULTS: The inter-observer accordance of POLPREP was 0.8 (intra-class correlation coefficient; 0.79 consultants, 0.85 trainees). The intra-observer repeatability was 0.64 (Fleiss kappa value; 0.64 consultants, 0.64 trainees). The lesions detection rate was significantly higher in clean (scores 2 and 3; 19.7%) than in "unclean" segments (score 1; 7.7%, P = 0.049). Score 3 was associated with over three-fold higher lesion detection than score 1 (odds ratio 3.2, 95% confidence interval 1.1-9; P = 0.03). CONCLUSIONS: The proposed POLPREP scale allows for unified assessment of upper gastrointestinal tract mucosal cleanliness. The higher cleanliness scores are related with greater upper gastrointestinal pathologies detection.

On the Track of New Endoscopic Alternatives for the Treatment of Selected Gastric GISTs-A Pilot Study.

Background and Objectives: GISTs (Gastrointestinal stromal tumors) are the most common mesenchymal gastrointestinal tract tumours and are mainly located in the stomach. Their malignant potential depends on size, location, and type. Endoscopic techniques are a less invasive modality for patients not eligible for surgery. ESD (endoscopic submucosal dissection) is mainly used for the removal of smaller GISTs, with intraluminal growth and a more superficial location. Thus, R0 resection capability in some cases may be not sufficient, limited by tumour size, location in the gastric wall, and its connection level with the muscularis propria. In such cases, an endoscopic full-thickness resection can become a new alternative. In this retrospective pilot study, we evaluated ESD and hybrid resection techniques in terms of safety, efficacy, and disease recurrence for selected types of gastric GISTs. Materials and Methods: A retrospective comparison was conducted in a group of patients who underwent ESD or a hybrid technique combining endoscopic resection with endoscopic suturing using the OverStitch system (HT) for type II or III gastric GISTs. A total of 21 patients aged 70 ± 8 years underwent endoscopic resection. Seventeen lesions were treated with ESD and four with the HT. Results: R0 resection was achieved in all patients treated using HT (type III lesions) and in 53% of those treated with ESD (p = 0.08). None of the type III lesions treated with ESD were excised with R0. Lesions treated with R0 ESD resections were significantly smaller (1.76 ± 0.35 cm) than those with R1 ESD resections (2.39 ± 0.40 cm) (p < 0.01). The mean lesion size treated with the HT was 2.88 ± 0.85 cm. Conclusions: HT may be a new resection modality for large gastric GISTs with high muscularis propria connection grades. Further studies are required to evaluate its safety and efficacy and to form precise inclusion criteria for endoscopic resection techniques.

Optimal Endoscopic Resection Technique for Selected Gastric GISTs. The Endoscopic Suturing System Combined with ESD-a New Alternative?

Background and Study Aim: In terms of therapeutic management, gastrointestinal stromal tumors (GISTs) seem to be the most difficult group of subepithelial gastrointestinal lesions (SELs). Despite various treatment option, choice of optimal management remains a dilemma in daily practice. Our aim was to evaluate a new hybrid resection technique of gastric GISTs type III as a modality of endoscopic full-thickness resection. Methods: Three males and one female (mean age of 68) were qualified for the procedure. Endoscopic full-thickness resections consisted of the endoscopic resection combined with suturing by Apollo OverStitch System. The main inclusion criterium was a complete diagnosis of GISTs (computed tomography (CT), endoscopic ultrasound (EUS), fine-needle biopsy (FNB)) with the evaluation of the tumor features, especially, the location in the gastric wall. All of the tumors were type III with a diameter between 20-40 mm. The lesions were located in the corpus (1), antrum (1) and between gastric body and fundus (2). All procedures were performed in 2019. Results: The technical and therapeutic success rate was 100% and the mean resection time 107.5 min. Neither intra- nor postprocedural complications were observed. In all four cases, R0 resection was achieved. Histopathologic assessment confirmed GIST with <5mitose/50HPF in all of the tumors, with very low risk. Conclusion: Based on our outcomes, endoscopic resection combined with the sewing by Apollo OverStitch of gastric GISTs type III, with the diameter between 20-40 mm, seems to be an effective therapeutic option with a good safety profile, however further studies with a larger treatment group are needed.

Mutational Mosaics of Cell-Free DNA from Pancreatic Cyst Fluids.

BACKGROUND: Pancreatic cyst fluids (PCFs) enriched in tumor-derived DNA are a potential source of new biomarkers. The study aimed to analyze germinal variants and mutational profiles of cell-free (cf)DNA shed into the cavity of pancreatic cysts. METHODS: The study cohort consisted of 71 patients who underwent endoscopic ultrasound fine-needle aspiration of PCF. Five malignant cysts, 19 intraductal papillary mucinous neoplasms (IPMNs), 11 mucinous cystic neoplasms (MCNs), eight serous cystic neoplasms (SCNs), and 28 pseudocysts were identified. The sequencing of 409 genes included in Comprehensive Cancer Panel was performed using Ion Proton System. The mutation rate of the KRAS and GNAS canonical loci was additionally determined using digital PCR. RESULTS: The number of mutations detected with NGS varied from 0 to 22 per gene, and genes with the most mutations were: TP53, KRAS, PIK3CA, GNAS, ADGRA2, and APC. The frequencies of the majority of mutations did not differ between non-malignant cystic neoplasms and pseudocysts. NGS detected KRAS mutations in malignant cysts (60%), IPMNs (32%), MCNs (64%), SCNs (13%), and pseudocysts (14%), with GNAS mutations in 20%, 26%, 27%, 13%, and 21% of samples, respectively. Digital PCR-based testing increased KRAS (68%) and GNAS (52%) mutations detection level in IPMNs, but not other cyst types. CONCLUSIONS: We demonstrate relatively high rates of somatic mutations of cancer-related genes, including KRAS and GNAS, in cfDNA isolated from PCFs irrespectively of the pancreatic cyst type. Further studies on molecular mechanisms of pancreatic cysts malignant transformation in relation to their mutational profiles are required.

Endoscopic Ultrasound-Guided Treatment of Gastric Varices Using Coils and Cyanoacrylate Glue Injections: Results after 1 Year of Experience.

BACKGROUND AND AIMS: Gastric varices (GVs) occur in 20% of patients with portal hypertension. GVs are associated with a 65% risk of bleeding over the course of 2 years and have a mortality rate of up to 20%. The standard treatment for GVs is obliteration with cyanoacrylate (CYA). This study presents our experience with combined therapy (vascular coils and CYA) under endoscopic ultrasound (EUS) guidance. METHODS: 16 patients (9 male and 7 female) were included into our study. Etiology of portal hypertension included: portal vein thrombosis (PVT) (31.0%), isolated splenic vein thrombosis (SVT) (25.0%), alcoholic cirrhosis (12.5%), hepatitis C cirrhosis (19.0%), and alcoholic cirrhosis with PVT (12.5%). Varices type GOV-2 were diagnosed in 8 patients, type IGV-1 and IGV-2 in 6 and 2 patients, respectively. Indications for treatment were based on endoscopic and endosonographic evaluations of GVs. Inclusion and exclusion criteria were also specified. Technique depended on the size of varices (different size of coils + CYA additionally). The results were based on the achievement of technical success, therapeutic effects, and number of adverse events. Average follow-up period was 327 days. RESULTS: From January to August 2017, 16 patients were treated with EUS-guided obliteration of GVs using vascular coils only or coils with CYA injections. 6 (37.5%) and 10 (62.5%) patients underwent primary and secondary prophylaxis for hemorrhage, respectively. Technical success was achieved in 15 patients (94.0%). Mean numbers of implanted coils and CYA volume during one procedure were 1.7 and 2 mL, respectively. Therapeutic success was achieved in all patients treated with the combination. There were no serious complications such as embolization or death due to the procedure. Three patients (19.0%) had transient abdominal pain and two (12.5%) had transient fever. 1 patient had clinical symptoms of gastrointestinal bleeding. CONCLUSIONS: Based on our retrospective research we have concluded, that EUS-guided implantation of intravascular coils combined with cyanoacrylate injections is an effective method of treatment with an acceptable number of complications.

Initial experience with endoscopic ultrasound-guided gallbladder drainage.

INTRODUCTION: Patients with acute cholecystitis who are unsuitable for cholecystectomy undergo conservative treatment or percutaneous transhepatic gallbladder drainage. As these two methods are not always successful, further treatment options are needed. One increasingly popular method is endoscopic ultrasound-guided gallbladder drainage (EUSGBD), whereby stents are placed so as to create a permanent fistula connecting the gallbladder to the stomach or the duodenal bulb, thus enabling drainage of its contents to the gastrointestinal tract. AIM: To present our early experience with EUSGBD for the treatment of cholecystitis in patients who are not suitable for cholecystectomy. MATERIAL AND METHODS: The procedure was performed in 5 patients with acute cholecystitis. Two patients also had symptoms of biliary obstruction due to pancreatic head cancer. An ultrasound endoscope was used to create a fistula between the gallbladder and the stomach or between the gallbladder and the duodenal bulb, in which a self-expandable metallic stent (SEMS) was placed. RESULTS: All procedures were performed with no perioperative complications. In all patients, the clinical symptoms of cholecystitis subsided within 3-15 days. In those patients who also showed symptoms of biliary obstruction, these symptoms subsided within 3-6 days following the procedure. CONCLUSIONS: The EUSGBD seems to be an effective and safe treatment for acute cholecystitis in patients unsuitable for cholecystectomy. It can also be used to treat jaundice caused by obstruction of the common bile duct, when no other methods can be used. The method is particularly promising in cases of concurrent acute cholecystitis and common bile duct obstruction.

Dysregulation of Mucosal Membrane Transporters and Drug-Metabolizing Enzymes in Ulcerative Colitis.

Intestinal transporters and metabolizing enzymes are the important factors of the intestinal absorption barrier. Because there is evidence that their expression and function may be affected during inflammatory conditions, we investigated gene expression, protein abundance, and regulation of relevant intestinal transporters and metabolizing enzymes in the intestinal mucosa of patients with ulcerative colitis (UC). Specimens from inflamed and noninflamed tissues of 10 patients with UC as well as colonic control tissues of 10 patients without inflammation were subjected to gene (9 enzymes, 15 transporters, 9 cytokines) and microRNA (N = 54) expression analysis. Protein abundance was quantified by liquid chromatography-tandem mass spectrometry-based targeted proteomics. Gene expression of several metabolizing enzymes (e.g., CYP2C9, UGT1A1) and transporters such as ABCB1 (ABCB1), ABCG2 (ABCG2), and monocarboxylate transporter 1 (MCT1, SLC16A1) were significantly decreased during inflammation and negatively correlated to microRNAs. On contrary, multidrug resistance-protein 4 (MRP4, ABCC4), organic anion-transporting polypeptide 2B1 (OATP2B1, SLCO2B1), and organic cation transporter-like 2 (ORCTL2, SLC22A18) were significantly elevated in inflamed tissue. However, at protein level, these findings could only be confirmed for MCT1. UC is associated with complex changes in the intestinal expression of enzymes, transporters, cytokines, and microRNAs, which may affect efficacy of anti-inflammatory drug therapy or the disease state itself.

Mass Spectrometry-Based Comprehensive Analysis of Pancreatic Cyst Fluids.

Pancreatic cyst fluids (PCFs) enriched in tumour-derived proteins are considered a potential source of new biomarkers. This study aimed to determine compositional and quantitative differences between the degradome and proteome of PCFs aspirated from different types of pancreatic cyst lesions (PCLs). 91 patients who underwent endoscopic ultrasound-fine needle aspiration under routine clinical diagnosis of PCLs were enrolled. Four cysts were malignant (CAs), and 87 were nonmalignant and consisted of 18 intraductal papillary mucinous neoplasms (IPMNs), 14 mucinous cystic neoplasms (MCNs), nine serous cystic neoplasms (SCNs), 29 pseudocysts (PCs), and 17 unclassified. Profiles of the <5 kDa fraction, the degradome, and the trypsin-digested proteome were analysed using an LTQ-Orbitrap Elite mass spectrometer coupled with a nanoACQUITY LC system. Qualitative analyses identified 796 and 366 proteins in degradome and proteome, respectively, and 689 (77%) and 285 (78%) of them were present in the Plasma Proteome Database. Gene Ontology analysis showed a significant overrepresentation of peptidases and peptidases inhibitors in both datasets. In the degradome fraction, quantitative values were obtained for 6996 peptides originating from 657 proteins. Of these, 2287 peptides were unique to a single type, and 515 peptides, derived from 126 proteins, were shared across cyst types. 32 peptides originating from 12 proteins had differential (adjusted p-value ≤0.05, FC ≥1.5) abundance in at least one of the five cysts types. In proteome, relative expression was measured for 330 proteins. Of them, 33 proteins had significantly (adjusted p-value ≤0.05, FC ≥1.5) altered abundance in at least one of the studied groups and 19 proteins appeared to be unique to a given cyst type. PCFs are dominated by blood proteins and proteolytic enzymes. Although differences in PCF peptide composition and abundance could aid classification of PCLs, the unpredictable inherent PCF proteolytic activity may limit the practical applications of PCF protein profiling.

Impaired Hepatic Adaptation to Chronic Cholestasis induced by Primary Sclerosing Cholangitis.

Pathogenesis of primary sclerosing cholangitis (PSC) may involve impaired bile acid (BA) homeostasis. We analyzed expressions of factors mediating enterohepatic circulation of BA using ileal and colonic (ascending and sigmoid) biopsies obtained from patients with PSC with and without ulcerative colitis (UC) and explanted PSC livers. Two-fold increase of BA-activated farnesoid X receptor (FXR) protein levels were seen in ascending and sigmoid colon of PSC patients with correspondingly decreased apical sodium-dependent BA transporter (ASBT) gene expression. This was associated with increased OSTß protein levels in each part of analyzed gut. An intestinal fibroblast growth factor (FGF19) protein expression was significantly enhanced in ascending colon. Despite increased hepatic nuclear receptors (FXR, CAR, SHP), and FGF19, neither CYP7A1 suppression nor CYP3A4 induction were observed. The lack of negative regulation of BA synthesis may be accountable for lower levels of cholesterol observed in PSC in comparison to primary biliary cholangitis (PBC). In conclusion, chronic cholestasis in PSC induces adaptive changes in expression of BA transporters and FXR in the intestine. However hepatic impairment of expected in chronic cholestasis downregulation of CYP7A1 and upregulation of CYP3A4 may promote BA-induced liver injury in PSC.

Do founder mutations characteristic of some cancer sites also predispose to pancreatic cancer?

Understanding of the etiology and risk of pancreatic cancer (PaCa) is still poorly understood. This study evaluated the prevalence of 10 Polish founder mutations in four genes among PaCa patients and assessed their possible association with the risk of disease in Poland. In the study 383 PaCa patients and 4,000 control subjects were genotyped for founder mutations in: BRCA1 (5382insC, 4153delA, C61G), CHEK2 (1100delC, IVS2 + 1G > A, del5395, I157T), NBS1 (657del5) and PALB2 (509_510delGA, 172_175delTTGT). A statistically significant association between the 657del5 mutation and an increased risk of pancreatic cancer was observed for NBS1 gene. The Slavic NBS1 gene mutation (657delACAAA) was detected in 8 of 383 (2.09%) unselected cases compared with 22 of 4,000 (0.55%) controls (OR: 3.80, p = 0.002). The PALB2 509_510delGA and 172_175delTTGT mutations combined were seen in 2 (0.52%) unselected cases of PaCa and in 8 (0.20%) of 4,000 controls (OR: 2.61, p = 0.49). For BRCA1, the three mutations combined were detected in 4 of 383 (1.04%) PaCa patients and in 17 of 4,000 (0.42%) controls (OR: 2.46, p = 0.20). CHEK2 mutations were not associated with the risk of pancreatic cancer (OR: 1.11, p = 0.72). The founder mutation in NBS1 (657del5) was associated with an increased risk of PaCa in heterozygous carriers, indicating that this mutation appears to predispose to cancer of the pancreas. By identifying pancreatic cancer risk groups, founder mutation testing in Poland should be considered for people at risk for PaCa.

Serum Concentrations of Selenium and Copper in Patients Diagnosed with Pancreatic Cancer.

PURPOSE: Understanding of the etiology and pathogenesis of pancreatic cancer (PaCa) is still insufficient. This study evaluated the associations between concentrations of selenium (Se) and copper (Cu) in the serum of PaCa patients. MATERIALS AND METHODS: The study included 100 PaCa patients and 100 control subjects from the same geographical region in Poland. To determine the average concentration of Se, Cu, and ratio Cu:Se in the Polish population, assay for Se and Cu was performed in 480 healthy individuals. Serum levels of Se and Cu were measured using inductively coupled plasma mass spectrometry. RESULTS: In the control group, the average Se level was 76 µg/L and Cu 1,098 µg/L. The average Se level among PaCa patients was 60 µg/L and the mean Cu level was 1,432 µg/L. The threshold point at which any decrease in Se concentration was associated with PaCa was 67.45 µg/L. The threshold point of Cu level above which there was an increase in the prevalence of PaCa was 1,214.58 µg/L. In addition, a positive relationship was observed between increasing survival time and Se plasma level. CONCLUSION: This retrospective study suggests that low levels of Se and high levels of Cu might influence development of PaCa and that higher levels of Se are associated with longer survival in patients with PaCa. The results suggest that determining the level of Se and Cu could be incorporated into a risk stratification scheme for the selection and surveillance control examination to complement existing screening and diagnostic procedures.

Selenium as a marker of cancer risk and of selection for control examinations in surveillance.

Publication is summarization of existing data being results of literature review and our experience on usefulness of selenium as a diagnostic marker selection for control examinations in surveillance and as a marker of patients with high risk of cancers.

A microRNA-based test improves endoscopic ultrasound-guided cytologic diagnosis of pancreatic cancer.

BACKGROUND & AIMS: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in combination with cytopathology is the optimal method for diagnosis and staging of pancreatic ductal adenocarcinoma (PDAC) and other pancreatic lesions. Its clinical utility, however, can be limited by high rates of indeterminate or false-negative results. We aimed to develop and validate a microRNA (miRNA)-based test to improve preoperative detection of PDAC. METHODS: Levels of miRNAs were analyzed in a centralized clinical laboratory by relative quantitative polymerase chain reaction in 95 formalin-fixed paraffin-embedded specimens and 228 samples collected by EUS-FNA during routine evaluations of patients with solid pancreatic masses at 4 institutions in the United States, 1 in Canada, and 1 in Poland. RESULTS: We developed a 5-miRNA expression classifier, consisting of MIR24, MIR130B, MIR135B, MIR148A, and MIR196, that could identify PDAC in well-characterized, formalin-fixed, paraffin-embedded specimens. Detection of PDAC in EUS-FNA samples increased from 78.8% by cytology analysis alone (95% confidence interval, 72.2%-84.5%) to 90.8% when combined with miRNA analysis (95% confidence interval, 85.6%-94.5%). The miRNA classifier correctly identified 22 additional true PDAC cases among 39 samples initially classified as benign, indeterminate, or nondiagnostic by cytology. Cytology and miRNA test results each were associated significantly with PDAC (P < .001), with positive predictive values greater than 99% (95% confidence interval, 96%-100%). CONCLUSIONS: We developed and validated a 5-miRNA classifier that can accurately predict which preoperative pancreatic EUS-FNA specimens contain PDAC. This test might aid in the diagnosis of pancreatic cancer by reducing the number of FNAs without a definitive adenocarcinoma diagnosis, thereby reducing the number of repeat EUS-FNA procedures.

Isolated right posterior bile duct injury following cholecystectomy: report of two cases.

Anatomic variations of the right biliary system are one of the most common risk factors for sectoral bile duct injury (BDI) during cholecystectomy. Isolated right posterior BDI may in particular be a challenge for both diagnosis and management. Herein we describe two cases of isolated right posterior sectoral BDI that took place during laparoscopic cholecystectomy. Despite effective external biliary drainage from the liver hilum in both cases, there was a persistent biliary leak observed which was not visible on endoscopic retrograde cholangiogram. Careful evaluation of images from both endoscopic and magnetic resonance cholangiograms revealed the diagnosis of an isolated right posterior sectoral BDI. These were treated with a delayed bisegmental (segments 6 and 7) liver resection and a Roux-en-Y hepaticojejunostomy respectively with good outcomes at 24 and 4 mo of follow-up. This paper discusses strategies for prevention of such injuries along with the diagnostic and therapeutic challenges it offers.

Endoscopic submucosal dissection for the treatment of neoplastic lesions in the gastrointestinal tract.

AIM: To investigate the indications, resection rate, and safety of endoscopic submucosal dissection (ESD) for neoplastic lesions in the gastrointestinal tract at a European referral center. METHODS: We carried out a retrospective analysis of the ESD procedures performed in our center for mucosal neoplastic and submucosal lesions of the gastrointestinal tract. The duration of the procedure, en bloc and complete (R0) resection rates, and complication rates were evaluated. Variables were reported as mean ± SD or simple proportions. Univariate analysis and comparisons of procedure times and resection rates were performed using Mann-Whitney U tests, or χ(2) tests for dichotomous variables. RESULTS: Between 2007 and 2011, ESD was performed in a total of 103 patients (46.7% male, mean age 64.0 ± 12.7 years). The indications for the procedure were epithelial tumor (n = 54), submucosal tumor (n = 42), or other (n = 7). The total en bloc resection rate was 90.3% (93/103) and R0 resection rate 80.6% (83/103). The median speed of the procedure was 15.0 min/cm(2). The complete resection rate was lower for submucosal tumors arising from the muscle layer (68%, 15/22, P < 0.05). Resection speed was quicker for submucosal tumors localized in the submucosal layer than for lesions arising from the muscularis propria layer (8.1 min/cm(2) vs 17.9 min/cm(2), P < 0.05). The R0 resection rate and speed were better in the last 24 mo (90.1%, 49/54 and 15.3 min/cm(2)) compared to the first 3 years of treatment (73.5%, 36/49, P < 0.05 and 22.0 min/cm(2), P < 0.05). Complications occurred in 14.6% (n = 15) of patients, including perforation in 5.8% (n = 6), pneumoperitoneum in 3.9% (n = 4), delayed bleeding in 1.9% (n = 2), and other in 2.9% (n = 3). Only one patient with delayed perforation required surgical treatment. During the mean follow-up of 26 ± 15.3 mo, among patients with R0 resection, recurrence occurred in one patient (1.2%). CONCLUSION: ESD is an effective and safe method for resection of neoplastic lesions with low recurrence. Speed and the R0 resection rate increased after 50 procedures.