Alireza Sedarat

Suboptimal accuracy of carcinoembryonic antigen in differentiation of mucinous and nonmucinous pancreatic cysts: results of a large multicenter study.

BACKGROUND AND AIMS The exact cutoff value at which pancreatic cyst fluid carcinoembryonic antigen (CEA) level distinguishes pancreatic mucinous cystic neoplasms (MCNs) from pancreatic nonmucinous cystic neoplasms (NMCNs) is unclear. The aim of this multicenter retrospective study was to evaluate the diagnostic accuracy of cyst fluid CEA levels in differentiating between MCNs and NMCNs. METHODS Consecutive patients who underwent EUS with FNA at 3 tertiary care centers were identified. Patients with histologic confirmation of cyst type based on surgical specimens served as the criterion standard for this analysis. Demographic characteristics, EUS morphology, FNA fluid, and cytology results were recorded. Multivariate logistic regression analysis to identify predictors of MCNs was performed. Receiver-operating characteristic (ROC) curves were generated for CEA levels. RESULTS A total of 226 patients underwent surgery (mean age, 61 years, 96% white patients, 39% female patients) of whom 88% underwent Whipples procedure or distal pancreatectomy. Based on surgical histopathology, there were 150 MCNs and 76 NMCNs cases. The median CEA level was 165 ng/mL. The area under the ROC curve for CEA levels in differentiating between MCNs and NMCNs was 0.77 (95% confidence interval, 0.71-0.84, P < .01) with a cutoff of 105 ng/mL, demonstrating a sensitivity and specificity of 70% and 63%, respectively. The cutoff value of 192 ng/mL yielded a sensitivity of 61% and a specificity of 77% and would misdiagnose 39% of MCN cases. CONCLUSIONS Cyst fluid CEA levels have a clinically suboptimal accuracy level in differentiating MCNs from NMCNs. Future studies should focus on novel cyst fluid markers to improve risk stratification of pancreatic cystic neoplasms.

Risk factors for aggressive nonfunctional pancreatic neuroendocrine tumors and the role of endoscopic ultrasound guided fine-needle aspiration.

Background: Nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) are increasingly being diagnosed but management, especially of small tumors, remains a clinical dilemma. Endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) is now routinely used for diagnosis of pancreatic neuroendocrine tumors (pNETs) but has not been well studied as a tool for identifying aggressive disease. Materials and Methods: A systematic search of the cytology database identified all patients at our center who underwent EUS-FNA from 1999 through 2011 and were diagnosed with NF-pNET. Results: A total of 50 patients were identified. Though patients with metastatic disease had a mean tumor size of 40 mm compared to 25 mm in patients without metastatic disease (P = 0.04), we also identified several patients with tumors <20 mm who presented with metastatic disease. Furthermore, we found no statistically significant difference in metastatic disease between tumors <20 mm and >20 mm (P = 0.13). Using receiver operating characteristic (ROC) analysis, we found that using a cutoff point of 20 mm only led to a sensitivity of 85% in screening for metastases, while lowering the cutoff point to 18 mm allowed for a sensitivity of 95%. Conclusion: Currently, guidelines suggest that only patients with tumors greater than 20 mm undergo surgical resection, as tumors less than this size are thought to have low risk of metastases. Our analysis suggests that these recommendations could lead to undertreating patients with small tumors. Tumor size alone may be inadequate as a marker for aggressive NF-pNETs. Given this, other risk factors for aggressive pNETs should be studied to help identify the patients most likely to benefit from surgery.

Evaluation of the 2015 AGA guidelines on pancreatic cystic neoplasms in a large surgically confirmed multicenter cohort

Absract Background and study aims The American Gastroenterological Association (AGA) recently published guidelines for the management of asymptomatic pancreatic cystic neoplasms (PCNs). We aimed to evaluate the diagnostic characteristics of the AGA guidelines in appropriately recommending surgery for malignant PCNs. Patients and methods A retrospective multicenter study was performed of patients who underwent endoscopic ultrasound (EUS) for evaluation of PCNs who ultimately underwent surgical resection from 2004 – 2014. Demographics, EUS characteristics, fine-needle aspiration (FNA) results, type of resection, and final pathologic diagnosis were recorded. Patients were categorized into 2 groups (surgery or surveillance) based on what the AGA guidelines would have recommended. Performance characteristics for the diagnosis of cancer or high-grade dysplasia (HGD) on surgical pathology were calculated. Results Three hundred patients underwent surgical resection for PCNs, of whom the AGA guidelines would have recommended surgery in 121 (40.3 %) and surveillance in 179 (59.7 %) patients. Among patients recommended for surgery, 45 (37.2 %) had cancer, whereas 76 (62.8 %) had no cancer/HGD. Among patients recommended for surveillance, 170 (95.0 %) had no cancer/HGD; however, 9 (5.0 %) patients had cancer that would have been missed. For the finding of cancer/HGD on surgical pathology, the AGA guidelines had 83.3 % sensitivity (95 % CI 70.7 – 92.1), 69.1 % specificity (95 % CI 62.9 – 74.8), 37.2 % positive predictive value (95 % CI 28.6 – 46.4), 95.0 % negative predictive value (95 % CI 90.7 – 97.7), and 71.7 % accuracy (95 % CI 67.4 – 74.6). Conclusions The 2015 AGA guidelines would have resulted in 60 % fewer patients being referred for surgical resection, and accurately recommended surveillance in 95 % of patients with asymptomatic PCNs. Future prospective studies are required to validate these guidelines. Meeting presentations: Presented in part at Digestive Diseases Week 2016

Digital PCR Improves Mutation Analysis in Pancreas Fine Needle Aspiration Biopsy Specimens

Applications of precision oncology strategies rely on accurate tumor genotyping from clinically available specimens. Fine needle aspirations (FNA) are frequently obtained in cancer management and often represent the only source of tumor tissues for patients with metastatic or locally advanced diseases. However, FNAs obtained from pancreas ductal adenocarcinoma (PDAC) are often limited in cellularity and/or tumor cell purity, precluding accurate tumor genotyping in many cases. Digital PCR (dPCR) is a technology with exceptional sensitivity and low DNA template requirement, characteristics that are necessary for analyzing PDAC FNA samples. In the current study, we sought to evaluate dPCR as a mutation analysis tool for pancreas FNA specimens. To this end, we analyzed alterations in the KRAS gene in pancreas FNAs using dPCR. The sensitivity of dPCR mutation analysis was first determined using serial dilution cell spiking studies. Single-cell laser-microdissection (LMD) was then utilized to identify the minimal number of tumor cells needed for mutation detection. Lastly, dPCR mutation analysis was performed on 44 pancreas FNAs (34 formalin-fixed paraffin-embedded (FFPE) and 10 fresh (non-fixed)), including samples highly limited in cellularity (100 cells) and tumor cell purity (1%). We found dPCR to detect mutations with allele frequencies as low as 0.17%. Additionally, a single tumor cell could be detected within an abundance of normal cells. Using clinical FNA samples, dPCR mutation analysis was successful in all preoperative FNA biopsies tested, and its accuracy was confirmed via comparison with resected tumor specimens. Moreover, dPCR revealed additional KRAS mutations representing minor subclones within a tumor that were not detected by the current clinical gold standard method of Sanger sequencing. In conclusion, dPCR performs sensitive and accurate mutation analysis in pancreas FNAs, detecting not only the dominant mutation subtype, but also the additional rare mutation subtypes representing tumor heterogeneity.

Predictors for Surgical Referral in Patients with Pancreatic Cystic Lesions Undergoing Endoscopic Ultrasound: Results from a Large Multicenter Cohort Study

Objective Endoscopic ultrasound (EUS) plays an integral role in the evaluation of pancreatic cysts lesions (PCLs). The aim of the study was to determine predictors of surgical referral in patients with PCLs undergoing EUS. Methods We performed a multicenter retrospective study of patients undergoing EUS for evaluation of PCLs. Demographics, EUS characteristics, and fine-needle aspiration results were recorded. Patients were categorized into surgery or surveillance groups on the basis of post-EUS recommendations. Univariate and multivariate analyses were performed to identify predictors of surgical referral. Results 1804 patients were included. 1301 patients were recommended to undergo surveillance and 503 patients were referred for surgical evaluation, of which 360 patients underwent surgery. Multivariate analysis revealed the following 5 independent predictors of surgical referral: symptoms of weight loss on presentation (odds ratio [OR], 2.69; 95% confidence interval [CI], 1.44–5.03), EUS findings of associated solid mass (OR, 7.34; 95% CI, 3.81–14.16), main duct communication (OR, 4.13; 95% CI, 1.71–9.98), multilocular macrocystic morphology (OR, 2.79; 95% CI, 1.78–4.38), and fine-needle aspiration findings of mucin on cytology (OR, 3.06; 95% CI, 1.94–4.82). Conclusions This study identifies factors associated with surgical referral in patients with PCLs undergoing EUS. Future studies should focus on creation of risk stratification models to determine the need for surgery or enrollment in surveillance programs.

Laparoscopic-Assisted Percutaneous Endoscopic Gastrostomy.

There are a variety of techniques for gastrostomy tube placement. Endoscopic and radiologic approaches have almost entirely superseded surgical placement. However, an aging population and significant advancements in modern healthcare have resulted in patients with increasingly complex medical issues or postsurgical anatomy. The rising prevalence of obesity has also created technical challenges for proceduralists of many specialties. When patients with these comorbidities develop the need for long-term enteral nutrition and feeding tube placement, standard approaches such as percutaneous endoscopic gastrostomy (PEG) by endoscopists and percutaneous image-guided gastrostomy (PIG) by interventional radiologists may be technically difficult or impossible. For these challenging situations, laparoscopic-assisted PEG (LAPEG) is an alternative option. LAPEG combines the advantages of PEG with direct intraperitoneal visualization, helping ensure a safe tube placement tract free of intervening organs or structures. In this review, we highlight some of the important factors of first-line gastrostomy techniques, with an emphasis on the utility and procedural technique of LAPEG when they are not feasible.

Tu1919 Diagnostic Accuracy of Carcinoembryonic Antigen (CEA) in Cyst Fluid Analysis in Histologically Confirmed Pancreatic Cysts: Results From a Large, Multicenter Cohort Study

Background: The phosphatidylinositol 3-kinase (PI3K)/Akt/mTORC1/S6K pathway plays a pivotal role in the proliferation and survival of pancreatic ductal adenocarcinoma (PDAC) cells and is aberrantly activated in pancreatic cancer tissues. In addition to growth-promoting signaling, mTORC1/S6K also mediates negative feedback loops that restrain upstream signaling via insulin/IGF receptor and other tyrosine kinase receptors. Suppression of these feedback loops by selective mTORC1 inhibitors, e.g. by rapamycin and its analogs, unleashes overactivation of the PI3K/Akt pathway that potentially oppose the anti-proliferative effects of mTOR inhibitors. This prompted the development of active-site mTORC1/2 kinase inhibitors (TOR-KIs) and dual PI3K and mTOR inhibitors (PI3K/TOR-KIs). Recently, we reported that TOR-KIs induce an unexpected increase in the activity of the ERK pathway in PDAC cells through a PI3K-independent pathway. Here, we examined whether PI3K/TOR-KIs also induce ERK pathway over-activation in PDAC cells. Results: To determine the effect of dual PI3K/TOR inhibition on ERK activation, we treated serum-starved cultures of PDAC cells (MiaPaca-2 and PANC-1) with increasing concentrations of the dual PI3K/TOR-KI NPVBEZ235 for 2 h followed by stimulation with insulin and neurotensin, a potent mitogenic combination for these cells. As expected, prior exposure to NPV-BEZ235 potently blocked mTORC1 activation (scored by S6 phosphorylation at Ser-240/244) and mTORC2-mediated Akt phosphorylation at Ser-473, in a concentration-dependent manner. Strikingly, we also demonstrate, for the first time that exposure to NPV-BEZ235 markedly enhanced the increase in the phosphorylation of ERK at Thr-202 and Tyr-204. Maximal ERK over-activation coincided with complete inhibition of Akt phosphorylation at Ser-473 (produced at 100500 ηM NPV-BEZ235). ERK over-activation was also seen when PDAC cells were stimulated with 2% fetal bovine serum instead of insulin and neurotensin and when a different PI3K/ TOR-KI (PKI-587) was used instead of NPV-BEZ235. Treatment with the MEK inhibitors U126 or PD0325901 (1-5 μM) prevented ERK over-activation induced by PI3K/TOR-KIs. In order to examine whether the over-activation of the ERK pathway counterbalances the growth-suppressive effect of PI3K/TOR-KIs, PDAC cells were treated with NPV-BEZ235, PD0325901 or a combination of NPV-BEZ235 and PD0325901. The combination of these drugs caused a more pronounced inhibition of cell growth than that produced by each inhibitor added individually. Conclusion: Collectively, our results highlight the importance of discovering novel signaling crosstalk to anticipate mechanisms of tumor resistance to new drugs. The capability of predicting drug resistance can assist in developing rational and effective strategies for developing combination therapies in PDAC.

Inspection of endoscope instrument channels after reprocessing using a prototype borescope

BACKGROUND AND AIMS Visual inspection of the instrument channel has been proposed as a quality assurance step during endoscope reprocessing. However, the nature and severity of findings in a broad array of endoscopes (gastroscopes, colonoscopes, duodenoscopes, and echoendoscopes) after systemic implementation of an inspection protocol remain unknown. In addition, a study using borescope inspection in upper endoscopes and colonoscopes raised concerns about persistent simethicone residue despite full reprocessing. METHODS A pilot inspection study using a prototype borescope (SteriCam Inspection Scope; SteriView Inc, San Rafael, Calif) was performed on routinely used endoscopes after high-level disinfection, manual forced-air dry of the instrument channel, and overnight vertical storage. Video recordings 1.5 to 2 minutes in duration were reviewed for visible moisture, debris, discoloration, scratches, channel shredding (scratches that result in strips or filaments of the channel lining protruding into the lumen), and visible evidence of biofilm or simethicone residue. RESULTS A total of 97 inspections of 59 endoscopes were reviewed. The most common finding was scratches, seen in 51 devices (86%). Channel shredding was found in 35 devices (59%). Intrachannel debris was identified in 22 (23%) of the 97 inspections. No moisture was seen (0%) in the 74 inspections performed after forced-air dry and overnight vertical storage compared with moisture in 5 of 18 inspections (28%) performed after storage alone. No visual evidence of biofilm or simethicone residue was discovered despite its frequent use in our unit. CONCLUSION Internal defects of the instrument channel appear to occur frequently. Manual forced-air drying of the channel appears to be highly effective in eliminating moisture compared with overnight hang drying alone. Video inspection of the endoscope channel may be useful to audit reprocessing performance and to identify damaged endoscopes.

Endoscopic Therapies for Gastroparesis

Purpose of ReviewGastroparesis remains a difficult-to-treat disease with limited therapeutic options. Though patients often have a common syndrome of stereotypic symptoms, the underlying pathophysiology is heterogeneous, often leading to variable treatment responses. Due to limitations in medical and surgical therapies, endoscopic options have been increasingly explored. These options can be broadly categorized into pyloric-directed therapy, non-pyloric-directed therapy, and nutritional support. In this review, we will highlight current and emerging endoscopic options, such as gastric per-oral endoscopic myotomy (G-POEM).Recent FindingsEarly retrospective studies on G-POEM offer encouraging results up to one year out, with an acceptable safety profile. Other pyloric-directed therapies, such as pyloric dilation and stenting, have also been explored.SummaryWhile emerging endoscopic therapeutic options are encouraging, efficacy will likely depend on a better characterization of underlying pathophysiology and improved patient selection. Future prospective, controlled studies are needed.

Endoscopic Ultrasound-Guided Fine Needle Aspiration Accurately Diagnoses Smaller Pancreatic Neuroendocrine Tumors Compared To Computer Tomography-Guided Fine Needle Aspiration

Introduction The role of EUS-guided FNA as a highly sensitive modality in the diagnosis of pancreatic adenocarcinoma is well documented. However, there is little published data on the role of EUS-FNA in diagnosing pancreatic neuroendocrine tumors (NETs). Objective The aim of this study is to compare the sensitivity of EUS-FNA to that of CT-FNA for diagnosing pancreatic NETs. Methods This is a single institution retrospective analysis of the operating characteristics of EUS-FNA and CT-FNA in detecting pancreatic NETs. Only patients with a final diagnosis of pancreatic NET were selected for this study. Procedure related data, including tumor size and location, and presence of a cytotechnologist were recorded. The results of each FNA were compared to the final clinico-pathological diagnosis to calculate sensitivity. Results Twenty-eight patients undergoing FNA (19 by EUS, 9 by CT) were analyzed. NETs diagnosed by EUS-FNA were smaller compared with CT-FNA (2.7 ± 0.9cm vs. 6.5 ± 2.1cm, p = 0.009) and were more often found in the pancreatic head (47.4% vs. 11.1%, p = 0.035). There were no significant differences in sensitivity between EUS-FNA and CT-FNA specimens (73.7% vs. 88.9%, p = 0.33). Conclusion EUS-guided FNA is as sensitive as CT-guided FNA in diagnosing pancreatic NETs, but its main advantage is in the diagnosis of smaller pancreatic NETs in the head of the pancreas. It may also be the preferred approach in the diagnosis of multifocal pancreatic NETs in the setting of MEN I Syndrome.