A combination of molecular markers and clinical features improve the classification of pancreatic cysts

Insights into the Pathogenesis of Pancreatic Cystic Neoplasms

With the current epidemic of diagnosed pancreatic cystic neoplasms on the rise, a substantial amount of work has been done to unravel their biology, thus leading to implications on clinical decision making. Recent genetic profiling of resected human specimens has identified alterations in signaling pathways involving KRAS and GNAS signaling as early events in the pathogenesis of intraductal pancreatic mucinous neoplasms. Progressively, mutations in genes such as TP53, SMAD4, RNF43, and others are thought to characterize invasive and advanced lesions. The role of inflammation in fueling the growth and transformation of these cysts has also begun to be studied with greater interest. A number of promising clinical studies have attempted to integrate these genetic insights into classifying these cysts and treating patients. We have reviewed existing literature on similar lines besides commenting on some useful animal models that recapitulate molecular and phenotypic progression of these cysts.

Active Surveillance Beyond 5 Years Is Required for Presumed Branch-Duct Intraductal Papillary Mucinous Neoplasms Undergoing Non-Operative Management

OBJECTIVES

To evaluate the results of active surveillance beyond 5 years in patients with branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) without worrisome features (WF) and high-risk stigmata (HRS) undergoing non-operative management.

METHODS

Patients with a minimum follow-up of 5 years who underwent surveillance with at least yearly magnetic resonance imaging were included. New onset of and predictors of WF/HRS during follow-up as well as long-term survival were analyzed.

RESULTS

In all, 144 patients were followed for a median of 84 months. At diagnosis multifocal BD-IPMNs were found in 53% of cases and mean size of the largest cyst was 15.5 mm. Changes during follow-up were observed in 69 patients (48%). New onset of WF/HRS were observed in 26 patients (18%) but the rate of HRS was only 4%. WF and HRS developed after a median follow-up of 71 and 77.5 months from diagnosis, respectively, and without previous changes in 19/26 patients. Independent predictors of WF/HRS development were size at diagnosis>15 mm, increase in number of lesions, main pancreatic duct growth rate ≥0.2 mm/year, cyst growth rate >1 mm/year. Overall, the rate of pancreatic invasive malignancy was 2% and the 12-year disease-specific survival was 98.6%.

CONCLUSIONS

Long-term nonoperative management is safe for BD-IPMNs without WF and HRS. Discontinuation of surveillance cannot be recommended since one out of six patients developed WF/HRS far beyond 5 years of surveillance and without previous relevant modifications. An intensification of follow-up should be considered after 5 years.

Pancreatic Cysts - Part 2: Should We Be Less Cyst Centric?

The management of pancreatic cysts is a common problem faced by physicians and surgeons. Pancreatic cysts are important because some of them are mucin-producing cysts (MPCs), which may harbor or develop pancreatic ductal adenocarcinoma. Thus, accurate classification of pancreatic cysts and diagnosis of MPCs offer a potential for the prevention or early detection of pancreatic cancer. However, the diagnosis and management of asymptomatic pancreatic cysts are complicated by 2 factors. First, incidentally detected pancreatic cysts are often misdiagnosed as branch duct intraductal papillary mucinous neoplasms. Although most are MPCs, there are other types of cysts, such as serous cystadenomas, which are managed differently. Second, only a minority of MPCs will ultimately develop into invasive pancreatic ductal adenocarcinoma. Thus, on the one hand, pancreatic cysts offer a unique opportunity to identify precursors to pancreatic cancer and improve outcomes. On the other hand, misdiagnosis and overzealous testing or unnecessary surgery may lead to high cost and harm to patients. Several guidelines have been developed by various groups for the management of pancreatic cysts. In this article, we review the strengths and weaknesses of the American Gastroenterology Association guidelines, highlight key recommendations requiring further validation, and provide our balanced approach to diagnosing and managing pancreatic cysts.

Pancreatic Cysts and Guidelines

Pancreatic cysts, especially incidental asymptomatic ones seen on noninvasive imaging such as CT or MR imaging, remain a clinical challenge. The etiology of such cysts may range from benign cysts without any malignant potential such as pancreatic pseudocysts and serous cystadenomas to premalignant or frankly malignant cysts such as mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, cystic degeneration associated with solid tumors such as pancreatic ductal adenocarcinoma or pancreatic endocrine neoplasms, and solid pseudopapillary neoplasms. The clinical challenge in 2017 is to accurately preoperatively diagnose them and their malignant potential before deciding about surgery, surveillance or doing nothing. This review will focus on the currently available clinical guidelines for doing so.

Pancreatic Cysts: Controversies, Advances, Diagnoses, and Therapies

Pancreatic cysts are commonly found on cross-sectional imaging. The question arises in determining which lesions are premalignant or malignant and may require further testing, intervention, or follow-up. In pancreatic cysts without obvious malignancy on imaging, we approach them using the Four "S" Criteria. These are (1) symptoms that may be originating from the pancreatic cyst; (2) size of the cyst 2 cm or larger and/or main pancreatic duct greater than 5 mm; (3) survival of the patient, based on comorbidity index to determine surgical fitness; and then endoscopic ultrasound with fine needle aspiration (FNA) recommended to determine (4) solid component presence in the cyst, namely, nodule or thick walls, as well as to perform FNA to obtain cyst content. Current cyst fluid analysis options include use of cytology to determine presence of malignancy and carcinoembryonic antigen and fluid genetics to identify potentially premalignant lesions. The aims of this article are to explore current management guidelines for pancreatic cysts, present a comprehensive approach to pancreatic cysts, and explain the advantages and disadvantages of each option for evaluation of pancreatic cysts including endoscopic ultrasound with FNA with cyst fluid analysis using an evidence-based approach.

Fhit down-regulation is an early event in pancreatic carcinogenesis

Aberrant Fhit expression characterizes a large proportion of primary pancreatic ductal adenocarcinomas (PDACs), but fragmentary information is available on Fhit expression during the phenotypic changes of pancreatic ductal epithelium during multistep transformation. We assessed Fhit expression by immunohistochemistry in two different multistep pancreatic carcinogenic processes: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). We considered 105 surgically treated PDACs/IPMNs and selected 30 samples of non-neoplastic pancreatic parenchyma, 50 PanIN lesions, 30 IPMNs, 15 IPMNs with associated invasive carcinoma, and 60 adenocarcinomas. Normal pancreatic ducts and surrounding acinar cells consistently showed moderate to strong Fhit immunoreactivity. Significant down-regulation of Fhit expression was observed in association with increasing severity of dysplastia/neoplastia in both carcinogenic processes. This was further confirmed by studying multiple lesions obtained from the same surgical specimen. Of 60 PDACs, only 14 showed Fhit expression comparable to normal pancreatic ductal epithelium, while the remainder (77%) showed clearly negative or reduced Fhit expression. This study demonstrates that Fhit down-regulation is an early event in both multistep carcinogenic processes leading to PDAC.

Management of Incidental Pancreatic Cysts: A White Paper of the ACR Incidental Findings Committee

The ACR Incidental Findings Committee (IFC) presents recommendations for managing pancreatic cysts that are incidentally detected on CT or MRI. These recommendations represent an update from the pancreatic component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Pancreas Subcommittee-which included abdominal radiologists, a gastroenterologist, and a pancreatic surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion, and were finalized by informal iterative consensus. Algorithm branches successively categorize pancreatic cysts based on patient characteristics and imaging features. They terminate with an ascertainment of benignity and/or indolence (sufficient to discontinue follow-up), or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected pancreatic cysts.

Genomic Characterization of Low- and High-Grade Pancreatic Mucinous Cystic Neoplasms Reveals Recurrent KRAS Alterations in "High-Risk" Lesions

OBJECTIVES

Pancreatic ductal adenocarcinoma arises from the following 3 distinct precursor lesions: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm (MCN). Genetic abnormalities in the first 2 precursor lesions have been well characterized, but there are limited data on progression pathways in MCNs. This study aimed to characterize genomic differences between MCNs with low-grade (LG) and high-grade (HG) dysplasia or carcinoma.

METHODS

Neoplastic epithelium from surgical resections of 25 MCNs, 16 with LG dysplasia and 9 with HG dysplasia or invasive carcinoma, was analyzed by targeted massively parallel sequencing.

RESULTS

KRAS mutations were most frequent, present in 9 HG (100%) and 3 LG (19%) tumors, 2 of the latter also having discrete areas of HG tumor with the same mutation. TP53 mutations and CDKN2A loss were identified in 5 HG tumors (56%) each but not in LG tumors.

CONCLUSIONS

The low frequency of KRAS alterations in cysts without a HG component suggests that a subset of MCNs may have a low risk for malignant progression. Novel single-nucleotide variants that occur at a lower rate may help identify this group and provide a substrate for new diagnostic, prognostic, and therapeutic targets.

Bisulfite-converted duplexes for the strand-specific detection and quantification of rare mutations

The identification of mutations that are present at low frequencies in clinical samples is an essential component of precision medicine. The development of molecular barcoding for next-generation sequencing has greatly enhanced the sensitivity of detecting such mutations by massively parallel sequencing. However, further improvements in specificity would be useful for a variety of applications. We herein describe a technology (BiSeqS) that can increase the specificity of sequencing by at least two orders of magnitude over and above that achieved with molecular barcoding and can be applied to any massively parallel sequencing instrument. BiSeqS employs bisulfite treatment to distinguish the two strands of molecularly barcoded DNA; its specificity arises from the requirement for the same mutation to be identified in both strands. Because no library preparation is required, the technology permits very efficient use of the template DNA as well as sequence reads, which are nearly all confined to the amplicons of interest. Such efficiency is critical for clinical samples, such as plasma, in which only tiny amounts of DNA are often available. We show here that BiSeqS can be applied to evaluate transversions, as well as small insertions or deletions, and can reliably detect one mutation among >10,000 wild-type molecules.

Diversity of Precursor Lesions For Pancreatic Cancer: The Genetics and Biology of Intraductal Papillary Mucinous Neoplasm

Pancreatic ductal adenocarcinoma (PDA), one of the most lethal cancers worldwide, is associated with two main types of morphologically distinct precursors—pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). Although the progression of PanIN into invasive cancer has been well characterized, there remains an urgent need to understand the biology of IPMNs, which are larger radiographically detectable cystic tumors. IPMNs comprise a number of subtypes with heterogeneous histopathologic and clinical features. Although frequently remaining benign, a significant proportion exhibits malignant progression. Unfortunately, there are presently no accurate prognosticators for assessing cancer risk in individuals with IPMN. Moreover, the fundamental mechanisms differentiating PanIN and IPMN remain largely obscure, as do those that distinguish IPMN subtypes. Recent studies, however, have identified distinct genetic profiles between PanIN and IPMN, providing a framework to better understand the diversity of the precursors for PDA. Here, we review the clinical, biological, and genetic properties of IPMN and discuss various models for progression of these tumors to invasive PDA.

Intracellular HMGB1 as a novel tumor suppressor of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) driven by oncogenic K-Ras remains among the most lethal human cancers despite recent advances in modern medicine. The pathogenesis of PDAC is partly attributable to intrinsic chromosome instability and extrinsic inflammation activation. However, the molecular link between these two events in pancreatic tumorigenesis has not yet been fully established. Here, we show that intracellular high mobility group box 1 (HMGB1) remarkably suppresses oncogenic K-Ras-driven pancreatic tumorigenesis by inhibiting chromosome instability-mediated pro-inflammatory nucleosome release. Conditional genetic ablation of either single or both alleles of HMGB1 in the pancreas renders mice extremely sensitive to oncogenic K-Ras-driven initiation of precursor lesions at birth, including pancreatic intraepithelial neoplasms, intraductal papillary mucinous neoplasms, and mucinous cystic neoplasms. Loss of HMGB1 in the pancreas is associated with oxidative DNA damage and chromosomal instability characterized by chromosome rearrangements and telomere abnormalities. These lead to inflammatory nucleosome release and propagate K-Ras-driven pancreatic tumorigenesis. Extracellular nucleosomes promote interleukin 6 (IL-6) secretion by infiltrating macrophages/neutrophils and enhance oncogenic K-Ras signaling activation in pancreatic lesions. Neutralizing antibodies to IL-6 or histone H3 or knockout of the receptor for advanced glycation end products all limit K-Ras signaling activation, prevent cancer development and metastasis/invasion, and prolong animal survival in Pdx1-Cre;K-Ras^G12D/+;Hmgb1^−/− mice. Pharmacological inhibition of HMGB1 loss by glycyrrhizin limits oncogenic K-Ras-driven tumorigenesis in mice under inflammatory conditions. Diminished nuclear and total cellular expression of HMGB1 in PDAC patients correlates with poor overall survival, supporting intracellular HMGB1 as a novel tumor suppressor with prognostic and therapeutic relevance in PDAC.

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

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.

Evaluation of AGA and Fukuoka Guidelines for EUS and surgical resection of incidental pancreatic cysts

Objectives Management of asymptomatic pancreatic cysts is challenging. Guidelines by the American Gastroenterological Association (AGA) and International Association of Pancreatology (Fukuoka) seek to identify high-risk patients. We assessed performance of these guidelines in selecting patients for endoscopic ultrasound (EUS) and/or surgery. Methods PART I - We retrospectively studied 143 asymptomatic cysts with magnetic resonance imaging (MRI) followed by EUS. Appropriate selection for EUS was defined as: malignant cytology or surgical pathology, or development of concerning features on MRI as defined by the guidelines. PART II - We retrospectively studied 152 resected cysts to assess the performance of guidelines in selecting cysts for surgery using malignant histology as the outcome. Results PART I - Of 143 EUS, 43 (30.1 %) were male with median age 65.0 years (interquartile range [IQR] 58.0 - 73.0). AGA guideline demonstrated lower sensitivity (17.6 % versus 35.3 %, P = 0.03), higher specificity (94.5 % versus 66.1 %, p < 0.001), and higher accuracy (76.2 % versus 58.7 %, P = 0.002) than Fukuoka. There was no difference in positive predictive value (50.0 % versus 24.5 %, P = 0.15) and negative predictive value (78.6 % versus 76.6 %, p=0.75). PART II - Of 152 resected cysts, 45 (29.8 %) were male with median age 59.0 years (IQR 47.3 - 66.7). There was no difference in performance characteristics of the guidelines in selecting cysts for surgery. AGA and Fukuoka guidelines missed 25.0 % and 18.8 % of malignant cysts, respectively (P = 1.00). Conclusions For referral to EUS, the AGA guideline was highly specific compared to Fukuoka; both suffered from poor sensitivity, although the Fukuoka guideline was relatively more sensitive than AGA. For referral to surgery, both guidelines have modest sensitivity and specificity and miss a similar percentage of malignant lesions.

Predicting the Grade of Dysplasia of Pancreatic Cystic Neoplasms Using Cyst Fluid DNA Methylation Markers

Purpose: Pancreatic cysts are common and pose diagnostic and management challenges. Pancreatic cyst fluid markers have the potential to aid in the management of cysts with concerning imaging findings. Our aim was to evaluate cyst fluid methylated DNA markers for their accuracy for predicting the histologic grade of neoplastic pancreatic cysts.Experimental Design: Pancreatic cyst fluid samples from 183 patients (29 discovery and 154 validation) aspirated after surgical resection were analyzed for methylated DNA at selected genes (SOX17, BNIP3, FOXE1, PTCHD2, SLIT2, EYA4, and SFRP1) using methylation-specific droplet-digital PCR (dd-QMSP). Methylated DNA levels were evaluated for their accuracy at predicting the grade of dysplasia of the pancreatic cyst.Results: All six markers evaluated in the validation set could accurately distinguish high-risk cystic neoplasms (with high-grade dysplasia and/or associated invasive cancer) from low-risk cysts (lower grades of dysplasia) with accuracies from 79.8% to 83.6%. Methylated SOX17 had the highest overall accuracy as a single marker (sensitivity, 78.4%; specificity, 85.6%; accuracy 83.6%, cutoff; 25 methylated DNA molecules/μL cyst fluid). The best four-gene combination had 84.3% sensitivity, 89.4% specificity, and 88.0% accuracy at distinguishing cysts with high-grade dysplasia and/or invasive cancer from those without. All six markers were independent predictors of having invasive cancer/high-grade dysplasia after adjusting for clinical/imaging factors known to be associated with grade of dysplasia. The combination of methylated SOX17 with cytology better predicted neoplastic grade than cytology alone.Conclusions: A panel of methylated gene markers quantified by dd-QMSP can be used to predict the grade of dysplasia of pancreatic cysts. Clin Cancer Res; 23(14); 3935-44. ©2017 AACR.

Screening for Pancreatic Cancer

Pancreatic cancer (PC) is a highly fatal disease that can only be cured by complete surgical resection. However, most patients with PC have unresectable disease at the time of diagnosis, highlighting the need to detect PC and its precursor lesions earlier in asymptomatic patients. Screening is not cost-effective for population-based screening of PC. Individuals with genetic risk factors for PC based on family history or known PC-associated genetic syndromes, however, can be a potential target for PC screening programs. This article provides an overview of the epidemiology and genetic background of familial PC and discusses diagnostic and management approaches.

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

Value of adding GNAS testing to pancreatic cyst fluid KRAS and carcinoembryonic antigen analysis for the diagnosis of intraductal papillary mucinous neoplasms

BACKGROUND AND AIM

Molecular analysis of pancreatic cyst fluid (PCF) has been proposed as a novel method for differentiating pancreatic cystic lesions (PCL). The present study aimed to investigate the value of GNAS testing when added to KRAS and carcinoembryonic antigen (CEA) testing of PCF for the diagnosis of intraductal papillary mucinous neoplasms (IPMN).

METHODS

Prospectively collected endoscopic ultrasonography fine-needle aspiration (EUS-FNA) data were analyzed retrospectively for GNAS and KRAS mutations and CEA results. IPMN were histologically confirmed or supported by imaging and EUS-FNA findings (KRAS, CEA, cytology). Performance characteristics of GNAS added to KRAS and CEA for the diagnosis of IPMN were calculated.

RESULTS

The study population consisted of 197 patients with cyst fluid test results. Cysts were histologically classified in 33 patients and by clinical criteria in 164 patients. The IPMN group included 108 patients and the non-IPMN group included 89 patients. GNAS was positive in 51 patients (47.2%) with IPMN. Forty-two of these patients (82.3%) also had a KRAS mutation. Adding GNAS to KRAS increased the diagnostic accuracy from 76.6% to 79.1% (P > 0.05). Adding GNAS to CEA increased the diagnostic accuracy from 66.4% to 80.7 % (P < 0.05), but did not achieve a diagnostic superiority to KRAS testing alone (80.7% vs 76.6%, P > 0.05). The diagnostic accuracy of the triple combination was significantly better than all single tests (P < 0.05).

CONCLUSION

GNAS mutation is a highly specific test for IPMN. When GNAS testing is added to CEA and KRAS, a significantly greater overall accuracy (86.2%) is achieved.

A novel approach for selecting combination clinical markers of pathology applied to a large retrospective cohort of surgically resected pancreatic cysts

OBJECTIVE

Our objective was to develop an approach for selecting combinatorial markers of pathology from diverse clinical data types. We demonstrate this approach on the problem of pancreatic cyst classification.

MATERIALS AND METHODS

We analyzed 1026 patients with surgically resected pancreatic cysts, comprising 584 intraductal papillary mucinous neoplasms, 332 serous cystadenomas, 78 mucinous cystic neoplasms, and 42 solid-pseudopapillary neoplasms. To derive optimal markers for cyst classification from the preoperative clinical and radiological data, we developed a statistical approach for combining any number of categorical, dichotomous, or continuous-valued clinical parameters into individual predictors of pathology. The approach is unbiased and statistically rigorous. Millions of feature combinations were tested using 10-fold cross-validation, and the most informative features were validated in an independent cohort of 130 patients with surgically resected pancreatic cysts.

RESULTS

We identified combinatorial clinical markers that classified serous cystadenomas with 95% sensitivity and 83% specificity; solid-pseudopapillary neoplasms with 89% sensitivity and 86% specificity; mucinous cystic neoplasms with 91% sensitivity and 83% specificity; and intraductal papillary mucinous neoplasms with 94% sensitivity and 90% specificity. No individual features were as accurate as the combination markers. We further validated these combinatorial markers on an independent cohort of 130 pancreatic cysts, and achieved high and well-balanced accuracies. Overall sensitivity and specificity for identifying patients requiring surgical resection was 84% and 81%, respectively.

CONCLUSIONS

Our approach identified combinatorial markers for pancreatic cyst classification that had improved performance relative to the individual features they comprise. In principle, this approach can be applied to any clinical dataset comprising dichotomous, categorical, and continuous-valued parameters.

Endoscopic Ultrasound and Related Technologies for the Diagnosis and Treatment of Pancreatic Disease - Research Gaps and Opportunities: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

A workshop was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases to address the research gaps and opportunities in pancreatic endoscopic ultrasound (EUS). The event occurred on July 26, 2017 in 4 sessions: (1) benign pancreatic diseases, (2) high-risk pancreatic diseases, (3) diagnostic and therapeutics, and (4) new technologies. The current state of knowledge was reviewed, with identification of numerous gaps in knowledge and research needs. Common themes included the need for large multicenter consortia of various pancreatic diseases to facilitate meaningful research of these entities; to standardize EUS features of different pancreatic disorders, the technique of sampling pancreatic lesions, and the performance of various therapeutic EUS procedures; and to identify high-risk disease early at the cellular level before macroscopic disease develops. The need for specialized tools and accessories to enable the safe and effective performance of therapeutic EUS procedures also was discussed.

II Brazilian consensus statement on endoscopic ultrasonography

BACKGROUND AND OBJECTIVES

At the time of its introduction in the early 80s, endoscopic ultrasonography (EUS) was indicated for diagnostic purposes. Recently, EUS has been employed to assist or to be the main platform of complex therapeutic interventions.

METHODS

From a series of relevant new topics in the literature and based on the need to complement the I Brazilian consensus on EUS, twenty experienced endosonographers identified and reviewed the pertinent literature in databases. The quality of evidence, strength of recommendations, and level of consensus were graded and voted on.

RESULTS

Consensus was reached for eight relevant topics: treatment of gastric varices, staging of nonsmall cell lung cancer, biliary drainage, tissue sampling of subepithelial lesions (SELs), treatment of pancreatic fluid collections, tissue sampling of pancreatic solid lesions, celiac neurolysis, and evaluation of the incidental pancreatic cysts.

CONCLUSIONS

There is a high level of evidence for staging of nonsmall cell lung cancer; biopsy of SELs as the safest method; unilateral and bilateral injection techniques are equivalent for EUS-guided celiac neurolysis, and in patients with visible ganglia, celiac ganglia neurolysis appears to lead to better results. There is a moderate level of evidence for: yield of tissue sampling of pancreatic solid lesions is not influenced by the needle shape, gauge, or employed aspiration technique; EUS-guided and percutaneous biliary drainage present similar clinical success and adverse event rates; plastic and metallic stents are equivalent in the EUS-guided treatment of pancreatic pseudocyst. There is a low level of evidence in the routine use of EUS-guided treatment of gastric varices.

A Gastric Glycoform of MUC5AC Is a Biomarker of Mucinous Cysts of the Pancreas

Molecular indicators to specify the risk posed by a pancreatic cyst would benefit patients. Previously we showed that most cancer-precursor cysts, termed mucinous cysts, produce abnormal glycoforms of the proteins MUC5AC and endorepellin. Here we sought to validate the glycoforms as a biomarker of mucinous cysts and to specify the oligosaccharide linkages that characterize MUC5AC. We hypothesized that mucinous cysts secrete MUC5AC displaying terminal N-acetylglucosamine (GlcNAc) in either alpha or beta linkage. We used antibody-lectin sandwich assays to detect glycoforms of MUC5AC and endorepellin in cyst fluid samples from three independent cohorts of 49, 32, and 66 patients, and we used monoclonal antibodies to test for terminal, alpha-linked GlcNAc and the enzyme that produces it. A biomarker panel comprising the previously-identified glycoforms of MUC5AC and endorepellin gave 96%, 96%, and 87% accuracy for identifying mucinous cysts in the three cohorts with an average sensitivity of 92% and an average specificity of 94%. Glycan analysis showed that MUC5AC produced by a subset of mucinous cysts displays terminal alpha-GlcNAc, a motif expressed in stomach glands. The alpha-linked glycoform of MUC5AC was unique to intraductal papillary mucinous neoplasms (IPMN), whereas terminal beta-linked GlcNAc was increased in both IPMNs and mucinous cystic neoplasms (MCN). The enzyme that synthesizes alpha-GlcNAc, A4GNT, was expressed in the epithelia of mucinous cysts that expressed alpha-GlcNAc, especially in regions with high-grade dysplasia. Thus IPMNs secrete a gastric glycoform of MUC5AC that displays terminal alpha-GlcNAc, and the combined alpha-GlcNAc and beta-GlcNAc glycoforms form an accurate biomarker of mucinous cysts.

DNA testing of pancreatic cyst fluid: is it ready for prime time?

Pancreatic cysts are a clinical quandary in both diagnosis and management. Although many cysts, such as pseudocysts and serous cystadenomas, are benign and can be monitored clinically, mucinous cysts, such as intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, have the potential to progress to pancreatic cancer. Considering the poor prognosis of pancreatic cancer, the detection of a pancreatic cyst can be a source of anxiety for both the patient and physician. This diagnosis in turn can lead to expensive, invasive, and even harmful surveillance and treatment options. As a consequence, several national and international guidelines for the management of pancreatic cysts have been developed over the past decade. However, these guidelines rely on standard clinical assessment, radiographical imaging, and ancillary fluid studies that have insufficient sensitivity and specificity. The application of DNA-based molecular techniques has emerged as an adjunct to the assessment of pancreatic cysts. The cellular content of pancreatic cyst fluid aspirate is often suboptimal for analysis, but DNA isolated from lysed or exfoliated cells within the cyst can be analysed for genetic abnormalities. Moreover, whole exome sequencing and targeted sequencing of the major pancreatic cysts has identified unique mutational profiles for cyst type and genetic alterations that coincide with the development of pancreatic cancer. In this Review, we discuss the major cystic lesions of the pancreas and their underlying molecular pathology, current management guidelines for pancreatic cysts, and integration of DNA-based molecular testing within this field.

Endoscopic ultrasound-guided fine-needle aspiration plus KRAS and GNAS mutation in malignant intraductal papillary mucinous neoplasm of the pancreas

Background:KRAS and GNAS mutations are common in intraductal papillary mucinous neoplasia of the pancreas (IPMN). The aims of this study were to assess the role of pre-therapeutic cytopathology combined with KRAS and GNAS mutation assays within cystic fluid sampled by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) to predict malignancy of IPMN. Patients and methods: We prospectively included 37 IPMN patients with clinical and/or imaging predictors of malignancy (men: 24; mean age: 69.5 years). Cytopathology (performed on cystic fluid and/or IPMN nodules), KRAS (Exon 2, codon 12) and GNAS (Exon 8, codon 201) mutations assays (using TaqMan^® allelic discrimination) were performed on EUS-FNA material. The final diagnosis was obtained from IPMN resections (n = 18); surgical biopsies, EUS-FNA analyses, and follow-up (n = 19): 10 and 27 IPMN were benign and malignant, respectively. Results: Sensitivity, specificity, positive and negative predictive values, and accuracy of cytopathology alone to diagnose IPMN malignancy were 55 %, 100 %, 100 %, 45 %, and 66 %, respectively. When KRAS-mutation analysis was combined with cytopathology these values were 92 %, 50 %, 83 %, 71 %, and 81 %, respectively. GNAS assays did not improve the performances of cytopathology alone or those of cytopathology plus a KRAS assay. Conclusions: In patients with a likelihood of malignant IPMN at pre-therapeutic investigation, testing for KRAS mutations in cystic fluid sampling by EUS-FNA improved the results of cytopathology for the diagnosis of malignancy whereas GNAS mutation assay did not.

EUS for pancreatic cystic neoplasms: The roadmap to the future is much more than just a few shades of gray

Pancreatic cystic and neoplasms are being diagnosed with increasing frequency. Accurate diagnosis and determination of benign versus malignant lesions is crucial for determining need for surveillance versus surgery or endoscopic therapy as well as avoiding unnecessary surgery in cysts with no malignant potential. Tumor markers such as KRAS and GNAS hold promise, but which molecular marker or a combination of markers is most useful and cost effective remains to be seen. Advanced imaging with confocal laser endomicroscopy can serve as an optical biopsy and play a part in the diagnostic algorithm. Microforceps aided biopsy of pancreatic cyst wall and tumor contents hold great promise as they allow direct tissue acquisition. Much progress has been made in the role of EUS guided evaluation of pancreatic cystic neoplasms over the last several years, and with the advances enumerated above, the future is more than just a few shades of gray. Future studies should include prospective multi-arm trials of microforceps biopsy versus conventional EUS-FNA and use of biochemical and molecular markers, confocal laser endomicroscopy or a combination thereof to determine best approach to pancreatic cystic neoplasms. In Osler's words, 'Medicine is a science of uncertainty and an art of probability'. Incorporation of advanced imaging and molecular markers into a new diagnostic algorithm with subsequent validation through retrospective and prospective studies has the potential to increase diagnostic accuracy and guide optimal management of patients and improve outcomes.

Role of serial EUS-guided FNA on pancreatic cystic neoplasms: a retrospective analysis of repeat carcinoembryonic antigen measurements

BACKGROUND AND AIMS

Pancreatic cystic neoplasms (PCNs) often need interval surveillance, including repeat EUS, but the role of repeat FNA with fluid analysis is poorly defined. The aim of this analysis is to evaluate the potential clinical significance of serial carcinoembryonic antigen (CEA) measurements by EUS-guided FNA (EUS-FNA) in the surveillance for PCNs.

PATIENTS

Patients who underwent EUS-FNA for PCNs were studied retrospectively. EUS-FNA findings were compared between index and prior procedures among patients who underwent repeat EUS-FNA.

RESULTS

A total of 400 patients with PCNs underwent EUS-FNA. Eighty-seven of those patients had prior EUS-FNA with cyst fluid analysis. Patients with repeat FNA were significantly more likely to have multiple cysts (57% vs 41%; P = .008), multilocular cysts (75% vs 62%; P = .042), connection to pancreatic duct (33% vs 18%; P = .005), and higher initial CEA levels (94.8 vs 25.6 ng/mL; P = .003) compared with patients who had only a single FNA. A comparison of prior and index FNAs did not show significant differences in EUS or cyst fluid analysis findings. After log transformation, the association between CEA level at prior and index FNA was moderate (R² = 0.626; P < .001), but cystic fluid CEA classification with a cutoff value of 192 ng/mL changed in 17 patients (20%), without significant changes in EUS findings.

CONCLUSIONS

Repeat surveillance EUS-FNA resulted in stable CEA levels in the majority of patients, with spurious fluctuations of CEA in approximately 20% of patients. These data call into question any clinical significance attributed to an isolated interval rise in CEA level, especially in light of a stable EUS examination.

Molecular Genetics of Pancreatic Neoplasms

Pancreatic neoplasms have a wide range of histologic types with distinct clinical outcomes. Recent advances in high-throughput sequencing technologies have greatly deepened our understanding of pancreatic neoplasms. Now, the exomes of major histologic types of pancreatic neoplasms have been sequenced, and their genetic landscapes have been revealed. This article reviews the molecular changes underlying pancreatic neoplasms, with a special focus on the genetic changes that characterize the histologic types of pancreatic neoplasms. Emphasis is also made on the molecular features of key genes that have the potential for therapeutic targets.

Intraductal Tubulopapillary Neoplasm of the Pancreas: An Update From a Pathologist's Perspective

Context.—Intraductal tubulopapillary neoplasm (ITPN) is a rare intraductal epithelial neoplasm of the pancreas recently recognized as a distinct entity by the World Health Organization classification in 2010. It is defined as an intraductal, grossly visible, tubule-forming epithelial neoplasm with high-grade dysplasia and ductal differentiation without overt production of mucin. The diagnosis can be challenging owing to morphologic overlap with other intraductal lesions and its rarity. While recent advances in molecular genetic studies of ITPN have provided new tools to facilitate clinical diagnosis, the limited number of cases has yielded limited follow-up data to guide management.

Objective.—To provide a clinical, pathologic, and molecular update on ITPN with respect to clinical presentation, imaging findings, histopathologic features, differential diagnosis, biological behavior, molecular characteristics, and treatment options.

Data Sources.—Analysis of the pertinent literature (PubMed) and authors' research and clinical practice experience based on institutional and consultation materials.

Conclusions.—Clinical presentation, imaging findings, histopathology, immunohistochemistry studies, molecular characteristics, prognosis, and treatment options of ITPN are reviewed. Important differential diagnoses with other intraductal neoplasms of the pancreas—especially intraductal papillary mucinous neoplasm—using histopathologic, molecular, and immunohistochemical studies, are discussed. Despite the recent progress, more studies are necessary to assess the biology and genetics of ITPN for a better understanding of the prognostic factors and treatment options.

Plectin-1 as a Biomarker of Malignant Progression in Intraductal Papillary Mucinous Neoplasms: A Multicenter Study

OBJECTIVE

This study aimed to evaluate Plectin-1 expression as a biomarker of malignant risk for intraductal papillary mucinous neoplasms (IPMNs).

METHODS

Plectin-1 immunohistochemistry (IHC) was performed retrospectively on surgical (n = 71) and cytological (n = 33) specimens from Mayo Clinic Jacksonville and UCLA Medical Center, including IPMNs with low-grade dysplasia, high-grade dysplasia (HGD), or an associated invasive adenocarcinoma.

RESULTS

Plectin-1 expression was increased in invasive adenocarcinoma compared with adjacent in situ IPMN (P = 0.005), as well as the in situ HGD component of IPMNs with invasive cancer compared with HGD of IPMNs without invasive cancer (P = 0.02). Plectin IHC discriminated IPMNs with invasive adenocarcinoma from noninvasive IPMN (area under the curve [AUC] of 0.79, 75% sensitivity, and 85% specificity) but was insufficient for discriminating HGD IPMN from low-grade dysplasia IPMNs in surgical resections (AUC of 0.67, 56% sensitivity, and 64% specificity) or fine-needle aspiration specimens (AUC of 0.45).

CONCLUSIONS

Although Plectin-1 IHC has insufficient accuracy to be used as a definitive biomarker for malignant risk in the evaluation of IPMN biopsy or cytological specimens, increased Plectin-1 expression observed in both invasive cancer and in situ HGD of malignant IPMNs suggests that it might be successfully leveraged as a cyst fluid biomarker or molecular imaging target.

Management of Patients With Pancreatic Cysts: Analysis of Possible False-Negative Cases of Malignancy

GOALS

To examine the utility of integrated molecular pathology (IMP) in managing surveillance of pancreatic cysts based on outcomes and analysis of false negatives (FNs) from a previously published cohort (n=492).

BACKGROUND

In endoscopic ultrasound with fine-needle aspiration (EUS-FNA) of cyst fluid lacking malignant cytology, IMP demonstrated better risk stratification for malignancy at approximately 3 years' follow-up than International Consensus Guideline (Fukuoka) 2012 management recommendations in such cases.

STUDY

Patient outcomes and clinical features of Fukuoka and IMP FN cases were reviewed. Practical guidance for appropriate surveillance intervals and surgery decisions using IMP were derived from follow-up data, considering EUS-FNA sampling limitations and high-risk clinical circumstances observed. Surveillance intervals for patients based on IMP predictive value were compared with those of Fukuoka.

RESULTS

Outcomes at follow-up for IMP low-risk diagnoses supported surveillance every 2 to 3 years, independent of cyst size, when EUS-FNA sampling limitations or high-risk clinical circumstances were absent. In 10 of 11 patients with FN IMP diagnoses (2% of cohort), EUS-FNA sampling limitations existed; Fukuoka identified high risk in 9 of 11 cases. In 4 of 6 FN cases by Fukuoka (1% of cohort), IMP identified high risk. Overall, 55% of cases had possible sampling limitations and 37% had high-risk clinical circumstances. Outcomes support more cautious management in such cases when using IMP.

CONCLUSIONS

Adjunct use of IMP can provide evidence for relaxed surveillance of patients with benign cysts that meet Fukuoka criteria for closer observation or surgery. Although infrequent, FN results with IMP can be associated with EUS-FNA sampling limitations or high-risk clinical circumstances.

Pancreatic Cancer Chemoprevention Translational Workshop: Meeting Report

Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States with a 5-year survival rate of less than 10%. The Division of Cancer Prevention of the National Cancer Institute sponsored the Pancreatic Cancer Chemoprevention Translational Workshop on September 10 to 11, 2015. The goal of the workshop was to obtain information regarding the current state of the science and future scientific areas that should be prioritized for pancreatic cancer prevention research, including early detection and intervention for high-risk precancerous lesions. The workshop addressed the molecular/genetic landscape of pancreatic cancer and precursor lesions, high-risk populations and criteria to identify a high-risk population for potential chemoprevention trials, identification of chemopreventative/immunopreventative agents, and use of potential biomarkers and imaging for assessing short-term efficacy of a preventative agent. The field of chemoprevention for pancreatic cancer is emerging, and this workshop was organized to begin to address these important issues and promote multi-institutional efforts in this area. The meeting participants recommended the development of an National Cancer Institute working group to coordinate efforts, provide a framework, and identify opportunities for chemoprevention of pancreatic cancer.

Current concepts in the diagnosis and pathobiology of intraepithelial neoplasia: A review by organ system

Answer questions and earn CME/CNE In this report, a team of surgical pathologists has provided a review of intraepithelial neoplasia in a host of (but not all) anatomic sites of interest to colleagues in various medical specialties, namely, uterine cervix, ovary, breast, lung, head and neck, skin, prostate, bladder, pancreas, and esophagus. There is more experience with more readily accessible sites (such as the uterine cervix and skin) than with other anatomic sites, and the lack of uniform terminology, together with divergent biology in various sites, makes it difficult to paint a unifying, relevant portrait. The authors' aim was to provide a framework from which to move forward as we care for patients with such precancerous lesions. CA Cancer J Clin 2016;66:408-436. © 2016 American Cancer Society.

Molecular Detection of Gastrointestinal Neoplasia: Innovations in Early Detection and Screening

Emerging molecular tools promise to extend the diagnostic reach of the endoscopist and open doors to population screening for gastrointestinal (GI) cancers. This review briefly addresses biological considerations in marker detection and types of markers, highlights examples of tools under development at each organ site, and appraises the possibility of universal GI cancer screening. The outlook is positive, but further technical refinement and rigorous clinical validation are needed before most of these new approaches are ready for clinical application.

Requirement of a single high-risk feature as an indication for EUS for the diagnosis of asymptomatic pancreatic cysts

BACKGROUND AND AIMS

Endoscopic ultrasound (EUS) is widely used to evaluate pancreatic cysts. Recent American Gastroenterological Association (AGA) guideline limits EUS for evaluation of cysts with at-least two high-risk features (size ≥ 3 cm, dilated main pancreatic duct or presence of a solid component). We have investigated the impact of this guideline on sensitivity of EUS for pancreatic cancer and the reduction of EUS procedures for pancreas cysts.

METHODS

EUS procedures performed between 2004 and 2015 and related patient records were retrospectively reviewed to determine the presence or absence of high-risk features, and for the results of fine needle aspiration cytology.

RESULTS

Two hundred ten patients (108 males) underwent EUS for diagnostic evaluation of pancreatic cysts. Four patients (1.9%), all with at-least one high-risk feature, were diagnosed with cytologically-proven pancreatic cancer. Only 2 patients with cancer had at-least two high-risk features that would have warranted EUS examination based on the new AGA guideline. The requirement for at-least two high-risk features would have decreased the number of EUS procedures by 91%, but reduced the sensitivity for pancreatic malignancy to 50%. If only one high-risk feature was required, EUS procedures would have been decreased by 67%, with a sensitivity of 100%.

CONCLUSION

Limiting EUS to patients with pancreatic cysts with 2 or more high-risk features may substantially reduce the sensitivity for pancreatic malignancy. Performing EUS in patients with at least one high-risk feature may substantially decrease the need of invasive procedures without reducing sensitivity for detecting malignancy.

Treatment of branch-duct intraductal papillary mucinous neoplasms of the pancreas: state of the art

The diagnosis of branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) has been dramatically increased. BD-IPMNs are frequently discovered as incidental findings in asymptomatic individuals, mainly in elderly patients. An accurate evaluation of BD-IPMNs with high-resolution imaging techniques and endoscopic ultrasound is necessary. Patients with high-risk stigmata (HRS, obstructive jaundice, enhanced solid component) should undergo resection. Patients with worrisome features (WF, cyst size ≥3 cm, thickened enhanced cyst walls, non-enhanced mural nodules, and clinical acute pancreatitis) may undergo either a strict surveillance based on patients' characteristics (age, comorbidities) or surgical resection. Non-operative management is indicated for BD-IPMNs without HRS and WF. Patients with BD-IPMN who do not undergo resection may develop malignant change over time as well as IPMN-distinct pancreatic cancer. However, non-operative management of BD-IPMNs lacking WF and HRS is safe and the risk of malignant degeneration seems relatively low. The optimal surveillance protocol is currently unclear.

Detection of Hot-Spot Mutations in Circulating Cell-Free DNA From Patients With Intraductal Papillary Mucinous Neoplasms of the Pancreas

Intraductal papillary mucinous neoplasms (IPMNs) are the most frequent cystic pancreatic tumors. Little is known about their molecular alterations, but mutations in GNAS have been reported to promote IPMN formation. A tumor-derived fraction of circulating cell-free DNA (cfDNA), isolated from blood samples, contains many of the same mutations as the primary tumor, and could be a tool for noninvasive disease monitoring. We found that the total amount of cfDNA can discriminate between individuals without pancreatic lesions (controls) and patients with Fukuoka-negative branch-duct IPMN or pancreatic cancer. Furthermore, we detected GNAS mutations in cfDNA from patients with IPMN, but not in patients with serous cystadenoma or controls. Analyses of cfDNA might therefore be used in the diagnosis of patients with IPMN or in monitoring disease progression.

Surgical and molecular pathology of pancreatic neoplasms

BACKGROUND

Histologic characteristics have proven to be very useful for classifying different types of tumors of the pancreas. As a result, the major tumor types in the pancreas have long been classified based on their microscopic appearance.

MAIN BODY

Recent advances in whole exome sequencing, gene expression profiling, and knowledge of tumorigenic pathways have deepened our understanding of the underlying biology of pancreatic neoplasia. These advances have not only confirmed the traditional histologic classification system, but also opened new doors to early diagnosis and targeted treatment.

CONCLUSION

This review discusses the histopathology, genetic and epigenetic alterations and potential treatment targets of the five major malignant pancreatic tumors - pancreatic ductal adenocarcinoma, pancreatic neuroendocrine tumor, solid-pseudopapillary neoplasm, acinar cell carcinoma and pancreatoblastoma.

American Gastroenterological Association guidelines are inaccurate in detecting pancreatic cysts with advanced neoplasia: a clinicopathologic study of 225 patients with supporting molecular data

BACKGROUND AND AIMS

The American Gastroenterological Association (AGA) recently reported evidence-based guidelines for the management of asymptomatic neoplastic pancreatic cysts. These guidelines advocate a higher threshold for surgical resection than prior guidelines and imaging surveillance for a considerable number of patients with pancreatic cysts. The aims of this study were to assess the accuracy of the AGA guidelines in detecting advanced neoplasia and present an alternative approach to pancreatic cysts.

METHODS

The study population consisted of 225 patients who underwent EUS-guided FNA for pancreatic cysts between January 2014 and May 2015. For each patient, clinical findings, EUS features, cytopathology results, carcinoembryonic antigen analysis, and molecular testing of pancreatic cyst fluid were reviewed. Molecular testing included the assessment of hotspot mutations and deletions for KRAS, GNAS, VHL, TP53, PIK3CA, and PTEN.

RESULTS

Diagnostic pathology results were available for 41 patients (18%), with 13 (6%) harboring advanced neoplasia. Among these cases, the AGA guidelines identified advanced neoplasia with 62% sensitivity, 79% specificity, 57% positive predictive value, and 82% negative predictive value. Moreover, the AGA guidelines missed 45% of intraductal papillary mucinous neoplasms with adenocarcinoma or high-grade dysplasia. For cases without confirmatory pathology, 27 of 184 patients (15%) with serous cystadenomas (SCAs) based on EUS findings and/or VHL alterations would continue magnetic resonance imaging (MRI) surveillance. In comparison, a novel algorithmic pathway using molecular testing of pancreatic cyst fluid detected advanced neoplasias with 100% sensitivity, 90% specificity, 79% positive predictive value, and 100% negative predictive value.

CONCLUSIONS

The AGA guidelines were inaccurate in detecting pancreatic cysts with advanced neoplasia. Furthermore, because the AGA guidelines manage all neoplastic cysts similarly, patients with SCAs will continue to undergo unnecessary MRI surveillance. The results of an alternative approach with integrative molecular testing are encouraging but require further validation.

Cyst Fluid Telomerase Activity Predicts the Histologic Grade of Cystic Neoplasms of the Pancreas

PURPOSE

Pancreatic cysts frequently pose clinical dilemmas. On one hand, cysts with high-grade dysplasia offer opportunities for cure, on the other hand, those with low-grade dysplasia are easily over treated. Cyst fluid markers have the potential to improve the evaluation of these cysts. Because telomerase activity is commonly activated in malignant cells, we evaluated the diagnostic performance of cyst fluid telomerase activity measurements for predicting histologic grade.

EXPERIMENTAL DESIGN

Telomerase activity was measured using telomerase repeat amplification with digital-droplet PCR in surgically aspirated cyst fluid samples from 219 patients who underwent pancreatic resection for a cystic lesion (184 discovery, 35 validation) and 36 patients who underwent endoscopic ultrasound fine-needle aspiration. Methodologic and clinical factors associated with telomerase activity were examined.

RESULTS

Telomerase activity was reduced in samples that had undergone prior thawing. Among 119 samples not previously thawed, surgical cyst fluids from cystic neoplasms with high-grade dysplasia ± associated invasive cancer had higher telomerase activity [median (interquartile range), 1,158 (295.9-13,033)] copies/μL of cyst fluid than those without [19.74 (2.58-233.6) copies/μL; P < 0.001)]. Elevated cyst fluid telomerase activity had a diagnostic accuracy for invasive cancer/high-grade dysplasia of 88.1% (discovery), 88.6% (validation), and 88.2% (merged). Among cysts classified preoperatively as having "worrisome features," cyst fluid telomerase activity had high diagnostic performance (sensitivity 73.7%, specificity 90.6%, accuracy, 86.1%). In multivariate analysis, telomerase activity independently predicted the presence of invasive cancer/high-grade dysplasia.

CONCLUSIONS

Cyst fluid telomerase activity can be a useful predictor of the neoplastic grade of pancreatic cysts. Clin Cancer Res; 22(20); 5141-51. ©2016 AACRSee related commentary by Allen et al., p. 4966.

Pancreatic Cystic Neoplasms: An Update

The incidence of pancreatic cystic neoplasms is rising, in part from detection through the increasing use of high-resolution cross-sectional imaging techniques. Initial diagnosis is generally based on imaging characteristics identified on computed tomography and/or MRI. Endoscopic ultrasound provides further imaging characterization and also enables fluid aspiration and analysis to additionally aid differentiation. The general approach to these lesions includes surgical intervention and/or surveillance imaging. Taking into account diverse presentations, varying malignant potential, and the uncertain natural history of some of these lesions, an evidence-based approach is limited. This article discusses recent updates in the diagnosis and management of cystic neoplasms of the pancreas.

Pancreatic Cysts

Pancreatic cysts are more common than before, largely because of widespread abdominal imaging. Pancreatic cystic neoplasms (PCN) are relevant to risk selection on 2 counts: they constitute more than 50% of all pancreatic cysts and, in contrast to the other 2 cyst types, are capable of malignant transformation. The majority of PCNs are benign at time of diagnosis and will follow a benign course. The challenge is to identify those PCNs that are malignant or will undergo malignant transformation with time. The purpose of this article is to provide pointers that can help meet this challenge while also summarizing the ongoing debate about their optimal management.

A MicroRNA Panel in Pancreatic Cyst Fluid for the Risk Stratification of Pancreatic Cysts in a Prospective Cohort

A subset of pancreatic cystic neoplasms are regarded as precursor lesions of pancreatic cancer, but only a minority of all pancreatic cystic neoplasms will undergo malignant transformation. MicroRNAs are increasingly recognized as molecular targets in carcinogenesis. Previously, a 9-microRNA (miR) signature was suggested to discriminate between high risk and low risk pancreatic cystic neoplasm. In this study, we aimed to validate this 9-miR panel in a prospective cohort. Total miR was isolated from pancreatic cyst fluid and expression of miR18a, miR24, miR30a-3p, miR92a, miR99b, miR106b, miR142-3p, miR342-3p, and miR532-3p was analyzed by singleplex Taqman MicroRNA Assay. A total of 62 patient samples were analyzed. During follow-up, 24 (38.7%) patients underwent resection, of which 6 (9.7%) patients showed at least high grade dysplasia. A logistic regression model presented a “predicted risk” score which significantly differed between low and high risk cysts, either including all patients or only those with histological confirmation of diagnosis. Using a set cut-off of 50%, the sensitivity of the model for the total cohort was 10.0%, specificity 100.0%, positive predicted value 100.0%, negative predicted value 85.2%, and diagnostic accuracy of 85.5%. Thus, while observing a significant difference between low and high risk cysts, clinical implementation of this biomarker panel is as yet unlikely to be beneficial in the management of pancreatic cysts.

Recurrence of Solid Pseudopapillary Tumor: A Rare Pancreatic Tumor

Solid pseudopapillary tumor of the pancreas (SPTP) is a rare disease of young females that does not usually recur after resection. Here we report a case of an elderly female with history of SPTP ten years ago who presented with anorexia and a palpable left lower quadrant abdominal mass. Imaging revealed metastatic disease and US-guided biopsy of the liver confirmed the diagnosis of SPTP. Due to her advanced age and comorbidities, she elected to undergo hospice care. The objective of this case report is to increase awareness of this tumor and its possibility of recurrence, necessitating further guidelines for follow-up.

Molecular Analyses of Aspirated Cystic Fluid for the Differential Diagnosis of Cystic Lesions of the Pancreas: A Systematic Review and Meta-Analysis

Background. Researchers have evaluated various molecular tests for improving the differential diagnosis of cystic lesions of the pancreas. Methods. Six electronic databases were searched for articles on molecular tests for the diagnosis of pancreatic cysts. Measures of accuracy were extracted from selected articles and pooled by the random-effects model. Summary receiver operating characteristic curves were used to analyze the overall accuracy of the molecular tests. Pooled sensitivity and specificity values [95% confidence intervals] are reported. Results. The systematic review included eight studies of 428 patients in total. We determined the sensitivities and specificities of tests for KRAS mutations (0.47 [0.39-0.54], 0.98 [0.93-0.99]) and loss of heterozygosity (0.63 [0.54-0.71], 0.76 [0.63-0.87]) for distinguishing mucinous from nonmucinous cysts, as well as the sensitivities and specificities of tests for KRAS mutations (0.59 [0.46-0.71], 0.78 [0.71-0.85]) and loss of heterozygosity (0.89 [0.78-0.96], 0.69 [0.60-0.76]) for differentiating malignant from benign cysts. Conclusion. Tests of KRAS mutations could confirm but not exclude a diagnosis of a mucinous or malignant pancreatic cyst.