American gastroenterological association technical review on the diagnosis and management of asymptomatic neoplastic pancreatic cysts

Surgical treatment for pancreatic cystic lesions-implications from the multi-center and prospective German StuDoQ|Pancreas registry

PURPOSE

The detection of pancreatic cystic lesions (PCL) causes uncertainty for physicians and patients, and international guidelines are based on low evidence. The extent and perioperative risk of resections of PCL in Germany needs comparison with these guidelines to highlight controversies and derive recommendations.

METHODS

Clinical data of 1137 patients who underwent surgery for PCL between 2014 and 2019 were retrieved from the German StuDoQ|Pancreas registry. Relevant features for preoperative evaluation and predictive factors for adverse outcomes were statistically identified.

RESULTS

Patients with intraductal papillary mucinous neoplasms (IPMN) represented the largest PCL subgroup (N = 689; 60.6%) while other entities (mucinous cystic neoplasms (MCN), serous cystic neoplasms (SCN), neuroendocrine tumors, pseudocysts) were less frequently resected. Symptoms of pancreatitis were associated with IPMN (OR, 1.8; P = 0.012) and pseudocysts (OR, 4.78; P < 0.001), but likewise lowered the likelihood of MCN (OR, 0.49; P = 0.046) and SCN (OR, 0.15, P = 0.002). A total of 639 (57.2%) patients received endoscopic ultrasound before resection, as recommended by guidelines. Malignancy was histologically confirmed in 137 patients (12.0%), while jaundice (OR, 5.1; P < 0.001) and weight loss (OR, 2.0; P = 0.002) were independent predictors. Most resections were performed by open surgery (N = 847, 74.5%), while distal lesions were in majority treated using minimally invasive approaches (P < 0.001). Severe morbidity was 28.4% (N = 323) and 30d mortality was 2.6% (N = 29). Increased age (P = 0.004), higher BMI (P = 0.002), liver cirrhosis (P < 0.001), and esophageal varices (P = 0.002) were independent risk factors for 30d mortality.

CONCLUSION

With respect to unclear findings frequently present in PCL, diagnostic means recommended in guidelines should always be considered in the preoperative phase. The therapy of PCL should be decided upon in the light of patient-specific factors, and the surgical strategy needs to be adapted accordingly.

Limitations and prospects in the management of IPMN: a retrospective, single-center observational study

BACKGROUND

With increasing use and enhanced accuracy of cross-sectional imaging, the diagnosis of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas has increased over the last few decades. The extent to which malignant transformation occurs remains unclear, making the management of IPMNs controversial. The aim of this study was to evaluate the progression rate and outcome of follow-up in patients with IPMNs.

METHODS

A database of all patients diagnosed with IPMN at the Cantonal Hospital HFR Fribourg, Switzerland, between January 2006 and December 2019 with a follow-up of at least 6 months was analyzed retrospectively. Descriptive statistics were performed on patient demographics, IPMN characteristics, and follow-up data.

RESULTS

A total of 56 patients were included in this study. Ten patients underwent primary surgery, 46 were enrolled in a surveillance program.21.7% (n = 5) of patients under surveillance presented with worrisome features of IPMN; progression rates were significantly higher in these patients (p = 0.043). Most progression occurred in the early follow-up period. Five patients underwent surgery due to progression, of which 2 presented high-grade dysplasia and 2 malignancy on postoperative histology.

CONCLUSIONS

The limited predictive value of current guidelines may lead to surgical overtreatment, and the decision to proceed with surgical resection should be made with caution. Further prospective analyses and the development of novel biomarkers are needed to better understand the natural history of IPMN and improve diagnostic precision.

Pancreatic Cystic Neoplasms: Diagnosis and Management

Pancreatic cancer is one of the most lethal cancers, largely related to the difficulties with early detection, as it typically presents in later stages. Pancreatic cystic neoplasms (PCN) are commonly diagnosed as incidental findings on routine imaging. PCN is becoming more frequently detected with the increasing ease and frequency of obtaining cross-sectional images. Certain subtypes of pancreatic cysts have the potential to progress to malignancy, and therefore, clinicians are tasked with creating a patient-centered management plan. The decision of whether to undergo surgical resection or interval surveillance can be challenging given the criteria, including PCN size, pancreatic duct dilation, presence of a mural nodule, and clinical symptoms that play a potential role in risk stratification. Furthermore, the guidelines available from the major gastrointestinal societies all differ in their management recommendations. In this review, we detail an overview of the different types of PCNs and compare major guidelines for both diagnosis and management. We include emerging evidence for next-generation sequencing as well as confocal needle endomicroscopy to aid in the diagnosis and determination of malignancy potential and diagnosis.

Prospective, Multi-Institutional, Real-Time Next-Generation Sequencing of Pancreatic Cyst Fluid Reveals Diverse Genomic Alterations That Improve the Clinical Management of Pancreatic Cysts

BACKGROUND & AIMS

Next-generation sequencing (NGS) of pancreatic cyst fluid is a useful adjunct in the assessment of patients with pancreatic cyst. However, previous studies have been retrospective or single institutional experiences. The aim of this study was to prospectively evaluate NGS on a multi-institutional cohort of patients with pancreatic cyst in real time.

METHODS

The performance of a 22-gene NGS panel (PancreaSeq) was first retrospectively confirmed and then within a 2-year timeframe, PancreaSeq testing was prospectively used to evaluate endoscopic ultrasound-guided fine-needle aspiration pancreatic cyst fluid from 31 institutions. PancreaSeq results were correlated with endoscopic ultrasound findings, ancillary studies, current pancreatic cyst guidelines, follow-up, and expanded testing (Oncomine) of postoperative specimens.

RESULTS

Among 1933 PCs prospectively tested, 1887 (98%) specimens from 1832 patients were satisfactory for PancreaSeq testing. Follow-up was available for 1216 (66%) patients (median, 23 months). Based on 251 (21%) patients with surgical pathology, mitogen-activated protein kinase/GNAS mutations had 90% sensitivity and 100% specificity for a mucinous cyst (positive predictive value [PPV], 100%; negative predictive value [NPV], 77%). On exclusion of low-level variants, the combination of mitogen-activated protein kinase/GNAS and TP53/SMAD4/CTNNB1/mammalian target of rapamycin alterations had 88% sensitivity and 98% specificity for advanced neoplasia (PPV, 97%; NPV, 93%). Inclusion of cytopathologic evaluation to PancreaSeq testing improved the sensitivity to 93% and maintained a high specificity of 95% (PPV, 92%; NPV, 95%). In comparison, other modalities and current pancreatic cyst guidelines, such as the American Gastroenterology Association and International Association of Pancreatology/Fukuoka guidelines, show inferior diagnostic performance. The sensitivities and specificities of VHL and MEN1/loss of heterozygosity alterations were 71% and 100% for serous cystadenomas (PPV, 100%; NPV, 98%), and 68% and 98% for pancreatic neuroendocrine tumors (PPV, 85%; NPV, 95%), respectively. On follow-up, serous cystadenomas with TP53/TERT mutations exhibited interval growth, whereas pancreatic neuroendocrine tumors with loss of heterozygosity of ≥3 genes tended to have distant metastasis. None of the 965 patients who did not undergo surgery developed malignancy. Postoperative Oncomine testing identified mucinous cysts with BRAF fusions and ERBB2 amplification, and advanced neoplasia with CDKN2A alterations.

CONCLUSIONS

PancreaSeq was not only sensitive and specific for various pancreatic cyst types and advanced neoplasia arising from mucinous cysts, but also reveals the diversity of genomic alterations seen in pancreatic cysts and their clinical significance.

Long-standing diabetes mellitus increases concomitant pancreatic cancer risk in patients with intraductal papillary mucinous neoplasms

BACKGROUND

When monitoring patients with an intraductal papillary mucinous neoplasm (IPMN), it is important to consider both IPMN-derived carcinoma and concomitant ductal adenocarcinoma (PDAC). The latter is thought to have a poorer prognosis. We retrospectively analyzed the risk factors for concomitant PDAC in IPMN.

METHODS

In total, 547 patients with pancreatic cysts, including IPMNs inappropriate for surgery on initial diagnosis, encountered from April 2005 to June 2019, were reviewed. We performed surveillance by imaging examination once or twice a year.

RESULTS

Five IPMNs with high-grade dysplasia and one IPMN associated with invasive carcinoma were encountered. In comparison, 14 concomitant PDACs were encountered. The prognosis was very poor for concomitant PDACs. All 14 PDAC patients had IPMNs. In patients with IPMNs, long-standing diabetes mellitus was the only significant risk factor for concomitant PDAC in both univariate and multivariate analyses (P < 0.001 and P < 0.01, respectively). Furthermore, patients with IPMNs and diabetes mellitus had a high frequency of concomitant PDACs (9.5%, 9/95) in a median 48-month surveillance period.

CONCLUSIONS

When monitoring IPMNs, the development of not only IPMN-derived carcinomas but also concomitant PDACs should be considered. During this period, it may be prudent to concentrate on patients with other risk factors for PDAC, such as long-standing diabetes mellitus.

Early phase trial of intracystic injection of large surface area microparticle paclitaxel for treatment of mucinous pancreatic cysts

Background and study aims  Mucinous pancreatic cystic lesions (PCLs) have the potential for malignant transformation, for which the only accepted curative modality is surgery. A novel intracystic therapy with large surface area microparticle paclitaxel (LSAM-PTX) may treat PCLs without local or systemic toxicities. Safety and preliminary efficacy of LSAM-PTX for the treatment of PCLs administered by endoscopic ultrasound-guided fine-needle injection (EUS-FNI) was evaluated. Patients and methods  Ten subjects with confirmed PCLs (size > 1.5 cm) received intracystic LSAM-PTX via EUS-FNI at volumes equal to those aspirated from the cyst in sequential cohorts at 6, 10, and 15 mg/mL in a standard "3 + 3" dose-escalation protocol. The highest dose with acceptable safety and tolerability was taken into the confirmatory phase where nine additional subjects received two injections of LSAM-PTX 12 weeks apart. Subjects were followed for 6 months after initial LSAM-PTX treatment for endpoints including: adverse events (AEs), tolerability, pharmacokinetic analysis of systemic paclitaxel drug levels, and change in cyst volume. Results  Nineteen subjects completed the study. No dose-limiting toxicities, treatment-related serious AEs, or clinically significant laboratory changes were reported. Systemic paclitaxel concentrations did not exceed 3.5 ng/mL at any timepoint measured and fell below 1 ng/mL by Week 2, supporting the lack of systemic toxicity. By Week 24 a cyst volume reduction (10-78 %) was seen in 70.6 % of subjects. Conclusions  Intracystic injection of LSAM-PTX into mucinous PCLs resulted in no significant AEs, a lack of systemic absorption, and resulted in reduction of cyst volume over a 6 month period.

Classification of pancreatic cystic neoplasms using radiomic feature analysis is equivalent to an experienced academic radiologist: a step toward computer-augmented diagnostics for radiologists

PURPOSE

A wide array of benign and malignant lesions of the pancreas can be cystic and these cystic lesions can have overlapping imaging appearances. The purpose of this study is to compare the diagnostic accuracy of a radiomics-based pancreatic cyst classifier to an experienced academic radiologist.

METHODS

In this IRB-approved retrospective single-institution study, patients with surgically resected pancreatic cysts who underwent preoperative abdominal CT from 2003 to 2016 were identified. Pancreatic cyst(s) and background pancreas were manually segmented, and 488 radiomics features were extracted. Random forest classification based on radiomics features, age, and gender was evaluated with fourfold cross-validation. An academic radiologist blinded to the final pathologic diagnosis reviewed each case and provided the most likely diagnosis.

RESULTS

214 patients were included (64 intraductal papillary mucinous neoplasms, 33 mucinous cystic neoplasms, 60 serous cystadenomas, 24 solid pseudopapillary neoplasms, and 33 cystic neuroendocrine tumors). The radiomics-based machine learning approach showed AUC of 0.940 in pancreatic cyst classification, compared with AUC of 0.895 for the radiologist.

CONCLUSION

Radiomics-based machine learning achieved equivalent performance as an experienced academic radiologist in the classification of pancreatic cysts. The high diagnostic accuracy can potentially maximize the efficiency of healthcare utilization by maximizing detection of high-risk lesions.

Effectiveness of Abdominal Ultrasonography for Improving the Prognosis of Pancreatic Cancer during Medical Checkup: A Single Center Retrospective Analysis

Recent advancements in surgical and anti-cancer therapies have provided significant hope of long survival in patients with pancreatic cancer (PC). To realize this hope, routine medical checkups of asymptomatic people should be performed to identify operable PCs. In this study, we evaluated the efficacy of medical checkups using abdominal ultrasonography (US). We retrospectively analyzed 374 patients with PC at our institute between 2010 and 2021. We divided these patients into several groups according to the diagnostic approach and compared their background and prognosis. These groups comprised PCs diagnosed through (a) symptoms, 242 cases; (b) US during medical checkup for asymptomatic individuals, 17; and other means. Of the 374 patients, 192 were men (51.3%), and the median age was 74 years (34−105). Tumors were located in the pancreatic tail in 67 patients (17.9%). Excision ratio and 5-year survival rate were significantly better in group (b) than in (a) (58.8% vs. 23.1%, p < 0.01 and 42.2% vs. 9.4%, p < 0.001, respectively). The prognosis of patients diagnosed using US during medical checkup was better than that of patients identified through symptomatic presentation of PC. US for asymptomatic individuals with PC might be one of the useful modalities for promoting better prognosis of PCs.

Accuracy and agreement of a large panel of endosonographers for endomicroscopy-guided virtual biopsy of pancreatic cystic lesions

BACKGROUND

Although emerging data evidences that EUS-guided needle-based confocal laser endomicroscopy (nCLE) accurately diagnoses pancreatic cystic lesions (PCLs), there are a lack of interobserver agreement (IOA) studies utilizing reference histopathological diagnosis and for specific PCL subtypes. Hence, we sought to assess the IOA, intra-observer reliability (IOR), and diagnostic performance of EUS-nCLE using a large cohort of patients with histopathological diagnosis amongst a broad panel of international observers.

METHODS

EUS-nCLE videos (n = 76) of subjects with PCLs [intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystadenoma (SCA), pseudocyst, and cystic-neuroendocrine tumors/solid pseudopapillary neoplasm (cystic-NET/SPN)], simulating clinical prevalence rates were obtained from 3 prospective studies. An international panel of 13 endosonographers with nCLE experience, blinded to all PCL data, evaluated the video library twice with a two-week washout for PCL differentiation (mucinous vs. non-mucinous) and subtype diagnosis.

RESULTS

The IOA (κ = 0.82, 95% CI 0.77-0.87) and IOR (κ = 0.82, 95% CI 0.78-0.85) were "almost perfect" to differentiate mucinous vs. non-mucinous PCLs. For PCL subtype, IOA was highest for SCA (almost perfect; κ = 0.85), followed by IPMN (substantial, κ = 0.72), and cystic-NET/SPN (substantial, κ = 0.73). The IOA was moderate for MCN (κ = 0.47), and pseudocyst (κ = 0.57). Compared to histopathology, observers differentiated mucinous vs. non-mucinous PCLs with high accuracy (94.8%, 95% CI 93.3-96.1). For detecting specific PCLs subtypes, EUS-nCLE was highly accurate in diagnosing non-mucinous cysts (SCA: 98%; cystic-NET/SPN: 96%; pseudocyst: 96%) and slightly less accurate for mucinous lesions (IPMN: 86%; MCN: 84%).

CONCLUSION

Diagnosis of PCLs by EUS-nCLE guided virtual biopsy is very accurate and reliable for the most prevalent pancreatic cysts in clinical practice.

Nomogram to predict malignancy in branch duct type intraductal papillary mucinous neoplasms

Prediction of malignancy in branch duct (BD)-type intraductal papillary mucinous neoplasms (BD-IPMNs) is difficult. In this retrospective study, we showed the performance of imaging biomarker and biochemical biomarker in identifying the malignant BD-IPMNs. A total of 97 patients with pathological proved BD-IPMNs were included in this study. Imaging data were collected from magnetic resonance imaging (MRI). Malignant BD-IPMNs were defined as those with high grade dysplasia and invasive carcinoma. There were 10 patients with malignant BD-IPMNs (10.3%). Significant difference was found in prevalence of mural nodule and tumor size >3.0 cm between patients with and without malignant BD-IPMNs (44.4% vs 3.1%, P < .01; 80.0% vs 33.3%, P < .01). Significant differences were observed in mural nodule and elevated carbohydrate antigen 19-9 (CA19-9) between patients with and without invasive carcinoma (40.0% vs 7.6, P = .05; 60% vs 15.3%, P = .04). Mural nodule and tumor size >3.0 cm were the independent associated factor for malignant BD-IPMNs. The odds ratio (OR) was 5.22 (95% confidence interval [CI]: 1.04-31.16) for mural nodule and was 6.80 (95% CI: 1.16-39.71) for cyst size >3.0 cm. The combined model of mural nodule and tumor size showed good performance in identifying malignant BD-IPMNs (area under the curve [AUC] = 0.82, 95%CI: 0.67-0.97). Our data show that mural nodule and cystic size can be used as predictor of malignancy in BD-IPMN. The predictive performance is acceptable.

Clinical Utility of the Contrast-Enhanced Endoscopic Ultrasound Guided Fine Needle Aspiration in the Diagnosis of Pancreatic Cyst

Endoscopic ultrasound fine needle aspiration (EUS-FNA) cytology from an intracystic fluid is useful in the differentiation of pancreatic cysts, with low sensitivity, which increases when the solid component is targeted. The clinical utility of contrast-enhanced guided EUS-FNA (CH-EUS-FNA) in the solid component is not known. We aimed to assess the diagnostic value of CH-EUS-FNA in enhanced mural nodules and discrimination between different cysts using contrast-enhanced endoscopic ultrasound (CH-EUS). The prospective study recruited patients with pancreatic cysts with an unclear diagnosis. The CH-EUS was followed by CH-EUS-FNA. The final diagnosis was based on surgery or the correlation between clinical history, cross-sectional imaging, echoendoscopic morphology, cystic fluid analysis, and follow-up. Fifty-eight patients with pancreatic cysts were evaluated. The mucinous cysts had wall arterial enhancement more often than non- mucinous cysts (p < 0.0001), with 90.2% sensitivity and 70.6% specificity. The CH-EUS-FNA from cystic fluid and mural nodules identified mucinous cysts and malignancy with 82.4% and 84.2% sensitivity and 92% and 100% specificity. Twenty-one cysts had solid components, but only 13 were enhanced mural nodules on EUS assessment with conclusive cytology in all cases and malignancy in 76.9%. Contrast-enhanced endoscopic ultrasound should be completed in all PCN with solid components in order to avoid unnecessary EUS-FNA and to guide FNA for the identification of malignant cysts.

Pancreatic Cystic Neoplasms

Early detection of high-risk pancreatic cystic lesions enables potentially curative surgical resection, and early detection of lesions without worrisome features may lead to appropriate surveillance. Regrettably, differentiating premalignant and malignant cysts from nonmalignant ones remains challenging. However, emerging additional diagnostic tools, including the needle biopsy with microforceps and needle-based confocal laser endomicroscopy, are of exciting potential along with cyst fluid analysis".

Comparison of Society Guidelines for the Management and Surveillance of Pancreatic Cysts: A Review

Importance

The identification of incidental pancreas cystic lesions (PCLs) has increased in recent decades with the expanded use and improved sensitivity of cross-sectional imaging. Because the overall risk of malignancy associated with PCLs is low, yet the relative morbidity of pancreatic surgery is high, evidence-based guidelines are necessary for appropriate surveillance and management. Therefore, this article provides a review of existing guidelines regarding surveillance and management of PCLs and highlights recent advances in the diagnostic evaluation of cysts and the postresection management of mucinous lesions.

Observations

There are 5 main guidelines related to the management of PCLs: the American Gastrointestinal Association (AGA) guidelines, the American College of Gastroenterology (ACG) guidelines, the American College of Radiology (ACR) recommendations, the European evidence-based guidelines, and the International Association of Pancreatology (IAP)/Fukuoka guidelines. These guidelines are based on retrospective studies that do not account or control for most tumor- and patient-specific factors. These guidelines also vary in scope, recommendations for surgical resection vs surveillance, as well as duration and type of follow-up.

Conclusions and Relevance

PCL guidelines should be viewed within the context of the data limitations on which they are based. PCL subtype-specific guidelines on surveillance and treatment are needed. In the future, the integration of cyst-specific genomic analysis, as well as evolutions in advanced diagnostic tools, such as cyst fluid next-generation sequencing and EUS-guided confocal laser endomicroscopy, may also better inform treatment guidelines. Owing to the current low-quality evidence on which many guidelines are based and the inherent morbidity of pancreas surgery, it is imperative that patients with PCLs are referred to institutions with advanced diagnostics and a multidisciplinary approach to patient surveillance and management.

Application of Artificial Intelligence in the Management of Pancreatic Cystic Lesions

The rate of incidentally detected pancreatic cystic lesions (PCLs) has increased over the past decade and was recently reported at 8%. These lesions pose a unique challenge, as each subtype of PCL carries a different risk of malignant transformation, ranging from 0% (pancreatic pseudocyst) to 34–68% (main duct intraductal papillary mucinous neoplasm). It is imperative to correctly risk-stratify the malignant potential of these lesions in order to provide the correct care course for the patient, ranging from monitoring to surgical intervention. Even with the multiplicity of guidelines (i.e., the American Gastroenterology Association guidelines and Fukuoka/International Consensus guidelines) and multitude of diagnostic information, risk stratification of PCLs falls short. Studies have reported that 25–64% of patients undergoing PCL resection have pancreatic cysts with no malignant potential, and up to 78% of mucin-producing cysts resected harbor no malignant potential on pathological evaluation. Clinicians are now incorporating artificial intelligence technology to aid in the management of these difficult lesions. This review article focuses on advancements in artificial intelligence within digital pathomics, radiomics, and genomics as they apply to the diagnosis and risk stratification of PCLs.

Number of Worrisome Features and Risk of Malignancy in Intraductal Papillary Mucinous Neoplasm

BACKGROUND

The 2017 revised International Association of Pancreatology guidelines for management of intraductal papillary mucinous neoplasm (IPMN) describe worrisome features (WF) and high-risk stigmata (HRS), recommending resection in the latter and further work-up and close surveillance for patients with WF. The effect of multiple WF on the likelihood of malignancy has not been evaluated.

STUDY DESIGN

Eight hundred ten patients who underwent pancreatic resection for IPMN in 2 tertiary referral centers were identified from prospective institutional databases. Patients were retrospectively categorized into subgroups according to the number of WF or HRS and presence of malignancy, defined as high-grade dysplasia (HGD) or invasive cancer on final pathology.

RESULTS

Three hundred seventy-nine (47%) patients had HRS, 370 (46%) had 1 or more WF, and 61 patients (7%) had neither. Malignancy was present in 70% (n = 267) of patients with HRS and in 30% (n = 127) of those with WF. Only 3 of 61 patients without WF/HRS had malignancy, and all only in the form of HGD. The risk of malignancy increased in a stepwise fashion with the number of WF, to 22%, 34%, and 59% with 1, 2, and 3 WF, respectively (p = 0.001), and reached 100% in patients with 4 or more WF. Although the relative risks differed for particular WF, the areas under the curve were not statistically different.

CONCLUSION

We confirm that presence of HRS in IPMN is associated with a very high likelihood of malignancy. The presence of a single WF has a malignancy risk of 22%, and additional WF increase this risk significantly. When 3 or more WF are present, the risk is similar to that of HRS.

Translation of a Protease Turnover Assay for Clinical Discrimination of Mucinous Pancreatic Cysts

The classification of pancreatic cyst fluids can provide a basis for the early detection of pancreatic cancer while eliminating unnecessary procedures. A candidate biomarker, gastricsin (pepsin C), was found to be present in potentially malignant mucinous pancreatic cyst fluids. A gastricsin activity assay using a magnetic bead-based platform has been developed using immobilized peptide substrates selective for gastricsin bearing a dimeric rhodamine dye. The unique dye structure allows quantitation of enzyme-cleaved product by both fluorescence and surface enhanced Raman spectroscopy (SERS). The performance of this assay was compared with ELISA assays of pepsinogen C and the standard of care, carcinoembryonic antigen (CEA), in the same clinical sample cohort. A retrospective cohort of mucinous (n = 40) and non-mucinous (n = 29) classes of pancreatic cyst fluid samples were analyzed using the new protease activity assay. For both assay detection modes, successful differentiation of mucinous and non-mucinous cyst fluid was achieved using 1 µL clinical samples. The activity-based assays in combination with CEA exhibit optimal sensitivity and specificity of 87% and 93%, respectively. The use of this gastricsin activity assay requires a minimal volume of clinical specimen, offers a rapid assay time, and shows improvements in the differentiation of mucinous and non-mucinous cysts using an accurate standardized readout of product formation, all without interfering with the clinical standard of care.

State-of-the-Art Update of Pancreatic Cysts

Andrew Canakis.

Incidence and Risk Factors for New-Onset Diabetes Mellitus After Surgical Resection of Pancreatic Cystic Lesions: A MarketScan Study

OBJECTIVES

There is a paucity of literature evaluating new-onset diabetes mellitus (NODM) after resection of pancreatic cystic lesions (PCLs). We sought to characterize the incidence and risk factors associated with NODM after partial pancreatectomy for PCLs.

METHODS

We utilized the IBM MarketScan Database (2012-2018) to identify all nondiabetic adults who underwent partial pancreatectomy for PCLs. Patients with any other pancreatic disease were excluded. We performed Kaplan-Meier analysis and multivariable Cox proportional hazards regression to define the incidence and risk factors of postoperative NODM.

RESULTS

Among 311 patients, the overall risk (95% confidence interval) of NODM was 9.1% (6.3-12.9%), 15.1% (11.3-20.2%), and 20.2% (15.3-26.4%) at 6, 12 and 24 months, respectively. Multivariable analysis (adjusted hazard ratio; 95% confidence interval) revealed that older age (1.97; 1.04-3.72; 55-64 vs 18-54 years), obesity (2.63; 1.35-5.12), hypertension (1.79; 1.01-3.17), and cardiovascular disease (2.54; 1.02-6.28) were independent predictors of NODM. Rates of NODM were similar after distal pancreatectomy versus pancreaticoduodenectomy.

CONCLUSIONS

Within 2 years, 1 in 5 patients without any other pancreatic disease will develop NODM after partial pancreatectomy for PCLs. Those with advanced age, metabolic syndrome features, and/or cardiovascular disease may benefit from preoperative counseling and intensive postoperative monitoring, education, and treatment for diabetes mellitus.

An update on EUS-guided ablative techniques for pancreatic cystic lesions

Pancreatic cystic lesions (PCLs) are increasingly being recognized due to improvements and widespread use of cross-sectional imaging. With an estimated prevalence of 15% in general population, incidentally discovered PCLs represent a dilemma in management. While pancreatectomies offer a chance of cure, the morbidity is considerable in patients with high surgical risks. More recently, EUS-guided approaches for cyst ablation are being offered in clinical trials for the management of PCLs. EUS-chemoablation studies have progressed from first investigating safety and efficacy of EUS-guided alcohol lavage to single-agent paclitaxel ablation. Recent studies have shown that alcohol lavage may not be required, and long-term resolution can be achieved by chemoablation alone. EUS-guided lauromacrogol ablation and EUS-guided radiofrequency ablation (RFA) are new techniques that have shown promising results in a few small studies. Overall, the current literature suggests that EUS-guided paclitaxel ablation has better cyst resolution rates compared to other existing minimally invasive techniques including ethanol injection, lauromacrogol ablation, or RFA. This article will review EUS-guided PCL ablation approaches and future directions the field is headed into.

Comorbidities Drive the Majority of Overall Mortality in Low-Risk Mucinous Pancreatic Cysts Under Surveillance

BACKGROUND & AIMS

The Charlson Comorbidity Index (CACI) has been suggested as a tool to determine comorbidity burden and guide management for patients with mucinous pancreatic cysts (Intrapapillary Mucinous Neoplasms and Mucinous Cystic Neoplasms), but has not been studied well among "low-risk" mucinous pancreatic cysts i.e. without worrisome features (WF) and high-risk stigmata (HRS). This study sought to determine the comorbidity burden among surveillance population of low-risk pancreatic cysts and provide their follow-up mortality outcomes.

METHODS

A single center study retrospectively reviewed a prospective pancreatic cyst database and included individuals with low-risk cysts undergoing serial imaging during 2016. Electronic medical records were reviewed to determine their baseline age-adjusted CACI (age-CACI). After 4 years, their progression to WF, disease specific (pancreatic malignancy-related, DSM), extra-pancreatic (EPM), and overall mortalities (OM) were determined using Kaplan-Meir Survival Analysis.

RESULTS

502 individuals underwent prospective surveillance. The study included 440 individuals with low-risk suspected or presumed mucinous cysts and excluded 50 and 12 individuals with WF and HRS respectively. Over a median follow-up of 56 months, 12 WF progressions, 2 DSMs, 42 EPMs, and 44 OMs were observed. Baseline age-CACI had good predictive capacity for 4-year EPM (Area-Under Curve: 0.87; p< .0001). The median age-CACI of 4 enabled cohort stratification into Low (age-CACI <4) and High CACI (age-CACI ≥4) groups. A significantly higher OM (p< .001) was observed among the High CACI group as compared to the Low CACI group.

CONCLUSION

Through real-time application of CACI to patient outcomes, our analysis supports incorporation of this comorbidity assessment tool in making shared surveillance decisions among low-risk pancreatic cyst population.

Recent advances in the diagnostic evaluation of pancreatic cystic lesions

Pancreatic cystic lesions (PCLs) are becoming more prevalent due to more frequent abdominal imaging and the increasing age of the general population. It has become crucial to identify these PCLs and subsequently risk stratify them to guide management. Given the high morbidity associated with pancreatic surgery, only those PCLs at high risk for malignancy should undergo such treatment. However, current diagnostic testing is suboptimal at accurately diagnosing and risk stratifying PCLs. Therefore, research has focused on developing new techniques for differentiating mucinous from non-mucinous PCLs and identifying high risk lesions for malignancy. Cross sectional imaging radiomics can potentially improve the predictive accuracy of primary risk stratification of PCLs at the time of detection to guide invasive testing. While cyst fluid glucose has reemerged as a potential biomarker, cyst fluid molecular markers have improved accuracy for identifying specific types of PCLs. Endoscopic ultrasound guided approaches such as confocal laser endomicroscopy and through the needle microforceps biopsy have shown a good correlation with histopathological findings and are evolving techniques for identifying and risk stratifying PCLs. While most of these recent diagnostics are only practiced at selective tertiary care centers, they hold a promise that management of PCLs will only get better in the future.

Risk Stratification of Pancreatic Cysts With Confocal Laser Endomicroscopy

In the modern era of high-quality cross-sectional imaging, pancreatic cysts (PCs) are a common finding. The prevalence of incidental PCs detected on cross-sectional abdominal imaging (such as CT scan) is 3%-14% which increases with age, up to 8% in those 70 years or older. Although PCs can be precursors of future pancreatic adenocarcinoma, imaging modalities such as CT scan, MRI, or endoscopic ultrasound with fine-needle aspiration (EUS-FNA) are suboptimal at risk stratifying the malignant potential of individual cysts. An inaccurate diagnosis could potentially overlook premalignant lesions, which can lead to missed lesions, lead to unnecessary surveillance, or cause significant long-term surgical morbidity from unwarranted removal of benign lesions. Although current guidelines recommend an EUS or MRI for surveillance, they lack the sensitivity to risk stratify and guide management decisions. Needle-based confocal laser endomicroscopy (nCLE) with EUS-FNA can be a superior diagnostic modality for PCs with sensitivity and accuracy exceeding 90%. Despite this, a significant challenge to the widespread use of nCLE is the lack of adequate exposure and training among gastroenterologists for the real-time interpretation of images. Better understanding, training, and familiarization with this novel technique and the imaging characteristics can overcome the limitations of nCLE use, improving clinical care of patients with PCs. Here, we aim to review the types of CLE in luminal and nonluminal gastrointestinal disorders with particular attention to the evaluation of PCs. Furthermore, we discuss the adverse events and safety of CLE.

The association between serum ferritin levels and malignant intraductal papillary mucinous neoplasms

BACKGROUND

Serum ferritin levels are elevated in many malignancies. In this study, we showed the performance of serum ferritin in identifying malignant intraductal papillary mucinous neoplasms (IPMNs).

METHODS

A total of 151 patients with pathologically confirmed IPMNs were enrolled. Serum tumor biomarker (carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA)) levels and serum ferritin levels were recorded. Lesion location, tumor size, diameter of the main pancreatic duct (MPD), mural nodule, and IPMN type, were collected from imaging examinations. IPMNs with high grade dysplasia and associated invasive carcinoma were considered malignant IPMNs.

RESULTS

Serum ferritin levels in patients with malignant IPMNs were higher than those in patients with nonmalignant IPMNs (p <  0.05). Serum ferritin was an independent factor for the occurrence of malignant IPMNs (odds ratio (OR) = 1.18, 95% confidence interval (CI):1.01-1.39). A similar trend was found between high serum ferritin (> 149 ng/ml) and malignant IPMNs (OR = 5.64, 95% CI:1.78-17.92). The area under the curve (AUC) of serum ferritin was higher than that of CEA and CA19-9 in identifying malignant IPMNs (AUC = 0.67 vs. AUC = 0.58, 0.65). The combination of serum ferritin with IPMN type showed a similar performance to MPD diameter and the combination of serum CA19-9 with IPMN types in identifying malignant IPMNs (AUC = 0.78 vs. AUC = 0.79, 0.77) and invasive carcinoma (AUC = 0.77 vs. AUC = 0.79, 0.79).

CONCLUSIONS

Elevated serum ferritin is a factor associated with malignant IPMNs. Serum ferritin may be a useful marker for identifying malignancy in IPMNs.

Contrast-enhanced EUS for the characterization of mural nodules within pancreatic cystic neoplasms: systematic review and meta-analysis

BACKGROUND AND AIMS

Pancreatic cystic neoplasms (PCNs) carry a considerable malignancy risk. Along with main duct dilation, the presence of enhanced mural nodules represents a significant risk factor for malignancy. Several articles assessed the role of contrast-enhanced EUS (CE-EUS) for the identification of malignant features in mural nodules. We evaluate the pooled diagnostic performance of CE-EUS for the identification of high-grade dysplasia or invasive carcinoma among mural nodules in PCNs.

METHODS

A systematic review (Medline, PubMed, EMBASE) and meta-analysis were conducted. Subgroup analysis was used to assess the usefulness of a dedicated contrast-harmonic (CH-EUS). The primary outcome was pooled sensitivity for identification of high-grade dysplasia or invasive carcinoma.

RESULTS

Ten studies (532 patients) were included. Pooled sensitivity of CE-EUS was 88.2% (95% confidence interval [CI], 82.7%-92.5%), specificity 79.1% (95% CI, 74.5%-83.3%), and diagnostic accuracy 89.6% (95% CI, 83.4%-95.8%). Eight studies (320 patients) were conducted using CH-EUS: pooled sensitivity increased to 97.0% (95% CI, 92.5%-99.2%), specificity to 90.4% (95% CI, 85.2%-94.2%), and diagnostic accuracy to 95.6% (95% CI, 92.6%-98.7%). At 42% disease prevalence (pretest probability), a positive CH-EUS increased the disease probability to 88%, whereas a negative test decreased the disease probability to 2%. The number needed to diagnose was 1.5 (95% CI, 1.7-1.3) for CE-EUS and just 1.2 (95% CI, 1.3-1.1) for CH-EUS.

CONCLUSIONS

This study provided robust evidence on CE-EUS value for the characterization of mural nodules within PCNs. A dedicated contrast-harmonic mode, namely CH-EUS, provided an increased diagnostic yield in the identification and characterization of malignant mural nodules.

Intraductal Papillary Mucinous Neoplasms of the Pancreas: A Review of Their Genetic Characteristics and Mouse Models

Simple Summary

Pancreatic cancer is one of the deadliest cancers with the lowest survival rate. Little progress has been achieved in prolonging the survival for patients with pancreatic adenocarcinoma. Hence, special attention should be paid to pre-cancerous lesions, for instance, an intraductal papillary mucinous neoplasm (IPMN). Here, we reviewed its genetic characteristics and the mouse models involving mutations in specific pathways, and updated our current perception of how this lesion develops into a precursor of invasive cancer.

Abstract

The intraductal papillary mucinous neoplasm (IPMN) is attracting research attention because of its increasing incidence and proven potential to progress into invasive pancreatic ductal adenocarcinoma (PDAC). In this review, we summarized the key signaling pathways or protein complexes (GPCR, TGF, SWI/SNF, WNT, and PI3K) that appear to be involved in IPMN pathogenesis. In addition, we collected information regarding all the genetic mouse models that mimic the human IPMN phenotype with specific immunohistochemistry techniques. The mouse models enable us to gain insight into the complex mechanism of the origin of IPMN, revealing that it can be developed from both acinar cells and duct cells according to different models. Furthermore, recent genomic studies describe the potential mechanism by which heterogeneous IPMN gives rise to malignant carcinoma through sequential, branch-off, or de novo approaches. The most intractable problem is that the risk of malignancy persists to some extent even if the primary IPMN is excised with a perfect margin, calling for the re-evaluation and improvement of diagnostic, pre-emptive, and therapeutic measures.

Opportunistic Detection for Pancreatic Cystic Lesions During Chest Multidetector CT Scans for Lung Cancer Screening

Purpose

The purpose of this study was to analyze the prevalence of and risk factors for incidental pancreatic cystic lesions (PCLs) in the Chinese general population. Furthermore, the association between baseline imaging findings and PCL progression was also investigated.

Patients and Methods

A total of 9826 individuals who underwent computed tomography (CT) examinations for lung cancer screening between January 1, 2018 and January 1, 2019 were included in this study. The participants’ CT imaging findings and biochemical biomarker levels were reviewed and analyzed. PCLs detected during the screening were followed up for 12 months. Associations between imaging findings and clinical factors with PCL progression were explored.

Results

PCLs were observed in 172 of the 9826 participants. The crude prevalence of PCLs in total population was 1.75%. In subjects aged >60 years, the prevalence of PCLs was 3.2% (102/3151). The occurrence of PCLs was significantly increased with an increase of age in both men and women (p < 0.001). High-risk PCLsL commonly located in pancreatic head showed extrapancreatic growth, and had high urea levels (p = 0.005, p = 0.015, p = 0.002, respectively) compared with low-risk PCLs. Location in the pancreatic head (odds ratio (OR) = 6.286, 95% confidence interval (CI): 1.842–21.452) and extrapancreatic growth (OR = 4.049, 95% CI: 1.235–13.333) were risk factors for PCL progression.

Conclusion

PCLs are not uncommon in the Chinese general population. Location in the pancreatic head and extrapancreatic growth are the independent predictors of high-risk of PCLs and PCL progression.

Prevalence, Incidence, and Risk of Progression of Asymptomatic Pancreatic Cysts in Large Sample Real-world Data

OBJECTIVES

Using large-sample, real-world administrative claims data, we evaluated the prevalence of putatively asymptomatic pancreatic cysts, the historical growth in their incident diagnosis, and their risk of malignant progression.

METHODS

Data were sourced from IBM MarketScan administrative claims databases of more than 200 million patients. Period prevalence was assessed using 700,000 individuals without conditions that predispose to pancreatic cyst. The standardized cumulative incidence was compared with the cross-sectional abdominal imaging rate from 2010-2017. The risk of progression to pancreatic cancer for 14,279 newly diagnosed patients with a cyst was estimated using Kaplan-Meier analysis.

RESULTS

Standardized prevalence increased exponentially with age and was 1.84% (95% confidence interval, 1.80%-1.87%) for patients older than 45. Standardized incidence nearly doubled from 2010-2017 (6.3 to 11.4 per 10,000), whereas the imaging rate changed from only 8.0% to 9.4%. The cumulative risk of pancreatic cancer at 7 years was 3.0% (95% confidence interval, 2.4%-3.5%), increasing linearly (R2 = 0.991) with an annual progression risk of 0.47%.

CONCLUSIONS

Using large-sample data, we show a significant burden of asymptomatic pancreatic cysts, with an annual risk of progression to cancer of 0.47% for 7 years. Rapid growth in cyst diagnosis over the last decade far outpaced increases in the imaging rate.

Management of pancreatic cysts and guidelines: what the gastroenterologist needs to know

The prevalence of pancreatic cysts has increased significantly over the last decade, partly secondary to increased quality and frequency of cross-sectional imaging. While the majority never progress to cancer, a small number will and need to be followed. The management of pancreatic cysts can be both confusing and intimidating due to the multiple guidelines with varying recommendations. Despite the differences in the specifics of the guidelines, they all agree on several high-risk features that should get the attention of any clinician when assessing a pancreatic cyst: presence of a mural nodule or solid component, dilation of the main pancreatic duct (or presence of main duct intraductal papillary mucinous neoplasm), pancreatic cyst size ⩾3–4 cm, or positive cytology on pancreatic cyst fluid aspiration. Other important criteria to consider include rapid cyst growth (⩾5 mm/year), elevated serum carbohydrate antigen 19-9 levels, new-onset diabetes mellitus, or acute pancreatitis thought to be related to the cystic lesion.

Updates in diagnosis and management of pancreatic cysts

Incidental pancreatic cysts are commonly encountered with some cysts having malignant potential. The most common pancreatic cystic neoplasms include serous cystadenoma, mucinous cystic neoplasm and intraductal papillary mucinous neoplasm. Risk stratifying pancreatic cysts is important in deciding whether patients may benefit from endoscopic ultrasound (EUS) or surgical resection. Surgery should be reserved for patients with malignant cysts or cysts at high risk for developing malignancy as suggested by various risk features including solid mass, nodule and dilated main pancreatic duct. EUS may supplement magnetic resonance imaging findings for cysts that remain indeterminate or have concerning features on imaging. Various cyst fluid markers including carcinoembryonic antigen, glucose, amylase, cytology, and DNA markers help distinguish mucinous from nonmucinous cysts. This review will guide the practicing gastroenterologist in how to evaluate incidental pancreatic cysts and when to consider referral for EUS or surgery. For presumed low risk cysts, surveillance strategies will be discussed. Managing pancreatic cysts requires an individualized approach that is directed by the various guidelines.

Comparing accuracy of high-risk features for detecting advanced neoplasia in pancreatic cystic lesions: a systematic review and meta-analysis

Background

The American Gastroenterological Association recommends endoscopic ultrasound (EUS) for evaluating pancreatic cystic lesions (PCL) with ≥2 high-risk features (HRF), whereas the American College of Gastroenterology recommends EUS for ≥1 HRF. This systematic review and meta-analysis compared the diagnostic accuracy of using ≥1 vs. ≥2 HRF for assessing the risk of advanced neoplasia (AN) and performing EUS in PCL.

Methods

An electronic database search was performed for eligible studies. AN was defined as pancreatic adenocarcinoma, intraductal papillary mucinous neoplasm or mucinous cystadenoma with high-grade dysplasia, pancreatic intraepithelial neoplasia and pancreatic neuroendocrine tumors. HRF included cyst size ≥3 cm, solid component, and dilated pancreatic duct ≥5 mm. The primary outcome was the sensitivity and specificity of using ≥1 vs. ≥2 HRF as an indication for EUS to detect AN in PCL.

Results

Of 38 studies initially screened, 8 were included in the final analysis. Seven studies assessed the accuracy of ≥2 HRF and 4 studies assessed ≥1 HRF. The pooled sensitivity, specificity, positive and negative predictive values of EUS for detecting AN were 41.7% (95% confidence interval 19.5-67.8%), 90.8% (81.9-95.5%), 30.4% (19.4-44.2%) and 94.3% (89.6-97.0%) with ≥2HRFs, and 77.1% (66.1-85.3%), 72.7% (50.4-87.5%), 17.95% (10.3-29.4%), 98.1% (90.8-99.6%), respectively, with ≥1 HRF.

Conclusion

Performing EUS for PCL with ≥1 HRF could offer greater sensitivity in detecting AN compared to ≥2 HRF, with a similar negative predictive value.

Low high-density lipoprotein cholesterol levels are associated with malignant intraductal papillary mucinous neoplasms: A multicenter study

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) can potentially undergo malignant transformation. Studies have shown that high-density lipoprotein cholesterol (HDL-c) was associated with the risk of cancer. In this study, the association between HDL-c and the incidence of malignancy in IPMNs was investigated.

MATERIALS AND METHODS

226 patients with histologically proven IPMNs who underwent surgery were included in the present study. Patients were assigned to a training group (n = 151) and validation group (n = 75). Patients' demographic information, clinical data, and histopathological evaluation findings were obtained from medical records. Malignant IPMNs were defined as lesions that showed high grade dysplasia and invasive carcinoma. Logistic regression analyses were used to show the association between HDL-c and malignant IPMNs. Receiver operating characteristic (ROC) curves were generated to analyze predictive performance.

RESULTS

The prevalence of low HDL-c levels was higher in patients with malignant IPMNs than in those with non-malignant IPMNs (P < 0.01) in both the training group and validation group. The prevalence of malignant IPMNs decreased with an increase in HDL-c levels both in patients with all types of IPMNs, as well as in those with branch-duct IPMNs (BD-IPMNs).Logistic analysis showed that low HDL-c levels were associated with malignant IPMNs (odds ratio (OR) = 20.56, 95 % confidence interval (CI): 2.58-163.64, P < 0.01) in all types of IPMNs and BD-IPMNs (OR = 17.6, 95 %CI: 1.16-268.46, P = 0.02 ).The predictive performance of mural nodules plus low HDL-c levels was higher than that of mural nodules alone or mural nodules plus cyst size for the identification of malignant BD-IPMNs.

CONCLUSIONS

HDL-c levels may serve a potential biomarker for identifying malignant IPMNs and improve the predictive ability of malignancy in BD-IPMNs.

Fatty Pancreas: An Underappreciated Intersection of the Metabolic Profile and Pancreatic Adenocarcinoma

Although the prevalence of pancreatic cancer is increasing, treatment strategies remain limited, and success is rare. A growing body of evidence links pancreatic cancer to pre-existing metabolic disorders, including, but not limited to, type 2 diabetes mellitus and obesity. An infrequently described finding, fatty pancreas, initially described in the context of obesity in the early 20th century, appears to be at the crossroads of type 2 diabetes and obesity on the one hand, and the development of pancreatic cancer on the other. Similarly, other conditions of the pancreas, such as intrapancreatic mucinous neoplasms, also seem to be related to diabetes while increasing the subsequent risk of pancreatic cancer. In this review, the author explores the diagnostic criteria for, and prevalence of, fatty pancreas and the potential link to other pancreatic conditions, including pancreatic cancer. Diagnostic limitations, and areas of controversy are also addressed, as are potential therapeutic approaches to fatty pancreas intended to reduce the subsequent risk of pancreatic cancer.

Pancreatic cystic neoplasms: a review of current recommendations for surveillance and management

Pancreatic cystic neoplasms (PCN) comprise of a diverse array of pancreatic cysts, including intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), serous cystic neoplasms (SCN), cystic neuroendocrine tumors (cNET), and many others. Increasing use of cross-sectional imaging has resulted in greater numbers of PCNs discovered incidentally. The overall risk of malignancy is low, but can vary considerably between different classes of PCNs. Furthermore, many pancreatic cysts are indeterminate on imaging, and the inability to reliably predict the course of disease remains a challenge for radiologists. Due to the variability in disease course and a lack of high-quality studies on PCNs, there is no universal consensus when it comes to balancing optimal surveillance while avoiding the risk for overtreatment. Currently, there are three widely accepted international guidelines outlining guidelines for surveillance and management of PCNs: the American Gastroenterological Association (AGA) in 2015, the International Association of Pancreatology (IAP) last revised in 2017, and the European Study Group on Cystic Tumours of the Pancreas (European) last revised in 2018. In 2017, the American College of Radiology released its own comprehensive set of recommendations for managing indeterminate pancreatic cysts that are detected incidentally on CT or MRI. The purpose of this paper is to describe the key differences between the ACR recommendations and the aforementioned three sets of guidelines regarding cyst management, imaging surveillance, performance, and cost-effectiveness.

High performance in risk stratification of intraductal papillary mucinous neoplasms by confocal laser endomicroscopy image analysis with convolutional neural networks (with video)

BACKGROUND AND AIMS

EUS-guided needle-based confocal laser endomicroscopy (EUS-nCLE) can differentiate high-grade dysplasia/adenocarcinoma (HGD-Ca) in intraductal papillary mucinous neoplasms (IPMNs) but requires manual interpretation. We sought to derive predictive computer-aided diagnosis (CAD) and artificial intelligence (AI) algorithms to facilitate accurate diagnosis and risk stratification of IPMNs.

METHODS

A post hoc analysis of a single-center prospective study evaluating EUS-nCLE (2015-2019; INDEX study) was conducted using 15,027 video frames from 35 consecutive patients with histopathologically proven IPMNs (18 with HGD-Ca). We designed 2 CAD-convolutional neural network (CNN) algorithms: (1) a guided segmentation-based model (SBM), where the CNN-AI system was trained to detect and measure papillary epithelial thickness and darkness (indicative of cellular and nuclear stratification), and (2) a reasonably agnostic holistic-based model (HBM) where the CNN-AI system automatically extracted nCLE features for risk stratification. For the detection of HGD-Ca in IPMNs, the diagnostic performance of the CNN-CAD algorithms was compared with that of the American Gastroenterological Association (AGA) and revised Fukuoka guidelines.

RESULTS

Compared with the guidelines, both n-CLE-guided CNN-CAD algorithms yielded higher sensitivity (HBM, 83.3%; SBM, 83.3%; AGA, 55.6%; Fukuoka, 55.6%) and accuracy (SBM, 82.9%; HBM, 85.7%; AGA, 68.6%; Fukuoka, 74.3%) for diagnosing HGD-Ca, with comparable specificity (SBM, 82.4%; HBM, 88.2%; AGA, 82.4%; Fukuoka, 94.1%). Both CNN-CAD algorithms, the guided (SBM) and agnostic (HBM) models, were comparable in risk stratifying IPMNs.

CONCLUSION

EUS-nCLE-based CNN-CAD algorithms can accurately risk stratify IPMNs. Future multicenter validation studies and AI model improvements could enhance the accuracy and fully automatize the process for real-time interpretation.

Narrative review of intraductal papillary mucinous neoplasms: pathogenesis, diagnosis, and treatment of a true precancerous lesion

OBJECTIVE

Although considerable progress has been made in our understanding of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, there are still some problems to be solved.

BACKGROUND

IPMN is one of the most important precancerous lesions of pancreatic cancer, but the relationship between IPMN and pancreatic cancer, and the specific mechanism of the development from IPMN to invasive carcinoma, remain to be explored in depth. With the development of imaging, the detection rate of IPMN has been greatly improved. However, the degree of malignancy of IPMN is difficult to assess, and its classification criteria and surgical treatment strategies are still controversial. Therefore, there is an urgent need for the best treatment plan for IPMN and research that can better predict IPMN recurrence and tumor malignancy.

METHODS

From the online database Web of Science (https://webofknowledge.com/) and PubMed (https://pubmed.ncbi.nlm.nih.gov/), we use specific retrieval strategies to retrieve relevant articles based on the topics we discussed, and we review and discuss them.

CONCLUSIONS

This paper discusses the related research and progress of IPMN in recent years to improve the understanding of the incidence, diagnosis, treatment, and prognosis of this disease. The follow-up and monitoring of IPMN is particularly important, but the specific strategy also remains controversial.

Early detection of pancreatic cancer using DNA-based molecular approaches

Due to its poor prognosis and the late stage at which it is typically diagnosed, early detection of pancreatic cancer is a pressing clinical problem. Advances in genomic analysis of human pancreatic tissue and other biospecimens such as pancreatic cyst fluid, pancreatic juice and blood have opened the possibility of DNA-based molecular approaches for early detection of pancreatic cancer. In this Review, we discuss and focus on the pathological and molecular features of precancerous lesions of the pancreas, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm and mucinous cystic neoplasm, which are target lesions of early detection approaches. We also discuss the most prevalent genetic alterations in these precancerous lesions, including somatic mutations in the oncogenes KRAS and GNAS as well as tumour suppressor genes CDKN2A, TP53 and SMAD4. We highlight the latest discoveries related to genetic heterogeneity and multifocal neoplasia in precancerous lesions. In addition, we review specific approaches, challenges and clinically available assays for early detection of pancreatic cancer using DNA-based molecular techniques. Although detection and risk stratification of precancerous pancreatic neoplasms are difficult problems, progress in this field highlights the promise of molecular approaches for improving survival of patients with this disease.

An abbreviated MRI protocol for surveillance of cystic pancreatic lesions

PURPOSE

Cystic pancreatic lesions (CPLs) are common and increasingly encountered in clinical radiology practice. The appropriate imaging surveillance strategy for lower-risk CPLs (branch duct-intraductal papillary mucinous neoplasms and indeterminant small cystic lesions) has been a topic of intense study and debate in recent years. MRI is considered the investigation of choice for initial characterisation and follow-up of CPLs. Follow-up intervals for CPLs vary from 6 months to 2 years and surveillance may be lifelong or until the patient is no longer considered fit for potential surgical intervention. This creates a significant burden on MRI resources as a standard protocol pancreatic MRI may have an acquisition time of up to 35-50 min. However, the necessity of contrast-enhanced sequences and diffusion weighted imaging (DWI) for routine follow-up of CPLs has been questioned in recent years.

METHODS

We reviewed the available evidence to determine whether an abbreviated MRI (A-MRI) protocol may be safely adopted for surveillance of CPLs, as has been implemented in other clinical scenarios.

RESULTS

A number of recent retrospective studies have indicated that an A-MRI, omitting contrast-enhanced and DWI, may be used for CPL surveillance without any suspicious features or cases of malignancy being missed. Although small number of cases may need to be recalled for additional MR sequences based on the A-MRI findings, there is still a significant overall timesaving.

CONCLUSION

The best available evidence currently suggests that an A-MRI protocol should be considered for routine surveillance of CPLs. Prospective studies are required to ensure the findings reported in these retrospective case studies are backed up in ongoing clinical practice.

Factors affecting the rates of adherence to surveillance recommendations for incidental pancreatic cystic lesions in a large urban safety net hospital

Background

Pancreatic cystic lesions (PCLs) are a heterogenous group of lesions with varying degrees of malignant potential. PCLs are often incidentally detected on imaging. Management for patients without an immediate indication for resection or tissue sampling entails radiographic surveillance to assess for features concerning for malignant transformation. This study aims to determine the rates of adherence to surveillance recommendations for incidental PCLs, and identify factors associated with adherence or loss of follow-up.

Methods

We conducted a single-centre retrospective study of patients at a tertiary safety net hospital with incidentally discovered asymptomatic PCLs. Follow-up was defined as having undergone repeat imaging as recommended in the radiology report. Data were analysed using logistic regression.

Results

Within our cohort (n=172), 123 (71.5%) subjects completed follow-up imaging. Attending a gastroenterology appointment was most strongly associated with completing follow-up for PCLs and remained significant (p=0.001) in a multivariate logistic regression model. Subjects without a documented primary care provider were less likely to have follow-up (p=0.028). Larger cyst size was associated with completion of follow-up in univariate only (p=0.067).

Conclusion

We found that follow-up of an incidentally discovered PCLs was completed in the majority of our subjects. Incomplete follow-up for PCLs occurred in up to one in three to four patients in our cohort. Access to primary care and utilisation of subspecialty gastroenterology care are associated with completion of follow-up for PCLs. If validated, our findings can guide potential interventions to improve follow-up rates for PCLs.

Recommendations for the Management of Incidental Pancreatic Findings in Adults by the Canadian Association of Radiologists Incidental Findings Working Group

The Canadian Association of Radiologists Incidental Findings Working Group consists of both academic subspecialty and general radiologists and is tasked with adapting and expanding upon the American College of Radiology incidental findings white papers to more closely apply to Canadian practice patterns, particularly more comprehensively dealing with the role of ultrasound and pursuing more cost-effective approaches to the workup of incidental findings without compromising patient care. Presented here are the 2021 Canadian guidelines for the management of pancreatic incidental findings. Topics covered include anatomic variants, fatty atrophy, pancreatic calcifications, ductal ectasia, and management of incidental pancreatic cysts.

Pancreatic Disorders of Pregnancy

The pancreas is an organ with both exocrine and endocrine functions that has a vital role in both digestion as well as glucose metabolism. Although pancreatic dysfunction and disorders are rare in pregnancy, they are becoming increasingly more common. Recognition of these disorders and understanding how they can affect pregnancy is imperative to allow for proper management. We provide an overview of the most common pancreatic disorders that are seen in pregnancy.

Focal Pancreatic Lesions: Role of Contrast-Enhanced Ultrasonography

The introduction of contrast-enhanced ultrasonography (CEUS) has led to a significant improvement in the diagnostic accuracy of ultrasound in the characterization of a pancreatic mass. CEUS, by using a blood pool contrast agent, can provide dynamic information concerning macro- and micro-circulation of focal lesions and of normal parenchyma, without the use of ionizing radiation. On the basis of personal experience and literature data, the purpose of this article is to describe and discuss CEUS imaging findings of the main solid and cystic pancreatic lesions with varying prevalence.