Can we better predict the biologic behavior of incidental IPMN? A comprehensive analysis of molecular diagnostics and biomarkers in intraductal papillary mucinous neoplasms of the pancreas

Pancreas Cyst Diagnosis and Advances in Cyst Fluid Analysis

Pancreatic Cystic Neoplasms (PCN) represent a diverse group of tumors, some of which may progress to pancreatic cancer. Considering their high prevalence in the general population, the development of reliable biomarkers is crucial. The ideal biomarker will accurately diagnose the subtype of PCN and assess the risk of high-grade dysplasia or invasive cancer. Cyst fluid analysis has emerged as a promising approach to accomplish this goal, yet no single marker has yet gained unanimous support for routine inclusion in PCN evaluation.

Association of high-risk stigmata and worrisome features with advanced neoplasia in intraductal papillary mucinous neoplasms (IPMN): A systematic review

BACKGROUND

This systematic review aimed to assess the diagnostic accuracy of the International Consensus Fukuoka Guidelines (ICG2017) in identifying high-risk lesions of Intraductal Papillary Mucinous Neoplasms (IPMNs).

METHODS

The ICG2017 revision committee conducted a comprehensive literature review to establish evidence-based statements on IPMNs. The review focused on articles examining the diagnostic value of imaging features (e.g., cyst or main pancreatic duct diameter), clinical symptoms associated with IPMN, and serum biomarkers. Five clinical questions regarding high-risk stigmata (HRS) and worrisome features (WF) in the ICG2017 guidelines were addressed.

RESULTS

A total of 210 articles were reviewed. The findings revealed a significant association between the presence of mural nodules ≥5 mm in diameter or solid components with contrast enhancement and the diagnosis of high-grade dysplasia or invasive carcinoma. Contrast-enhanced diagnostic tools, such as CT, MRI, or EUS, demonstrated the highest prediction rate and were recommended. Positive cytology was identified as an HRS, while symptoms like acute pancreatitis and cyst diameter growth ≥2.5 mm per year were considered WFs. The use of nomograms and multiple diagnostic factors was recommended for optimal IPMN management.

CONCLUSIONS

This systematic review provides evidence supporting the improved diagnostic accuracy of ICG2017 in identifying high-risk lesions of IPMN. The multidisciplinary incorporation of HRS and WF based on imaging findings and clinical symptoms is crucial. These findings should inform the revision of ICG2017, enhancing the evaluation and management of IPMN patients. By implementing these recommendations, clinicians can make more informed decisions, leading to better diagnosis and treatment outcomes for high-risk IPMN cases.

Real-Life Management of Pancreatic Cysts: Simplified Review of Current Guidelines

Pancreatic cysts are becoming a popular diagnostic tool due to the increased availability of high-quality cross-sectional imaging. Pancreatic cystic lesions constitute closed, liquid-containing cavities, which are either neoplastic or non-neoplastic. While serous lesions often follow a benign course, mucinous lesions can hide carcinoma and, therefore, require different management. Moreover, all cysts should be considered mucinous until proven otherwise, thus limiting the errors in managing these entities. Due to the need for high contrast soft tissue imaging, magnetic resonance imaging represents an elective, non-invasive diagnostic tool. Endoscopic ultrasound (EUS) has started gaining more prominence with regard to the proper diagnosis and management of pancreatic cysts, offering quality information with minimal risks. Enabling both the acquisition of endoscopic images of the papilla and the endosonographic high-quality evaluation of septae, mural nodules along with the vascular patterns of the lesion contribute to a definitive diagnosis. Moreover, the possibility of obtaining cytological or histological samples could become mandatory in the foreseeable future, allowing for more precise molecular testing. Future research should focus on detecting methods to quickly diagnose high-grade dysplasia or early cancer for patients with pancreatic cysts, thus allowing time for appropriate treatment and avoiding surgical overtreatment or over surveillance in selected cases.

The Landmark Series: Intraductal Papillary Mucinous Neoplasms of the Pancreas-From Prevalence to Early Cancer Detection

Modern series report a prevalence of pancreatic cysts in the general population of up to 50% in prospective studies. Of these, about half will be pancreatic cystic neoplasms (PCNs) that have varying degrees of malignant potential. Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are the most common PCNs and are known predecessors of pancreatic adenocarcinoma. Critically, they are one of the only radiographically identifiable precursors of pancreatic cancer and thus provide an opportunity for early cancer detection and surgical resection with curative intent. The combination of high prevalence and potential for malignant degeneration underscore the relevance of discussing the best management of IPMNs and improving the existing standard of care. Landmark data on IPMN prevalence, guidelines, surveillance, biomarkers, and immune landscape are highlighted.

The tumour immune microenvironment and microbiome of pancreatic intraductal papillary mucinous neoplasms

Pancreatic intraductal papillary mucinous neoplasms (IPMNs) have gained substantial attention because they represent one of the only radiographically identifiable precursors of invasive pancreatic ductal adenocarcinoma. Although most of these neoplasms have low-grade dysplasia and will remain indolent, a subset of IPMNs will progress to invasive cancer. The role of the immune system in the progression of IPMNs is unclear, but understanding its role could reveal the mechanism of neoplastic progression and targets for immunotherapy to inhibit progression or treat invasive disease. The available evidence supports a shift in the immune composition of IPMNs during neoplastic progression. Although low-grade lesions contain a high proportion of effector T cells, high-grade IPMNs, and IPMNs with an associated invasive carcinoma lose the T-cell infiltrate and are characterised by a predominance of immunosuppressive elements. Several possible therapeutic strategies emerge from this analysis that are unique to IPMNs and its microbiome.

Computer-aided differentiates benign from malignant IPMN and MCN with a novel feature selection algorithm

In clinical practice, differentiating benign from malignant intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN) preoperatively is crucial for deciding future treating algorithm. However, it remains challenging as benign and malignant lesions usually show similarities in both imaging appearances and clinical indices. Therefore, a robust and accurate computer-aided diagnosis (CAD) system based on radiomics and clinical indices was proposed in this paper to solve this dilemma. In the proposed CAD system, 107 patients were enrolled, where 90 cases were randomly selected for the training set with 5-fold cross validation to build the diagnostic model, while 17 cases were remained for an independent testing set to validate the performance. 436 high-throughput radiomics features while 9 clinical indices were designed and extracted. A novel feature selection algorithm named BLR (Bootstrapping repeated LASSO with Random selections) was proposed to select the most effective features. Then the selected features were sent to Support Vector Machine (SVM) to differentiate the benign or malignant. In the cross-validation cohort and independent testing cohort, the area under receiver operating characteristic curve (AUC) of CAD scheme were 0.83 and 0.92, respectively. The results fully prove the proposed CAD system achieves significant effect in tumors diagnosis.

Multi-Omic Biomarkers as Potential Tools for the Characterisation of Pancreatic Cystic Lesions and Cancer: Innovative Patient Data Integration

Pancreatic cancer (PC) is regarded as one of the most lethal malignant diseases in the world, with GLOBOCAN 2020 estimates indicating that PC was responsible for almost half a million deaths worldwide in 2020. Pancreatic cystic lesions (PCLs) are fluid-filled structures found within or on the surface of the pancreas, which can either be pre-malignant or have no malignant potential. While some PCLs are found in symptomatic patients, nowadays many PCLs are found incidentally in patients undergoing cross-sectional imaging for other reasons-so called 'incidentalomas'. Current methods of characterising PCLs are imperfect and vary hugely between institutions and countries. As such, there is a profound need for improved diagnostic algorithms. This could facilitate more accurate risk stratification of those PCLs that have malignant potential and reduce unnecessary surveillance. As PC continues to have such a poor prognosis, earlier recognition and risk stratification of PCLs may lead to better treatment protocols. This review will focus on the importance of biomarkers in the context of PCLs and PCand outline how current 'omics'-related work could contribute to the identification of a novel integrated biomarker profile for the risk stratification of patients with PCLs and PC.

GNAS mutation detection in circulating cell-free DNA is a specific predictor for intraductal papillary mucinous neoplasms of the pancreas, especially for intestinal subtype

Pancreatic cystic neoplasms (PCNs) are a heterogeneous group with varying risks of malignancy. To explore the clinical utility of liquid biopsy in cyst type classification, we analyzed the GNAS/KRAS mutations in circulating cell-free DNA (cfDNA) obtained from 57 patients with histologically diagnosed PCNs, including 34 with intraductal papillary mucinous neoplasms (IPMNs) and compared the mutant allele prevalence and variant patterns with the paired resected specimens using next-generation sequencing. The positive prevalence of GNAS mutations in cfDNA of patients with IPMN (n = 11, 32%) was significantly higher than that in those with other PCNs (0%, P = 0.002). Conversely, KRAS mutations were detected in cfDNA of only 2 (6%) IPMN patients. The paired-sample comparison revealed highly concordance between the GNAS mutation status of cfDNA and resected IPMN specimens. Similar distributions of GNAS mutation positivity in cfDNA were observed across the different histological grades, whereas IPMNs with intestinal subtype showed a significantly higher prevalence of GNAS mutations than other subtypes (P = 0.030). GNAS mutation positivity in cfDNA was significantly associated with the acellular mucin pool of histological findings in primary IPMN lesions (P = 0.017). Detection of GNAS mutation in cfDNA can serve as a novel biomarker for cyst type classification and differentiation of intestinal subtype IPMN from the other PCNs.

Cyst Fluid Biosignature to Predict Intraductal Papillary Mucinous Neoplasms of the Pancreas with High Malignant Potential

BACKGROUND

Current standard-of-care technologies, such as imaging and cyst fluid analysis, are unable to consistently distinguish intraductal papillary mucinous neoplasms (IPMNs) of the pancreas at high risk of pancreatic cancer from low-risk IPMNs. The objective was to create a single-platform assay to identify IPMNs that are at high risk for malignant progression.

STUDY DESIGN

Building on the Verona International Consensus Conference branch duct IPMN biomarker review, additional protein, cytokine, mucin, DNA, and microRNA cyst fluid targets were identified for creation of a quantitative polymerase chain reaction-based assay. This included messenger RNA markers: ERBB2, GNAS, interleukin 1β, KRAS, MUCs1, 2, 4, 5AC, 7, prostaglandin E2R, PTGER2, prostaglandin E synthase 2, prostaglandin E synthase 1, TP63; microRNA targets: miRs 101, 106b, 10a, 142, 155, 17, 18a, 21, 217, 24, 30a, 342, 532, 92a, and 99b; and GNAS and KRAS mutational analysis. A multi-institutional international collaborative contributed IPMN cyst fluid samples to validate this platform. Cyst fluid gene expression levels were normalized, z-transformed, and used in classification and regression analysis by a support vector machine training algorithm.

RESULTS

From cyst fluids of 59 IPMN patients, principal component analysis confirmed no institutional bias/clustering. Lasso (least absolute shrinkage and selection operator)-penalized logistic regression with binary classification and 5-fold cross-validation used area under the curve as the evaluation criterion to create the optimal signature to discriminate IPMNs as low risk (low/moderate dysplasia) or high risk (high-grade dysplasia/invasive cancer). The most predictive signature was achieved with interleukin 1β, MUC4, and prostaglandin E synthase 2 to accurately discriminate high-risk cysts from low-risk cysts with an area under the curve of up to 0.86 (p = 0.002).

CONCLUSIONS

We have identified a single-platform polymerase chain reaction-based assay of cyst fluid to accurately predict IPMNs with high malignant potential for additional studies.

The Use of Biomarkers in the Risk Stratification of Cystic Neoplasms

Cyst fluid biomarkers may be used to identify pancreatic cyst subtypes. Biomarkers are selected based on their ability to accurately distinguish mucinous from nonmucinous cysts and to risk stratify cysts based on malignant potential. Biomarkers of interest include but are not limited to amylase, oncogenes, DNA analysis, and epigenetic markers. The introduction of next-generation sequencing and molecular panels has aided in improved diagnostic accuracy and risk stratification. This review presents the diagnostic performance of currently available biomarkers and proposes an algorithm to incorporate their use in the diagnosis of pancreatic cysts.

Management of Intraductal Papillary Mucinous Neoplasms: Controversies in Guidelines and Future Perspectives

Purpose of review

Management of intraductal papillary mucinous neoplasm (IPMN) is currently based on consensus, in the absence of evidence-based guidelines. In recent years, several consensus guidelines have been published, with distinct management strategies. In this review, we will discuss these discrepancies, in order to guide treating physicians in clinical management.

Recent findings

The detection rate of pancreatic cysts has increased substantially with the expanded use of high-quality imaging techniques to up to 45%. Of these cysts, 24–82% are IPMNs, which harbour a malignant potential. Timely detection of high-risk lesions is therefore of great importance. Surgical management is based on the presence of clinical and morphological high-risk features, yet the majority of resected specimens appear to be low risk.

Summary

International collaboration and incentive large-scale prospective registries of individuals undergoing cyst surveillance are needed to accumulate unbiased data and develop evidence-based guidelines. Additionally, development of non-invasive, accurate diagnostic tools (e.g. biomarkers) is needed to differentiate between neoplastic and non-neoplastic pancreatic cysts and detect malignant transformation at an early stage (i.e. high-grade dysplasia).

What is the Incidence of Malignancy in Resected Intraductal Papillary Mucinous Neoplasms? An Analysis of Over 100 US Institutions in a Single Year

BACKGROUND

A subset of intraductal papillary mucinous neoplasms (IPMNs) will progress to invasive adenocarcinoma, however identifying invasive from non-invasive disease preoperatively remains challenging. The rate of malignancy in resected IPMNs in the US remains unclear.

OBJECTIVE

We aimed to determine the rate of malignancy and factors associated with high-risk pathology in resected IPMNs.

METHODS

The most recent annual cohort of patients undergoing pancreatectomy included in the American College of Surgeons National Surgical Quality Improvement Program were assessed, and contributions of demographics, preoperative laboratory values, and outcome data to level of IPMN dysplasia were analyzed. The main outcomes were incidence of invasive carcinoma or high-grade dysplasia.

RESULTS

Of 5025 pancreatectomies in 1 year, 478 patients underwent pancreatectomy for IPMN. Invasive carcinoma/high-grade dysplasia was identified in 23% of resected lesions, and there was no difference in patient characteristics or type of resection performed in patients with invasive versus non-invasive pathology. Patients with invasive IPMNs presented significantly more often with high liver function tests, >10% weight loss, clinical jaundice and stent placement, and were more likely to undergo an open operation (p = 0.03). There were no differences in perioperative outcomes. Adjusted logistic regression identified an association between invasive disease and non-soft pancreatic gland texture (odds ratio 0.19, 95% confidence interval 0.05-0.68, p < 0.01).

CONCLUSIONS

Approximately 10% of all pancreatectomies in the US are for IPMNs. In these patients, treated after the revised international consensus guidelines, only 23% of IPMNs contained invasive or high-grade histology. Resections carried similar morbidity regardless of pathology. Improved biomarkers are needed to aid in surgical selection.