Intraductal Papillary Mucinous Neoplasms in Hereditary Cancer Syndromes

Multi-omic markers of intraductal papillary mucinous neoplasms progression into pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal and common form of pancreatic cancer, it has no specific symptoms, and most of the patients are diagnosed when the disease is already at an advanced stage. Chemotherapy typically has only a modest effect, making surgery the most effective treatment option. However, only a small percentage of patients are amenable to surgery. One viable strategy to reduce PDAC death burden associated with the disease is to focus on precursor lesions and identify markers able to predict who will evolve into PDAC. While most PDACs are believed to be preceded by pancreatic intraepithelial neoplasms (PanINs), 5-10 % arise from Intraductal papillary mucinous neoplasms (IPMNs), which are mass-forming cystic lesions that are very common in the general population. IPMNs offer an invaluable model of pancreatic carcinogenesis for researchers to analyse, as well as a target population for PDAC early detection by clinicians. The evolution of IPMN into cancer is a complex and multistep process, therefore the identification of individual markers will not be the solution. In recent years, multiple omics technologies have been instrumental to identify possible biomarkers of IPMN progression and carcinogenesis. The only foreseeable strategy will be to integrate multi-omics data, alongside clinical and morphological features, into a progression score or signature using either standard epidemiologic tools or artificial intelligence. The aim of this manuscript is to review the current knowledge on genetic biomarkers and to briefly mention also additional omics, such as metabolomics, the exposome, the miRNome and epigenomics of IPMNs.

Precursor lesions in familial and hereditary pancreatic cancer

Infiltrating ductal adenocarcinoma of the pancreas, referred to here as "pancreatic cancer," is one of the deadliest of all of the solid malignancies. The five-year survival rate in the United States for individuals diagnosed today with pancreatic cancer is a dismal 12%. Many invasive cancers, including pancreatic cancer, however, arise from histologically and genetically well-characterized precursor lesions, and these precancers are curable. Precursor lesions therefore are an attractive target for early detection and treatment. This is particularly true for individuals with an increased risk of developing invasive cancer, such as individuals with a strong family history of pancreatic cancer, and individuals with a germline variant known to increase the risk of developing pancreatic cancer. There is therefore a need to understand the precursor lesions that can give rise to invasive pancreatic cancer in these individuals.

The cross-talk between the macro and micro-environment in precursor lesions of pancreatic cancer leads to new and promising circulating biomarkers

Pancreatic cancer (PC) is a clinically challenging tumor to combat due to its advanced stage at diagnosis as well as its resistance to currently available therapies. The absence of early symptoms and known detectable biomarkers renders this disease incredibly difficult to detect/manage. Recent advances in the understanding of PC biology have highlighted the importance of cancer-immune cell interactions, not only in the tumor micro-environment but also in distant systemic sites, like the bone marrow, spleen and circulating immune cells, the so-called macro-environment. The response of the macro-environment is emerging as a determining factor in tumor development by contributing to the formation of an increasingly immunogenic micro-environment promoting tumor homeostasis and progression. We will summarize the key events associated with the feedback loop between the tumor immune micro-environment (TIME) and the tumor immune macroenvironment (TIMaE) in pancreatic precancerous lesions along with how it regulates disease development and progression. In addition, liquid biopsy biomarkers capable of diagnosing PC at an early stage of onset will also be discussed. A clearer understanding of the early crosstalk between micro-environment and macro-environment could contribute to identifying new molecular therapeutic targets and biomarkers, consequently improving early PC diagnosis and treatment.

Molecular Pathology of Pancreatic Cystic Lesions with a Focus on Malignant Progression

The malignant progression of pancreatic cystic lesions (PCLs) remains understudied with a knowledge gap, yet its exploration is pivotal for effectively stratifying patient risk and detecting cancer at its earliest stages. Within this review, we delve into the latest discoveries on the molecular level, revealing insights into the IPMN molecular landscape and revised progression model, associated histologic subtypes, and the role of inflammation in the pathogenesis and malignant progression of IPMN. Low-grade PCLs, particularly IPMNs, can develop into high-grade lesions or invasive carcinoma, underscoring the need for long-term surveillance of these lesions if they are not resected. Although KRAS and GNAS remain the primary oncogenic drivers of neoplastic development in IPMNs, additional genes that are important in tumorigenesis have been recently identified by whole exome sequencing. A more complete understanding of the genes involved in the molecular progression of IPMN is critical for effective monitoring to minimize the risk of malignant progression. Complicating these strategies, IPMNs are also frequently multifocal and multiclonal, as demonstrated by comparative molecular analysis. Algorithms for preoperative cyst sampling and improved radiomic techniques are emerging to model this spatial and temporal genetic heterogeneity better. Here, we review the molecular pathology of PCLs, focusing on changes associated with malignant progression. Developing models of molecular risk stratification in PCLs which can complement radiologic and clinical features, facilitate the early detection of pancreatic cancer, and enable the development of more personalized surveillance and management strategies are summarized.

Risk Factors for Progression in Patients Undergoing Surveillance for Pancreatic Cysts

OBJECTIVE

To identify risk factors associated with the progression of pancreatic cysts in patients undergoing surveillance.

BACKGROUND

Previous studies of intraductal papillary mucinous neoplasms (IPMNs) rely on surgical series to determine malignancy risk and have inconsistently identified characteristics associated with IPMN progression.

METHODS

We conducted a retrospective review of 2197 patients presenting with imaging concerning for IPMN from 2010 to 2019 at a single institution. Cyst progression was defined as resection or pancreatic cancer development.

RESULTS

The median follow-up time was 84 months from the presentation. The median age was 66 years, and 62% were female. Ten percent had a first-degree relative with pancreatic cancer, and 3.2% had a germline mutation or genetic syndrome associated with an increased risk of pancreatic ductal adenocarcinoma (PDAC). Cumulative incidence of progression was 17.8% and 20.0% at 12 and 60 months postpresentation, respectively. Surgical pathology for 417 resected cases showed noninvasive IPMN in 39% of cases and PDAC with or without associated IPMN in 20%. Only 18 patients developed PDAC after 6 months of surveillance (0.8%). On multivariable analysis, symptomatic disease [hazard ratio (HR)=1.58; 95% CI: 1.25-2.01], current smoker status (HR=1.58; 95% CI: 1.16-2.15), cyst size (HR=1.26; 95% CI: 1.20-1.33), main duct dilation (HR=3.17; 95% CI: 2.44-4.11), and solid components (HR=1.89; 95% CI: 1.34-2.66) were associated with progression.

CONCLUSIONS

Worrisome features on imaging at presentation, current smoker status, and symptomatic presentation are associated with IPMN progression. Most patients progressed within the first year of presentation to Memorial Sloan Kettering Cancer Center (MSKCC). Further investigation is necessary to develop personalized cyst surveillance strategies.

Pancreatic Cancer and the Family Connection: The Role of Advanced Practitioners in Screening and Educating Genetically At-Risk Individuals

Pancreatic cancer is the third leading cause of cancer deaths in the United States. It has a 95% mortality rate within 5 years of the initial diagnosis. Pancreatic ductal adenocarcinoma is the most commonly diagnosed histotype. The average age at diagnosis is 70 years. Familial forms of pancreatic cancer have been associated with pathogenic variants in predisposing genes, including ATM, BRCA1, BRCA2, PALB2, CDKN2A, STK11, MLH1, and MSH2. Collecting information on the patient's family history may serve as a primary tool to screen an individual's risk for familial pancreatic cancer. More advanced screening options for individuals at risk include endoscopic ultrasonography, magnetic resonance imaging, and magnetic resonance cholangiopancreatography. Due to pancreatic cancer's high mortality rate, routine screening of individuals at risk for developing familial pancreatic cancer may result in early diagnosis and improved survivability. This review aims to characterize the genetic risk factors associated with pancreatic cancer and recognize available screening options for at-risk individuals.

Pancreatic Cancer Screening for At-Risk Individuals (Pancreas Scan Study): Yield, Harms, and Outcomes From a Prospective Multicenter Study

INTRODUCTION

Guidelines endorse pancreatic cancer screening in genetically susceptible individuals. We conducted a prospective, multicenter study to determine yield, harms, and outcomes of pancreatic cancer screening.

METHODS

All high-risk individuals undergoing pancreatic cancer screening at 5 centers from 2020 to 2022 were prospectively enrolled. Pancreas findings were designated as low-risk (fatty or chronic pancreatitis-like changes), intermediate-risk (neuroendocrine tumor [NET] <2 cm or branch-duct intraductal papillary mucinous neoplasm [IPMN]), or high-risk lesions (high-grade pancreatic intraepithelial neoplasia/dysplasia, main-duct IPMN, NET >2 cm, or pancreatic cancer). Harms from screening included adverse events during screening or undergoing low-yield pancreatic surgery. Annual screening was performed using endoscopic ultrasound and or magnetic resonance cholangiopancreatography. Annual screening for new-onset diabetes using fasting blood sugar was also performed ( ClinicalTrials.gov : NCT05006131).

RESULTS

During the study period, 252 patients underwent pancreatic cancer screening. Mean age was 59.9 years, 69% were female, and 79.4% were White. Common indications were BRCA 1/2 (36.9%), familial pancreatic cancer syndrome kindred (31.7%), ataxia telangiectasia mutated (3.5%), Lynch syndrome (6.7%), Peutz-Jeghers (4.3%), and familial atypical multiple mole melanoma (3.5%). Low-risk lesions were noted in 23.4% and intermediate-risk lesions in 31.7%, almost all of which were branch-duct IPMN without worrisome features. High-risk lesions were noted in 2 patients (0.8%), who were diagnosed with pancreas cancer at stages T2N1M0 and T2N1M1. Prediabetes was noted in 18.2% and new-onset diabetes in 1.7%. Abnormal fasting blood sugar was not associated with pancreatic lesions. There were no adverse events from screening tests, and no patient underwent low-yield pancreatic surgery.

DISCUSSION

Pancreatic cancer screening detected high-risk lesions with lower frequency than previously reported. No harms from screening were noted.

Are All Cysts Created Equal?: Pancreatic Cystic Neoplasms in Patients with Familial or Genetic Risk Factors for Pancreatic Cancer

Pancreatic cystic lesions (PCLs) have become more prevalent over time, particularly in asymptomatic individuals. Current screening guidelines for incidental PCLs offer a unified approach to surveillance and management, predicated on "worrisome features." Although PCLs are common in the general population, their prevalence may be higher in high-risk individuals (HRI, unaffected patients with specific familial and/or genetic risk factors). As more PCLs are diagnosed and more HRI identified, it is important to promote research that bridges data gaps and introduces nuance to risk assessment tools, ensuring tailoring of guidelines to the needs of HRI with varying pancreatic cancer risk factors.

Role of pancreatic ductal adenocarcinoma risk factors in intraductal papillary mucinous neoplasm progression

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is lethal due to its late diagnosis and lack of successful treatments. A possible strategy to reduce its death burden is prevention. Intraductal papillary mucinous neoplasms (IPMNs) are precursors of PDAC. It is difficult to estimate the incidence of IPMNs because they are asymptomatic. Two recent studies reported pancreatic cysts in 3% and 13% of scanned subjects. The possibility of identifying a subgroup of IPMN patients with a higher probability of progression into cancer could be instrumental in increasing the survival rate. In this study, genetic and non-genetic PDAC risk factors were tested in a group of IPMN patients under surveillance.

Methods

A retrospective study was conducted on 354 IPMN patients enrolled in two Italian centres with an average follow-up of 64 months. With the use of DNA extracted from blood, collected at IPMN diagnosis, all patients were genotyped for 30 known PDAC risk loci. The polymorphisms were analysed individually and grouped in an unweighted polygenic score (PGS) in relation to IPMN progression. The ABO blood group and non-genetic PDAC risk factors were also analysed. IPMN progression was defined based on the development of worrisome features and/or high-risk stigmata during follow-up.

Results

Two genetic variants (rs1517037 and rs10094872) showed suggestive associations with an increment of IPMN progression. After correction for multiple testing, using the Bonferroni correction, none of the variants showed a statistically significant association. However, associations were observed for the non-genetic variables, such as smoking status, comparing heavy smokers with light smokers (HR = 3.81, 95% 1.43-10.09, p = 0.007), and obesity (HR = 2.46, 95% CI 1.22-4.95, p = 0.012).

Conclusion

In conclusion, this study is the first attempt to investigate the presence of shared genetic background between PDAC risk and IPMN progression; however, the results suggest that the 30 established PDAC susceptibility polymorphisms are not associated with clinical IPMN progression in a sample of 354 patients. However, we observed indications of cigarette smoking and body mass index (BMI) involvement in IPMN progression. The biological mechanism that could link these two risk factors to progression could be chronic inflammation, of which both smoking and obesity are strong promoters.

Prevalence of a BRCA2 Pathogenic Variant in Hereditary-Breast-and-Ovarian-Cancer-Syndrome Families with Increased Risk of Pancreatic Cancer in a Restricted Italian Area

PVs and LPVs in BRCA1/2 genes are correlated to a high risk of developing breast cancer and/or ovarian cancer (Hereditary Breast and Ovarian Cancer syndrome, HBOC); additionally, in recent years, an increasing number of BRCA 1/2 variants have been identified and associated with pancreatic cancer. Epidemiologic studies have highlighted that inherited factors are involved in 10% to 20% of PCs, mainly through deleterious variants of BRCA2. The frequency of BRCA1/2 germline alterations fluctuates quite a lot among different ethnic groups, and the estimated rate of PVs/LPVs variants in Italian HBOC families is not very accurate, according to different reports. The aim of our study is to describe the prevalence of a BRCA2 PV observed in a selected cohort of HBOC patients and their relatives, whose common origin is the eastern coast of Emilia Romagna, a region of Italy. This study provides insight into the frequency of the variant detected in this area and provides evidence of an increased risk of pancreatic and breast cancer, useful for genetic counseling and surveillance programs.

Clinical and Molecular Attributes and Evaluation of Pancreatic Cystic Neoplasm

Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are all considered "Pancreatic cystic neoplasms (PCNs)" and show a varying risk of developing into pancreatic ductal adenocarcinoma (PDAC). These lesions display different molecular characteristics, mutations, and clinical manifestations. A lack of detailed understanding of PCN subtype characteristics and their molecular mechanisms limits the development of efficient diagnostic tools and therapeutic strategies for these lesions. Proper in vivo mouse models that mimic human PCNs are also needed to study the molecular mechanisms and for therapeutic testing. A comprehensive understanding of the current status of PCN biology, mechanisms, current diagnostic methods, and therapies will help in the early detection and proper management of patients with these lesions and PDAC. This review aims to describe all these aspects of PCNs, specifically IPMNs, by describing the future perspectives.

Pancreatic Cystic Lesions: A Focused Review on Cyst Clinicopathological Features and Advanced Diagnostics

Macroscopic, endomicroscopic, and histologic findings and correlation are an integral part of the diagnostic evaluation of pancreatic cystic lesions (PCLs), as complementing morphologic features seen by different specialties are combined to contribute to a final diagnosis. However, malignancy risk stratification of PCLs with worrisome features can still be challenging even after endoscopic ultrasound guided-fine needle aspiration (EUS-FNA) with cytological evaluation. This review aims to summarize cyst clinicopathological features from the pathologists' perspective, coupled with knowledge from advanced diagnostics-confocal laser endomicroscopy and cyst fluid molecular analysis, to demonstrate the state-of-art risk stratification of PCLs. This review includes illustrative photos of surgical specimens, endomicroscopic and histologic images, and a summary of cyst fluid molecular markers.

Modern aspects of the management of pancreatic intraductal papillary mucinous neoplasms: a narrative review

Intraductal papillary mucinous neoplasms (IPMNs) account for approximately 35% of all cystic tumors in the pancreas and represent the largest subgroup. They are characterized by mucin production and intraductal papillary epithelium growth. IPMNs range from benign to malignant lesions. Biomarkers combined with 18F-Fluorodeoxyglucose-positron emission tomography (18FDG-PET) is the best diagnostic tool. The risk of malignant transformation for main-duct IPMNs is between 34-68% and for low-risk branch-duct (BD)-IPMNs it is 1.1%. Monitoring is crucial for determining the optimal time of surgical excision. Novel artificial intelligence combining clinical, tumor biomarkers, imaging and molecular genomics plays a determinant role in the evaluation of such lesions. The first diagnostic tool is multidetector helical computed tomography (MDHCT) or up-to-date magnetic resonance imaging (MRI). MRI detects malignancy by enhancing mural nodules ≥3 mm. Novel endosonographic interventional techniques have been added to the diagnostic armamentarium. Pancreatoscopy is feasible and effective but challenging for evaluating the diagnosis, invasiveness, and extent of IPMNs. Its findings may change the surgical approach. Pancreatic juice and duodenal fluid have been used recently for molecular biological analysis. The genes most frequently altered include Kirsten rat sarcoma viral proto-oncogene (KRAS), tumor protein p53 (TP53), cyclin-dependent kinase inhibitor 2A (CDKN2A), SMAD family member 4 (SMAD4), and guanine nucleotide-binding protein, alpha stimulating (GNAS). Despite the advances in diagnostic modalities, assessment of this premalignant lesion of pancreatic cancer, with its poor prognosis, is a challenging task. Pancreatectomy is the indicated approach for malignant or high-risk IPMNs with potent malignancy. Conservative management or enucleation for preserving the pancreas of low-risk BD-IPMNs is recommended, but long-term follow-up for recurrence is necessary. The management of IPMNs must be individualized based on preoperative high-risk stigmata and worrisome features.