Predictive Factors for the Metachronous Development of High-risk Lesions in the Remnant Pancreas After Partial Pancreatectomy for Intraductal Papillary Mucinous Neoplasm

Familial Intraductal Papillary Mucinous Neoplasm Associated With the Germline MSH6 Missense Variant and Progression of Pancreatic cancer

OBJECTIVES

Intraductal papillary mucinous neoplasm (IPMN) in individuals with at least one first-degree relative with IPMN is defined as familial IPMN. However, few studies have reported on familial IPMN, its clinical characteristics, or the associated genetic factors.

MATERIALS AND METHODS

We report the case of a 58-year-old woman with multifocal IPMN and a mural nodule in the pancreatic body. The patient underwent a distal pancreatectomy and developed pancreatic head cancer 1 year and 6 months postoperatively. The patient had a family history of multifocal IPMN in her father. Therefore, a genetic predisposition to IPMN and pancreatic cancer was suspected. The patient was analyzed for germline variants, and the resected IPMN was subjected to immunohistochemical and somatic variant analyses.

RESULTS

Next-generation sequencing revealed a heterozygous germline missense variant in exon 5 of MSH6 (c.3197A>G; Tyr1066Cys). The pathogenicity of this variant of uncertain significance was suspected based on multiple in silico analyses, and the same MSH6 variant was identified in the patient's father's colonic adenoma. The mural nodule in the pancreatic body was pathologically diagnosed as a high-grade IPMN with ossification and somatic KRAS and PIK3CA variants.

CONCLUSIONS

This case revealed a possible genetic factor for familial IPMN development and presented interesting clinicopathological findings.

Novel Insights into Postoperative Surveillance in Resected Pancreatic Cystic Neoplasms-A Review

Pancreatic cystic lesions (PCL) are frequently encountered in clinical practice and some are referred to surgery due to their neoplastic risk or malignant transformation. The management of PCL involves complex decision-making, with postoperative surveillance being a key component for long-term outcomes, due to the potential for recurrence and postoperative morbidity. Unfortunately, the follow-up of resected patients is far from being optimal and there is a lack of consensus on recommendations with regard to timing and methods of surveillance. Here, we summarize the current knowledge on the postoperative surveillance of neoplastic pancreatic cysts, focusing on the mechanisms and risk factors for recurrence, the recurrence rates according to the initial indication for surgery, the final result of the surgical specimen and neoplastic risk in the remaining pancreas, as well as the postsurgical morbidity comprising pancreatic exocrine insufficiency, metabolic dysfunction and diabetes after resection, according to the type of surgery performed. We analyze postsurgical recurrence rates and morbidity profiles, as influenced by different surgical techniques, to better delineate at-risk patients, and highlight the need for tailored surveillance strategies adapted to preoperative and operative factors with an impact on outcomes.

International evidence-based Kyoto guidelines for the management of intraductal papillary mucinous neoplasm of the pancreas

This study group aimed to revise the 2017 international consensus guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, and mainly focused on five topics; the revision of high-risk stigmata (HRS) and worrisome features (WF), surveillance of non-resected IPMN, surveillance after resection of IPMN, revision of pathological aspects, and investigation of molecular markers in cyst fluid. A new development from the prior guidelines is that systematic reviews were performed for each one of these topics, and published separately to provide evidence-based recommendations. One of the highlights of these new "evidence-based guidelines" is to propose a new management algorithm, and one major revision is to include into the assessment of HRS and WF the imaging findings from endoscopic ultrasound (EUS) and the results of cytological analysis from EUS-guided fine needle aspiration technique, when this is performed. Another key element of the current guidelines is to clarify whether lifetime surveillance for small IPMNs is required, and recommends two options, "stop surveillance" or "continue surveillance for possible development of concomitant pancreatic ductal adenocarcinoma", for small unchanged BD-IPMN after 5 years surveillance. Several other points are also discussed, including identifying high-risk features for recurrence in patients who underwent resection of non-invasive IPMN with negative surgical margin, summaries of the recent observations in the pathology of IPMN. In addition, the emerging role of cyst fluid markers that can aid in distinguishing IPMN from other pancreatic cysts and identify those IPMNs that harbor high-grade dysplasia or invasive carcinoma is discussed.

Recurrence following Resection of Intraductal Papillary Mucinous Neoplasms: A Systematic Review to Guide Surveillance

Patients who undergo resection for non-invasive IPMN are at risk for long-term recurrence. Further evidence is needed to identify evidence-based surveillance strategies based on the risk of recurrence. We performed a systematic review of the current literature regarding recurrence patterns following resection of non-invasive IPMN to summarize evidence-based recommendations for surveillance. Among the 61 studies reviewed, a total of 8779 patients underwent resection for non-invasive IPMN. The pooled overall median follow-up time was 49.5 months (IQR: 38.5-57.7) and ranged between 14.1 months and 114 months. The overall median recurrence rate for patients with resected non-invasive IPMN was 8.8% (IQR: 5.0, 15.6) and ranged from 0% to 27.6%. Among the 33 studies reporting the time to recurrence, the overall median time to recurrence was 24 months (IQR: 17, 46). Existing literature on recurrence rates and post-resection surveillance strategies for patients with resected non-invasive IPMN varies greatly. Patients with resected non-invasive IPMN appear to be at risk for long-term recurrence and should undergo routine surveillance.

Systematic review of challenging issues in pathology of intraductal papillary mucinous neoplasms

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are a cystic precursor to pancreatic cancer. IPMNs deemed clinically to be at high-risk for malignant progression are frequently treated with surgical resection, and pathological examination of the pancreatectomy specimen is a key component of the clinical care of IPMN patients.

METHODS

Systematic literature reviews were conducted around eight topics of clinical relevance in the examination of pathological specimens in patients undergoing resection of IPMN.

RESULTS

This review provides updated perspectives on morphological subtyping of IPMNs, classification of intraductal oncocytic papillary neoplasms, nomenclature for high-grade dysplasia, assessment of T stage, distinction of carcinoma associated or concomitant with IPMN, role of molecular assessment of IPMN tissue, role of intraoperative assessment by frozen section, and preoperative evaluation of cyst fluid cytology.

CONCLUSIONS

This analysis provides the foundation for data-driven approaches to several challenging issues in the pathology of IPMNs.

Pancreatic ductal adenocarcinomas concomitant with intraductal papillary mucinous neoplasms of the pancreas: A investigation of those clinicopathological features by analyzing 48 patients who underwent surgery for those lesions

BACKGROUND

Differences between pancreatic ductal adenocarcinomas (PDACs) concomitant with intraductal papillary mucinous neoplasm (IPMN) (C-PDACs), those without IPMN (NC-PDACs) and invasive cancers derived from IPMN (IC-Ds) have not been fully clarified.

METHODS

Forty-eight patients with C-PDAC were included to investigate the differences in 1) clinicopathological features and 2) post-operative courses among the three invasive cancer groups.

RESULTS

1) Characteristics of C-PDACs were mostly similar to those of NC-PDACs; whereas, between C-PDACs and IC-Ds, the rate of mucinous carcinoma (2%/25%, p = 0.003) and pathological stage (IA, 15%/36%, p = 0.033; III, 31%/4%, p = 0.015) significantly differed. Most C-PDACs coexisted with small, multifocal IPMNs without mural nodules. 2) Cumulative 5-year recurrence-free survival (RFS) rate related to extra-pancreatic recurrence was significantly worse in C-PDACs than in IC-Ds (35%/69%, p = 0.008) and was not significantly different between C-PDACs and NC-PDACs (35%/18%). This related to intra-pancreatic recurrence tended to be poor in the order of IC-Ds, C-PDACs, and NC-PDACs (69%/82%/93%).

CONCLUSIONS

Because characteristics of IPMNs remarkably differed between C-PDACs and IC-Ds, another algorithm specific to the early detection of C-PDACs is necessary. Appropriate post-operative managements according to the two types of recurrences may contribute to the improvement in the prognoses of C-PDACs/IC-Ds.

Surveillance after resection of non-invasive intraductal papillary mucinous neoplasms (IPMN). A systematic review

BACKGROUND

The ideal surveillance strategy after partial pancreatectomy for non-invasive IPMN remains undefined and existing guidelines provide conflicting recommendations. The present study was developed in anticipation of the joint meeting of the International Association of Pancreatology (IAP) and the Japan Pancreas Society (JPS) held in Kyoto in July 2022.

METHODS

An international team of experts developed the four clinical questions (CQ) to operationalize issues pertaining to surveillance of patients in this context. A systematic review was designed following the PRISMA guidelines and registered in PROSPERO. The search strategy was executed in PubMed/Medline (Ovid), Embase, the Cochrane Library and Web of Science databases. Four investigators individually extracted data from the selected studies and drafted recommendations for each CQ. These were subsequently discussed and agreed upon that the IAP/JPS meeting.

RESULTS

From a total of 1098 studies identified through the initial search, 41 studies were included in the review and informed the recommendations. No studies providing level one data were identified in this systematic review, all studies included were cohort or case-control studies.

CONCLUSIONS

There is a lack of level 1 data addressing the issue of surveillance of patients following partial pancreatectomy for non-invasive IPMN. The definition of remnant pancreatic lesion in this setting is largely heterogeneous across all studies evaluated. Herein we propose an inclusive definition of remnant pancreatic lesions to guide future prospective efforts for reporting the natural history and long-term outcomes of these patients.

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.

Intraductal Papillary Mucinous Neoplasms in Hereditary Cancer Syndromes

Hereditary pancreatic cancer, which includes patients with familial pancreatic cancer (FPC) and hereditary pancreatic cancer syndromes, accounts for about 10% of all pancreatic cancer diagnoses. The early detection of pre-cancerous pancreatic cysts has increasingly become a focus of interest in recent years as a potential avenue to lower pancreatic cancer incidence and mortality. Intraductal papillary mucinous cystic neoplasms (IPMNs) are recognized precursor lesions of pancreatic cancer. IPMNs have high prevalence in patients with hereditary pancreatic cancer and their relatives. While various somatic mutations have been identified in IPMNs, certain germline mutations associated with hereditary cancer syndromes have also been identified in IPMNs, suggesting a role in their formation. While the significance for the higher prevalence of IPMNs or similar germline mutations in these high-risk patients remain unclear, IPMNs do represent pre-malignant lesions that need close surveillance. This review summarizes the available literature on the incidence and prevalence of IPMNs in inherited genetic predisposition syndromes and FPC and speculates if IPMN and pancreatic cancer surveillance in these high-risk individuals needs to change.

Pancreatic resections for benign intraductal papillary mucinous neoplasms: Collateral damages from friendly fire

BACKGROUND

Surgical resection of intraductal papillary mucinous neoplasms is based on preoperative high-risk stigmata/worrisome features, but the risk of overtreatment remains high. The aim of this study was to evaluate surgical indications and perioperative and long-term complications in patients with low-grade intraductal papillary mucinous neoplasms.

METHODS

Patients who underwent surgical resection between 2009 and 2018 with a final histology of low-grade intraductal papillary mucinous neoplasms were included. Surgical indications, type of surgery, and short- and long-term outcomes were evaluated.

RESULTS

A significant decrease in the rate of patients resected for low-grade intraductal papillary mucinous neoplasms was observed (43.6% in 2009-2012 vs 27.8% in 2013-2018; P = .003), and 133 patients were finally included (62 women, median age: 68 years). Of these, 24.1% had 1 worrisome feature, 39.8% had ≥2 worrisome features, 18.8% had ≥1 high-risk stigmata, and 15.8% had ≥1 worrisome features + 1 high-risk stigmata. Overall surgical morbidity was 55.6%, 15.8% had Clavien-Dindo ≥3 complications, reoperation rate was 3.8%, and 90-day postoperative mortality was 1.5%. After a median follow-up of 60 months, 13 patients (11.5%) had a recurrence of benign intraductal papillary mucinous neoplasm in the pancreatic remnant, and 2 patients (1.8%) developed pancreatic ductal adenocarcinoma. After partial pancreatectomy, 51.3% of patients were taking pancreatic enzyme replacement therapy. Among nondiabetics, 26% developed diabetes after partial pancreatectomy, of which 38% were insulin-dependent. Eighteen patients (13.7%) developed incisional hernia.

CONCLUSION

Given the rates of morbidity and long-term complications after pancreatic resections, surgeons should attentively balance the true risks of intraductal papillary mucinous neoplasm degeneration with the risks of surgical resection in each patient.

Optimal surveillance of intraductal papillary mucinous neoplasms of the pancreas focusing on remnant pancreas recurrence after surgical resection

BACKGROUND

The international consensus guidelines for intraductal papillary mucinous neoplasm of the pancreas (IPMN) presented clinical features as indications for surgery. Whereas surveillance for recurrence, including de novo lesions, is essential, optimal surveillance protocols have not been established.

AIM AND METHODS

This study aimed to assess the clinical features of recurrence at the remnant pancreas (Rem-Panc) and extra-pancreas (Ex-Panc) after surgery for IPMN. Ninety-one patients of IPMN that underwent detailed preoperative assessment and pancreatectomy were retrospectively analyzed, focusing especially on the type of recurrence.

RESULTS

The IPMNs were finally diagnosed as low-grade dysplasia (LDA, n = 42), high-grade dysplasia (HAD, n = 19), and invasive carcinoma (IPMC, n = 30). Recurrence was observed in 26 patients (29%), of which recurrence was seen at Rem-Panc in 19 patients (21%) and Ex-Panc in 7 patients (8%). The frequency of Rem-Panc recurrence was 10% in LDA, 21% in HDA, and 37% in IPMC. On the other hand, Ex-Panc recurrence was observed only in IPMC (23%). Ex-Panc recurrence showed shorter median recurrence-free survival (RFS) and overall survival (OS) than Rem-Panc recurrence (median RFS 8 months vs. 35 months, p < 0.001; median OS 25 months vs. 72 months, p < 0.001). Regarding treatment for Rem-Panc recurrence, repeat pancreatectomy resulted in better OS than no repeat pancreatectomy (MST 36 months vs. 15.5 months, p = 0.033). On multivariate analysis, main duct stenosis or disruption as a preoperative feature (hazard ratio [HR] 10.6, p = 0.002) and positive surgical margin (HR 4.4, p = 0.018) were identified as risk factors for Rem-Panc recurrence.

CONCLUSIONS

The risk factors for Rem-Panc and Ex-Panc recurrence differ. Therefore, optimal surveillance on these features is desirable to ensure that repeat pancreatectomy for Rem-Panc recurrence can be an appropriate surgical intervention.

Metachronous occurrence of main-duct intraductal papillary mucinous neoplasm (IPMN) and adenocarcinoma in a chronic pancreatitis patient: A case report

RATIONALE

Chronic pancreatitis (CP) is a risk factor for developing pancreatic ductal adenocarcinoma (PDAC). In addition, a patient with partial pancreatectomy for intraductal papillary mucinous neoplasm (IPMN) can also lead to PDAC. In contrast, IPMN is a distinct disease entity, independent of CP, and there have been few reports that CP is the cause of IPMN. To the best of our knowledge, this is the first clinical case report of the metachronous occurrence of main-duct IPMN and PDAC with a 9 and half-year interval in a patient with chronic alcoholic pancreatitis.

PATIENT CONCERNS

A 50-year-old man with a long medical history of recurrent alcoholic pancreatitis and hepatitis over a decade was diagnosed with another episode of acute pancreatitis based on laboratory findings and clinical symptoms. The patient underwent pylorus-preserving pancreaticoduodenectomy (PPPD) for a small nodular lesion in the main duct of the pancreatic head and was diagnosed with main-duct IPMN low-grade dysplasia and associated fibrosing CP. Nine and a half years later, a 59-year-old man lost 7 kg over 3 months and was diagnosed with new-onset diabetes mellitus.

DIAGNOSIS

The patient was diagnosed with metachronous, well-differentiated PDAC with concomitant CP.

INTERVENTIONS

The patient underwent radical antegrade modular pancreatosplenectomy (RAMPS) for a small nodular mass in the remnant pancreas.

OUTCOMES

The patient was healthy for 44 months without evidence of tumor recurrence during clinical follow-up examinations including laboratory findings, tumor marker, and imaging studies.

LESSONS

Early diagnosis of metachronous pancreatic neoplasia in a patient with chronic pancreatitis could be made by correlating newly developed clinical symptoms and signs with careful radiological examinations.

Resection of Recurrent Pancreatic Cancer: Who Can Benefit?

Background

Recurrence after resection of pancreatic cancer occurs in up to 80% of patients in the first 2 years after complete resection. While most patients are not eligible for surgical treatment due to disseminated disease, a certain group of patients can be evaluated for re-resection of local recurrence. This review summarizes the current literature on surgical treatment of recurrent pancreatic cancer and potential prognostic factors.

Summary

Re-resection of recurrent pancreatic cancer provides a significant survival benefit to selected patients with acceptable procedure-related mortality. Median overall survival after re-resection of recurrent pancreatic cancer is up to 28 months. The most relevant clinical parameters associated with a prognostic benefit are young patient age (<65 years), time to initial resection (>10 months), and preoperative chemotherapy before re-resection. Molecular markers are currently under investigation and might help to improve patient selection in the future.

Key Message

Re-resection of recurrent pancreatic cancer is safe and feasible in experienced hands. Selected patients benefit from surgical treatment, but future studies are needed to identify reliable prognostic markers predicting survival.

A novel staging system and clinical predictive nomogram for more accurate staging and prognosis of malignant pancreatic intraductal papillary mucinous neoplasms: a population-based study

BACKGROUND

The current guidelines of the American Joint Committee on Cancer (AJCC) for the staging of exocrine pancreatic tumors seem inapplicable to malignant pancreatic intraductal papillary mucinous neoplasms (IPMN). Therefore, we aimed to improve the accuracy of clinical staging and prognosis for malignant IPMN by modifiing current AJCC system.

METHODS

We extracted data of 2001 patients with malignant IPMN from the Surveillance, Epidemiology, and End Results database between 2000 and 2016. Of these, 1401 patients were assigned to the primary cohort and 600 patients to the validation cohort.

RESULTS

In Kaplan-Meier analysis of the primary cohort, the current AJCC guidelines were unable to distinguish between certain tumor substages (IA and IB in the 7th, IB and IIA in the 8th). The modified system that we regrouped based on the median overall survival and hazard ratios, was superior in tumor stage classifications. Age > 70 years, tumors located in the body or tail, high-grade differentiated tumors, surgery, chemotherapy, and tumor, lymph node, and metastasis (TNM) stage were identified as independent predictive factors for overall survival. Compared to that of TNM-based systems, the concordance index of the clinical predictive nomogram significantly improved (0.819; 95% confidence interval, 0.805-0.833), with excellent area under the receiver operating characteristic curves (1-, 3-, and 5-year: 0.881, 0.889, and 0.879, respectively). The calibration curves also showed good agreement between prediction and actual observation. The analysis of treatment modalities revealed that surgery resulted in better survival for all resectable malignant IPMN. The analysis of chemotherapy data reveals its potential in improving the prognosis of treatment for patients with locally advanced or distant metastases.

CONCLUSIONS

Our modified staging system improves the distinction of tumor stages. The nomogram was a more accurate and clinically reliable tool for prognosis prediction of patients with malignant IPMN.

Cystic pancreatic lesions: MR imaging findings and management

Cystic pancreatic lesions (CPLs) are frequently casual findings in radiological examinations performed for other reasons in patients with unrelated symptoms. As they require different management according to their histological nature, differential diagnosis is essential. Radiologist plays a key role in the diagnosis and management of these lesions as imaging is able to correctly characterize most of them and thus address to a correct management. The first step for a correct characterization is to look for a communication between the CPLs and the main pancreatic duct, and then, it is essential to evaluate the morphology of the lesions. Age, sex and a history of previous pancreatic pathologies are important information to be used in the differential diagnosis. As some CPLs with different pathologic backgrounds can show the same morphological findings, differential diagnosis can be difficult, and thus, the final diagnosis can require other techniques, such as endoscopic ultrasound, endoscopic ultrasound-fine needle aspiration and endoscopic ultrasound-through the needle biopsy, and multidisciplinary management is important for a correct management.

Recurrent intraductal papillary mucinous neoplasms of the pancreas mimicking ampullary cancer

Although several studies have reported that some patients developed metachronous/recurrent intraductal papillary mucinous neoplasms (IPMNs) after partial pancreatectomy, recurrence of IPMN mimicking ampullary cancer is extremely rare. We report the case of a 62-year-old man who developed recurrent IPMN mimicking ampullary cancer. Every 3-6 months, the patient had received surveillance with computed tomography after distal pancreatectomy for IPMN, high-grade, pancreatobiliary type. However, a villous tumor at the major duodenal papilla was found incidentally by upper gastrointestinal endoscopy 2 years and 3 months after initial surgery, and the biopsy result was adenocarcinoma. Endoscopic ultrasonography showed a tumor at the periampullary lesion; however, the origin of the tumor could not be determined definitively. Remnant total pancreatectomy was performed, and the histological diagnosis revealed IPMN, high-grade, pancreatobiliary type. Some patients develop recurrent IPMN mimicking ampullary cancer; thus, careful surveillance for periampullary lesions as well as remnant pancreas should be performed.

Independent predictors of secondary invasive pancreatic remnant tumors after initial resection of an intraductal papillary mucinous neoplasm: a nationwide large-scale survey in Japan

PURPOSE

There is no standardized surveillance protocol after intraductal papillary mucinous neoplasm (IPMN) resection. We report the findings of a large-scale survey in Japan, investigating the independent predictors of secondary invasive tumors by analyzing the epidemiology of secondary tumors of the remnant pancreas after initial IPMN resection.

METHODS

An institutional questionnaire about the remnant pancreas after pancreas resection was distributed at the 41st Annual Meeting of the Japanese Society of Pancreatic Surgery in Tokyo. We retrospectively analyzed the patient data including pathological diagnosis, postoperative outcomes, and evaluation methods.

RESULTS

Redo pancreatectomy was performed for secondary disease in 213 (1.4%) of a total 15,777 patients. Eighty-eight of these 213 patients had undergone initial resection of IPMN. The types of secondary tumors after IPMN resection significantly depended on those of the primary tumors. Through short-interval and long-term follow-up, most of the secondary tumors were detected within 1-4 years. Logistic regression analysis revealed that the initial pathological diagnosis of invasive IPMN was an independent predictor of secondary invasive tumors in the remnant pancreas.

CONCLUSION

Primary invasive IPMN proved to be a significant predictor of secondary invasive IPMN. Both short-interval and long-term follow-up may help to determine the prognosis of patients after IPMN resection.

Concomitant Intraductal Papillary Mucinous Neoplasm in Pancreatic Ductal Adenocarcinoma Is an Independent Predictive Factor for the Occurrence of New Cancer in the Remnant Pancreas

OBJECTIVE

To determine the factors predicting the subsequent development of pancreatic ductal adenocarcinoma in remnant pancreas (PDAC-RP) after partial pancreatectomy for PDAC.

SUMMARY BACKGROUND DATA

PDAC-RP after partial pancreatectomy for PDAC is currently not so rare because of improved prognosis of PDAC patients due to recent advances in surgical techniques and adjuvant therapy. However, the predictive factors related to PDAC-RP remain unknown.

METHODS

We retrospectively reviewed the clinicopathological data of a consecutive series of 379 patients with PDAC treated by partial pancreatectomy between 1992 and 2015; 14 patients (3.69%) had PDAC-RP. Clinicopathological variables were compared between PDAC-RP and non-PDAC-RP.

RESULTS

In univariate analysis, concomitant intraductal papillary mucinous neoplasm (IPMN) (P = 0.0005), cancer location (body/tail) (P = 0.0060), and lower T factor in UICC (P = 0.0039) were correlated with PDAC-RP development. Multivariate analysis revealed concomitant IPMN (P = 0.0135) to be an independent predictive factor for PDAC-RP. PDAC concomitant with IPMN had higher cumulative incidence of PDAC-RP (47.5%/10 yrs) than PDAC without IPMN (9.96%/10 yrs) (P = 0.0071). Moreover, the density of pancreatic intraepithelial neoplasia lesions in the background pancreas of cases of PDAC concomitant with IPMN (1.86/cm) was higher than that of cases of PDAC without IPMN (0.91/cm) (P = 0.0007).

CONCLUSIONS

Concomitant IPMN in PDAC is an independent predictive factor for the development of new PDAC in remnant pancreas. Cancer susceptibility of remnant pancreas after resection for PDAC concomitant with IPMN is probably due to an increased density of pancreatic intraepithelial neoplasia lesions.

Recurrence patterns after surgical resection of intraductal papillary mucinous neoplasm (IPMN) of the pancreas; a multicenter, retrospective study of 1074 IPMN patients by the Japan Pancreas Society

BACKGROUND

Although there are numerous reports focusing on surgical indication for intraductal papillary mucinous neoplasm (IPMN), the recurrence patterns following surgery are less widely reported. To ascertain optimal treatment and postoperative surveillance for IPMN patients, we analyzed patterns and risk factors for recurrence after surgery for IPMN.

METHODS

This study is a retrospective, multi-institutional, observational study, including 1074 patients undergoing surgery for IPMN at 11 academic institutions. We analyzed the risk factors for recurrence after classifying postoperative recurrences into metachronous high-risk lesions (malignant progression of IPMN and/or metachronous pancreatic ductal adenocarcinoma) in the remnant pancreas and extra-pancreatic recurrence.

RESULTS

Of 1074 patients undergoing surgery for IPMN, 155 patients (14.4%) developed postoperative recurrence. We found that 34.3% of 70 high-risk lesions in the remnant pancreas occurred over 5 years after surgery, and survival of 36 patients undergoing second operation for high-risk lesions was better than that of 34 patients who did not (P = 0.04). We found four independent risk factors for metachronous high-risk lesions in remnant pancreas: symptoms [P = 0.005, hazard ratio (HR) 1.988], location of pancreatic body/tail (P < 0.001, HR 3.876), main duct size ≥ 10 mm (P = 0.021, HR 1.900), and high-grade dysplasia/invasive intraductal papillary mucinous carcinoma (IPMC) (P < 0.001, HR 3.204). Although six patients (0.7%) with low- or high-grade dysplasia IPMN developed extra-pancreatic recurrence, invasive IPMC was the strongest risk factor for extra-pancreatic recurrence (P < 0.001, HR 39.667).

CONCLUSION

We suggest that life-time continuous surveillance might be necessary for IPMN patients. Second surgery for metachronous high-risk lesions in remnant pancreas should be considered to improve survival.

Surgical strategy for intraductal papillary mucinous neoplasms of the pancreas

The current treatment strategy for intraductal papillary mucinous neoplasms (IPMNs), based on the international consensus guideline, has been accepted widely. However, reported outcomes after surgical resection for IPMN show that once the tumor progresses to invasive intraductal papillary mucinous carcinoma (IPMC), recurrence is not uncommon. The surgical treatment for IPMN is invasive and sometimes followed by complications. Therefore, the best timing for resection might be at the point when high-grade dysplasia (HGD) is evident. According to previous reports, main duct type IPMN has a high malignant potential and its surgical resection is universally accepted, whereas, the incidence of HGD/invasive IPMC in branch duct and mixed type IPMNs is thought to be lower. In addition to mural nodules and a dilated main pancreatic duct, cytology and measurement of the carcinoembryonic antigen level in the pancreatic juice might be useful to differentiate HGD/invasive IPMC from low-grade dysplasia. The nomogram proposed recently to predict the risk of HGD/invasive IPMC in IPMN patients might help surgeons decide on the best treatment strategy, depending on the patient's age and general condition. Second resection for high-risk lesions in the remnant pancreas might improve the survival of IPMN patients.

Subtype of intraductal papillary mucinous neoplasm of the pancreas is important to the development of metachronous high-risk lesions after pancreatectomy

Backgrounds/Aims

Although intraductal papillary mucinous neoplasm (IPMN) has showed a favorable prognosis compared to pancreatic ductal adenocarcinoma, its recurrence patterns have somewhat questionable in detail. After partial pancreatectomy for IPMN, the evaluation for risk of metachronous occurrence of high-risk lesions (HRL) in the residual pancreas is important to establish a postoperative surveillance modality and duration of follow-up. This study aimed to evaluate the factors that may predict the metachronous occurrence of HRL in the remnant pancreas after surgery of the IPMN.

Methods

From 2005 to 2016, clinicopathologic and surveillance data for 346 consecutive patients who underwent surgical resection for IPMN were reviewed retrospectively. Histologic subtype was classified as gastric, intestinal, pancreato-biliary, or oncocytic type.

Results

All of IPMN were classified as main duct (n=64, 18.5%), branch duct (n=171, 49.4%), and mixed type (n=111, 32.1%). Forty-eight patients (13.9%) experienced recurrence during follow-up. Among these, 9 patients (2.6%) were identified to metachronous development of HRL in the remnant pancreas. After multivariate analysis, high-grade dysplasia (HGD) or invasive carcinoma (IC) compared to low- or intermediate dysplasia was only independent risk factor for recurrence (HR 3.688, 95% CI 2.124– 12.524, p=0.009). The independent risk factors for metachronous development were HGD/IC (HR 8.414, 95% CI 4.310– 16.426, p=0.001), and intestinal/pancreato-biliary subtype compared to gastric subtype (HR 7.874, 95% CI 3.650– 27.027, p=0.010).

Conclusions

Patients with high-grade dysplasia or invasive carcinoma, and with intestinal or pancreatobiliary subtype should undergo close, long-term surveillance of the remnant pancreas after initial resection.

High-risk lesions in the remnant pancreas: fate of the remnant pancreas after pancreatic resection for pancreatic cancer and intraductal papillary mucinous neoplasms

Progress in diagnostic modalities, surgical procedures, and multidisciplinary treatment for pancreatic diseases has increased the number of long-term survivors after pancreatic resection. Several reports have focused on high-risk lesions (HRLs), including high-grade pancreatic intraepithelial neoplasia (PanIN), pancreatic ductal adenocarcinoma, high-grade intraductal papillary mucinous neoplasm (IPMN), and IPMN with an associated invasive carcinoma, in the remnant pancreas after partial pancreatic resection for pancreatic cancer or IPMN. The etiology of HRLs in the remnant pancreas is thought to be either isolated local recurrence of the initial lesion in the remnant pancreas or a newly developed primary lesion. Although it is difficult to distinguish between local recurrence and a new primary lesion, comparison of genetic alterations between two lesions may help with this distinction. Early detection of HRLs in the remnant pancreas may improve the prognosis of patients, and several investigators have proposed predictive factors for HRLs in the remnant pancreas after partial pancreatic resection for pancreatic cancer or IPMN. The reported short- and long-term outcomes of surgical resection of HRLs in the remnant pancreas are relatively favorable. Life-long surveillance of the remnant pancreas is recommended after partial pancreatic resection for pancreatic cancer or IPMN.

Early Detection of Pancreatic Cancer: Opportunities and Challenges

Most patients with pancreatic ductal adenocarcinoma (PDAC) present with symptomatic, surgically unresectable disease. Although the goal of early detection of PDAC is laudable and likely to result in significant improvement in overall survival, the relatively low prevalence of PDAC renders general population screening infeasible. The challenges of early detection include identification of at-risk individuals in the general population who would benefit from longitudinal surveillance programs and appropriate biomarker and imaging-based modalities used for PDAC surveillance in such cohorts. In recent years, various subgroups at higher-than-average risk for PDAC have been identified, including those with familial risk due to germline mutations, a history of pancreatitis, patients with mucinous pancreatic cysts, and elderly patients with new-onset diabetes. The last 2 categories are discussed at length in terms of the opportunities and challenges they present for PDAC early detection. We also discuss current and emerging imaging modalities that are critical to identifying early, potentially curable PDAC in high-risk cohorts on surveillance.

Clinical assessment of the GNAS mutation status in patients with intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by cystic dilation of the pancreatic duct, caused by mucin hypersecretion, with slow progression via the adenoma-carcinoma sequence mechanism. Mutation of GNAS at codon 201 is found exclusively in IPMNs, occurring at a rate of 41-75%. Recent advances in molecular biological techniques have demonstrated that GNAS mutation might play a role in the transformation of IPMNs after the appearance of neoplastic cells, rather than in the tumorigenesis of IPMNs. GNAS mutation is observed frequently in the intestinal subtype of IPMNs with MUC2 expression, and less frequently in IPMNs with concomitant pancreatic ductal adenocarcinoma (PDAC). Research has focused on assessing GNAS mutation status in clinical practice using various samples. In this review, we discuss the clinical application of GNAS mutation assessment to differentiate invasive IPMNs from concomitant PDAC, examine the clonality of recurrent IPMNs in the remnant pancreas using resected specimens, and differentiate pancreatic cystic lesions using cystic fluid collected by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), duodenal fluid, and serum liquid biopsy samples.

High-Grade Dysplasia in Resected Main-Duct Intraductal Papillary Mucinous Neoplasm (MD-IPMN) is Associated with an Increased Risk of Subsequent Pancreatic Cancer

BACKGROUND

There is lack of consensus on post-operative surveillance for resected non-invasive intraductal papillary neoplasms (IPMNs). In this study we explored risk factors for subsequent PC in patients with MD-IPMN undergoing partial pancreatectomy.

METHODS

We searched the Mayo Clinic surgical pathology database for all cases of resected MD-IPMN between 1997 and 2014. Cases with histologically confirmed main pancreatic duct involvement either isolated or in a mixed pattern with branch-duct involvement were included. Outcomes of PC in the remnant pancreas, and death related to MD-IPMN were assessed with survival analyses (Kaplan-Meier and Cox regression).

RESULTS

Among the 179 patients with resected MD-IPMN the incidence of concomitant PC and high-grade dysplasia (HGD) in the resected specimen was 23 and 14%, respectively. The mean duration of follow-up was 4.31 years (range 0.12-13.5 years). Excluding 28 subjects who either underwent initial total pancreatectomy or partial pancreatectomy with surgical margins positive for PC/HGD, the 5-year incidence of subsequent PC was 12%, including 60.6% and 15.6% in those with initial PC and HGD, respectively. The 10-year incidence of PC was 21.2% overall, 60.6% for PC, 38.3% for HGD, and 3.0% for LGD. Risk of subsequent PC was significantly higher for those with initial PC compared with HGD (HR = 4.95, 95% CI: 1.63-15.03, p = 0.005 and for HGD compared with LGD (HR = 11.30, 95% CI: 1.55-82.26, p = 0.017).

CONCLUSIONS

Patients with MD-IPMN with PC or HGD undergoing segmental pancreatectomy are at higher risk of subsequent PC and may benefit from post-operative surveillance. The post-operative surveillance intervals in resected MD-IPMNs need to be tailored based on dysplasia grade.

Clinical Management and Surgical Decision-Making of IPMN of the Pancreas

Intraductal papillary mucinous neoplasm (IPMN) is the most common pancreatic cystic neoplasm (PCN). The increased attention to IPMN is due to its unique features of malignant progression, being different between main duct IPMN and branch duct IPMN, and increased de novo development of conventional pancreatic ductal adenocarcinoma elsewhere in the pancreas. The increased interest in IPMN led to publication of many guidelines on its clinical management. This chapter aims to summarize and compare characteristics of nine guidelines on the clinical management of IPMN and other PCNs published in the English literature and further to show a current strategy for surgical decision making in the management of IPMN.

Current concepts in molecular genetics and management guidelines for pancreatic cystic neoplasms: an essential update for radiologists

Cystic neoplasms in the pancreas are encountered frequently on imaging, often detected incidentally during evaluation for other conditions. They can have a variety of clinical and imaging presentations, and similarly, wide-ranging prognostic and treatment implications. In the majority, imaging helps in diagnosis of pancreatic cystic neoplasms (PCNs) and guides management decisions. But, a significant minority of the PCNs remain indeterminate. There have been multiple recent advances in biomarkers and molecular genetics which will likely prove helpful in risk stratification of PCNs. Several prominent national and international societies, as well as consensus groups have put forth recommendations to help guide management of PCNs. The purpose of this article is to discuss the role of imaging in evaluation of PCNs, review the recent advances in molecular genetics and pancreatic cyst fluid analysis, and analyze the pros and cons of major evidence-based and consensus guidelines for management of PCNs.

Intrapancreatic recurrence of intraductal tubulopapillary neoplasm (ITPN) 16 years after the initial surgery for noninvasive ITPN: a case report

Background

Intraductal tubulopapillary neoplasm (ITPN) is a rare pancreatic intraductal neoplasm. It is characterized by a tubulopapillary growth pattern, entirely high-grade atypical cells, minimal cytoplasmic mucin, and no obvious luminal mucin secretion. Most of its biological nature remains unclear.

Case presentation

We herein report a case of intrapancreatic recurrence of ITPN in the remnant pancreas of a patient who underwent pancreatoduodenectomy 16 years previously for a noninvasive intraductal pancreatic head tumor. We reexamined the primary tumor and compared it with the most recently resected specimen. Histologically, the primary tumor showed a tubulopapillary growth of high-grade atypical cells with scanty cytoplasmic mucin, which was similar to the recently resected specimen except for the invasive area. Immunohistochemically, the neoplastic cells in both specimens showed focal staining of MUC1 and positivity for MUC6 but negativity for MUC2, MUC5AC, CDX2, and trypsin. Molecular analysis revealed no KRAS/GNAS/BRAF/PIK3CA mutations in either of the specimens.

Conclusions

These findings of the original tumor and recently resected tumor were compatible with the features of ITPN. Thus, recurrence is possible even for a primary noninvasive ITPN, and long-term surveillance is recommended.

Role of SpyGlass-DStm in the preoperative assessment of pancreatic intraductal papillary mucinous neoplasm involving the main pancreatic duct

BACKGROUND/OBJECTIVES

It is often difficult to determine an adequate resection line during pancreatectomy for intraductal papillary mucinous neoplasm involving the main pancreatic duct during partial pancreatectomy. The aim of this study was to evaluate the usefulness of improved peroral pancreatoscopy using SpyGlass-DS^tm in the preoperative assessment of intraductal papillary mucinous neoplasm involving the main pancreatic duct.

METHODS

We collected and retrospectively analyzed clinicopathological data from seven consecutive patients who underwent preoperative assessment of intraductal papillary mucinous neoplasm involving the main duct using SpyGlass-DS^tm.

RESULTS

Good imaging quality of the intraductal protruding lesion was obtained in all seven patients, and only one adverse event was noted wherein a patient had mild pancreatitis. Six patients underwent pancreatectomy. In one patient, masked-type concomitant pancreatic ductal adenocarcinoma and low-length dysplastic lesion was found near the surgical margin, which was not detected by preoperative imaging modalities including SpyGlass-DS^tm. The sensitivity of targeting biopsy during SpyGlass-DS^tm to diagnose high-grade dysplasia was 0%.

CONCLUSIONS

SpyGlass-DS^tm can be safely performed in patients with intraductal papillary mucinous neoplasm involving the main duct, and has excellent visualization of the target lesion. However, challenges include poor diagnostic ability of targeting biopsy, and, therefore, intraoperative frozen section is still needed to obtain negative surgical margins.

Intraductal Papillary Mucinous Neoplasm of the Pancreas as the Main Focus for Early Detection of Pancreatic Adenocarcinoma

For early detection of pancreatic cancer, interests are now focused on the detection of high-risk individuals to undergo screening examinations. Intraductal papillary mucinous neoplasm (IPMN) is a unique dual precursor of pancreatic cancer, characterized by progression to invasive cancer and the development of pancreatic adenocarcinoma either concomitantly (synchronous occurrence) or even after resection of IPMN (metachronous occurrence). Careful examination and surveillance of patients with IPMN may therefore lead to early detection of pancreatic cancer. By reviewing only reports describing detailed breakdown of the morphological types of IPMN and numbers of patients with noninvasive and invasive carcinoma in each type, the rough frequencies of noninvasive carcinoma in main duct IPMNs and branch duct IPMNs (BD-IPMNs) are 20% and 10%, respectively, and those of invasive carcinoma are 40% and 13%, respectively. Roughly 5% of all patients with IPMN had concomitant adenocarcinoma. The real frequency of carcinoma in BD-IPMNs would be far lower because most patients with small asymptomatic BD-IPMNs do not undergo resection. Intraductal papillary mucinous neoplasm can be the main focus for early detection of pancreatic cancer to achieve favorable prognosis after surgical resection. The optimal protocol for surveillance and method for early detection of pancreatic cancer are to be determined.

Classification, Morphology, Molecular Pathogenesis, and Outcome of Premalignant Lesions of the Pancreas

CONTEXT

- Invasive pancreatic ductal adenocarcinoma has a greater than 90% mortality rate at 5 years. Understanding noninvasive, curable precursor lesions gives us the best hope for reducing mortality from pancreatic ductal adenocarcinoma. The 3 pancreatic precursor lesions that have been well studied include intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia.

OBJECTIVE

- To give an update on the latest clinical, molecular, and pathologic advances in intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia for the general surgical pathologist.

DATA SOURCES

- The current literature was analyzed and the authors' experiences with institutional and consult material were incorporated.

CONCLUSIONS

- Our understanding of the molecular alterations that lead from pancreatic precursor lesion to invasive carcinoma continues to evolve. These advances aid clinicians in their treatment decisions and researchers in their search for actionable, druggable targets.

Intraductal Papillary Mucinous Neoplasms of the Pancreas: Strategic Considerations

Intraductal papillary mucinous neoplasms (IPMN) are cystic neoplasms with the potential for progression to pancreatic cancer. Recognized by the global medical community just over two decades ago, IPMN have gained great epidemiological and clinical relevance thanks to the widespread use of cross-sectional abdominal imaging, which has led to a surge in the number of incidental pancreatic cysts being diagnosed. As our understanding of this disease has improved, we now know that some IPMN have a very elevated risk of cancer and require surgical resection, while others are low-risk lesions and can be followed. The approach to IPMN must therefore strike a balance between preventing the over-utilization of surgery and the timely recognition and treatment of patients with high-risk lesions. Several clinical, radiographic, and laboratory parameters have been proposed to risk-stratify IPMN, leading to the publication of management guidelines that do not always converge in their recommendations. The goal of this clinical therapeutic review is to describe the strategic approach to IPMN at the Massachusetts General Hospital, and how our current understanding, management algorithm, and future directions have been informed by research efforts at our institution and other centers.

Surveillance of patients with intraductal papillary mucinous neoplasm with and without pancreatectomy with special reference to the incidence of concomitant pancreatic ductal adenocarcinoma

BACKGROUND

The presence of an intraductal papillary mucinous neoplasm is important in the detection of concomitant pancreatic ductal adenocarcinoma. The aim of this study was to elucidate the incidence and timing of development of concomitant pancreatic ductal adenocarcinoma in patients with and without pancreatectomy for intraductal papillary mucinous neoplasm.

METHODS

We reviewed retrospectively the surveillance data for 22 patients who underwent pancreatectomy for pancreatic ductal adenocarcinoma concomitant with intraductal papillary mucinous neoplasm (pancreatic ductal adenocarcinoma-resection group), 180 who underwent pancreatectomy for intraductal papillary mucinous neoplasm (intraductal papillary mucinous neoplasm-resection group), and 263 whose intraductal papillary mucinous neoplasms were left untreated (nonresection group). The incidence and timing of the development of a concomitant pancreatic ductal adenocarcinoma during the surveillance of patients with and without partial pancreatectomy for intraductal papillary mucinous neoplasm were investigated using the Kaplan-Meier method.

RESULTS

During a median surveillance period of 40 months (range 6-262 months), 5 patients in the pancreatic ductal adenocarcinoma-resection group, 6 in the intraductal papillary mucinous neoplasm-resection group, and 8 in the nonresection group developed concomitant pancreatic ductal adenocarcinoma. The estimated 5-year (17%) and 10-year (56%) cumulative incidences of secondary pancreatic ductal adenocarcinoma in the pancreatic ductal adenocarcinoma-resection group were significantly greater than those in the other two groups (P < .01). Conversely, the difference in the estimated cumulative incidence of concomitant pancreatic ductal adenocarcinoma between the intraductal papillary mucinous neoplasm-resection and nonresection groups was not significant (5-year, 5.0% vs 2.2%; 10-year, 5.0% vs 8.7%; P = .87).

CONCLUSION

Long-term (≥5-year) surveillance in patients with intraductal papillary mucinous neoplasm is necessary and important because of the potential for development of concomitant pancreatic ductal adenocarcinoma. Those with a history of resection of concomitant pancreatic ductal adenocarcinoma at the time of the initial operation are at quite high risk for the development of secondary pancreatic ductal adenocarcinoma.

Natural History of Patients Followed Radiographically with Mucinous Cysts of the Pancreas

OBJECTIVE

The aim of this study was to evaluate the outcome of patients presumed to have mucinous cysts of the pancreas who were initially selected for radiographic surveillance.

METHODS

Patients with a pancreatic cyst and a measured cyst fluid carcinoembryonic antigen (CEA) ≥192 ng/mL were included. Patients were stratified by those who underwent initial resection and those who were recommended for radiographic surveillance. The natural history of these two groups was examined.

RESULTS

From 1999 to 2014, 227 patients were identified who had a cyst fluid CEA ≥192 ng/mL (median 961, range 192-300,000 ng/mL). Immediate resection was performed on 63 patients (28%). Initial radiographic surveillance was recommended for 164 patients; 87% did not have main pancreatic duct dilation, and 87% met consensus criteria for radiographic surveillance. After a median follow-up of 56 months, 48 of the 164 patients (29%) had undergone resection. Ultimately, there were three cases (2%) of high-grade dysplasia and two cases of invasive carcinoma (1%) within these 164 patients selected for observation. Three of the five cases of either high-grade dysplasia or invasive carcinoma were among the 22 patients followed outside of consensus guidelines.

CONCLUSIONS

Appropriately selected patients with mucinous pancreatic cysts can be safely followed with serial surveillance with a low risk of malignant progression.

Pancreatic Cancer Arising From the Remnant Pancreas: Is It a Local Recurrence or New Primary Lesion?

Local recurrence of pancreatic cancer (PC) can occur in the pancreatic remnant. In addition, new primary PC can develop in the remnant. There are limited data available regarding this so-called remnant PC. The aim of this review was to describe the characteristics and therapeutic strategy regarding remnant PC. A literature search was performed using Medline published in English according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The incidence of remnant PC has been reported to be 3% to 5%. It is difficult to distinguish local recurrence from new primary PC. Genetic diagnosis such as Kirsten rat sarcoma viral oncogene homolog mutation may resolve this problem. For patients with remnant PC, repeated pancreatectomy can be performed. Residual total pancreatectomy is the most common procedure. Recent studies have described the safety of the operation because of recent surgical progress and perioperative care. The patients with remnant PC without distant metastasis have shown good long-term outcomes, especially those who underwent repeated pancreatectomy. Adjuvant chemotherapy may contribute to longer survival. In conclusion, this review found that both local recurrence and new primary PC can develop in the pancreatic remnant. Repeated pancreatectomy for the remnant PC is a feasible procedure and can prolong patient survival.

[Resection of main duct and mixed type IPMN ≥5 mm]

The incidence of cystic pancreatic lesions is steadily increasing due to the technical advances in imaging. Within the group of cystic pancreatic lesions intraductal papillary mucinous neoplasms (IPMNs) depict an important entity. Due to a possible progression to malignancy the clinical strategy has to be well chosen. For primary diagnostic work-up imaging by magnetic resonance imaging (MRI) with MR cholangiopancreatography (MRCP) and computed tomography (CT) scanning is recommended. Additional information can be gained by endosonography and a biopsy of the cystic lesion, allowing analysis of biomarkers, such as GNAS and KRAS mutation as wells as NLR. These can help to differentiate between IPMN and other cystic lesions although the clinical importance for the diagnosis of main duct (MD) and mixed IPMN is limited. The current guidelines (Fukuoka and EU guidelines) recommend resection of MD and mixed IPMN following oncological standards. For the definition of MD-IPMN, a duct dilatation between 5-10 mm is needed when following the current guidelines; however, current publications claim an even lower cut-off of ≥5 mm due to the risk of malignant progression. Intraoperative frozen sections are recommended to evaluate the margins status and extended resection is recommended for residual high-grade dysplasia. Surveillance of potentially at risk patients is recommended at regular intervals of 6-12 months while patients with malignant IPMN should be followed according to pancreatic cancer protocols. A screening for extrapancreatic malignancy is not indicated.

Targeted DNA Sequencing Reveals Patterns of Local Progression in the Pancreatic Remnant Following Resection of Intraductal Papillary Mucinous Neoplasm (IPMN) of the Pancreas

OBJECTIVE

The aim of this study was to characterize patterns of local progression following resection for pancreatic intraductal papillary mucinous neoplasms (IPMN) using targeted next-generation sequencing (NGS).

BACKGROUND

Progression of neoplastic disease in the remnant pancreas following resection of IPMN may include development of a new IPMN or ductal adenocarcinoma (PDAC). However, it is not clear whether this progression represents recurrence of the same neoplasm or an independent second neoplasm.

METHODS

Targeted-NGS on genes commonly mutated in IPMN and PDAC was performed on tumors from (1) 13 patients who developed disease progression in the remnant pancreas following resection of IPMN; and (2) 10 patients who underwent a resection for PDAC and had a concomitant IPMN. Mutations in the tumors were compared in order to determine the relationship between neoplasms. In parallel, clinical and pathological characteristics of 260 patients who underwent resection of noninvasive IPMN were reviewed to identify risk factors associated with local progression.

RESULTS

We identified 3 mechanisms underlying local progression in the remnant pancreas: (1) residual microscopic disease at the resection margin, (2) intraparenchymal spread of neoplastic cells, leading to an anatomically separate but genetically related recurrence, and (3) multifocal disease with genetically distinct lesions. Analysis of the 260 patients with noninvasive IPMNs showed that family history of pancreatic cancer (P = 0.027) and high-grade dysplasia (HGD) (P = 0.003) were independent risk factors for the development of an IPMN with HGD or an invasive carcinoma in the remnant pancreas.

CONCLUSIONS

Using NGS, we identify distinct mechanisms for development of metachronous or synchronous neoplasms in patients with IPMN. Patients with a primary IPMN with HGD or with positive family history are at an increased risk to develop subsequent high-risk neoplasms in the remnant pancreas.

Intraductal papillary mucinous neoplasm of the pancreas - epidemiology, risk factors, diagnosis, and management

Intraductal papillary mucinous neoplasm (IPMN) is one of the most common cystic neoplasms of the pancreas. It is a heterogeneous disease and can be divided into ductal types and morphological subtypes. The incidence of IPMN is increasing, likely due to the widespread use of cross-sectional imaging and a growing elderly population. IPMN poses an increasing demand on the health care system. Current guidelines provide indications for surgery and recommendations for surveillance, but management of IPMN is still challenging in routine clinical practice. In this article, we review current knowledge about IPMN and provide future directions for improving diagnosis and management.

Revisions of international consensus Fukuoka guidelines for the management of IPMN of the pancreas

The management of intraductal papillary mucinous neoplasm (IPMN) continues to evolve. In particular, the indications for resection of branch duct IPMN have changed from early resection to more deliberate observation as proposed by the international consensus guidelines of 2006 and 2012. Another guideline proposed by the American Gastroenterological Association in 2015 restricted indications for surgery more stringently and recommended physicians to stop surveillance if no significant change had occurred in a pancreatic cyst after five years of surveillance, or if a patient underwent resection and a non-malignant IPMN was found. Whether or not it is safe to do so, as well as the method and interval of surveillance, has generated substantial debate. Based on a consensus symposium held during the meeting of the International Association of Pancreatology in Sendai, Japan, in 2016, the working group has revised the guidelines regarding prediction of invasive carcinoma and high-grade dysplasia, surveillance, and postoperative follow-up of IPMN. As the working group did not recognize the need for major revisions of the guidelines, we made only minor revisions and added most recent articles where appropriate. The present guidelines include updated information and recommendations based on our current understanding, and highlight issues that remain controversial or where further research is required.

Comparison of guidelines for intraductal papillary mucinous neoplasm: What is the next step beyond the current guidelines?

Management of intraductal papillary mucinous neoplasm is controversial, and several guidelines have aimed to establish an adequate strategy for surgical resection and surveillance. We compared various intraductal papillary mucinous neoplasm guidelines and considered new matters that are pivotal for improved treatment of intraductal papillary mucinous neoplasm. We identified and compared 11 published guidelines, three of which were major guidelines that mainly referred to the diagnosis and treatment of intraductal papillary mucinous neoplasm (International Association of Pancreatology 2012 guidelines, European Study Group on Cystic Tumours of the Pancreas 2013 guidelines, and American Gastroenterological Association 2015 guidelines). The main concerns of these three guidelines were indication for surgery and follow up of non-resected lesions. Among the differences between the three guidelines, the period of surveillance recommended was the most controversial matter. Meanwhile, several nomograms have been proposed to improve the diagnosis of intraductal papillary mucinous neoplasm from the level of experts' experiences to that of rational systems. We discuss the adequate strategy of surveillance for intraductal papillary mucinous neoplasm with and without pancreatectomy and nomograms aiming to predict the risk of malignancy in patients with intraductal papillary mucinous neoplasm.

Pancreatic Cancer Chemoprevention Translational Workshop: Meeting Report

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

Distinction of Invasive Carcinoma Derived From Intraductal Papillary Mucinous Neoplasms From Concomitant Ductal Adenocarcinoma of the Pancreas Using Molecular Biomarkers

OBJECTIVES

To clarify the usefulness of molecular biomarkers for distinguishing invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs [Inv-IPMN]) from concomitant pancreatic ductal adenocarcinoma (PDAC).

METHODS

Data from 19 patients with resected concomitant PDAC were retrospectively reviewed. KRAS/GNAS mutations and immunohistochemical (IHC) expression of p53 and p16/CDKN2A were assessed in both IPMN and distinct PDAC. As controls, KRAS/GNAS mutations and IHC labeling were assessed between invasive and noninvasive components in 1 lesion of 22 independent patients.

RESULTS

KRAS/GNAS mutation status of invasive and noninvasive components in Inv-IPMN was consistent in 18 (86%) of 21 patients. Conversely, mutational patterns in IPMN and distinct PDAC in the same pancreas differed from each other in 17 (89%) of 19. There were 10 (53%) and 8 (42%) of 19 patients who showed the same p53 and p16/CDKN2A staining between concomitant PDAC and distinct IPMN. In the Inv-IPMN cohort, 19 (86%) of 22 patients showed the same IHC expression pattern between the noninvasive and invasive components.

CONCLUSIONS

It may be possible to distinguish Inv-IPMN from concomitant PDAC by assessing these molecular biomarkers. More precise distinction of Inv-IPMN and concomitant PDAC will lead to adequate recognition of the natural history of IPMNs and hence optimal management.