Should non-invasive diffuse main-duct intraductal papillary mucinous neoplasms be treated with total pancreatectomy?

Diagnosis and Management of Pancreatic Cysts

As pancreatic cyst incidence rises, likely due to the ubiquitous increase in cross-sectional imaging, their management presents multiple challenges for both the practitioner and patient. It is critical that all pancreatic cysts are appropriately characterized, as treatment decisions depend on an accurate diagnosis. Diagnostic modalities such as cytology, biopsy, and cyst fluid biomarkers allow for definitive diagnosis of virtually all lesions. Some cysts, such as intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and cystic pancreatic endocrine neoplasms, have malignant potential and must be surveyed. Other cysts, such as serous cystadenomas and pancreatic fluid collections, do not have malignant potential. Surveillance strategies vary widely depending on cyst type and size and while multiple medical societies advocate surveillance, their published surveillance guidelines are heterogenous. Cysts with high-risk stigmata or worrisome features are usually resected, depending on the patient's surgical fitness. In patients unfit for resection, newer endoscopic ablative techniques are advocated. Controversial aspects regarding cyst management include whether surveillance can be stopped, how surveillance should be performed, and the extensive financial burden cyst management places on the health care system. Further study into the natural history of cystic lesions, including definitive determination of the rate of malignant transformation for each cyst type, is essential.

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.

Innovation in the Surgical Management of Pancreatic Cystic Neoplasms: Same Operations, Narrower Indications, and an Individualized Approach to Decision-Making

Historically, the management of pancreatic cystic neoplasms (PCN) has been operative. Early intervention for premalignant lesions, including intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms (MCN), offers an opportunity to prevent pancreatic cancer-with potential decrement to patients' short-term and long-term health. The operations performed have remained fundamentally the same, with most patients undergoing pancreatoduodenectomy or distal pancreatectomy using oncologic principles. The role of parenchymal-sparing resection and total pancreatectomy remains controversial. We review innovations in the surgical management of PCN, focusing on the evolution of evidence-based guidelines, short-term and long-term outcomes, and individualized risk-benefit assessment.

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.

Malignant potential and specific characteristics of pure main duct type intraductal papillary mucinous neoplasm

BACKGROUND

As the malignant potential of main duct (MD-) type intraductal papillary mucinous neoplasm (IPMN) has been discussed together with Mixed-type in most previous studies, the malignant potential of pure MD-type IPMN remains unclear. This study evaluated the specific characteristics and predictors of high-grade dysplasia (HGD) and invasive intraductal papillary mucinous carcinoma (IPMC) for pure MD-type IPMN.

METHODS

From 1,100 patients with IPMN, this study includes 387 patients that underwent surgery. We evaluated the specific characteristics of pure MD-type IPMN by comparing clinicopathological factors between MD-type (n = 79) and branch duct (BD-) type (n = 146) or Mixed-type IPMN (n = 162), and predictors of HGD/invasive IPMC in pure MD-type IPMN.

RESULTS

The rate of HGD/invasive IPMC was significantly higher in MD-type than in BD-type (70.9 vs. 48.6%, P = 0.001), although there was no difference between MD-type and Mixed-type IPMNs (P = 0.343). Recurrence-free survival (RFS) and disease-specific survival (DSS) of patients with MD-type were better than those of patients with Mixed-type (P = 0.008 and P = 0.009, respectively). There were no significant differences in RFS, overall survival, and DSS between patients with MD-type and patients with BD-type IPMNs. Multivariate analysis showed two independent predictors of HGD/invasive IPMC in MD-type IPMN; mural nodule height ≥5 mm (P = 0.025, odds ratio [OR]; 16.949) and carcinoembryonic antigen (CEA) level in the pancreatic juice obtained by preoperative endoscopic retrograde pancreatography ≥50 ng/ml (P = 0.039, OR; 9.091).

CONCLUSIONS

Measurement of mural nodule height and CEA in the pancreatic juice might be useful in determining surgical indication for pure MD-type IPMN, although further studies for confirmation are essential.