Incidental cystic neoplasms of pancreas: what is the optimal interval of imaging surveillance?

Systematic review on surveillance for non-resected branch-duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

The management of branch-duct type intraductal papillary mucinous neoplasms (BD-IPMN) varies in existing guidelines. This study investigated the optimal surveillance protocol and safe discontinuation of surveillance considering natural history in non-resected IPMN, by systematically reviewing the published literature.

METHODS

This review was guided by PRISMA. Research questions were framed in PICO format "CQ1-1: Is size criteria helpful to determine surveillance period? CQ1-2: How often should surveillance be carried out? CQ1-3: When should surveillance be discontinued? CQ1-4: Is nomogram predicting malignancy useful during surveillance?". PubMed was searched from January-April 2022.

RESULTS

The search generated 2373 citations. After screening, 83 articles were included. Among them, 33 studies were identified for CQ1-1, 19 for CQ1-2, 26 for CQ1-3 and 12 for CQ1-4. Cysts <1.5 or 2 cm without worrisome features (WF) were described as more indolent, and most studies advised an initial period of surveillance. The median growth rate of cysts <2 cm ranged from 0.23 to 0.6 mm/year. Patients with cysts <2 cm showing no morphological changes and no WF after 5-years of surveillance have minimal malignancy risk of 0-2%. Two nomograms created with over 1000 patients had AUCs of around 0.8 and appear to be feasible in a real-world practice.

CONCLUSIONS

For patients with suspected BD-IPMN <2 cm and no other WF, less frequent surveillance is recommended. Surveillance may be discontinued for cysts that remain stable during 5-year surveillance, with consideration of patient condition and life expectancy. With this updated surveillance strategy, patients with non-worrisome BD-IPMN should expect more streamlined management and decreased healthcare utilization.

Optimal Follow-up of Incidental Pancreatic Cystic Lesions without Worrisome Features: Clinical Outcome after Long-term Follow-up

Background/Aims

: The optimal duration and interval of follow-up for cystic lesions of the pancreas (CLPs) is not well established. This study was performed to investigate the optimal duration and interval of follow-up for CLPs in clinical practice.

Methods

: Patients with CLPs without worrisome features or high-risk stigmata underwent follow-up with computed tomography at 6, 12, 18, and 24 months and then every 12 months thereafter. A retrospective analysis of prospectively collected data was performed.

Results

: A total of 227 patients with CLPs detected from 2000 to 2008 (mean initial diameter, 1.3±0.6 cm) underwent follow-up for a median of 120 months. Twenty-two patients (9.7%) underwent surgery after a median of 47.5 months. Malignancies developed in four patients (1.8%), one within 5 years and three within 10 years. One hundred and fourteen patients (50.2%) were followed up for more than 10 years. No malignancy developed after 10 years of follow-up. During surveillance, 37 patients (16.3%) experienced progression to surgical indication. In patients with CLPs less than 2 cm in diameter, development of surgical indications did not occur within 24 months of follow-up.

Conclusions

: CLPs should be continuously monitored after 5 years because of the persistent potential for malignant transformation of CLPs. An interval of 24 months for initial follow-up might be enough for CLPs with initial size of less than 2 cm in clinical practice.

Surveillance of Pancreatic Cystic Neoplasms

Pancreatic cystic neoplasms (PCNs) are increasingly detected because of the widespread use of cross-sectional imaging and overall aging population. While the majority of these cysts are benign, some can progress to advanced neoplasia (defined as high-grade dysplasia and invasive cancer). As the only widely accepted treatment for PCNs with advanced neoplasia is surgical resection, accurate preoperative diagnosis, and stratification of malignant potential for deciding about surgery, surveillance or doing nothing remains a clinical challenge. Surveillance strategies for pancreatic cysts (PCNs) combine clinical evaluation and imaging to assess changes in cyst morphology and symptoms that may indicate advanced neoplasia. PCN surveillance heavily relies on various consensus clinical guidelines that focus on high-risk morphology, surgical indications, and surveillance intervals and modalities. This review will focus on current concepts in the surveillance of newly diagnosed PCNs, especially on low-risk presumed intraductal papillary mucinous neoplasms (those without worrisome features and high-risk stigmata), and appraise current clinical surveillance guidelines.

Pancreatic CT density is an optimal imaging biomarker for earlier detection of malignancy in the pancreas with intraductal papillary mucinous neoplasm

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are typically detected as incidental findings by computed tomography (CT); however, the conventional surveillance is not valid for the early detection of concomitant pancreatic cancer. The pancreas of IPMN is often accompanied by fatty infiltration in the parenchyma, and pancreatic fatty infiltration could be evaluated by pancreatic CT density (pancreatic index, PI). We aimed to investigate whether PI could be an imaging biomarker for the early prediction of malignancies in the pancreas with IPMN.

METHODS

Two different cohorts were investigated. (Investigation cohort): A total of 1137 patients with initially low-risk IPMN were compensated by initial IPMN findings, and 2 groups (malignancy/possible benign, 50 cases each) were investigated for yearly changes in PI and for the cutoff value of PI indicating the development of malignancies. (Validation cohort): To validate the cutoff value, 256 patients radiologically suspected of having IPMNs were investigated.

RESULTS

(Investigation-cohort): The malignancy group showed a gradual decrease in PI every year, and PI significantly differed among the 2 groups 1 year prior to the last investigation. The cutoff value of PI was set at 0.65. (Validation-cohort): A total of 55% of the patients with a PI below the cutoff value had malignancy in the pancreas, including concomitant pancreatic cancer, and the cutoff value was the most significant risk factors for the development of malignancies in the pancreas compared to the conventional risk factors for IPMN.

CONCLUSIONS

Decreasing PI would be an optimal imaging biomarker for earlier detection of malignancies in the pancreas with IPMN.

Systematic review and meta-analysis of observational studies on BD-IPMNS progression to malignancy

BACKGROUND

The vast majority of presumed branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas are referred to a surveillance program due to the relatively low risk of malignancy. We aim to evaluate all available data from observational studies focused on the risks of BD-IPMN progression and malignancy to provide vital insights into its management in clinical practice.

METHODS

A comprehensive search was conducted at PubMed, Cochrane, Web of Science and Embase for observational studies published before January 1st, 2020. The progression of BD-IPMN was defined as the development of worrisome features (WFs) or high-risk stigmata (HRS) during surveillance. Overall malignancy was defined as all malignancies, such as malignant IPMN, concomitant pancreatic ductal adenocarcinoma (PDAC) and other malignancies, including BD-IPMN with high-grade sec. Baltimore consensus 2015 or BD-IPMN with high-grade dysplasia (carcinoma in situ) sec. WHO 2010. A meta-analysis was performed to investigate the presence of a mural nodule as a possible predictor of malignancy.

RESULTS

Twenty-four studies were included, with a total of 8941 patients with a presumed BD-IPMN. The progression rate was 20.2%, and 11.8% underwent surgery, 29.5% of whom showed malignancy at the final pathology. Of those, 78% had malignant IPMNs, and 22% had concomitant pancreatic cancer. Overall, 0.5% had distant metastasis. The meta-analysis showed that the risk of malignancy in the presence of a mural nodule >5 mm had a RR of 5.457 (95% CI 1.404-21.353), while a nonenhancing mural nodule or an enhancing mural nodule < 5 mm had a RR of 5.286 (95% CI 1.805-15.481) of harboring malignancy.

CONCLUSION

Most presumed BD-IPMNs entering surveillance do not become malignant. Of those submitted to surgery, concomitant PDAC adds to the overall risk of detecting malignancy.

[Indications for the Surgical Management of Pancreatic Cystic Lesions]

A steady improvement in modern imaging as well as increasing age in society have led to an increasing number of cystic pancreatic tumours being detected. Pancreatic cysts are a clinically challenging entity because they span a broad biological spectrum and their differentiation is often difficult, especially in small tumours. Therefore, they require a differentiated indication for indication of surgery. To determine recommendations for the surgical indication in cystic tumours of the pancreas, a quality committee for pancreatic diseases of the German Society for General and Visceral Surgery performed a systematic literature search and created this review. Based on the current evidence, signs of malignancy and high-risk criteria (icterus due to cystic pancreatic duct obstruction in the bile duct, enhancing mural nodules ≥ 5 mm or solid components in the cyst or pancreatic duct ≥ 10 mm), as well as symptoms, are a surgical indication, independently of the cyst entity (except pseudocysts). If the entity of the pancreatic cyst is detectable by diagnostic imaging, all main duct IPMN and IPMN of the mixed type, all MCN > 4 cm and all SPN should be resected. SCN and branch-duct IPMN without worrisome features do not constitute an indication for surgery. The indication of operation in branch-duct IPMN with relative risk criteria and MCN < 4 cm is the subject of current discussions and should be individualised. By defining indication recommendations, the present work aims to improve the indication quality in cystic pancreatic tumours. However, the surgical indication should always be individualised, taking into account age, comorbidities and the patient's wishes.

Clinical and radiological features that predict malignant transformation in cystic lesions of the pancreas: a retrospective case note review

Background: Pancreatic cystic lesions (PCL) are being detected with increasing frequency. Current methods of stratifying risk of malignant transformation are imperfect. This study aimed to determine the frequency of pancreatic malignancy in patients with PCL and define clinical and radiological features that predict malignant transformation in patients managed by surgery and/or surveillance.

Methods: A retrospective cohort of adults who were evaluated in a tertiary hepatopancreaticobiliary centre between January 2000 - December 2013 with a confirmed PCL and followed up for at least 5 years. All cystic lesions were discussed at a weekly multidisciplinary meeting.

Results: Of the 1,090 patients diagnosed with a PCL, 768 patients were included in the study: 141 patients were referred for immediate pancreatic resection, 570 entered surveillance while 57 had a malignant PCL which was unresectable at diagnosis (n=47) or were unfit for surgery (n=10). In those who were resected following presentation, malignancy was present in 38%. During follow-up 2% of those entering a surveillance programme underwent malignant transformation. Clinical and radiological features associated with a high-risk PCL included older age, symptoms, associated solid component or dilated main pancreatic duct. In intraductal papillary mucinous neoplasms, larger size was not a feature of malignant transformation (benign vs. malignant 30mm vs. 23mm; P= 0.012).

Conclusion: The sensitivity of standard diagnostic tests leading to immediate surgery for high-risk PCL (malignant or mucinous) was 92% but with a specificity of just 5%. Surveillance of PCL without high-risk features within a multidisciplinary meeting was associated with a low incidence of cancer development, supporting the use of worrisome clinical and radiological features in the initial stratification of PCL.

Follow-up of Incidentally Detected Pancreatic Cystic Neoplasms: Do Baseline MRI and CT Features Predict Cyst Growth?

Background Incidental detection of pancreatic cystic neoplasm (PCN) has increased. Since a small percentage of PCNs possess malignant potential, management is challenging. The recently revised American College of Radiology (ACR) recommendations define PCN measurement and growth for different categories based on baseline cyst size. However, no data are available regarding PCN growth rate under the ACR-defined size categories. Purpose To assess growth of incidentally detected PCNs on long-term imaging follow-up using revised ACR recommendations and to evaluate the association between baseline imaging features and growth. Materials and Methods This retrospective study included PCNs with baseline imaging performed between January 2002 and May 2017, with two or more cross-sectional imaging studies performed at least 12 months apart. PCN assessment was based on ACR 2017 recommendations. Cyst features, including location, septations, and mural nodules and multiplicity, were noted. Time to cyst progression (growth by ACR criteria) was examined by using baseline PCN size, among other factors. Results A total of 646 cysts in 390 patients were followed up for a median of 50 months (range, 12-186 months). A total of 184 (28.5%) cysts increased in size, 52 (8.1%) decreased in size, and 410 (63.4%) remained stable. For groups in which baseline PCN size was smaller than 5 mm, 5-14 mm, 15-25 mm, and larger than 25 mm, growth was noted in seven (13.2%), 106 (28.9%), 49 (32.2%), and 22 (29.7%) cysts, respectively. ACR baseline size categories (subhazard ratio: 2.8 [5-14-mm PCN group], 3.4 [15-25-mm PCN group], and 2.7 [>25 mm group], as compared with the <5 mm PCN group; P < .05 for each) demonstrated association with growth. Presence of mural nodules, septations, or lesion multiplicity failed to demonstrate association with growth. Among PCNs smaller than 5 mm at baseline, 100% of PCNs at 3-year follow-up and 94.2% of PCNs at 5-year follow-up were likely to remain stable. Conclusion American College of Radiology baseline size category of 15-25-mm pancreatic cystic neoplasms (PCNs) demonstrated the highest (3.1 times) likelihood of growth, as compared with the category of PCNs smaller than 5 mm. PCNs smaller than 5 mm at baseline did not demonstrate growth at 3-year imaging follow-up. © RSNA, 2019 Online supplemental material is available for this article.

[Cystic lesions of the pancreas : Differential diagnostics and treatment]

Cystic space-occupying lesions of the pancreas represent incidental findings in most cases. As there is a potential risk of malignant transformation further evaluation of the lesions as well as a follow-up of these patients is usually recommended. Before this work-up is initiated the clinical situation of the patient as a whole and comorbidities, age and personal preferences have to be taken into account. So far there are no biomarkers that reliably predict the risk of malignant transformation. Imaging by magnetic resonance tomography (MRI) in combination with magnetic resonance cholangiopancreatography (MRCP) is more accurate than computed tomography to identify worrisome features. During follow-up, endoscopic ultrasound (EUS) can be used as complementary method to MRI/MRCP. Using contrast enhancement or endoscopic fine needle aspiration (EUS-FNA) may influence the therapeutic strategy in some patients. Whereas for some cystic pancreatic lesions consensus has been reached, varying recommendations exist for intraductal papillary mucinous neoplasms (IPMN). There is consensus that in main-duct as well as in mixed-type IPMN surgery is recommended. The management of branch-duct type IPMN, however, remains controversial. A multidisciplinary expert panel including gastroenterologists, visceral surgeons, radiologists and pathologists is essential to discuss all cases of patients with cystic pancreatic lesions and to guarantee an optimal, patient-centered treatment recommendation.

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.

Utility of transabdominal ultrasound for surveillance of known pancreatic cystic lesions: prospective evaluation with MRI as reference standard

OBJECTIVES

To prospectively assess the utility of transabdominal ultrasound in surveillance of known pancreatic cystic lesions (PCL) using same day MRI as reference standard.

METHODS

In an IRB-approved study with written informed consent, patients with known PCL underwent pancreas US on same day as surveillance MRI. US was performed blinded to same date MRI results. Transverse (TR), antero-posterior (AP), cranio-caudal (CC), and longest any plane diameter, were measured for each PCL at US and MRI. Visualization was correlated with patient (weight, abdominal diameter, thickness of abdominal fat, sex) and cyst (location, size, internal complexity) factors.

RESULTS

252 PCLs evaluated in 57 subjects (39 females; mean age 67 (range 39-86) yrs). Mean maximum PCL diameter 8.5 (range 2-92) mm. US identified 100% (5/5) of cysts ≥3 cm; 92% (12/13) ≥2 and <3 cm; 78% (43/55) ≥1 and <2 cm; 35% (27/78) ≥5 mm and <1 cm; and 16% (16/101) <5 mm. US visualization correlated with PCL location (<0.0001), size (p < 0.0001), patient gender (p = 0.005), participation of attending radiologist (p = 0.03); inversely with patient weight (p = 0.012) and AP abdominal diameter (p = 0.01).

CONCLUSION

Many PCLs are visualized and accurately measured at follow-up with transabdominal ultrasound. Visualization correlates with lesion size, location, patient sex, weight, and abdominal diameter.

European evidence-based guidelines on pancreatic cystic neoplasms

Evidence-based guidelines on the management of pancreatic cystic neoplasms (PCN) are lacking. This guideline is a joint initiative of the European Study Group on Cystic Tumours of the Pancreas, United European Gastroenterology, European Pancreatic Club, European-African Hepato-Pancreato-Biliary Association, European Digestive Surgery, and the European Society of Gastrointestinal Endoscopy. It replaces the 2013 European consensus statement guidelines on PCN. European and non-European experts performed systematic reviews and used GRADE methodology to answer relevant clinical questions on nine topics (biomarkers, radiology, endoscopy, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), serous cystic neoplasm, rare cysts, (neo)adjuvant treatment, and pathology). Recommendations include conservative management, relative and absolute indications for surgery. A conservative approach is recommended for asymptomatic MCN and IPMN measuring <40 mm without an enhancing nodule. Relative indications for surgery in IPMN include a main pancreatic duct (MPD) diameter between 5 and 9.9 mm or a cyst diameter ≥40 mm. Absolute indications for surgery in IPMN, due to the high-risk of malignant transformation, include jaundice, an enhancing mural nodule >5 mm, and MPD diameter >10 mm. Lifelong follow-up of IPMN is recommended in patients who are fit for surgery. The European evidence-based guidelines on PCN aim to improve the diagnosis and management of PCN.

Progression of Pancreatic Branch Duct Intraductal Papillary Mucinous Neoplasm Associates With Cyst Size

BACKGROUNDS & AIMS

Most guidelines for management of patients with intraductal papillary mucinous neoplasms (IPMN) vary in proposed surveillance intervals and durations-these are usually determined based on expert opinions rather than substantial evidence. The progression of and optimal surveillance intervals for branch-duct IPMNs (BD-IPMN) has not been widely studied. We evaluated the progression of BD-IPMN under surveillance at a single center, and determined optimal follow-up intervals and duration.

METHODS

We performed a retrospective analysis of 1369 patients with BD-IPMN seen at Seoul National University Hospital in Korea from January 2001 through December 2016. We included only patients whose imaging studies showed classical features of BD-IPMN, and collected data from each patient over time periods of at least 3 years. We reviewed radiologic and pathologic findings, and performed linear and binary logistic regressions to estimate cyst growth.

RESULTS

The median annual growth rate of the cyst was 0.8 mm over a median follow-up time of 61 months. During surveillance, 46 patients (3.4%) underwent surgery because of disease progression after a median follow-up time (in this group) of 62 months. Worrisome features were observed in 209 patients (15.3%) during surveillance, including cyst size of 3 cm or more (n = 109, 8.0%), cyst wall thickening (n = 51, 3.7%), main pancreatic duct dilatation (n = 77, 5.6%), and mural nodule (n = 43, 3.1%). Along with annual rate of cyst growth, incidences of main pancreatic duct dilatation and mural nodules associated with the sizes of cysts at detection (P < .001).

CONCLUSIONS

In a retrospective analysis of patients with BD-IPMN followed for more than 5 years, we found most cysts to be indolent, but some rapidly grew and progressed. Surveillance protocols should therefore be individualized based on initial cyst size and rate of growth.

Incidental, Small (< 3 cm), Unilocular, Pancreatic Cysts: Factors That Predict Lesion Progression during Imaging Surveillance

OBJECTIVE

To explore the features that predict size increase and development of potential malignant features in incidentally detected, unilocular cystic pancreatic lesions (CPLs) less than 3 cm in diameter, during subsequent follow-up.

MATERIALS AND METHODS

We retrieved data of patients diagnosed with unilocular CPLs less than 3 cm in diameter during the period from November 2003 through December 2014, using a computerized search. All serial CT and MR images were analyzed to identify the number, size, and location of CPLs; dilatation of the main pancreatic duct; and occurrence of worrisome features and high-risk stigmata of malignancy in the lesion. The characteristics of CPLs were compared between the increase (i.e., size increase during subsequent follow-up) and no-increase groups. For CPLs in the increase group, subgroup analysis was performed according to the lesion size at the last follow-up (< 3 cm vs. ≥ 3 cm).

RESULTS

Among 553 eligible patients, 132 (23.9%) had CPLs that increased in size, and 421 (76.1%) had CPLs that did not, during follow-up. Of the 132, 12 (9.1%) CPLs increased to diameters ≥ 3 cm at the final follow-up. Among the various factors, follow-up duration was a significant independent factor for an interval size increase of CPLs (p < 0.001). In the increase group, initial cyst size was a significant independent factor to predict later size increase to or beyond 3 cm in diameter (p < 0.001), and the initial cyst diameter ≥ 1.5 cm predicted such a growth with a sensitivity and specificity of 83% and 72%, respectively. No significant factors to predict the development of potential malignant features were identified.

CONCLUSION

Follow-up duration was associated with an interval size increase of CPLs. Among the growing CPLs, initial cyst size was associated with future lesion growth to and beyond 3 cm.

Appropriate Interval for Imaging Follow-up of Small Simple Pancreatic Cysts

CONTEXT

The frequency at which patients should undergo follow-up imaging of small pancreatic cysts is problematic because different medical societies have different follow-up guidelines.

OBJECTIVE

To determine whether short-term follow-up of small pancreatic cysts is necessary to detect pancreatic cancer or cystic neoplasia.

DESIGN

We retrospectively reviewed all abdominal magnetic resonance imaging (MRI) studies obtained in a geographically isolated health maintenance organization between January 1, 2012, and December 31, 2014, looking for pancreatic cysts. For each patient with one or more simple cysts, we recorded the size of the largest cyst. For patients with cysts, all their other computed tomography and MRI studies were reviewed to determine any change in size or morphology. The electronic medical record of every patient who underwent MRI was reviewed to determine development of pancreatic cancer.

MAIN OUTCOME MEASURES

Change in cyst size on images.

RESULTS

Of 1946 patients, 342 were found to have at least 1 pancreatic cyst. A total of 228 patients had additional imaging from which to determine rates of change. The mean rate (standard deviation) of change for these cysts was 0.1 ± 2.0 mm/y. None of those cysts measuring 2 cm or smaller on MRI grew more than 5 mm in 2 years.

CONCLUSION

Our data validate the clinical efficacy of obtaining follow-up imaging no sooner than 24 months after the initial detection of a simple pancreatic cyst 2 cm or smaller. Patients with cysts are more likely to have pancreatic cancer, but earlier follow-up imaging would not change their diagnosis of pancreatic cancer.

Surveillance and Outcomes of Nonresected Presumed Branch-Duct Intraductal Papillary Mucinous Neoplasms: A Meta-analysis

OBJECTIVES

Guidelines regarding the surveillance of intraductal papillary mucinous neoplasms (IPMNs) are controversial because of uncertain risk of malignancy, agnosticism regarding the use of endoscopic ultrasound, and their recommendation to stop surveillance after 5 years. We present a systematic review and meta-analysis of the risk of malignancy and other end points and estimate the value of endoscopic ultrasound for surveillance.

METHODS

We systematically searched MEDLINE for studies with a cohort of patients with presumed branch-duct IPMN who initially were managed nonsurgically. Data regarding study characteristics, surveillance, and outcomes were extracted. Incidence rates of morphologic progression, malignancy, surgery, and death were calculated with a random effects model.

RESULTS

Twenty-four studies with 3440 patients and 13,097 patient-years of follow-up were included. Rates of morphologic progression, surgery, malignancy, and death were 0.0379, 0.0250, 0.0098, and 0.0043 per patient-year, respectively. Endoscopic ultrasound was not associated with significantly different rates of these outcomes.

CONCLUSIONS

The risk of malignancy calculated in this study was low and in line with recent systematic reviews. Endoscopic ultrasound does not have marginal use in surveillance. Given the limitations of a systematic review of nonrandomized studies, further studies are needed to determine the optimal surveillance of branch-duct IPMNs.

Clinical Approach to Incidental Pancreatic Cystic Neoplasm in Outpatient Clinics

Cystic lesions of the pancreas are increasingly observed due to increased use of abdominal images. The malignant rate of pancreas cystic lesion varies widely between various types. Identification of malignant or high-risk lesions is important when determining the appropriate course of management. Using these image findings, including cyst size, presence of solid components, and pancreatic duct involvement, the 2012 International Association of Pancreatology (IAP) and the 2015 American Gastroenterological Association (AGA) guidelines provide a rationale in identifying higher risk patients requiring further workups using an endoscopic ultrasound (EUS). EUS with fine needle aspiration and cytology allows confirmation of the cyst type and determines the risk of malignancy. Small cysts with no suspicious features may undergo the regular imaging study for regular surveillance due to low risk for malignancy. In this review, the differences between the 2012 IAP and 2015 AGA guidelines are presented, In addition to possible recommendations for management and surveillance.

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.

Association of Preoperative Risk Factors With Malignancy in Pancreatic Mucinous Cystic Neoplasms: A Multicenter Study

Importance

Pancreatic mucinous cystic neoplasms (MCNs) harbor malignant potential, and current guidelines recommend resection. However, data are limited on preoperative risk factors for malignancy (adenocarcinoma or high-grade dysplasia) occurring in the setting of an MCN.

Objectives

To examine the preoperative risk factors for malignancy in resected MCNs and to assess outcomes of MCN-associated adenocarcinoma.

Design, Setting, and Participants

Patients who underwent pancreatic resection of MCNs at the 8 academic centers of the Central Pancreas Consortium from January 1, 2000, through December 31, 2014, were retrospectively identified. Preoperative factors of patients with and without malignant tumors were compared. Survival analyses were conducted for patients with adenocarcinoma.

Main Outcomes and Measures

Binary logistic regression models were used to determine the association of preoperative factors with the presence of MCN-associated malignancy.

Results

A total of 1667 patients underwent resection of pancreatic cystic lesions, and 349 (20.9%) had an MCN (310 women [88.8%]; mean (SD) age, 53.3 [14.7] years). Male sex (odds ratio [OR], 3.72; 95% CI, 1.21-11.44; P = .02), pancreatic head and neck location (OR, 3.93; 95% CI, 1.43-10.81; P = .01), increased radiographic size of the MCN (OR, 1.17; 95% CI, 1.08-1.27; P < .001), presence of a solid component or mural nodule (OR, 4.54; 95% CI, 1.95-10.57; P < .001), and duct dilation (OR, 4.17; 95% CI, 1.63-10.64; P = .003) were independently associated with malignancy. Malignancy was not associated with presence of radiographic septations or preoperative cyst fluid analysis (carcinoembryonic antigen, amylase, or mucin presence). The median serum CA19-9 level for patients with malignant neoplasms was 210 vs 15 U/mL for those without (P = .001). In the 44 patients with adenocarcinoma, 41 (93.2%) had lymph nodes harvested, with nodal metastases in only 14 (34.1%). Median follow-up for patients with adenocarcinoma was 27 months. Adenocarcinoma recurred in 11 patients (25%), with a 64% recurrence-free survival and 59% overall survival at 3 years.

Conclusions and Relevance

Adenocarcinoma or high-grade dysplasia is present in 14.9% of resected pancreatic MCNs for which risks include male sex, pancreatic head and neck location, larger MCN, solid component or mural nodule, and duct dilation. Mucinous cystic neoplasm-associated adenocarcinoma appears to have decreased nodal involvement at the time of resection and increased survival compared with typical pancreatic ductal adenocarcinoma. Indications for resection of MCNs should be revisited.

Management of Incidental Pancreatic Cysts: A White Paper of the ACR Incidental Findings Committee

The ACR Incidental Findings Committee (IFC) presents recommendations for managing pancreatic cysts that are incidentally detected on CT or MRI. These recommendations represent an update from the pancreatic component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Pancreas Subcommittee-which included abdominal radiologists, a gastroenterologist, and a pancreatic surgeon-developed this algorithm. The recommendations draw from published evidence and expert opinion, and were finalized by informal iterative consensus. Algorithm branches successively categorize pancreatic cysts based on patient characteristics and imaging features. They terminate with an ascertainment of benignity and/or indolence (sufficient to discontinue follow-up), or a management recommendation. The algorithm addresses most, but not all, pathologies and clinical scenarios. Our goal is to improve quality of care by providing guidance on how to manage incidentally detected pancreatic cysts.

Comparing 3 guidelines on the management of surgically removed pancreatic cysts with regard to pathological outcome

BACKGROUND AND AIMS

Currently, 3 guidelines are available for the management of pancreatic cysts. These guidelines vary in their indication for resection of high-risk cysts. We retrospectively compared the final pathologic outcome of surgically removed pancreatic cysts with the indications for resection according to 3 different guidelines.

METHODS

Patients who underwent pancreatic resection were extracted from our prospective pancreatic cyst database (2006-present). The final histopathologic diagnosis was compared with the initial indication for surgery stated by the guidelines of the International Association of Pancreatology (IAP), European Study Group on Cystic tumors of the Pancreas and American Gastroenterological Association (AGA). We considered surgery in retrospect justified for malignancy, high-grade dysplasia, solid pseudopapillary neoplasms, neuroendocrine tumors or symptom improvement. Furthermore, we evaluated the patients with suspected intraductal papillary mucinous neoplasm (IPMN) separately.

RESULTS

Overall, 115 patients underwent pancreatic resection. The preoperative diagnosis was correct in 83 of 115 patients (72%) and differentiation between benign and premalignant in 99 of 115 patients (86%). In retrospect, surgery was justified according to the aforementioned criteria in 52 of 115 patients (45%). For patients with suspected IPMN (n = 75) resection was justified in 36 of 67 (54%), 36 of 68 (53%), and 32 of 54 (59%) of patients who would have had surgery based on the IAP, European, or AGA guidelines, respectively. The AGA guideline would have avoided resection in 21 of 75 (28%) patients, versus 8 of 75 (11%) and 7 of 75 (9%) when the IAP or European guideline would have been applied strictly. Nevertheless, 4 of 33 patients (12%) with high-grade dysplasia or malignancy would have been missed with the AGA guidelines, compared with none with the IAP or European guidelines.

CONCLUSION

Although fewer patients undergo unnecessary surgery based on the AGA guidelines, the risk of missing malignancy or high-grade dysplasia with this guideline seems considerably high.

Intraductal papillary mucinous neoplasms and mucinous cystadenomas: current status and recommendations

The real prevalence of pancreatic cystic lesions remains unknown. The malignant potential of some of these lesions remains a cause for significant concern. Thus, it is mandatory to develop a strategy to clearly discriminate those cysts with a potential for malignant transformation from those that do not carry any significant risk. Intraductal papillary mucinous neoplasms and mucinous cystadenomas are mucinous cystic neoplasms with a known malignant potential that have gained greater recognition in recent years. However, despite the numerous studies that have been carried out, their differential diagnosis among other cysts subtypes and their therapeutic approach continue to be a challenge for clinicians. This review contains a critical approach of the current recommendations and management strategies regarding intraductal papillary mucinous neoplasms and mucinous cystadenomas, as well as highlighting the limitations exposed in current guidelines.

Long-term follow-up of neoplastic pancreatic cysts without high-risk stigmata: how often do we change treatment strategy because of malignant transformation?

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OBJECTIVE

Patients with potentially premalignant neoplastic pancreatic cysts without high-risk stigmata usually enter a surveillance program. Data on outcomes of such surveillance programs are scarce. We aimed to evaluate the resection rate and malignancy rate during follow-up.

MATERIAL AND METHODS

From our prospective database (2006-2015) of patients with pancreatic cysts, we analyzed patients with pancreatic cysts without high-risk stigmata with at least six months follow-up.

RESULTS

In total, 146 patients were followed for a median of 29 months (IQR 13.5-50 months). In 124 patients (84.9%), no changes in clinical or imaging characteristics occurred during follow-up. Thirteen patients (8.9%) developed an indication for surgery after a median follow-up of 25 months (IQR 12-42 months). Two patients did not undergo surgery because of comorbidity, 11 patients (7.5%) underwent resection. Indications for surgery were symptoms (n = 2), development of a pancreatic mass (n = 1), a new nodule (n = 2), thickened cyst wall (n = 1), pancreatic duct dilation (n = 3), and/or suspicion of mucinous cystic neoplasm (MCN) (n = 3). Postoperative histology showed one pancreatic malignancy not originating from the cyst, three mixed type-intraductal papillary mucinous neoplasm (IPMN), one side branch-IPMN, two MCN, one neuroendocrine tumor, one serous cystadenoma, one inflammatory cyst, and one lymphangioma. The highest grade of cyst dysplasia was borderline dysplasia.

CONCLUSIONS

Most neoplastic pancreatic cysts without high-risk stigmata at initial presentation show no substantial change during 1-4-year follow-up. Only 7.5% of patients underwent surgery and less than 1% of patients developed pancreatic malignancy. This indicates that additional markers are needed to tailor treatment of pancreatic cysts.

Pancreatic cysts: What imaging characteristics are associated with development of pancreatic ductal adenocarcinoma?

PURPOSE

To assess relationship between pancreatic cysts (PC) and pancreatic ductal adenocarcinoma (PDAC) and to compare imaging features of PC in subjects who develop PDAC and those who do not.

MATERIAL AND METHODS

This case-control IRB-approved HIPAA-compliant study included patients with PDAC (cases) and lung cancer (controls), diagnosed between 1/1/05-1/1/14. The most recent abdominal CT/MR of each patient done >6months prior to cancer diagnosis date was reviewed by radiologist blinded to case/control status. Presence of PC, number and size of largest PC, presence of main pancreatic duct (MPD) dilatation (MPD >3mm) were recorded. Simple PC was defined as lack of calcifications, septations and enhancement. Logistic regression models with binary outcome of PDAC were constructed.

RESULTS

There were 88 cases and 273 controls with mean ages of 69.6 years (±10.3) and 69.8 years (±12.0), respectively (p=0.864). PC were present in 21.6% (19/88) cases and in 9.2% (25/273) controls (p=0.002). The OR of PC for development of PDAC was 2.83, adjusting for age, sex and race (p=0.001). Mean PC size was 14.8mm (±8.7) in cases and 7.6mm (±8.0) in controls (p=0.007). PC were solitary in 6 (31.6%) of 19 cases and 21 (84.0%) of 25 controls (p=0.001). There was no significant difference in proportions of simple cysts or MPD dilatation between cases and controls. Multiple PC had 8.2 times increased odds of PDAC compared with solitary PC, adjusting for cyst size (p=0.007).

CONCLUSION

Multiple PC are associated with 8.2 times higher odds of PDAC compared with solitary PC.

Risk of pancreatic cancer in patients with pancreatic cyst

BACKGROUND AND AIMS

Certain pancreatic cysts (mucinous cystic neoplasm and side branch intraductal papillary mucinous neoplasm [IPMN]) have malignant potential and require surveillance. However, whether patients with pancreatic cysts have a higher long-term risk of pancreatic cancer (PaCa) has still not been established.

METHODS

This was a retrospective study of Veterans Administration patients. Patients noted to have pancreatic cysts on CT/magnetic resonance imaging (n = 1050) were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients aged <15 years (n = 425), patients with <1 year of follow-up (n = 13,259), and patients diagnosed to have PaCa within 1 year of identification of a pancreatic cyst (n = 102) or within 1 year of follow-up in the remaining patients in the database (n = 200) were excluded. Patients with pancreatic cystic lesions (group A, n = 755) and the remaining patients in the database without cysts (group B, n = 520,215) were followed from 1998 to 2007.

RESULTS

During the study period, in group A and B PaCa was diagnosed in 17 and 1206 patients, respectively, and the incidence rate of PaCa was 5.08 and .32 per 1000 patient-years, respectively. The hazard ratio of PaCa in all patients with cysts was 19.64 (95% CI, 12.12-31.82; P < .0001) when compared with the rest of the patients without cysts. In the subset of patients with cysts, without a history of acute or chronic pancreatitis (n = 241), the hazard ratio of PaCa (n = 5) was 18.80 (95% CI, 7.80-45.31; P < .0001).

CONCLUSION

Patients with pancreatic cysts have a significantly higher overall risk of PaCa. The etiologic distribution of cysts in our study patients is not available. Patients with mucinous cystic neoplasm and side branch IPMN are likely to have a higher risk of PaCa than our estimation of risk based on all etiologies.

Measurement of pancreatic cystic lesions on magnetic resonance imaging: efficacy of standards in reducing inter-observer variability

PURPOSE

The purpose of this study is to assess inter-observer variability in the measurement of pancreatic cystic lesions with MRI and to determine the impact of measurement standards.

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant study with waiver of informed consent, 144 MRI examinations, containing pancreatic cystic lesions measuring between 5 and 35 mm, were reviewed independently by two radiology attendings and two abdominal imaging fellows. Measurements were repeated by the same reviewers 12 weeks later after the introduction of measurement standards. Results were analyzed using within-subject standard deviation, intraclass correlation coefficient, and kappa.

RESULTS

Prior to standardization, the within-subject standard deviation, showing measurement variability in each cyst, was 4.0 mm, which was reduced to 3.3 mm after introduction of measurement standards (p < 0.01). Overall inter-observer agreement, kappa, improved from 0.59 to 0.65 (p = 0.04). The frequency of all four reviewers agreeing on size category increased from 51% to 60%. The intraclass correlation coefficient increased from 0.81 to 0.86.

CONCLUSIONS

There is significant and frequent inter-observer variability in the measurement of pancreatic cystic lesions with MRI which could affect clinical management. Implementation of measurement standards reduces measurement variability and aids in preventing erroneous reporting of growth and potentially unwarranted changes in management.

Delayed Growth in Incidental Pancreatic Cysts: Are the Current American College of Radiology Recommendations for Follow-up Appropriate?

PURPOSE

To evaluate growth kinetics of asymptomatic small (<2 cm) incidental pancreatic cysts and to assess potential implications of these in the context of current American College of Radiology recommendations.

MATERIALS AND METHODS

This institutional review board-approved HIPAA-compliant retrospective study with waiver of informed consent included patients with asymptomatic small incidental pancreatic cysts (diameter, 5-20 mm) with two or more magnetic resonance (MR) examinations performed at least 6 months apart at a tertiary institution. The largest cyst dimension was measured on T2-weighted single-shot fast spin-echo images by one of six radiologists (1-3 years of experience) who were trained to measure pancreatic cysts in a similar manner. All analysis was conducted at the patient level by choosing the cyst that exhibited the greatest growth over the follow-up period in each patient. Fisher exact, χ(2), and Kruskal-Wallis tests and analysis of variance were used to test correlation between cyst characteristics and growth.

RESULTS

A total of 259 patients (mean age, 65 years ± 11 [standard deviation], male-to-female ratio, 42:58) with 370 asymptomatic small incidental pancreatic cysts were included. At presentation, median cyst size was 9.4 mm (interquartile range [IQR], 7.0-12.2 mm), and 64 patients (25%; 95% confidence interval [CI]: 20, 30) had septations. The median imaging follow-up period was 2.2 years (IQR, 1.2-3.9 years; range, 0.5-11.0 years), with a median of three MR examinations (IQR, two to four examinations) per patient. In 171 (66%; 95% CI: 60, 72) of the 259 patients, cysts remained stable; in 18 (7%; 95% CI: 4, 11), cysts shrank; and in 70 (27%; 95% CI: 22, 33), cysts grew (median total growth and median annual growth of 4.8 mm and 2.3 mm/y, respectively). Age, cyst size, and cyst septation at presentation were not predictive of growth. Overall, 29 (11%), 16 (6%), and four (1.5%) of the cysts increased in size after 1, 2, and 3 years of initial stability, respectively. Of the 18 patients who underwent pancreatic surgery, only one patient with an intraductal papillary mucinous neoplasm had high-grade dysplasia. One patient developed pancreatic adenocarcinoma remotely at the location of the pancreatic cyst diagnosed 11 months prior.

CONCLUSION

In the majority of patients, asymptomatic small incidental pancreatic cysts remained stable during a median follow-up period of 2.2 years; however, in 27% of patients, cysts increased in size over time, with 11% growing after an initial 1-year period of stability. Current American College of Radiology recommendations to discontinue imaging follow-up after 1 year of stability may need to be reevaluated.

Incidental pancreatic cystic lesions: is there a relationship with the development of pancreatic adenocarcinoma and all-cause mortality?

PURPOSE

To establish the effect of incidental pancreatic cysts found by using computed tomographic (CT) and magnetic resonance (MR) imaging on the incidence of pancreatic ductal adenocarcinoma and overall mortality in patients from an inner-city urban U.S. tertiary care medical center.

MATERIALS AND METHODS

Institutional review board granted approval for the study and waived the informed consent requirement. The study population comprised cyst and no-cyst cohorts drawn from all adults who underwent abdominal CT and/or MR November 1, 2001, to November 1, 2011. Cyst cohort included patients whose CT or MR imaging showed incidental pancreatic cysts; no-cyst cohort was three-to-one frequency matched by age decade, imaging modality, and year of initial study from the pool without reported incidental pancreatic cysts. Patients with pancreatic cancer diagnosed within 5 years before initial CT or MR were excluded. Demographics, study location (outpatient, inpatient, or emergency department), dates of pancreatic adenocarcinoma and death, and modified Charlson scores within 3 months before initial CT or MR examination were extracted from the hospital database. Cox hazard models were constructed; incident pancreatic adenocarcinoma and mortality were outcome events. Adenocarcinomas diagnosed 6 months or longer after initial CT or MR examination were considered incident.

RESULTS

There were 2034 patients in cyst cohort (1326 women [65.2%]) and 6018 in no-cyst cohort (3,563 [59.2%] women); respective mean ages were 69.9 years ± 15.1(standard deviation) and 69.3 years ± 15.2, respectively (P = .129). The relationship between mortality and incidental pancreatic cysts varied by age: hazard ratios were 1.40 (95% confidence interval [ CI confidence interval ]: 1.13, 1.73) for patients younger than 65 years and 0.97 (95% CI confidence interval : 0.88, 1.07), adjusted for sex, race, imaging modality, study location, and modified Charlson scores. Incidental pancreatic cysts had a hazard ratio of 3.0 (95% CI confidence interval : 1.32, 6.89) for adenocarcinoma, adjusted for age, sex, and race.

CONCLUSION

Incidental pancreatic cysts found by using CT or MR imaging are associated with increased mortality for patients younger than 65 years and an overall increased risk of pancreatic adenocarcinoma.

Management of serous cystic neoplasms of the pancreas

Pancreatic serous cystadenomas are uncommon benign tumours that are often found incidentally on routine imaging examinations. Radiological imaging techniques alone have proven to be suboptimal to fully characterize cystic pancreatic lesions. Endoscopic ultrasound, with the addition of fine-needle aspiration in difficult cases, has showed greater diagnostic accuracy than conventional imaging techniques. The best management strategy of these neoplasms is still debated. Surgery should be limited only to symptomatic and highly selected cases and most of the patients should only be strictly monitored. In the current paper, we provide an updated overview on pancreatic serous cystadenomas, focusing our attention on epidemiology, clinical characteristics and diagnostic evaluation; finally, we also discuss different management strategies and areas for future research.

Moving beyond morphology: new insights into the characterization and management of cystic pancreatic lesions

The frequency of detection of cystic pancreatic lesions with cross-sectional imaging, particularly with multidetector computed tomography, magnetic resonance (MR) imaging, and MR cholangiopancreatography, is increasing, and many of these cystic pancreatic lesions are being detected incidentally in asymptomatic patients. Because there is considerable overlap in the cross-sectional imaging findings of cystic pancreatic lesions, and because many of these lesions being detected are smaller than 3 cm in diameter and lack any specific cross-sectional imaging features, it has become difficult to make informed decisions about patient management when the precise diagnosis remains uncertain. This article presents the limitations of cross-sectional imaging in patients with cystic pancreatic lesions, details advances in knowledge of the genomic and epigenomic changes that lead to progression of carcinogenesis, outlines the current understanding of the natural history of mucinous cystic lesions, and includes the current use and future potential of novel tumor markers and molecular analysis to characterize cystic pancreatic lesions more precisely. The need to move beyond cross-sectional imaging morphology and toward the use of new techniques to diagnose these lesions accurately is emphasized. An algorithm that uses these techniques is proposed and will hopefully lead to improved patient management.

Role of endoscopic ultrasonography in pancreatic cystic neoplasms: where do we stand and where will we go?

We increasingly encounter pancreatic cystic neoplasms (PCN) in clinical practice and the differential diagnoses vary widely from benign to malignant. There is no 'one and only' diagnostic procedure for PCN. Multiple modalities including computed tomography, magnetic resonance imaging, endoscopic retrograde cholangiopancreatography and endoscopic ultrasound (EUS) are widely used, but EUS has the advantage of anatomical proximity to the pancreas and upper gastrointestinal tract. In addition, EUS-guided fine-needle aspiration (EUS-FNA) provides both cytological evaluation and cyst fluid analysis. Although the role of EUS-FNA for PCN is established, the sensitivity of cytology is low and cyst fluid analysis is only useful for differentiation between mucinous and non-mucinous cysts. Recently, novel through-the-needle imaging under EUS-FNA, such as confocal laserendomicroscopy, is expected to attribute to a better diagnostic yield. Moreover, feasibility of cyst ablation has been reported and the role of EUS has expanded from diagnosis to treatment. However, clinical impact of cyst ablation in terms of safety, efficacy and cost-effectiveness should be validated further. In summary, EUS and EUS-guided intervention does and will play a central role in the management of PCN from surveillance to treatment, but many clinical questions remain unanswered, which warrants well-designed prospective clinical trials.

Incidental pancreatic cysts: natural history and diagnostic accuracy of a limited serial pancreatic cyst MRI protocol

OBJECTIVES

To examine the natural history of incidentally detected pancreatic cysts and whether a simplified MRI protocol without gadolinium is adequate for lesion follow-up.

METHODS

Over a 10-year period, 301-patients with asymptomatic pancreatic cysts underwent follow-up (45 months ± 30). The magnetic resonance imaging (MRI) protocol included axial, coronal T2-weighted images, MR cholangiopancreatographic and fat suppressed T1-weighted sequences before and after gadolinium. Three radiologists independently reviewed the initial MRI, the follow-up studies using first only unenhanced images, then secondly gadolinium-enhanced-sequences. Lesion changes during follow-up were recorded and the added value of gadolinium-enhanced sequences was determined by classifying the lesions into risk categories.

RESULTS

Three hundred and one patients (1,174 cysts) constituted the study population. Only 35/301 patients (12 %) showed significant lesion change on follow-up. Using multivariate analysis the only independent factor of lesion growth (OR = 2.4; 95 % CI, 1.7-3.3; P < 0.001) and mural nodule development (OR = 1.9; 95 % CI, 1.1-3.4, P = 0.03) during follow-up was initial lesion size. No patient with a lesion initial size less than 2 cm developed cancer during follow-up. Intra-observer agreement with and without gadolinium enhancement ranged from 0.86 to 0.97. After consensus review of discordant cases, gadolinium-enhanced sequences demonstrated no added value.

CONCLUSION

Most incidental pancreatic cystic lesions did not demonstrate change during follow-up. The addition of gadolinium-enhanced-sequences had no added-value for risk assignment on serial follow-up.

KEY POINTS

Significant growth of pancreatic cysts occurred in a minority of patients only. No lesion <2 cm demonstrated any change during the first year of follow-up. Intra-observer agreement between MR pancreatic protocols with and without gadolinium was excellent. Gadolinium application had limited value for follow-up of asymptomatic pancreatic cystic lesions.

Prediction of malignancy in cystic neoplasms of the pancreas: a population-based cohort study

OBJECTIVES

Pancreatic cystic neoplasms (PCNs) are being detected with increased frequency. The aims of this study were to determine the incidence of malignancy and develop an imaging-based system for prediction of malignancy in PCN.

METHODS

We conducted a retrospective cohort study of patients ≥18 years of age with confirmed PCN from January 2005 to December 2010 in a community-based integrated care setting in Southern California. Patients with history of acute or chronic pancreatitis were excluded. Malignancy diagnosed within 3 months of cyst diagnosis was considered as pre-existing. Subsequent incidence of malignancy during surveillance was calculated based on person-time at risk. Age- and gender-adjusted standardized incidence ratio (SIR) was calculated with the non-cyst reference population. Recursive partitioning was used to develop a risk prediction model based on cyst imaging features.

RESULTS

We identified 1,815 patients with confirmed PCN. A total of 53 (2.9%) of patients were diagnosed with cyst-related malignancy during the study period. The surveillance cohort consisted of 1,735 patients with median follow-up of 23.4 months. Incidence of malignancy was 0.4% per year during surveillance. The overall age- and gender-adjusted SIR for pancreatic malignancy was 35.0 (95% confidence level 26.6, 46.0). Using recursive partitioning, we stratified patients into low (<1%), intermediate (1-5%), and high (9-14%) risk of harboring malignant PCN based on four cross-sectional imaging features: size, pancreatic duct dilatation, septations with calcification as well as growth. Area under the receiver operator characteristic curve for the prediction model was 0.822 (training) and 0.808 (testing).

CONCLUSIONS

Risk of pancreatic malignancy was lower than previous reports from surgical series but was still significantly higher than the reference population. A risk stratification system based on established imaging criteria may help guide future management decisions for patients with PCN.

Treatment of pancreatic cystic neoplasm: surgery or conservative?

Pancreatic cystic neoplasms (PCNs) are a heterogeneous group of tumors with distinct biological features. These neoplasms are now being recognized more frequently owing to advances in cross-sectional imaging and increasing awareness. Guidelines for treatment of the common and clinically important PCNs frequently have been revised in view of the continuing controversies and evolving clinical data. This review summarizes the management approaches of the common and clinically important PCNs based on current evidence and guidelines.

IPMN: surgical treatment

PURPOSE

Cystic pancreatic tumors are being detected more frequently, and particularly, intraductal papillary mucinous neoplasia (IPMN) has recently attracted increased attention. The detection rate of IPMN has increased over the last decade; however, management of this neoplasm remains controversial.

METHODS

Based on a review of the relevant literature and the international guidelines, we discuss the diagnostic evaluation of IPMN, its treatment, and prognosis.

RESULTS

While IPMN represents only a distinct minority of all pancreatic cancers, they appear to be a relatively frequent neoplastic form of pancreatic cystic neoplasm. It may not be possible to differentiate main duct disease from branch duct disease (MD-IPMN vs. BD-IPMN) prior to surgery. This distinction has not only an impact on treatment but also on prognosis, as MD-IPMN is more often malignant. IPMN has updated consensus guideline indications for conservative and surgical resection.

CONCLUSIONS

Since patients with IPMN of the pancreas are at risk of developing recurrent IPMN and pancreatic ductal adenocarcinoma in the remnant pancreas and extrapancreatic malignancies, early recognition, treatment, and systemic surveillance are of great importance. No conclusions can be drawn from the available evidence with respect to the efficacy of surveillance and follow-up treatment programs. A better understanding of the natural course of IPMN and the biology of pancreatic cancer is mandatory to enable further diagnostic and treatment improvements.

European experts consensus statement on cystic tumours of the pancreas

Cystic lesions of the pancreas are increasingly recognized. While some lesions show benign behaviour (serous cystic neoplasm), others have an unequivocal malignant potential (mucinous cystic neoplasm, branch- and main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm). European expert pancreatologists provide updated recommendations: diagnostic computerized tomography and/or magnetic resonance imaging are indicated in all patients with cystic lesion of the pancreas. Endoscopic ultrasound with cyst fluid analysis may be used but there is no evidence to suggest this as a routine diagnostic method. The role of pancreatoscopy remains to be established. Resection should be considered in all symptomatic lesions, in mucinous cystic neoplasm, main duct intraductal papillary mucinous neoplasm and solid pseudo-papillary neoplasm as well as in branch duct intraductal papillary mucinous neoplasm with mural nodules, dilated main pancreatic duct >6mm and possibly if rapidly increasing in size. An oncological partial resection should be performed in main duct intraductal papillary mucinous neoplasm and in lesions with a suspicion of malignancy, otherwise organ preserving procedures may be considered. Frozen section of the transection margin in intraductal papillary mucinous neoplasm is suggested. Follow up after resection is recommended for intraductal papillary mucinous neoplasm, solid pseudo-papillary neoplasm and invasive cancer.

Pancreatic cystic neoplasms: management and unanswered questions

Approximately 10% of persons 70 years old or older are now diagnosed with pancreatic cysts, but it is not clear which ones require additional analysis, interventions, or follow-up. Primary care doctors rely on gastroenterologists for direction because no one wants to miss a diagnosis of pancreatic cancer, but meanwhile there is pressure to limit use of diagnostic tests and limit costs. We review the different cystic neoplasms of the pancreas and diagnostic strategies based on clinical features and imaging data. We discuss surgical and nonsurgical management of the most common cystic neoplasms, based on the recently revised Sendai guidelines. Intraductal papillary mucinous neoplasm (particularly the branch duct variant) is the lesion most frequently identified incidentally. We report what is known about its pathology, its risk of developing into pancreatic ductal adenocarcinoma, the pros and cons of current guidelines for management, and the potential role of endoscopic ultrasound in determining cancer risk. We also review surgical treatment and strategies for surveillance of pancreatic cysts.

Diagnosis and management of cystic pancreatic lesions

OBJECTIVE

The purpose of this review is to outline the management guidelines for the care of patients with cystic pancreatic lesions.

CONCLUSION

The guidelines are as follows: Annual imaging surveillance is generally sufficient for benign serous cystadenomas smaller than 4 cm and for asymptomatic lesions. Asymptomatic thin-walled unilocular cystic lesions smaller than 3 cm or side-branch intraductal papillary mucinous neoplasms should be followed up with CT or MRI at 6 and 12 months interval after detection. Cystic lesions with more complex features or with growth rates greater than 1 cm/year should be followed more closely or recommended for resection if the patient's condition allows surgery. Symptomatic cystic lesions, neoplasms with high malignant potential, and lesions larger than 3 cm should be referred for surgical evaluation. Endoscopic ultrasound with fine-needle aspiration (FNA) biopsy can be used preoperatively to assess the risk of malignancy.

Natural history of asymptomatic pancreatic cystic neoplasms

BACKGROUND

The management of asymptomatic pancreatic cysts is controversial and indications for excision are based on pathology and natural history.

OBJECTIVES

This study aimed to examine outcomes of asymptomatic lesions using a protocol based on size and cyst fluid analysis.

METHODS

Asymptomatic cysts were identified from a prospectively maintained database. Sequential cross-sectional imaging studies were assessed, and results of endoscopic ultrasound-guided aspiration were co-analysed.

RESULTS

A total of 338 asymptomatic patients underwent evaluation. Overall, 84 cysts were <1.5 cm and 254 were ≥1.5 cm in diameter. Median patient follow-up was 5.1 years [interquartile range (IQR): 4.1-6.9 years]. In the group in which cysts measured <1.5 cm in diameter, median cyst size was 1.0 cm (IQR: 0.6-1.2 cm) at presentation and increased to 1.2 cm (IQR: 0.7-1.6 cm) during follow-up. Five (6.0%) patients underwent resection, all within 2 months of presentation. In the group in which cysts measured ≥1.5 cm in diameter, median cyst size was 2.5 cm (IQR: 2.0-3.4 cm) at presentation and increased to 2.7 cm (IQR: 3.0-4.2 cm). A total of 63 (24.8%) patients underwent resection. Surgery was performed with 2 months in 53 (84.1%) patients, within 12 months in four (6.3%) patients and at >12 months post-presentation in six (9.5%) patients. A total of 70.6% of resected specimens were identified as malignancies or mucinous lesions.

CONCLUSIONS

Asymptomatic cysts of <1.5 cm in diameter can safely be followed by imaging and are expected to undergo little change. A quarter of all asymptomatic cysts measuring ≥1.5 cm are appropriately resected based on imaging and cyst fluid analysis.

Long-term outcome of cystic lesions in the pancreas: a retrospective cohort study

Background/Aims

The management guidelines for cystic lesions of the pancreas (CLPs) are not yet well established. This study was performed to document the long-term clinical outcome of CLPs and provide guidelines for the management and surveillance of CLPs.

Methods

In this retrospective cohort study, an additional follow-up was performed in 112 patients with CLPs enrolled from 1998 to 2004 during a previous study.

Results

During follow-up for the median period of 72.3 months, the size of the CLPs increased in 18 patients (16.1%). Six of these patients experienced growth of their CLPs after 5 years of follow-up. Twenty-six patients underwent surgery during follow-up, and four malignant cysts were detected. The overall rate of malignant progression during follow-up was 3.6%. The presence of mural nodules or solid components was independently associated with the presence of malignant CLPs. Seven patients underwent surgery after 5 years of follow-up. The pathologic findings revealed malignancies in two patients. There was only one pancreas-related death during follow-up.

Conclusions

The majority of CLPs exhibit indolent behavior and are associated with a favorable prognosis. However, long-term surveillance for more than 5 years should be performed because of the potential for growth and malignant transformation in CLPs.

International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas

The international consensus guidelines for management of intraductal papillary mucinous neoplasm and mucinous cystic neoplasm of the pancreas established in 2006 have increased awareness and improved the management of these entities. During the subsequent 5 years, a considerable amount of information has been added to the literature. Based on a consensus symposium held during the 14th meeting of the International Association of Pancreatology in Fukuoka, Japan, in 2010, the working group has generated new guidelines. Since the levels of evidence for all items addressed in these guidelines are low, being 4 or 5, we still have to designate them "consensus", rather than "evidence-based", guidelines. To simplify the entire guidelines, we have adopted a statement format that differs from the 2006 guidelines, although the headings are similar to the previous guidelines, i.e., classification, investigation, indications for and methods of resection and other treatments, histological aspects, and methods of follow-up. The present guidelines include recent information and recommendations based on our current understanding, and highlight issues that remain controversial and areas where further research is required.

Diagnostic accuracy of cyst fluid amphiregulin in pancreatic cysts

BACKGROUND

Accurate tests to diagnose adenocarcinoma and high-grade dysplasia among mucinous pancreatic cysts are clinically needed. This study evaluated the diagnostic utility of amphiregulin (AREG) as a pancreatic cyst fluid biomarker to differentiate non-mucinous, benign mucinous, and malignant mucinous cysts.

METHODS

A single-center retrospective study to evaluate AREG levels in pancreatic cyst fluid by ELISA from 33 patients with a histological gold standard was performed.

RESULTS

Among the cyst fluid samples, the median (IQR) AREG levels for non-mucinous (n = 6), benign mucinous (n = 15), and cancerous cysts (n = 15) were 85 pg/ml (47-168), 63 pg/ml (30-847), and 986 pg/ml (417-3160), respectively. A significant difference between benign mucinous and malignant mucinous cysts was observed (p = 0.025). AREG levels greater than 300 pg/ml possessed a diagnostic accuracy for cancer or high-grade dysplasia of 78% (sensitivity 83%, specificity 73%).

CONCLUSION

Cyst fluid AREG levels are significantly higher in cancerous and high-grade dysplastic cysts compared to benign mucinous cysts. Thus AREG exhibits potential clinical utility in the evaluation of pancreatic cysts.

Pancreatic mucinous cystadenoma in an adult with cystic fibrosis

Cystic fibrosis (CF) is the most frequent genetic disease in the Caucasian population. It seems to be associated with an increased risk of digestive cancer but only few cases of pancreatic tumors have been reported. As pancreatic lesions of the pancreas in CF patients are not rare, their etiological diagnosis is substantial. We report herein a case of a mucinous cystadenoma in a patient with CF. Diagnosis and management of pancreatic cystic tumors in patients at high risk of operative morbidity are challenging. When the potential malignancy of a pancreatic cystic mass cannot be well established in a CF patient, partly because of frequent chronic pancreatitis lesions, we suggest that surgical management should be undertaken instead of radiological surveillance.

Mucinous cystic neoplasms of the pancreas: definition of preoperative imaging criteria for high-risk lesions

BACKGROUND/AIM

Pancreatic mucinous cystic neoplasms (MCN) are premalignant lesions whose natural history is poorly known. Whether the dysplasia grade might be determined with precision by preoperative clinical and imaging criteria is not known. We aimed to determine if CT scan data might be useful to predict the grade of dysplasia in a series of 60 histologically proven MCN.

METHODS

All consecutive patients who were operated on with pathological confirmation of MCN were included. Careful CT scan evaluation was reviewed without knowledge of pathological results. Imaging and pathological results were correlated.

RESULTS

Sixty patients (59 females) were included. Low- and intermediate-grade dysplasias were identified in 47 and 3 patients (benign MCN), respectively, and high-grade dysplasia and invasive carcinoma in 7 and 3 patients (malignant MCN), respectively. Patients with benign lesions were significantly younger. None of the studied clinical data were statistically different to distinguish benign and malignant MCN, except age (42 vs. 48 years, p < 0.05). Only maximal diameter and mural nodules on CT scan were significantly more frequent in the malignant group. No malignant MCN had a maximal diameter <40 mm. At a 40-mm threshold, the sensitivity and specificity of the maximal diameter to diagnose malignant MCN were 100 and 54%, respectively. Mural nodules seen on CT scan were confirmed in all cases but one upon pathological examination of the surgical specimen. The sensitivity and specificity of the presence of a mural nodule seen on CT scan for the diagnosis of a malignant lesion were 100 and 98%, respectively.

CONCLUSION

Preoperative CT scan detection of a mural nodule within a cystic pancreatic neoplasm suggestive of MCN strongly suggests malignancy. A diameter <40 mm is associated with no risk of malignancy.

Cystic pancreatic lesions: current evidence for diagnosis and treatment

Pancreatic cystic neoplasms are detected at an increasing frequency due to an increased use and quality of abdominal imaging. There are well known differential diagnostic difficulties concerning these lesions. The aim is to review current literature on the diagnostic options and the following treatment for cystic lesions in the pancreas focusing on serous cystadenomas, primary mucinous neoplasm of the pancreas and mucinous cystadenocarcinomas, as well as intraductal papillary mucinous neoplasms, starting with excluding pseudocysts. A conservative approach is feasible in patients with a clinical presentation suggestive of an asymptomatic serous cystadenoma. Surgical management, as well as follow-up, is discussed for each of the types of neoplastic lesions, including an uncharacterized cyst, based on patient data, symptoms, serum analysis, cyst fluid analysis and morphological features. Aspects for future diagnostics and management of these neoplasia are commented upon.

Cystic lesions of the pancreas: changes in the presentation and management of 1,424 patients at a single institution over a 15-year time period

BACKGROUND

Cystic lesions of the pancreas are being identified more frequently, and a selective approach to resection is now recommended. The aim of this study was to assess the change in presentation and management of pancreatic cystic lesions evaluated at a single institution over 15 years.

STUDY DESIGN

A prospectively maintained registry of patients evaluated between 1995 and 2010 for the ICD-9 diagnosis of pancreatic cyst was reviewed. The 539 patients managed from 1995 to 2005 were compared with the 885 patients managed from 2005 to 2010.

RESULTS

A total of 1,424 patients were evaluated, including 1,141 with follow-up >6 months. Initial management (within 6 months of first assessment) was operative in 422 patients (37%) and nonoperative in 719 patients (63%). Operative mortality in patients initially submitted to resection was 0.7% (n = 3). Median radiographic follow-up in patients initially managed nonoperatively was 28 months (range 6 to 175 months). Patients followed radiographically were more likely to have cysts that were asymptomatic (72% versus 49%, p < 0.001), smaller (1.5 versus 3 cm, p < 0.001), without solid component (94% versus 68%, p < 0.001), and without main pancreatic duct dilation (88% versus 61%, p < 0.001). Changes prompting subsequent operative treatment occurred in 47 patients (6.5%), with adenocarcinoma identified in 8 (17%) and pancreatic endocrine neoplasm in 4 (8.5%). Thus, of the 719 patients initially managed nonoperatively, invasive malignancy was identified in 12 (1.7%), with adenocarcinoma seen in 1.1%.

CONCLUSION

Cystic lesions of the pancreas are being identified more frequently, yet are less likely to present with concerning features of malignancy. Carefully selected patients managed nonoperatively had a risk of malignancy that was equivalent to the risk of operative mortality in those patients who initially underwent resection.

Screening for pancreatic cancer: what can cyst fluid analysis tell us?

Pancreatic cysts are increasingly recognized as a dilemma in clinical practice because of their uncertain risk of malignancy. Because diagnosis by cytology is insensitive, current guidelines suggest using radiographic and clinical criteria to determine the appropriateness of surgery or surveillance, although this is far from perfect. Several cyst fluid biomarkers have been reported to aid diagnosis, and to date, carcinoembryonic antigen is the most accurate in detecting potentially cancerous mucinous cysts, but not in detecting malignant cysts. Recent studies have highlighted novel cyst fluid biomarkers based on DNA analysis, protein expression profiling, and secreted proteins that, if validated, may improve diagnosis and management.