Managing pancreatic cysts: less is more?

Role of endoscopic ultrasound in anticancer therapy: Current evidence and future perspectives

The digestive system is one of the most common sites of malignancies in humans. Since gastrointestinal tumors represent a massive global health burden both in terms of morbidity and health care expenditures, scientists continuously develop novel diagnostic and therapeutic methods to ameliorate the detrimental effects of this group of diseases. Apart from the well-established role of the endoscopic ultrasound (EUS) in the diagnostic course of gastrointestinal and hepatobiliary malignancies, we have recently become acquainted with a vast array of its therapeutic possibilities. A multitude of previously established, evidence-based methods that might now be guided by the EUS emerged: Radiofrequency ablation, brachytherapy, fine needle injection, celiac plexus neurolysis, and endoscopic submucosal dissection. In this review we endeavored to provide a comprehensive overview of the role of these methods in different malignancies of the digestive system, primarily in the treatment and symptom control in pancreatic cancer, and additionally in the management of hepatic, gastrointestinal tumors, and pancreatic cysts.

Comparing accuracy of high-risk features for detecting advanced neoplasia in pancreatic cystic lesions: a systematic review and meta-analysis

Background

The American Gastroenterological Association recommends endoscopic ultrasound (EUS) for evaluating pancreatic cystic lesions (PCL) with ≥2 high-risk features (HRF), whereas the American College of Gastroenterology recommends EUS for ≥1 HRF. This systematic review and meta-analysis compared the diagnostic accuracy of using ≥1 vs. ≥2 HRF for assessing the risk of advanced neoplasia (AN) and performing EUS in PCL.

Methods

An electronic database search was performed for eligible studies. AN was defined as pancreatic adenocarcinoma, intraductal papillary mucinous neoplasm or mucinous cystadenoma with high-grade dysplasia, pancreatic intraepithelial neoplasia and pancreatic neuroendocrine tumors. HRF included cyst size ≥3 cm, solid component, and dilated pancreatic duct ≥5 mm. The primary outcome was the sensitivity and specificity of using ≥1 vs. ≥2 HRF as an indication for EUS to detect AN in PCL.

Results

Of 38 studies initially screened, 8 were included in the final analysis. Seven studies assessed the accuracy of ≥2 HRF and 4 studies assessed ≥1 HRF. The pooled sensitivity, specificity, positive and negative predictive values of EUS for detecting AN were 41.7% (95% confidence interval 19.5-67.8%), 90.8% (81.9-95.5%), 30.4% (19.4-44.2%) and 94.3% (89.6-97.0%) with ≥2HRFs, and 77.1% (66.1-85.3%), 72.7% (50.4-87.5%), 17.95% (10.3-29.4%), 98.1% (90.8-99.6%), respectively, with ≥1 HRF.

Conclusion

Performing EUS for PCL with ≥1 HRF could offer greater sensitivity in detecting AN compared to ≥2 HRF, with a similar negative predictive value.

Natural history and optimal treatment strategy of intraductal papillary mucinous neoplasm of the pancreas: Analysis using a nomogram and Markov decision model

BACKGROUND/PURPOSE

With the increase in detection of intraductal papillary mucinous neoplasms (IPMN), a tailored approach is needed. This study was aimed at exploring the natural history of IPMN and suggest optimal treatment based on malignancy risk using a nomogram and Markov decision model.

METHODS

Patients with IPMN who underwent surveillance or surgery were included. Changes in worrisome features/high-risk stigmata and malignancy conversion rate were assessed. Life expectancy and quality-adjusted life year (QALY) were compared using a nomogram predicting malignancy.

RESULTS

Overall, 2006 patients with histologically confirmed or radiologically typical IPMN were enrolled. Of these, 1773 (88.4%), 81 (4.0%), and 152 (7.6%), respectively, had branch duct (BD)-, main duct-, and mixed-type IPMN at initial diagnosis. The cumulative risk of developing worrisome feature or high-risk stigmata was 19.0% and 35.0% at 5- and 10-year follow-up, respectively. The progression of malignancy rate at 10-year follow-up was 79.9% for main and mixed IPMNs and 5.9% for BD-IPMN. Nomogram-based malignancy risk prediction is well correlated with natural history based on pathologic biopsy and shows good stratification of survival. The decision model recommends surgery to maximize survival and QALY especially in those with >35% malignancy risk.

CONCLUSIONS

Compared with main duct- and mixed-type IPMN, which have a high risk of malignancy (79.9%), BD-IPMN is very indolent (5.9%). The nomogram-based decision model suggests surgery rather than surveillance for patients with a high malignancy risk. The optimal treatment strategy between surgery and surveillance should consider patients' health status, malignancy risk, and centers' experience.

Endoscopic ultrasound with fine needle aspiration is useful in pancreatic cysts smaller than 3 cm

Background

In current guidelines, endoscopic ultrasound with fine-needle aspiration (EUS-FNA) is recommended in pancreatic cystic lesions (PCLs) with worrisome features (size ≥ 3 cm, mural nodule, or Wirsung dilation).

Objective

To evaluate the diagnostic ability and assess the accuracy of EUS-FNA in PCLs smaller than 3 cm.

Methods

Retrospective study of PCLs < 3 cm (2007–2016) undergoing EUS-FNA. Clinical, EUS and pancreatic cystic fluid (PCF) data were prospectively registered. Performance of EUS-FNA with PCF analysis for the detection of malignancy and accuracy in surgical cohort were analyzed.

Results

We evaluated 115 patients with PCLs < 3 cm who underwent EUS-FNA. 19 patients underwent surgery, 7 had malignant, 8 pre-malignant, and the remaining 4 benign lesions. Mass/mural nodule was present in 27% of the cysts, CEA level was higher than 192 ng/mL in 39.4% of patients, and only 35% of cytologic samples were informative. Nevertheless, additional FNA for PCF analysis improved the diagnostic performance of EUS imaging—AUC = 0.80 versus AUC = 60.

Conclusion

EUS-FNA has good accuracy in PCLs < 3 cm. It confirmed malignancy even in lesions without worrisome features (nodule/mass), with two in every five resections showing high-risk/malignant lesions. EUS-FNA was also useful to diagnose benign cysts, possibly allowing surveillance to be stopped in one in every five patients.

Autophagy promotes malignant migration and invasion via miR-224-5p/BCL2 in pancreatic mucinous cystadenocarcinoma MCC1 cells

The prognosis of invasive pancreatic mucinous cystadenocarcinoma (MCC) is poor, and the molecular mechanism underlying its development remains unclear. The present study aimed to explore the potential role of autophagy in pancreatic MCC. The results demonstrated an increase in autophagy signaling in pancreatic MCC tissues and the MCC1 cell line compared with adjacent tissues and normal human pancreatic ductal epithelium (HPDE) cells. In addition, abnormal autophagy activation facilitated the migration and invasion of MCC1 cells. MicroRNA (miR)-224-5p expression levels were significantly higher in MCC1 cells compared with those in HPDE cells. Treatment with rapamycin further demonstrated that high levels of autophagy elevated miR-224-5p expression in MCC1 cells in a time-dependent manner. BCL2 was identified as a downstream target gene of miR-224-5p, which binds to the 3′-untranslated region of BCL2. In addition, the results of the present study demonstrated that BCL2 knockdown reversed the inhibition of autophagy mediated by the miR-224-5p inhibitor. To the best of our knowledge, this is the first study to evaluate the role of autophagy in pancreatic MCC. Thus, these results suggested that autophagy may be hyperactivated in pancreatic MCC. In addition, the present study identified a positive feedback loop between autophagy signaling and miR-224-5p, which may promote the aggressive migration and invasion of MCC1. These results may provide a new insight into the relationship between autophagy and tumor metastasis in pancreatic MCC.

Comparing the clinical impact of pancreatic cyst surveillance programs: A trial of the ECOG-ACRIN cancer research group (EA2185)

BACKGROUND

The optimal surveillance strategy for pancreatic cysts, which occur in up to 20% of the adult population, is ill defined. The risk of malignant degeneration of these cysts is low, however the morbidity and mortality associated with pancreatic cancer are high. Two clinical surveillance guidelines are in regular use. Both the Fukuoka and American Gastroenterological Association (AGA) guidelines rely on radiographic and endoscopic imaging. They differ primarily in their recommended frequencies of interval surveillance imaging. While evidence driven clinical guidelines should promote higher quality care, competing guidelines on the same topic may provide discordant recommendations and potential reduction in the quality and/or value of care.

OBJECTIVES

The primary objective is to compare the clinical effectiveness of the two surveillance guidelines to identify patients most likely to benefit from pancreatic resection. Secondary objectives include comparison of resource utilization, patient reported outcomes, incidental findings are other clinical outcomes.

METHODS

4606 asymptomatic patients with newly identified pancreatic cysts ≥1 cm in diameter will be randomized 1:1 to high intensity (Fukuoka) or low intensity (AGA) surveillance. All participants will be followed prospectively for 5 years.

CONCLUSION

Differing guidelines confuse providers, patients and policymakers. This large, prospective, randomized trial will compare the clinical effectiveness and resource allocation requirements of two guidelines addressing a common clinical entity. CLINICALTRIALS.

GOV IDENTIFIER

NCT04239573.

Diagnosis and management of pancreatic cystic neoplasms: current evidence and guidelines

Pancreatic cystic neoplasms (PCN) are a heterogeneous group of pancreatic cysts that include intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms and other rare cystic lesions, all with different biological behaviours and variable risk of progression to malignancy. As more pancreatic cysts are incidentally discovered on routine cross-sectional imaging, optimal surveillance for patients with PCN is becoming an increasingly common clinical problem, highlighting the need to balance cancer prevention with the risk of (surgical) overtreatment. This Review summarizes the latest developments in the diagnosis and management of PCN, including the quality of available evidence. Also discussed are the most important differences between the PCN guidelines from the American Gastroenterological Association, the International Association of Pancreatology and the European Study Group on Cystic Tumours of the Pancreas, including diagnostic and follow-up strategies and indications for surgery. Finally, new developments in the management of patients with PCN are addressed.

Advances in Pancreatic Cancer, Intraductal Papillary Mucinous Neoplasms, and Pancreatitis

According to the theme of the Golden Jubilee Issue of our journal, we present a commentary on landmark contributions reported in the journal on pancreatic cancer, pancreatic cysts, and intraductal papillary mucinous neoplasms (IPMN) and pancreatitis.

Less Is More: A Minimalist Approach to Endoscopy

A substantial literature documents inappropriate usage of gastrointestinal endoscopy in a variety of clinical settings. Overusage of endoscopy appears to be common, and 30% or more of procedures performed in some clinical settings have questionable indications. The potential reasons for overuse of endoscopy are multiple, and include cancer phobia, fear of medical malpractice litigation, profit motive, the investigation of "incidentalomas" found on other imaging, and underappreciation of the delayed harms of endoscopy, among other reasons. Clinical guidelines, which should limit overuse of endoscopy, may instead serve to promote it, if authors opt to be "conservative," recommending endoscopy in situations of unclear utility. Several strategies may decrease overuse of endoscopy, including careful attention to risk stratification when choosing patients to screen, adherence to guidelines for surveillance intervals for colonoscopy, the use of quality indicators to identify outliers in endoscopy utilization, and education on appropriate indications and the risks of overuse at the medical student, residency, and fellowship levels.

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.

Molecular Diagnostics in the Evaluation of Pancreatic Cysts

Within the past few decades, there has been a dramatic increase in the detection of incidental pancreatic cysts. It is reported a pancreatic cyst is identified in up to 2.6% of abdominal scans. Many of these cysts, including serous cystadenomas and pseudocysts, are benign and can be monitored clinically. In contrast, mucinous cysts, which include intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, have the potential to progress to pancreatic adenocarcinoma. In this review, we discuss the current management guidelines for pancreatic cysts, their underlying genetics, and the integration of molecular testing in cyst classification and prognostication.

Novel Biomarkers for Pancreatic Cysts

With increased utilization and ongoing advancements in cross-sectional abdominal imaging, the identification of a pancreatic cyst has become a frequent finding. While many pancreatic cysts are associated with a benign clinical course, others may transform into pancreatic ductal adenocarcinoma. However, distinguishing a benign from a malignant pancreatic cyst or pancreatic cyst with malignant potential on the basis of standard clinical findings, imaging parameters and ancillary studies can be challenging. Hence, a significant interest within the past decade has been the identification of novel biomarkers to accurately classify and prognosticate a pancreatic cyst. Within this review, we discuss novel DNA, miRNA, protein and metabolite biomarkers, and their relevance in clinical practice. In addition, we focus on future areas of research that have the potential to change pancreatic cyst management.

Evaluation of the 2015 AGA guidelines on pancreatic cystic neoplasms in a large surgically confirmed multicenter cohort

Background and study aims The American Gastroenterological Association (AGA) recently published guidelines for the management of asymptomatic pancreatic cystic neoplasms (PCNs). We aimed to evaluate the diagnostic characteristics of the AGA guidelines in appropriately recommending surgery for malignant PCNs. Patients and methods A retrospective multicenter study was performed of patients who underwent endoscopic ultrasound (EUS) for evaluation of PCNs who ultimately underwent surgical resection from 2004 - 2014. Demographics, EUS characteristics, fine-needle aspiration (FNA) results, type of resection, and final pathologic diagnosis were recorded. Patients were categorized into 2 groups (surgery or surveillance) based on what the AGA guidelines would have recommended. Performance characteristics for the diagnosis of cancer or high-grade dysplasia (HGD) on surgical pathology were calculated. Results Three hundred patients underwent surgical resection for PCNs, of whom the AGA guidelines would have recommended surgery in 121 (40.3 %) and surveillance in 179 (59.7 %) patients. Among patients recommended for surgery, 45 (37.2 %) had cancer, whereas 76 (62.8 %) had no cancer/HGD. Among patients recommended for surveillance, 170 (95.0 %) had no cancer/HGD; however, 9 (5.0 %) patients had cancer that would have been missed. For the finding of cancer/HGD on surgical pathology, the AGA guidelines had 83.3 % sensitivity (95 % CI 70.7 - 92.1), 69.1 % specificity (95 % CI 62.9 - 74.8), 37.2 % positive predictive value (95 % CI 28.6 - 46.4), 95.0 % negative predictive value (95 % CI 90.7 - 97.7), and 71.7 % accuracy (95 % CI 67.4 - 74.6). Conclusions The 2015 AGA guidelines would have resulted in 60 % fewer patients being referred for surgical resection, and accurately recommended surveillance in 95 % of patients with asymptomatic PCNs. Future prospective studies are required to validate these guidelines. Meeting presentations: Presented in part at Digestive Diseases Week 2016.

Pathology of Pancreatic Cancer Precursor Lesions

To better understand pancreatic ductal adenocarcinoma (PDAC) and improve its prognosis, it is essential to understand its origins. This article describes the pathology of the 3 well-established pancreatic cancer precursor lesions: pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. Each of these precursor lesions has unique clinical findings, gross and microscopic features, and molecular aberrations. This article focuses on histopathologic diagnostic criteria and reporting guidelines. The genetics of these lesions are briefly discussed. Early detection and adequate treatment of pancreatic cancer precursor lesions has the potential to prevent pancreatic cancer and improve the prognosis of PDAC.

Role of serial EUS-guided FNA on pancreatic cystic neoplasms: a retrospective analysis of repeat carcinoembryonic antigen measurements

BACKGROUND AND AIMS

Pancreatic cystic neoplasms (PCNs) often need interval surveillance, including repeat EUS, but the role of repeat FNA with fluid analysis is poorly defined. The aim of this analysis is to evaluate the potential clinical significance of serial carcinoembryonic antigen (CEA) measurements by EUS-guided FNA (EUS-FNA) in the surveillance for PCNs.

PATIENTS

Patients who underwent EUS-FNA for PCNs were studied retrospectively. EUS-FNA findings were compared between index and prior procedures among patients who underwent repeat EUS-FNA.

RESULTS

A total of 400 patients with PCNs underwent EUS-FNA. Eighty-seven of those patients had prior EUS-FNA with cyst fluid analysis. Patients with repeat FNA were significantly more likely to have multiple cysts (57% vs 41%; P = .008), multilocular cysts (75% vs 62%; P = .042), connection to pancreatic duct (33% vs 18%; P = .005), and higher initial CEA levels (94.8 vs 25.6 ng/mL; P = .003) compared with patients who had only a single FNA. A comparison of prior and index FNAs did not show significant differences in EUS or cyst fluid analysis findings. After log transformation, the association between CEA level at prior and index FNA was moderate (R² = 0.626; P < .001), but cystic fluid CEA classification with a cutoff value of 192 ng/mL changed in 17 patients (20%), without significant changes in EUS findings.

CONCLUSIONS

Repeat surveillance EUS-FNA resulted in stable CEA levels in the majority of patients, with spurious fluctuations of CEA in approximately 20% of patients. These data call into question any clinical significance attributed to an isolated interval rise in CEA level, especially in light of a stable EUS examination.

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.

American Gastroenterological Association guidelines are inaccurate in detecting pancreatic cysts with advanced neoplasia: a clinicopathologic study of 225 patients with supporting molecular data

BACKGROUND AND AIMS

The American Gastroenterological Association (AGA) recently reported evidence-based guidelines for the management of asymptomatic neoplastic pancreatic cysts. These guidelines advocate a higher threshold for surgical resection than prior guidelines and imaging surveillance for a considerable number of patients with pancreatic cysts. The aims of this study were to assess the accuracy of the AGA guidelines in detecting advanced neoplasia and present an alternative approach to pancreatic cysts.

METHODS

The study population consisted of 225 patients who underwent EUS-guided FNA for pancreatic cysts between January 2014 and May 2015. For each patient, clinical findings, EUS features, cytopathology results, carcinoembryonic antigen analysis, and molecular testing of pancreatic cyst fluid were reviewed. Molecular testing included the assessment of hotspot mutations and deletions for KRAS, GNAS, VHL, TP53, PIK3CA, and PTEN.

RESULTS

Diagnostic pathology results were available for 41 patients (18%), with 13 (6%) harboring advanced neoplasia. Among these cases, the AGA guidelines identified advanced neoplasia with 62% sensitivity, 79% specificity, 57% positive predictive value, and 82% negative predictive value. Moreover, the AGA guidelines missed 45% of intraductal papillary mucinous neoplasms with adenocarcinoma or high-grade dysplasia. For cases without confirmatory pathology, 27 of 184 patients (15%) with serous cystadenomas (SCAs) based on EUS findings and/or VHL alterations would continue magnetic resonance imaging (MRI) surveillance. In comparison, a novel algorithmic pathway using molecular testing of pancreatic cyst fluid detected advanced neoplasias with 100% sensitivity, 90% specificity, 79% positive predictive value, and 100% negative predictive value.

CONCLUSIONS

The AGA guidelines were inaccurate in detecting pancreatic cysts with advanced neoplasia. Furthermore, because the AGA guidelines manage all neoplastic cysts similarly, patients with SCAs will continue to undergo unnecessary MRI surveillance. The results of an alternative approach with integrative molecular testing are encouraging but require further validation.

Cystic lesions of the pancreas

Different types of benign or malignant cystic lesions can be observed in the pancreas. Pancreatic cystic lesions are classified under pathology terms into simple retention cysts, pseudocysts and cystic neoplasms. Mucinous cystic neoplasm is a frequent type of cystic neoplasm and has a malignant potential. Serous cystadenoma follows in frequency and is usually benign. Intraductal papillary mucinous neoplasms are the most commonly resected cystic pancreatic neoplasms characterized by dilated segments of the main pancreatic duct and/or side branches, the wall of which is covered by mucus secreting cells. These neoplasms can occupy the pancreatic head or any part of the organ. Solid pseudopapillary tumor is rare, has a low tendency for malignancy, and is usually located in the pancreatic body or tail. Endoscopic ultrasound with the use of fine-needle aspiration and cytology permits discrimination of those lesions. In this review, the main characteristics of those lesions are presented, as well as recommendations regarding their follow up and management according to recent guidelines.

Pancreatic Cysts

Pancreatic cysts are more common than before, largely because of widespread abdominal imaging. Pancreatic cystic neoplasms (PCN) are relevant to risk selection on 2 counts: they constitute more than 50% of all pancreatic cysts and, in contrast to the other 2 cyst types, are capable of malignant transformation. The majority of PCNs are benign at time of diagnosis and will follow a benign course. The challenge is to identify those PCNs that are malignant or will undergo malignant transformation with time. The purpose of this article is to provide pointers that can help meet this challenge while also summarizing the ongoing debate about their optimal management.

A MicroRNA Panel in Pancreatic Cyst Fluid for the Risk Stratification of Pancreatic Cysts in a Prospective Cohort

A subset of pancreatic cystic neoplasms are regarded as precursor lesions of pancreatic cancer, but only a minority of all pancreatic cystic neoplasms will undergo malignant transformation. MicroRNAs are increasingly recognized as molecular targets in carcinogenesis. Previously, a 9-microRNA (miR) signature was suggested to discriminate between high risk and low risk pancreatic cystic neoplasm. In this study, we aimed to validate this 9-miR panel in a prospective cohort. Total miR was isolated from pancreatic cyst fluid and expression of miR18a, miR24, miR30a-3p, miR92a, miR99b, miR106b, miR142-3p, miR342-3p, and miR532-3p was analyzed by singleplex Taqman MicroRNA Assay. A total of 62 patient samples were analyzed. During follow-up, 24 (38.7%) patients underwent resection, of which 6 (9.7%) patients showed at least high grade dysplasia. A logistic regression model presented a “predicted risk” score which significantly differed between low and high risk cysts, either including all patients or only those with histological confirmation of diagnosis. Using a set cut-off of 50%, the sensitivity of the model for the total cohort was 10.0%, specificity 100.0%, positive predicted value 100.0%, negative predicted value 85.2%, and diagnostic accuracy of 85.5%. Thus, while observing a significant difference between low and high risk cysts, clinical implementation of this biomarker panel is as yet unlikely to be beneficial in the management of pancreatic cysts.

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.