"Trivial" Cysts Redefine the Risk of Cancer in Presumed Branch-Duct Intraductal Papillary Mucinous Neoplasms of the Pancreas: A Potential Target for Follow-Up Discontinuation?

Progression vs Cyst Stability of Branch-Duct Intraductal Papillary Mucinous Neoplasms After Observation and Surgery

Importance

The progression of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas to malignant disease is still poorly understood. Observational and surgical series have failed to provide comprehensive information.

Objective

To identify dynamic variables associated with the development of malignant neoplasms by combining pathological features with data from preoperative repeated observations.

Design, Setting, and Participants

The Crossover Observational Multicentric Study included a retrospective cohort of patients with branch-duct IPMNs (BD IPMNs) enrolled in a surveillance program from January 1, 2000, to December 31, 2019. Patients were enrolled from 5 referral centers: the Pancreas Institute, Verona, Italy; Seoul National University Hospital, Seoul, South Korea; Singapore General Hospital, Singapore; Johns Hopkins School of Medicine, Baltimore, Maryland; and University of Texas MD Anderson Cancer Center, Houston. Patients underwent a minimum of 12 months of preoperative surveillance (median, 37 [interquartile range (IQR), 20-68] months).

Main Outcomes and Measures

Dynamic variables associated with malignant disease were explored to estimate the presence of high-grade dysplasia (HGD) and invasive cancer at final pathological examination.

Results

A total of 292 patients were included in the analysis (137 women [46.9%] and 155 men [53.1%]; median age, 64 [IQR, 56-71] years). During surveillance, 27 patients (9.2%) developed a worrisome feature after 5 years, and 46 of 276 (16.7%) developed high-risk stigmata (HRS). At final pathological evaluation, 107 patients (36.6%) had HGD or invasive cancer, and 16 (5.5%) had IPMNs with concomitant pancreatic ductal adenocarcinoma. Rates of HGD and invasive cancer at pathological evaluation significantly differed between those without worrisome features and those developing HRS from a previous worrisome feature (9 [27.3%] vs 13 [61.9%]; P < .001). Developing an additional worrisome feature during surveillance (odds ratio [OR], 3.24 [95% CI, 1.38-7.60]; P = .007) or an HRS from a baseline worrisome feature (OR, 2.87 [95% CI, 1.01-8.17]; P = .048) was associated with HGD at final pathological evaluation. Among HRS, development of jaundice on a low-risk cyst was independently associated with invasive cancer (OR, 16.04 [95% CI, 2.94-87.40]; P = .001).

Conclusions and Relevance

These findings suggest that in BD IPMNs under surveillance, harboring a stable worrisome feature carries the lowest risk of malignant disease. Development of additional worrisome features or HRS is associated with the presence of HGD, whereas the occurrence of jaundice is associated with invasive cancer.

The faith of non-surveilled pancreatic cysts: a bicentric retrospective study

BACKGROUND

Incidental discovery of pancreatic cystic neoplasms (PCLs) is a common and steadily increasing occurrence. The aim of this study was to investigate a cohort of patients presenting with incidentally detected PCLs which were not included in a surveillance protocol, and to compare their risk of malignant evolution with that of systematically surveilled lesions.

MATERIALS AND METHODS

A population of PCLs which did not receive surveillance over a period >10 years (population A) was selected at the Medical University of Vienna. A group of "low risk" branch duct intraductal papillary mucinous neoplasm ≤15 mm in size upon diagnosis undergoing a regular follow-up of at least 5 years at the University of Verona was selected as control (population B). The incidence of pancreatic cancer (PC), cumulative risk of PC and disease-specific survival were compared.

RESULTS

Overall, 376 patients with non-surveilled PCLs were included in study group A and compared to 299 patients in group B. This comparison resulted in similar incidence rates of PC (1.6% vs 1.7%, p = 0.938), a strong similarity in terms of disease-specific mortality rates (1.3% vs 0.3%, p = 0.171) and the 5- and 10-year cumulative risk of PC (≅ 1% and 2%, p = 0.589) and DSS (≅ 100% and 98%, p = 0.050).

CONCLUSION

The "price to pay" for a negligence-based policy in the population of non-surveilled PCLs was reasonable, and the incidence of PC was comparable to that reported for a population of low-risk cysts enrolled to a standardized surveillance protocol.

Actual malignancy risk of either operated or non-operated presumed mucinous cystic neoplasms of the pancreas under surveillance

BACKGROUND

Despite the low malignant potential of pancreatic mucinous cystic neoplasms (MCNs), surgery is still performed. The aim of this pragmatic study was to assess the outcome of surgery and surveillance for patients presenting with a presumed MCN at the first evaluation.

METHODS

Data for patients with a presumed MCN observed from 2000 to 2016 at the Verona Pancreas Institute and San Raffaele Hospital were extracted from prospective databases. The endpoints were risk of malignancy at pathology and rate of misdiagnosis for the surgical series, expressed as an odds ratio (OR) with 95 per cent confidence interval, and disease-specific survival (DSS) for the surveillance cohort investigated by the Kaplan-Meier method.

RESULTS

A total of 424 patients were identified. In the surgical series (229 patients), the rate of misdiagnosis was 19.2 per cent. The rate of malignant MCNs was 10.9 per cent (25 patients). The overall rate of malignancy, including misdiagnoses, was 11.3 per cent (26 patients). Predictors of malignancy were mural nodules (OR 27.75, 95 per cent c.i. 4.44-173.61; P < 0.001), size at least 50 mm (OR 13.39, 2.01 to 89.47; P = 0.007), and carbohydrate antigen 19.9 level (OR 3.98, 1.19 to 13.30; P = 0.025). In the absence of mural nodules and enhancing walls, none of the resected presumed MCNs smaller than 50 mm were malignant. Only patients with high-risk stigmata undergoing surgery experienced a significantly reduced 5-year DSS compared with all other patients (88 versus 100 per cent; P = 0.031).

CONCLUSION

Presumed MCNs with mural nodules, enhancing walls or cysts of 50 mm or larger should be considered for upfront surgical resection owing to the high risk of malignancy. In the absence of these features, the incidence of malignancy is negligible, favouring surveillance in selected patients given the low risk of malignancy and the high rate of misdiagnosis.

GRAPHICAL ABSTRACT

Pancreatic mucinous cystic neoplasms (MCNs) are well known preneoplastic lesions. Despite the low rate of cancer, lesions without radiological features of malignancy are resected systematically. In the absence of mural nodules, enhancing walls or cyst size 50 mm or more, the incidence of malignancy is negligible. Given the high risk of misdiagnosis, in the absence of such radiological features, surveillance of presumed MCNs seems safer.

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.

ABO Blood Group and Risk of Pancreatic Carcinogenesis in Intraductal Papillary Mucinous Neoplasms

BACKGROUND

ABO blood group has been associated with risks of various malignancies, including pancreatic cancer. No study has evaluated the association of ABO blood group with incidence of pancreatic carcinogenesis during follow-up of patients with intraductal papillary mucinous neoplasms (IPMN).

METHODS

Among 3,164 patients diagnosed with pancreatic cysts at the University of Tokyo (Tokyo, Japan) from 1994 through 2019, we identified 1,815 patients with IPMN with available data on ABO blood group. We studied the association of ABO blood group with incidence of pancreatic carcinoma, overall and by carcinoma types [IPMN-derived carcinoma or concomitant pancreatic ductal adenocarcinoma (PDAC)]. Utilizing competing-risks proportional hazards models, we estimated subdistribution hazard ratios (SHR) for incidence of pancreatic carcinoma with adjustment for potential confounders, including cyst characteristics.

RESULTS

During 11,518 person-years of follow-up, we identified 97 patients diagnosed with pancreatic carcinoma (53 with IPMN-derived carcinoma and 44 with concomitant PDAC). Compared with patients with blood group O, patients with blood groups A, B, and AB had multivariable SHRs (95% confidence intervals) for pancreatic carcinoma of 2.25 (1.25-4.07; P = 0.007), 2.09 (1.08-4.05; P = 0.028), and 1.17 (0.43-3.19; P = 0.76), respectively. We observed no differential association of ABO blood group with pancreatic carcinoma incidence by carcinoma types.

CONCLUSIONS

In this large long-term study, patients with IPMN with blood group A or B appeared to be at higher risk of pancreatic carcinoma compared with those with blood group O.

IMPACT

ABO blood group can be a biomarker for pancreatic cancer risk among patients with IPMNs.

A Review of the Diagnosis and Management of Premalignant Pancreatic Cystic Lesions

Pancreatic cystic lesions are an increasingly common clinical finding. They represent a heterogeneous group of lesions that include two of the three known precursors of pancreatic cancer, intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms (MCN). Given that approximately 8% of pancreatic cancers arise from these lesions, careful surveillance and timely surgery offers an opportunity for early curative resection in a disease with a dismal prognosis. This review summarizes the current evidence and guidelines for the diagnosis and management of IPMN/MCN. Current pre-operative diagnostic tests in pancreatic cysts are imperfect and a proportion of patients continue to undergo unnecessary surgical resection annually. Balancing cancer prevention while preventing surgical overtreatment, continues to be challenging when managing pancreatic cysts. Cyst fluid molecular markers, such as KRAS, GNAS, VHL, PIK3CA, SMAD4 and TP53, as well as emerging endoscopic technologies such as needle-based confocal laser endomicroscopy and through the needle microbiopsy forceps demonstrate improved diagnostic accuracy. Differences in management and areas of uncertainty between the guidelines are also discussed, including indications for surgery, surveillance protocols and if and when surveillance can be discontinued.

Sonographic characteristics and follow-up of pancreatic cysts

OBJECTIVES

To assess sonographic characteristics and outcome of patients with pancreatic cystic lesions seen by ultrasound.

METHODS

From our ultrasound electronic reporting database we identified all patients in which "pancreatic cyst" or "pancreatic cysts" were reported from 1995 to 2018. In patients with more than one sonogram, the first was used for our study. For each case, we recorded sonographic characteristics, maximal diameter, cyst location, and results of follow-up ultrasound, CT or magnetic resonance imaging, as well as patient sex, age, relative clinical history, and endoscopic ultrasound (EUS) or surgical findings when available.

RESULTS

Our study included 177 patients of whom 121 were female (68.4%). Mean age at diagnosis was 65 (±16, SD, range 22-99). Ultrasound was the initial diagnostic test in 122 (68.9%). Mean diameter of the index cyst was 13.7 mm (±11.5 mm, SD, range 2-91 mm). Among 177 index cysts, 155 were simple and 22 complex. Three complex cysts were surgically resected, yielding a primary pancreatic malignancy, a metastasis, and an epithelial-lined cyst. One simple cyst was resected, yielding a benign intraductal papillary mucinous neoplasm. Seventeen patients underwent EUS showing six mucinous cysts and 11 nonmucinous cysts. One hundred-eighteen patients had follow-up imaging for a mean time of 5.6 years (±3.8, range 0.25-21 years). One patient was presumed to have primary pancreatic cancer. The overall rate for primary pancreatic malignancy was 1.7% (2/118).

CONCLUSIONS

Cystic pancreatic lesions seen on ultrasound are most often benign, with a low risk of pancreatic malignancy. Ultrasound is an excellent method to follow-up these cysts.

Long-term follow-up of branch-duct intraductal papillary mucinous neoplasms with No change in first 5 Years of diagnosis

BACKGROUND

Discontinuation of branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) surveillance after 5 years of no change remains controversial. Long-term outcomes of BD-IPMN without significant changes in the first 5 years were evaluated.

METHODS

We performed a multi-center retrospective analysis of patients with BD-IPMN diagnosis from 2005 to 2011 (follow-up until 2017). Significant changes were defined as pancreatic cancer (PC), pancreatectomy, high-risk stigmata (HRS), worrisome features (WF) and worrisome EUS features (WEUS).

RESULTS

Of 982 patients who had no significant changes, 5 (0.5%), 7 (0.7%), 99 (10.1%), 4 (0.4%) patients developed PC, HRS, WF, WEUS, respectively, post-5 years. PC and HRS/WF/WEUS incidences at 12 years were 1.0% and 29.0%, respectively. Patients that developed HRS/WF/WEUS had larger cyst size in first 5 years compared to those that did not [16 (12-23) vs. 12 (9-17) mm, p = 0.0001], cyst size of >15 mm having higher cumulative incidence of HRS/WF/WEUS. PC mortality was 0.8%; all-cause mortality was 32%. Incidence of mortality due to PC was higher in HRS/WF/WEUS group, p < 0.0001. The mortality rate at 12 years for ACCI (age-adjusted Charlson Comorbidity Index) of ≤3, 4-6, and ≥7 were 3.5%, 19.9%, and 57.6% (p < 0.0001), respectively.

CONCLUSIONS

Incidence of PC in patients with BD-IPMN without significant changes in first 5 years of diagnosis remains low at 1.0%. Incidence of HRS/WF/WEUS was higher at 29.0%. PC-related mortality was higher in HRS/WF/WEUS group. These risks should be weighed against patients' overall mortality (utilizing scoring systems such as ACCI) when making surveillance decision of BD-IPMN beyond 5 years.

Factors Associated With the Risk of Progression of Low-Risk Branch-Duct Intraductal Papillary Mucinous Neoplasms

IMPORTANCE

Branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) are common pancreatic preneoplastic lesions, but their surveillance is not personalized.

OBJECTIVE

To investigate patient- and cyst-related factors associated with progression into worrisome features (WFs) or high-risk stigmata (HRS) categories of BD-IPMNs.

DESIGN, SETTING, AND PARTICIPANTS

Cyst- and patient-related factors of consecutive BD-IPMNs without WFs or HRS in 540 patients diagnosed from 2009 to 2018 with at least 12 months' surveillance until February 28, 2020, were registered in a 2-center ambispective cohort study in Italy. In a subgroup, the ABO blood group was studied for the first time in this setting.

EXPOSURE

Cyst-related and patients-related factors and ABO blood group.

MAIN OUTCOMES AND MEASURES

The study outcome was the appearance of WFs or HRS according to the 2017 International Association of Pancreatology guidelines. Survival probability was calculated using Kaplan-Meier curve and risk factors identified by Cox proportional hazards regression. ABO blood group was inferred through genotypes with DNA extraction.

RESULTS

Of 540 patients with BD-IPMNs (median age, 66 years [interquartile range, 58.5-72.0 years]; 337 women [62.4%]) undergoing surveillance for a median of 51.5 months (interquartile range, 28-84 months) for 2758 person-years, 130 patients (24.1%) experienced progression. Probability of progression was 3.7% at 1 year, 23.4% at 5 years, and 43.3% at 10 years; 15 patients (2.8%) underwent surgery, 7 patients (1.3%) had malignant histologic findings, and 3 patients (0.56%) died of pancreatic-associated disease. Initial cyst size greater than 15 mm (hazard ratio [HR], 2.05; 95% CI, 1.44-2.91), body mass index greater than 26.4 (HR, 1.72; 95% CI, 1.19-2.50), and heavy smoking (HR, 1.81; 95% CI, 1.14-2.86) were significant independent factors associated with progression risk. The AA blood genotype was also associated with progression risk (HR, 3.49; 95% CI, 1.04-11.71) compared with the OO genotype in the investigated subgroup.

CONCLUSIONS AND RELEVANCE

This analysis of factors associated with progression of BD-IPMNs according to recent guidelines suggests that cyst size alone is not a reliable factor for estimation of progression risk; however, along with other readily available data, size is helpful for planning personalized surveillance of BD-IPMNs.

The European evidence-based guidelines on pancreatic cystic neoplasms (PCN) in clinical practice: The development of relative and absolute indications for surgery during prospective IPMN surveillance

INTRODUCTION

The European evidence-based guidelines on PCN recommend surveillance for IPMN patients who are fit for surgery but who have no indication for immediate surgery. Our aim was to demonstrate the feasibility of the new guidelines in clinical practice.

METHODS

This is a prospective cohort study of patients included in the IPMN register in Tampere University Hospital, Finland. IPMN was diagnosed from January 1, 2013 to December 31, 2018. Patients were analyzed for surveillance and indications for surgery according to the European guidelines on PCN.

RESULTS

Out of 128 patients in register 23 was decided to operate upfront and 105 patients were included in the surveillance programme. Invasive carcinoma was found in 4/23 of operated patients. Median follow-up time was 26 months (6-69). Median size of the cyst at the beginning and end of the surveillance was 16 mm (4-58 mm). During surveillance 0/105 (0.0%) patients had or developed an absolute indication for surgery. Relative indication for surgery was present in 8/105 (7.6%) patients in the beginning surveillance and 9/105 (8.6%) patients developed at least one relative indication for surgery during surveillance. From the surveillance cohort 2/105 patients were operated. Surveillance was abandoned in 15/105 (14.1%) patients all due to poor general condition or other medical conditions.

CONCLUSIONS

In clinical practice, surveillance of IPMN according to the European guidelines on PCN is feasible. Among our patients 16% were detected to have relative indications for surgery during the median 26 (range 3-135) months of surveillance. Nearly 15% became surgically unfit during surveillance period.

Outcomes of limited resection for patients with intraductal papillary mucinous neoplasm of the pancreas: A single-center experience

BACKGROUND

/ObjectivesThe aim of this study was to clarify the oncological outcomes of patients with intraductal papillary mucinous neoplasm (IPMN) who underwent limited resection (LR).

METHODS

This retrospective study analyzed the data of 110 patients with IPMN. Patients with IPMN without a history of pancreatitis who had neither tumor infiltration nor regional lymph node swelling on imaging findings underwent LR. We assessed the oncological outcomes of LR for patients with IPMN by comparing the surgical outcomes of LR and standard resection.

RESULTS

LR was performed in 50 patients (45.5%), including duodenum-preserving pancreatic head resection (n = 31), middle-pancreatectomy (n = 12), spleen-preserving distal pancreatectomy (n = 3), total parenchymal pancreatectomy (n = 3), and partial resection (n = 1). In the LR group, 18 patients had postoperative complications of Clavien-Dindo classification ≥ IIIa. After histopathological examination, the presence of high-grade dysplasia (HGD) and invasive carcinoma (IC) were observed in nine and three patients, respectively, in the LR group, and eight and 22 patients, respectively, in the standard resection group. There was a significant difference in the histopathological diagnosis of IC between the two groups (p < 0.001). Finally, in the LR group, postoperative recurrences occurred in three patients, and the 5-, 10-, and 15-year disease-specific survival rates were all 97.0%.

CONCLUSIONS

For patients with IPMN judged to have no infiltrating lesions based on the detailed imaging examination, LR is acceptable and may be considered as an alternative to standard resection.

Risk of malignancy in small pancreatic cysts decreases over time

BACKGROUND

Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance.

METHODS

Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression.

RESULTS

806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years.

CONCLUSIONS

Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

Side-branch intraductal papillary mucinous neoplasms of the pancreas: outcome of MR imaging surveillance over a 10 years follow-up

Purpose

To evaluate the outcome of a MR imaging procotol in assessing the evolution of individuals with branch duct - intraductal papillary mucinous neoplasms (BD-IPMN) without worrisome features (WF) and/or high risk stigmata (HRS) at the time of the diagnosis in a follow-up period of at least 10 years.

Material and methods

A retrospective revision of a prospectively collected radiological database including a total number of 600 patients who were investigated and diagnosed with "presumed" diagnosis of BD-IPMN at MRI/MRCP at our Department since 2008 was performed. Inclusion criteria were: 1) absence of worrisome features and/or high-risk stigmata at the time of diagnosis (baseline); 2) a radiological follow-up with abdominal MRI/MRCP of at least 10 years. Changes in cysts size, development of WF, HRS and pancreatic cancer, and any other modification during the follow-up were retrospectively analysed by two observers in consensus.

Results

Sixty-nine patients fulfilled all the inclusion criteria. During surveillance, the cysts remained dimensionally unchanged or slightly reduced in size in 26.2% and 4.3% of cases respectively, whereas cyst enlargement was demonstrated in 69.5% of cases. Median annual growth rate was of 0.97 ± 0.87 mm/yr (range 0.13-5.0). WF and HRS developed in 10/69 (14.5%) and 3/69 (4.3%) cases, respectively. The incidence of pancreatic cancer in patients with BD-IPMN was 2.9%.

Conclusion

Our data confirm the low risk of pancreatic cancer development in patients with BD-IPMN, thus justifying an imaging follow-up. Worrisome features and high-risk stigmata were promptly identified during the follow-up, supporting the utility of our surveillance MR imaging protocol.

Branch Duct Intraductal Papillary Mucinous Neoplasms: Recommendations for Follow-Up and Surgery

BACKGROUND AND AIMS

Pancreatic cysts are increasingly diagnosed, mainly during abdominal imaging performed for other reasons. Between pancreatic cystic neoplasm, intraductal papillary mucinous neoplasms are the most common pre-malignant entities. Intraductal papillary mucinous neoplasms involving side branches overall harbor a low risk of malignancy, and in the recent past, a progressively more conservative approach has been consolidated. Purpose of this report is to summarize the evidence supporting the current practice for the management of branch duct intraductal papillary mucinous neoplasm and to offer a useful practical guide from first observation to post-operative follow-up.

MATERIALS AND METHODS

Review of the most important scientific literature on intraductal papillary mucinous neoplasms was made. In this review article, we also report the experience of a high volume center in managing Pancreatic cystic neoplasms.

RESULTS

The correct management during surveillance still is a matter of debate, since many guidelines have been published suggesting different clinical approaches. Recently, follow-up discontinuation has also been proposed in selected cases.

CONCLUSION

Despite significant improvements made by the increase of evidence, selecting surgical candidates because of an increased risk of malignant progression remains an unsolved issue and a hot topic for pancreatologists.

Surgical strategy for intraductal papillary mucinous neoplasms of the pancreas

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