Surgical management of patients with insulinomas: Result of 292 cases in a single institution

Pancreatic Neuroendocrine Tumors: What Is the Best Surgical Option?

Background: Pancreatic neuroendocrine tumors (pNETs) represent a rare subset of pancreatic cancer. Functional tumors cause hormonal changes and clinical syndromes, while non-functional ones are often diagnosed late. Surgical management needs multidisciplinary planning, involving enucleation, distal pancreatectomy with or without spleen preservation, central pancreatectomy, pancreaticoduodenectomy or total pancreatectomy. Minimally invasive approaches have increased in the last decade compared to the open technique. The aim of this study was to analyze the current diagnostic and surgical trends for pNETs, to identify better interventions and their outcomes. Methods: The study adhered to the PRISMA guidelines, conducting a systematic review of the literature from May 2008 to March 2022 across multiple databases. Several combinations of keywords were used ("NET", "pancreatic", "surgery", "laparoscopic", "minimally invasive", "robotic", "enucleation", "parenchyma sparing") and relevant article references were manually checked. The manuscript quality was evaluated. Results: The study screened 3867 manuscripts and twelve studies were selected, primarily from Italy, the United States, and China. A total of 7767 surgically treated patients were collected from 160 included centers. The mean age was 56.3 y.o. Enucleation (EN) and distal pancreatectomy (DP) were the most commonly performed surgeries and represented 43.4% and 38.6% of the total interventions, respectively. Pancreatic fistulae, postoperative bleeding, re-operation, and follow-up were recorded and analyzed. Conclusions: Enucleation shows better postoperative outcomes and lower mortality rates compared to pancreaticoduodenectomy (PD) or distal pancreatectomy (DP), despite the similar risks of postoperative pancreatic fistulae (POPF). DP is preferred over enucleation for the pancreas body-tail, while laparoscopic enucleation is better for head pNETs.

Clinicopathological Features of Insulinoma: A Single Tertiary Center Experience

Insulinoma is a rare pancreatic neuroendocrine tumor with an incidence of 1-4 cases per million. Here we present our 10 years of experience in 13 cases of insulinoma. We retrospectively reviewed all insulinoma patients diagnosed and treated between 2012 and 2022. Clinical and pathological features, diagnostic methods, and follow-up results of insulinoma patients were discussed. A total of 13 patients were included in this study (7 men, and 6 women). The mean age at the time of diagnosis was 58 (36.5-70.5) years. There is only one patient diagnosed with MEN-1 syndrome. The mean time from the onset of symptoms to the diagnosis was 15 (7-27.5) months. In the prolonged fasting test, symptomatic hypoglycemia occurred in all patients within 48 h. The median size of lesions was 15 (12-24) mm, and 46.2% of these lesions were isolated in the pancreatic tail. Ga-68 DOTATATE PET/CT detected lesions with 100% accuracy. Three patients met the criteria for malignant insulinoma. Octreotide LAR was given to 1 patient with metastatic disease and 1 patient who did not accept surgery. The metastatic patient received 8 cycles of Lu treatment and died after 51 months of follow-up. The diagnosis of insulinoma can be challenging. The 48-h fasting test period provided sufficient information for the diagnosis of insulinoma. Ga-68 DOTATATE PET/CT may be an alternative in cases where cross-sectional imaging cannot localize the pancreatic lesion.

Indocyanine green fluorescence imaging to localize insulinoma and provide three-dimensional demarcation for laparoscopic enucleation: a retrospective single-arm cohort study

BACKGROUND

Indocyanine green (ICG) fluorescence imaging is a new technology that can improve the real-time location of tumor edges and small nodules during surgery. However, no study has investigated its application in laparoscopic insulinoma enucleation. This study aimed to evaluate the feasibility and accuracy of this method for intraoperative localization of insulinomas and margin assessment during laparoscopic insulinoma enucleation.

MATERIALS AND METHODS

Eight patients who underwent laparoscopic insulinoma enucleation from October 2016 to June 2022 were enrolled. Two methods of ICG administration, ICG dynamic perfusion and three-dimensional (3D) demarcation staining, were utilized in the laparoscopic insulinoma enucleation. Tumor-to-background ratio (TBR) and histopathologic analysis were used to evaluate the feasibility and accuracy of these novel navigation methods in laparoscopic insulinoma enucleation.

RESULTS

All eight enrolled patients underwent both ICG dynamic perfusion and 3D demarcation staining. ICG dynamic perfusion images were available for six of them, among which five tumors could be recognized by TBR (largest TBR in each case 4.42±2.76), while the other could be distinguished by the disordered blood vessels in the tumor area. Seven out of eight specimens had successful 3D demarcation staining (TBR 7.62±2.62). All wound bed margins had negative frozen sections and final histopathologic diagnoses.

CONCLUSIONS

ICG dynamic perfusion may be helpful in observing the abnormal vascular perfusion of tumors, providing similar functionality to intraoperative real-time angiography. ICG injection under the tumor pseudocapsule may be a useful method for acquiring real-time, 3D demarcation for the resection of insulinoma.

Risk factors for complications after surgery for pancreatic neuroendocrine tumors

BACKGROUND

Surgical resection is the only potentially curative treatment for pancreatic neuroendocrine tumors. The choice for the type of procedure is influenced by the expected oncological benefit and the anticipated risk of procedure-specific complications. Few studies have focused on complications in these patients. This cohort study aimed to assess complications and risk factors after resections of pancreatic neuroendocrine tumors.

METHODS

Patients undergoing resection of a pancreatic neuroendocrine tumor were identified within 2 centers of excellence. Complications were assessed according to the Clavien-Dindo classification and the comprehensive complication index. Logistic regression was performed to compare surgical procedures with adjustment for potential confounders (Clavien-Dindo ≥3).

RESULTS

The cohort comprised 123 patients, including 12 enucleations, 50 distal pancreatectomies, 51 pancreatoduodenectomies, and 10 total/combined pancreatectomies. Mortality was 0.8%, a severe complication occurred in 41.5%, and the failure-to-rescue rate was 2.0%. The median comprehensive complication index was 22.6 (0-100); the comprehensive complication index increased after more extensive resections. After adjustment, a pancreatoduodenectomy, as compared to a distal pancreatectomy, increased the risk for a severe complication (odds ratio 3.13 [95% confidence interval 1.32-7.41]). Of the patients with multiple endocrine neoplasia type 1 or von Hippel-Lindau, 51.9% developed a severe complication vs 38.5% with sporadic disease. After major resections, morbidity was significantly higher in patients with multiple endocrine neoplasia type 1/von Hippel-Lindau (comprehensive complication index 45.1 vs 28.9, P = .029).

CONCLUSION

Surgery for pancreatic neuroendocrine tumors is associated with a high rate of complications but low failure-to-rescue in centers of excellence. Complications are procedure-specific. Major resections in patients with multiple endocrine neoplasia type 1/von Hippel-Lindau appear to increase the risk of complications.

[Surgery of pancreatic neuroendocrine neoplasms: state of the art]

Pancreatic neuroendocrine neoplasms (pNEN) have a rising incidence and are increasingly diagnosed at early and thus potentially resectable stages. Due to the rarity of these neoplasms the recommendations of currently available guidelines are mainly based on retrospective data. Surgical and oncological treatment of these rare diseases should only be performed at specialized centers. In cases of resectability without indications of diffuse metastases, complete resection with curative intent should be the treatment of choice. For small nonfunctional pNENs < 2 cm watch and wait strategies are recommended as an alternative to surgical treatment. Recent data, however, also showed an increased survival even of small (1-2 cm) pNENs after resection. For benign insulinomas and small nonfunctional well-differentiated pNENs parenchyma-sparing procedures, such as enucleation and segmental resection are available. The question of the influence of lymph node metastases on long-term disease-free survival and overall survival and consequently the role of systematic lymphadenectomy is still a matter of debate. In pNENs > 2 cm formal resection with lymphadenectomy is considered the gold standard. Minimally invasive and robotic-assisted procedures are of increasing importance also for formal pancreatic resection.

Case Report: Hypoglycemia Due to Metastatic Insulinoma in Insulin-Dependent Type 2 Diabetes Successfully Treated With 177 Lu-DOTATATE

We describe a 96-year-old man with insulin-dependent type 2 diabetes mellitus who, despite insulin cessation, presented with recurrent hypoglycemia associated with confirmed inappropriate endogenous hyperinsulinemia. ⁶⁸Ga-DOTATATE-PET/CT scans demonstrated increased uptake in the pancreatic tail with multiple large intensely active liver metastases. Liver biopsy confirmed the diagnosis of well-differentiated metastatic neuroendocrine tumor. He was unsuitable for surgical resection and long-acting somatostatin analog therapy was ineffective. Subsequent management with four cycles of Lutate [177-Lutetium-DOTA⁰-Tyr³-octreotate (¹⁷⁷Lu-DOTATATE)] resulted in resolution of hypoglycemia and ongoing clinical, biochemical, and radiological response 6 years after. This case is unique due to not only the paradoxical entity of insulinoma in insulin-dependent diabetes but also the positive sustained outcome after ¹⁷⁷Lu-DOTATATE, given that unresectable metastatic insulinoma carries a poor prognosis. We review published cases of metastatic insulinoma in patients with diabetes mellitus as well as the literature to-date investigating efficacy and safety of Lutate therapy in metastatic insulinoma.

Surgical management of insulinoma over three decades

BACKGROUND

This paper reports our experience of the perioperative management of patients with sporadic, non-malignant, pancreatic insulinoma.

METHODS

A retrospective monocentric cohort study was performed from January 1989 to July 2019, including all the patients who had been operated on for pancreatic insulinoma. The preoperative work-up, surgical management, and postoperative outcome were analyzed.

RESULTS

Eighty patients underwent surgery for sporadic pancreatic insulinoma, 50 of which were female (62%), with a median age of 50 (36-70) years. Preoperatively, the tumors were localized in 76 patients (95%). Computed tomography (CT) and magnetic resonance imaging allowed exact preoperative tumor localization in 76% of the patients (64-85 and 58-88 patients, respectively), increasing to 96% when endoscopic ultrasonography was performed. Forty-one parenchyma-sparing pancreatectomies (PSP) (including enucleation, caudal pancreatectomy, and uncinate process resection) and 39 pancreatic resections were performed. The mortality rate was 6% (n = 5), with a morbidity rate of 72%, including 24 severe complications (30%) and 35 pancreatic fistulas (44%). No differences were found between formal pancreatectomy and PSP in terms of postoperative outcome procedures. The surgery was curative in all the patients.

CONCLUSION

CT used in combination with endoscopic ultrasonography allows accurate localization of insulinomas in almost all patients. When possible, a parenchyma-sparing pancreatectomy should be proposed as the first-line surgical strategy.

Diagnostic performance of noninvasive imaging modalities for localization of insulinoma: A meta-analysis

BACKGROUND

Insulinoma is the most common functional neuroendocrine tumor found only in the pancreas. The early detection of insulinoma is of importance. Studies comparing the performance of noninvasive modalities were limited by sample size and heterogeneity between studies. The aim of this meta-analysis was to evaluate the diagnostic performance of PET/CT, SPECT/CT, CT and MRI for the localization of insulinoma, and to provide evidence for clinical practice.

METHODS

PubMed, Embase, Cochrane Library, Wanfang Data and China National Knowledge Infrastructure were searched from inception to May 31, 2021. Pooled sensitivity, specificity, positive Likelihood Ratio (+LR) and negative Likelihood Ratio (-LR), diagnostic odds ratio (DOR), and concordance rate were calculated.

RESULTS

A total of 19 studies including 708 patients of insulinoma reached the inclusion criteria. PET/CT imaging demonstrated a pooled sensitivity of 0.79 (95% CI: 0.54-0.92) and a pooled specificity of 0.84 (95% CI: 0.20-0.99). The pooled sensitivity and specificity of SPECT/CT were 0.77 (95% CI: 0.46-0.93) and 0.45 (95% CI: 0.22-0.70). CT showed an overall sensitivity of 0.54 (95% CI: 0.35-0.72) and specificity of 0.75 (95% CI: 0.54-0.88). The pooled sensitivity and specificity for MRI were 0.54 (95% CI: 0.31-0.75) and 0.65 (95% CI: 0.39-0.84), respectively. The concordance rates of PET, SPECT, CT, and MRI were 78% (95% CI: 66-90%), 74% (95% CI: 52-97%), 56% (95% CI: 41-72%), and 53% (95% CI: 33-73%), respectively.

CONCLUSION

Results of this study indicate that PET/CT demonstrated superior performance than SPECT/CT, CT and MRI for the localization of insulinoma. GLP-1R based PET/CT manifested better diagnostic performance in comparison with SSTR based PET/CT imaging modality.

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are relatively rare, but their incidence has increased significantly in the last decades. Precise diagnosis and prognostic stratification are crucial for proper patient management. Endoscopic ultrasound (EUS) is the modality of choice for diagnosis of solid pancreatic tumors, showing a higher tumor detection rate than other imaging modalities, especially for small size lesions. EUS also serves as a guide for preoperative sampling and other interventions. EUS-tissue acquisition is a safe and highly accurate technique for cyto/histological diagnosis of PanNENs with a well-demonstrated correlation between Ki-67 proliferation index values and tumor grading on EUS and surgical specimens according to the WHO 2017 classification. Furthermore, the possibility of a preoperative EUS-guided fine needle tattooing or fiducial markers placement may help the surgeon to locate small and deep tumors, thus avoiding formal pancreatic resections in favor of parenchymal-sparing surgery. Finally, locoregional ablative treatments using either ethanol injection or radiofrequency ablation have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients unfit for surgery with functioning or non-functioning PanNENs. This article review highlights the current role of EUS in PanNENs management, focusing on the present and future applications of EUS-guided interventions.

Multiple endocrine neoplasia type 1 (MEN-1) and neuroendocrine neoplasms (NENs)

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms with 6.4-times increasing age-adjusted annual incidence during the last four decades. NENs arise from neuroendocrine cells, which release hormones in response to neuronal stimuli and they are distributed into organs and tissues. The presentation and biological behaviour of the NENs are highly heterogeneous, depending on the organ. The increased incidence is mainly due to increased awareness and improved detection methods both in the majority of sporadic NENs (non-inherited), but also the inherited groups of neoplasms appearing in at least ten genetic syndromes. The most important one is multiple endocrine neoplasia type 1 (MEN-1), caused by mutations in the tumour suppressor gene MEN1. MEN-1 has been associated with different tumour manifestations of NENs e.g. pancreas, gastrointestinal tract, lungs, thymus and pituitary. Pancreatic NENs tend to be less aggressive when arising in the setting of MEN-1 compared to sporadic pancreatic NENs. There have been very important improvements over the past years in both genotyping, genetic counselling and family screening, introduction and validation of various relevant biomarkers, as well as newer imaging modalities. Alongside this development, both medical, surgical and radionuclide treatments have also advanced and improved morbidity, quality of life and mortality in many of these patients. Despite this progress, there is still space for improving insight into the genetic and epigenetic factors in relation to the biological mechanisms determining NENs as part of MEN-1. This review gives a comprehensive update of current evidence for co-occurrence, diagnosis and treatment of MEN-1 and neuroendocrine neoplasms and highlight the important progress now finding its way to international guidelines in order to improve the global management of these patients.

Clinical aspects of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome characterized by the co-occurrence of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumours (NETs) and/or pituitary adenomas. MEN1 can predispose patients to other endocrine and non-endocrine tumours, such as cutaneous tumours, central nervous system tumours and breast cancer. Endocrine tumours in patients with MEN1 differ from sporadic tumours in that they have a younger age at onset, present as multiple tumours in the same organ and have a different clinical course. Therefore, patients with overt MEN1 and those who carry a MEN1 mutation should be offered tailored biochemical and imaging screening to detect tumours and evaluate their progression over time. Fortunately, over the past 10 years, knowledge about the clinical phenotype of these tumours has markedly progressed, thanks to the implementation of national registries, particularly in France and the Netherlands. This Review provides an update on the clinical management of MEN1-related tumours. Epidemiology, the clinical picture, diagnostic work-up and the main lines of treatment for MEN1-related tumours are summarized. Controversial therapeutic aspects and issues that still need to be addressed are also discussed. Moreover, special attention is given to MEN1 manifestations in children and adolescents.

Diagnostic and procedural intraoperative ultrasound: technique, tips and tricks for optimizing results

Intraoperative ultrasound (IOUS) is a valuable adjunctive tool that can provide real-time diagnostic information in surgery that has the potential to alter patient management and decrease complications. Lesion localization, characterization and staging can be performed, as well as surveying for additional lesions and metastatic disease. IOUS is commonly used in the liver for hepatic metastatic disease and hepatocellular carcinoma, in the pancreas for neuroendocrine tumors, and in the kidney for renal cell carcinoma. IOUS allows real-time evaluation of vascular patency and perfusion in organ transplantation and allows for early intervention for anastomotic complications. It can also be used to guide intraoperative procedures such as biopsy, fiducial placement, radiation, or ablation. A variety of adjuncts including microbubble contrast and elastography may provide additional information at IOUS. It is important for the radiologist to be familiar with the available equipment, common clinical indications, technique, relevant anatomy and intraoperative imaging appearance to optimize performance of this valuable imaging modality.

Indications and outcomes of enucleation versus formal pancreatectomy for pancreatic neuroendocrine tumors

BACKGROUND

Pancreatoduodenectomy (PD) or distal pancreatectomy (DP) are common procedures for patients with a pancreatic neuroendocrine tumor (pNET). Nevertheless, certain patients may benefit from a pancreas-preserving resection such as enucleation (EN). The aim of this study was to define the indications and differences in long-term outcomes among patients undergoing EN and PD/DP.

METHODS

Patients undergoing resection of a pNET between 1992 and 2016 were identified. Indications and outcomes were evaluated, and propensity score matching (PSM) analysis was performed to compare long-term outcomes between patients who underwent EN versus PD/DP.

RESULTS

Among 1034 patients, 143 (13.8%) underwent EN, 304 (29.4%) PD, and 587 (56.8%) DP. Indications for EN were small size (1.5 cm, IQR:1.0-1.9), functional tumors (58.0%) that were mainly insulinomas (51.7%). After PSM (n = 109 per group), incidence of postoperative pancreatic fistula (POPF) grade B/C was higher after EN (24.5%) compared with PD/DP (14.0%) (p = 0.049). Median recurrence-free survival (RFS) was comparable among patients who underwent EN (47 months, 95% CI:23-71) versus PD/DP (37 months, 95% CI: 33-47, p = 0.480).

CONCLUSION

Comparable long-term outcomes were noted among patients who underwent EN versus PD/DP for pNET. The incidence of clinically significant POPF was higher after EN.

Updated Meta-analysis of Minimally Invasive Versus Open Surgery for Pancreatic Neuroendocrine Neoplasms

OBJECTIVES

The aim of this study was to compare the short-term and long-term outcomes of minimally invasive surgery (MIS) with those of open pancreas surgery (OPS) for the treatment of pancreatic neuroendocrine neoplasms (pNENs).

METHODS

Studies reporting the effects of MIS and OPS for pNENs, published on PubMed, Embase, and Cochrane Library before May 2020 were reviewed.

RESULTS

Seventeen cohort studies with a total of 1853 patients were eligible for analysis, including 655 patients in the MIS group and 1198 patients in the OPS group. The estimated blood loss, postoperative hospitalization time, overall complications, severe complications, spleen preservation, mortality, and recurrence in the MIS group were lower than those in the OPS group. The R0 rate, 3-year overall survival (OS), and 5-year OS in the MIS group were higher than those in the OPS group. There were no significant differences in operative time, postoperative pancreatic fistula, clinical postoperative pancreatic fistula, postoperative bleeding, reoperation, readmission, and 1-year OS.

CONCLUSIONS

Minimally invasive surgery can reach lower recurrence rate, higher long-term survival rate, and better outcomes in terms of estimated blood loss, postoperative hospitalization time, R0 rate, mortality, overall complications, and severe complications for pNENs. More high quality studies need to be conducted for further verification.

Surgical management of insulinomas at the Azerbaijan Medical University: a retrospective study of 21 cases over a 10-year period

Background/aim

This study represents the first report that evaluates the experience gathered from diagnosis, surgical treatment and outcome of insulinoma patients from Azerbaijan.

Materials and methods

We retrospectively review of insulinoma patients for a 10-year period. Collected data included patient demographics, laboratory and imaging tests, detailed surgical reports, histopathological examination of resected specimens, and clinical follow-up.

Results

Twenty-one insulinoma patients were identified. Male patients comprised 52.4%; mean age was 44 years. Mean time to diagnosis was 14 months; 61% patients had ≥3 medical referrals due to hypoglycemia-related symptoms. Diagnosis sensitivity of CT, MRI and US was 85%, 80%, and 55%, respectively. The mean glucose, insulin, C-peptide levels were 35.7 ± 9.5 mg/dL, 33.5 ± 21.9 µU/mL, and 3.74 ± 1.88 ng/mL, respectively. Pancreatic head and tail were the most frequent tumor locations; mean tumor size was 1.5 ± 0.7 cm. No statistical association was found between the tumor size and preoperative glucose, C-peptide and insulin levels. Distal pancreatectomy and enucleation were the most common surgical procedures. Local tumor recurrence rate was 14%. There was no mortality.

Conclusions

To prevent delayed diagnoses, physicians should be familiar with the typical symptoms of these rare tumors.

Whole-genome sequencing reveals distinct genetic bases for insulinomas and non-functional pancreatic neuroendocrine tumours: leading to a new classification system

OBJECTIVE

Insulinomas and non-functional pancreatic neuroendocrine tumours (NF-PanNETs) have distinctive clinical presentations but share similar pathological features. Their genetic bases have not been comprehensively compared. Herein, we used whole-genome/whole-exome sequencing (WGS/WES) to identify genetic differences between insulinomas and NF-PanNETs.

DESIGN

The mutational profiles and copy-number variation (CNV) patterns of 211 PanNETs, including 84 insulinomas and 127 NF-PanNETs, were obtained from WGS/WES data provided by Peking Union Medical College Hospital and the International Cancer Genome Consortium. Insulinoma RNA sequencing and immunohistochemistry data were assayed.

RESULTS

PanNETs were categorised based on CNV patterns: amplification, copy neutral and deletion. Insulinomas had CNV amplifications and copy neutral and lacked CNV deletions. CNV-neutral insulinomas exhibited an elevated rate of YY1 mutations. In contrast, NF-PanNETs had all three CNV patterns, and NF-PanNETs with CNV deletions had a high rate of loss-of-function mutations of tumour suppressor genes. NF-PanNETs with CNV alterations (amplification and deletion) had an elevated risk of relapse, and additional DAXX/ATRX mutations could predict an increased relapse risk in the first 2-year period.

CONCLUSION

These WGS/WES data allowed a comprehensive assessment of genetic differences between insulinomas and NF-PanNETs, reclassifying these tumours into novel molecular subtypes. We also proposed a novel relapse risk stratification system using CNV patterns and DAXX/ATRX mutations.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

Gamma Emitters in Pancreatic Endocrine Tumors Imaging in the PET Era: Is there a Clinical Space for 99mTc-peptides?

Background:

Pancreatic Neuroendocrine Tumors (PNETs) are rare neoplasms, sporadic or familial, even being part of a syndrome. Their diagnosis is based on symptoms, hormonal disorders or may be fortuitous. The role of Nuclear Medicine is important, mainly because of the possibility of a theranostic strategy. This approach is allowed by the availability of biochemical agents, which may be labeled with radionuclides suitable for diagnostic or therapeutic purposes, showing almost identical pharmacokinetics. The major role for radiopharmaceuticals is connected with radiolabeled Somatostatin Analogues (SSA), since somatostatin receptors are highly expressed on some of the neoplastic cell types.

Discussion:

Nowadays, in the category of radiolabeled SSA, although 111In-pentetreotide, firstly commercially proposed, is still used, the best choice for diagnosis is related to the so called DOTAPET radiotracers labeled with 68-Gallium (Ga), such as 68Ga-DOTATATE, 68Ga-DOTANOC, and 68Ga-DOTATOC. More recently, labeling with 64-Copper (Cu) (64Cu-DOTATATE) has also been proposed. In this review, we discuss the clinical interest of a SAA (Tektrotyd©) radiolabeled with 99mTc, a gamma emitter with better characteristics, with respect to 111Indium, radiolabeling Octreoscan ©. By comparing both pharmacokinetics and pharmacodynamics of Octreoscan©, Tektrotyd© and PET DOTA-peptides, on the basis of literature data and of our own experience, we tried to highlight these topics to stimulate further studies, individuating actual clinical indications for all of these radiotracers.

Conclusion:

In our opinion, Tektrotyd© could already find its applicative dimension in the daily practice of NETs, either pancreatic or not, at least in centers without a PET/CT or a 68Ga generator. Because of wider availability, a lower cost, and a longer decay, compared with respect to peptides labeled with 68Ga, it could be also proposed, in a theranostic context, for a dosimetry evaluation of patients undergoing Peptide Receptor Radionuclide Therapy (PRRT), and for non-oncologic indications of radiolabelled SSA. In this direction, and for a more rigorous cost/effective evaluation, more precisely individuating its clinical role, further studies are needed.

Distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis

BACKGROUND

The clinicopathological and prognostic features of insulinoma with synchronous metastases are unclear. This study aimed to verify the distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis.

METHODS

Patients with pancreatic neuroendocrine tumor (PanNET) were retrospectively enrolled and divided into cohort 1 (Fudan University Shanghai Cancer Center) and cohort 2 (Surveillance, Epidemiology, and End Results Program database). Both cohorts were further divided into three subgroups: insulinoma, nonfunctioning pancreatic neuroendocrine tumor (NF-PanNET), and non-insulinoma functioning pancreatic neuroendocrine tumor (NiF-PanNET).

RESULTS

Cohorts 1 and 2 comprised 505 and 2761 patients (1566 M0 patients and 1195 M1 patients), respectively. In cohort 1 and cohort 2 M0 subgroup, insulinoma showed longer disease-free survival, overall survival (OS), and disease-specific survival (DSS) than NiF-PanNET and NF-PanNET (not reached vs. 48 and 60months, p < 0.001; 183months vs. 87 and 109months, p < 0.001; 247months vs. 121 and 140months, p = 0.002). However, in cohort 2 M1, the mDSS for metastatic insulinoma was shorter than that for NiF-PanNET (31months vs. 61months, p = 0.045), while the mDSS and mOS were similar to those for NF-PanNET. The percentage of T1 and N0 patients was similar between the metastatic insulinoma subgroup and NiF-PanNET and NF-PanNET subgroups. The Ki-67 index and recurrence had a positive linear relationship only for NiF-PanNET and NF-PanNET (p = 0.009).

CONCLUSIONS

Insulinoma with synchronous metastasis showed clinicopathological and prognostic characteristics similar to those of NF-PanNET. Metastatic insulinoma had worse prognosis than non-insulinoma F-PanNET. These findings may help in the clinical management of metastatic insulinoma.

Homogenously isoattenuating insulinoma on biphasic contrast-enhanced computed tomography: Little benefits of diffusion-weighted imaging for lesion detection

The aim of the present study was to evaluate the diagnostic benefit of diffusion-weighted imaging (DWI) in the detection of homogenous isoattenuating insulinoma on biphasic contrast-enhanced computed tomography (CT) preoperatively and to determine which magnetic resonance (MR) sequences exhibited the best diagnostic performance. A total of 44 consecutive patients who underwent biphasic contrast-enhanced CT and conventional MR imaging (MRI), including DWI on a 3T scanner, were identified retrospectively. Apparent diffusion coefficient (ADC) values of insulinomas and the surrounding pancreatic parenchyma were compared using a Wilcoxon signed-rank test. Receiver operating characteristic analysis was used to compare the diagnostic accuracy of four randomized image sets [T2-weighted image (WI), axial T1WI, DWI and T2WI + DWI] for each reader. Axial T1-weighted MRI exhibited the highest relative sensitivity for each reader; DWI alone exhibited the lowest relative sensitivity and the lower inter-reader agreement. There was no significant difference in lesion detection between T2WI and T2WI + DWI image sets for each reader. The ADC values of the insulinoma were significantly lower compared with those of the surrounding parenchyma. In conclusion, DWI does not benefit the detection of homogenous isoattenuating insulinoma. Axial T1WI is the optimal pulse sequence. Quantitative assessment of the tumor ADC values may be a useful tool to characterize identified pancreatic neoplasms.

Insulinoma: A retrospective study analyzing the differences between benign and malignant tumors

BACKGROUND/OBJECTIVES

Insulinoma is a rare pancreatic tumor and, usually, a benign disease but can be a malignant one and, sometimes, a highly aggressive disease. The aim of this study was to determine differences between benign and malignant tumors.

METHODS

Retrospective study of 103 patients with insulinoma treated in a tertiary center. It was analyzed demographic, clinical, laboratory, localization and histologic analysis of tumor and follow up data of subjects in order to identify differences between individuals benign and malignant disease.

RESULTS

Almost all patients (87%) had a benign tumor and survival rates of 100% following pancreatic tumor surgery. Those with malignant tumors (13%) have a poor prognosis, 77% insulinoma-related deaths over a period of 1-300 months after the diagnosis with a survival rate of 24% in five years. The following factors are associated with an increased risk of malignant disease: duration of symptoms < 24 months, fasting time for the occurrence of hypoglycemia < 8 h, blood plasma insulin concentration ≥ 28 μU/mL and C-peptide ≥ 4.0 ng/mL at the glycemic nadir and tumor size ≥ 2.5 cm.

CONCLUSIONS

Our data help to base the literature about these tumors, reinforcing that although insulinoma is usually a single benign and surgically treated neoplasia, the malignant one is difficult to treat. We highlight the data that help predict a malignancy behavior of tumor and suggest a long follow up after diagnosis in these cases.

Role of surgery in pancreatic neuroendocrine tumor

Pancreatic neuroendocrine tumours (PNETs) are rare. They are generally accepted to be slow-growing and have an indolent course. These tumours can be non-functioning or functioning, consisting of a biochemically heterogeneous group of tumours including insulinomas, gastrinomas, carcinoids and glucagonomas. Although surgery remains the mainstay of treatment, controversy still exists especially for non-functioning tumours <2 cm in size. Whether these should be resected or undergo intensive surveillance remains unclear. The surgical approach depends on local expertise. Many studies have shown comparable short-term surgical outcome with laparoscopic pancreatic resection compared to open techniques, however data on long-term oncological outcome are still lacking. On the other hand, liver metastasis occurs in as high as 80% of PNET patients. Five-year survival rate is only 30% if left untreated compared to 60-80% if complete resection is achieved. Current evidence supports liver resection with an aim for symptomatic control and to improve survival in those with respectable disease and no extra-hepatic metastasis. Palliative debunking can be considered in those with intractable symptoms. This article reviews the current evidence on pancreatic resection for PNETs, in particular the role of laparoscopic resection and the management of liver metastasis.

Characteristics and Outcomes of 79 Patients with an Insulinoma: A Nationwide Retrospective Study in Finland

OBJECTIVE

Insulinomas are rare pancreatic tumours. Population-based data on their incidence, clinical picture, diagnosis, and treatment are almost nonexistent. The aim of this study was to clarify these aspects in a nationwide cohort of insulinoma patients diagnosed during three decades.

DESIGN AND METHODS

Retrospective analysis on all adult patients diagnosed with insulinoma in Finland during 1980-2010.

RESULTS

Seventy-nine patients were diagnosed with insulinoma over the research period. The median follow-up from diagnosis to last control visit was one (min 0, max 31) year. The incidence increased from 0.5/million/year in the 1980s to 0.9/million/year in the 2000s (p = 0.002). The median diagnostic delay was 13 months and did not change over the study period. The mean age at diagnosis was 52 (SD 16) years. The overall imaging sensitivity improved from 39% in the 1980s to 98% in the 2000s (p < 0.001). Seventy-one (90%) of the patients underwent surgery with a curative aim, two (3%) had palliative surgery, and 6 (8%) were inoperable. There were no significant differences in the types of surgical procedures between the 1980s, 1990s, and 2000s; tumour enucleations comprised 43% of the operations, distal pancreatic resections 45%, and pancreaticoduodenectomies 12%, over the whole study period. Of the patients who underwent surgery with a curative aim, 89% had a full recovery. Postoperative complications occurred in half of the patients, but postoperative mortality was rare.

CONCLUSIONS

The incidence of insulinomas has increased during the past three decades. Despite the improved diagnostic options, diagnostic delay has remained unchanged. To shorten the delay, clinicians should be informed and alert to consider the possibility of hypoglycemia and insulinoma, when symptomatic attacks are investigated in different sectors of the healthcare system. Developing the surgical treatment is another major target, in order to lower the overall complication rate, without compromising the high cure rate of insulinomas.

Is there any role for minimally invasive surgery in NET?

Neuroendocrine tumors (NET) represent the variability of almost benign lesions either secreting hormones occurring as a single lesion up to malignant lesions with metastatic potential. Treatment of NET is usually performed by surgical resection. Due to the rarity of NET, surgical treatment is mainly based on the experience and recommendations of experts and less on the basis of prospective randomized studies. In addition, the development and establishment of new surgical procedures is made more difficult by their rarity. The development of laparoscopic-assisted surgery has significantly improved the treatment of many diseases. Due to the well-known advantages of laparoscopic surgery, this method has also been increasingly used to treat NET. However, due to limited comparative data, the assumed superiority of laparoscopic surgery in the area NET remains often unclear or not yet proven. This review focuses on the present usage of laparoscopic techniques in the area of NET. Relating to the current literature, this review presents the evidence of various laparoscopic procedures for treatment of adrenal, pancreatic and intestine NET as well as extraadrenal pheochromocytoma and neuroendocrine liver metastases. Further, this review focuses on recent new developments of minimally invasive surgery in the area of NET. Here, robotic-assisted surgery and single-port surgery are promising approaches.

Surgical Therapy of Sporadic Pancreatic Neuroendocrine Neoplasias G1/G2

Background

Pancreatic neuroendocrine neoplasias (pNENs) are uncommon but fascinating tumors with an annual incidence of 1 per 100,000 people. pNENs present either as functional tumors, causing specific hormonal syndromes like Zollinger-Ellison syndrome (ZES) or organic hyperinsulinism, or as non-functional pancreatic tumors (NF-pNENs). The natural history of pNENs is highly variable. 90% of all insulinomas or small NF- pNENs are readily curable by surgical resection. Most other functional and late detected NF-pNENs have a less favorable chance for cure.

Methods

A systematic review of the literature was performed to identify the current state of the art with regard to the key issues of surgery in pNEN G1/G2.

Results

This article provides a comprehensive review of the current literature addressing the current challenges in pNEN surgery.

Conclusion

Patients with completely resected tumors generally have a good prognosis, and an aggressive surgical approach combined with conservative treatment options in patients with advanced disease rarely provides cure but often results in long-term survival.

The Value of Hybrid Angio-CT in Preoperative Detection and Localization of Insulinomas: A Single-Center Retrospective Study

OBJECTIVE

To investigate the performance of hybrid angio-CT in preoperative detection and localization for insulinomas.

METHODS

Fifty-four postoperative pathology-confirmed patients from April 2015 to March 2017 were retrospectively reviewed; all patients underwent angio-CT with administration of contrast media in SMA, GDA and SA due to negative, inconclusive or controversial findings by several preoperative diagnostic methods including TAUS, CEUS, EUS, ECT, EMRI and DSA. Surgery was used as gold standard for localization of insulinomas; detection sensitivity and localization accuracy of angio-CT were assessed and compared with other preoperative image options.

RESULTS

Fifty-six benign insulinomas (mean diameter, 15.8 mm) in 54 patients (18 men and 36 women) were found according to surgical results; the overall detection sensitivity of TAUS, CEUS, EUS, ECT, EMRI and DSA was 21.4, 78.4, 79.2, 70.0, 79.2 and 72.2%, respectively. The overall localization accuracy was 14.3, 58.8, 68.8, 60.0, 75.0 and 44.4%, respectively. A total of 53 tumors were detected by angio-CT, 51 tumors were accurately located, and the overall detection sensitivity and localization accuracy of angio-CT was 94.4 and 90.7%, which was significantly higher than that of all other preoperative diagnostic methods (p < 0.05). No any serious complications occurred during angio-CT.

CONCLUSION

Our study indicates the great potential value of angio-CT in the preoperative detection and localization of insulinomas; angio-CT can be used as a preferred invasive diagnostic method.

[Early endocrine neoplasia of the pancreas]

Pancreatic endocrine neoplasias (pNENs) are uncommon but fascinating tumors with a rising incidence. In accordance to its location, size and grading, the decision to operate the patient should always be made in an interdisciplinary approach. This article provides a comprehensive review of the current literature addressing the current challenges in pNEN surgery and shows that patients with completely resected small pNENs generally have an excellent prognosis, but also that surveillance may be a powerful tool.

Surgery in overweight patients with insulinoma: effects on weight loss

OBJECTIVE

Weight loss induced by the complete resection of insulinoma is controversial in overweight patients. The study sought to explore postoperative weight loss and metabolic changes in overweight insulinoma patients.

METHODS

A retrospective study was conducted to review the follow-up data of insulinoma patients with a BMI ≥25kg/m² who underwent complete lesion resection between May 2010 and May 2015. Body mass index (BMI), weight loss (WL) and percentage weight loss (%WL) were main outcomes.

RESULTS

Fifty-one patients were included with a median follow-up of 28 months. The BMI at 3 months, 1 year, 2 years and 3 years postoperatively were significantly lower than the preoperative BMI values (p < .01). The WL% was 12.9% at 3 months postoperatively without significant changes throughout the 3-year follow-up. WL and the %WL were significantly higher in the high BMI group (BMI≥ 27.5 kg/m²). Multivariate analysis indicated that higher initial BMI was associated with increased weight loss (p = .001). 63.8% of patients with hypertension recovered and improved sleep quality was evident in all patients with obstructive sleep apnea syndrome within 1 year postoperatively.

CONCLUSIONS

Weight significantly decreased postoperatively in overweight insulinoma patients, which was more evident in patients with higher BMI and metabolic comorbidities were largely improved.

Laparoscopic versus open distal pancreatectomy for nonfunctioning pancreatic neuroendocrine tumors: a large single-center study

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) account for 1-2% of all pancreatic neoplasms. Nonfunctioning PNETs (NF-PNETs) account for 60-90% of all PNETs. Laparoscopic distal pancreatectomy (LDP) is becoming the treatment of choice for benign lesions in the body and tail of the pancreas. However, LDP has not yet been widely accepted as the gold standard for NF-PNETs. The purpose of this study is to evaluate the clinical and oncologic outcomes after laparoscopic versus open distal pancreatectomy (ODP) for NF-PNETs.

METHODS

Between April 1995 and September 2016, 94 patients with NF-PNETs underwent open or laparoscopic distal pancreatectomy at Samsung Medical Center. Patients were divided into two groups: those who underwent LDP and those who underwent ODP. Both groups were compared in terms of clinical and oncologic variables.

RESULTS

LDP patients had a significantly shorter hospital stay compared with ODP patients, amounting to a mean difference of 2 days (p < 0.001). Overall complication rates did not differ significantly between the ODP and LDP groups (p = 0.379). The 3-year overall survival rates in the ODP and LDP groups were 93.7 and 100%, respectively (p = 0.069).

CONCLUSIONS

In this study, LDP for NF-PNETs had similar oncologic outcomes compared with ODP. In addition, LDP was associated with a shorter hospital stay compared with ODP. Therefore, LDP is a safe and effective procedure for patients with NF-PNETs. A multicenter study and a randomized controlled trial are needed to better assess the clinical and oncologic outcomes.

Prospective comparison of biphasic contrast-enhanced CT, volume perfusion CT, and 3 Tesla MRI with diffusion-weighted imaging for insulinoma detection

PURPOSE

To evaluate the diagnostic performance of biphasic contrast-enhanced CT (CECT), volume perfusion CT (VPCT) and 3 Tesla MRI with diffusion-weighted imaging (DWI), in patients with clinically suspected insulinomas.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board. Sixty-four patients with clinically suspected insulinomas underwent biphasic CECT, VPCT, and 3T MR with DWI. Two radiologists independently determined the presence/absence of tumor using a 5-scale confidence level. Conspicuity of the lesion and clarity of tumor-to-pancreatic duct distance were graded. Receiver operating characteristic analysis was performed to compare diagnostic performance.

RESULTS

Forty-seven patients were tumor positive, with 51 tumors. The differences between the areas under the curve values for tumor detection were as follows: 0.715 (CECT), 0.903 (VPCT), 0.832 (MRI without DWI) and 0.955 (MRI with DWI) for reader 1, and 0.738 (CECT), 0.895 (VPCT), 0.841 (MRI without DWI), and 0.956 (MRI with DWI) for reader 2. MRI with DWI and VPCT were significantly more accurate than CECT for insulinoma detection (P = 0.01 and 0.02 for reader 1, and P = 0.01 and 0.03 for reader 2). Lesion conspicuity was better on MRI compared with VPCT (P = 0.01), and both were better than CECT (both P < 0.01). Tumor-to-pancreatic duct distance was better appreciated on MRI, compared with CECT and VPCT (both P < 0.01). The weighted k values indicate good to excellent agreement between observers for determining tumor presence/absence (k = 0.64-0.84).

CONCLUSION

The 3T MRI with DWI and VPCT are significantly more accurate than CECT for insulinoma detection. MRI demonstrates higher tumor conspicuity and is superior in depicting the tumor-to-duct distance.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1648-1655.

Systematic review and meta-analysis on laparoscopic pancreatic resections for neuroendocrine neoplasms (PNENs)

The safety of laparoscopic resections (LPS) of pancreatic neuroendocrine neoplasms (PNENs) has been well established in the literature. Areas covered: Studies conducted between January 2003 and December 2015 that reported on LPS and open surgery (OPS) were reviewed. The primary outcomes were the rate of post-operative complications and the length of hospital stay (LoS) after laparoscopic and open surgical resection. The rate of recurrence was the secondary outcome. Eleven studies were included with a total of 907 pancreatic resections for PNENs, of whom, 298 (32.8%) underwent LPS and 609 (67.2%) underwent open surgery. LPS resulted in a significantly shorter LoS (p < 0.0001) and lower blood loss (p < 0.0001). The meta-analysis did not show any significant difference in the pancreatic fistula rate, recurrence rate or post-operative mortality between the two groups. Expert commentary: LPS is a safe approach even for PNENs and it is associated with a shorter LoS.

Efficacy of laparoscopic ultrasonography in laparoscopic resection of insulinoma

Insulinoma is the most common functioning islet cell tumor of the pancreas, with an annual incidence of 4 cases/1 million individuals. It is treated by surgical methods. Open surgery was once considered the standard approach for the treatment of insulinoma. However, the procedure is traumatic and requires a large incision, which does not satisfy the growing expectations of minimally invasive management of small-sized tumors. Insulinomas are usually benign solitary tumors and mostly occur sporadically, which makes them suitable candidates for laparoscopic management. The potential advantages of laparoscopic management of insulinoma over open surgery include shorter duration of hospitalization, quicker recovery, and better cosmetic effect. However, because of the small tumor size as well as the depth and uncertainty of the location of the tumor, laparoscopic localization of the lesion without tactile sensation is difficult. Laparoscopic ultrasonography can detect about 90% of insulinomas, and its sensitivity is comparable to that of manual palpation along with intraoperative ultrasonography during open surgery; thus, it ensures the feasibility of laparoscopic management of insulinoma and reinforces its advantage as a minimally invasive procedure. Laparoscopic ultrasonography is vital for the localization of insulinomas and characterization of the surrounding pancreatic structure and should, therefore, be considered an integral part of the laparoscopic management of insulinoma.

A Clinicopathological Study of Malignant Insulinoma in a Contemporary Series

OBJECTIVE

The aim of the study was to address the origin and natural history of malignant insulinoma.

METHODS

Retrospective review of medical records of patients diagnosed with insulinoma at Cedars-Sinai Medical Center between 2000 and 2015 was conducted. Hormonal expression in tumor specimens was examined by immunostaining.

RESULTS

All the 9 patients with malignant insulinoma (35% of 26 patients with insulinoma) already had liver metastasis at hypoglycemia presentation with bulky cumulative tumor burden. Six patients had de novo diagnosis, 2 had known metastatic nonfunctioning pancreatic neuroendocrine tumor, and 1 had a known pancreatic mass. Tumor grade at presentation was G1 in 4 patients, G2 in 4, and unknown in 1. Four patients died 2 to 32 months after presentation, all with extensive liver tumor involvement. Tumor expression of proinsulin and insulin was heterogeneous and overall infrequent. The proinsulin levels and proinsulin/insulin molar ratio in patients with malignant versus benign insulinoma were 334 versus 44 pmol/L and 2.1 versus 0.9, respectively.

CONCLUSIONS

Malignant insulinoma seems to arise from and behave like nonfunctioning pancreatic neuroendocrine tumor oncologically but with metachronous hyperinsulinemic hypoglycemia. High proinsulin levels and proinsulin/insulin molar ratio may suggest malignant insulinoma.

Role of laparoscopic enucleation in the treatment of pancreatic lesions: case series and case-matched analysis

BACKGROUND

Previous studies report successful application of laparoscopic pancreatic enucleation (LPE). However, the evidence is limited to small series. This study aimed to evaluate the indications, technique and outcome of LPE at a tertiary care institution.

METHODS

Between February 1998 and April 2016, 45 consecutive LPEs were performed at Oslo University Hospital-Rikshospitalet. Twenty-four (53.3 %) patients subjected to right-sided LPE (RLPE) were compared with 21 (46.7 %) patients who had undergone left-sided LPE (LLPE). A case-matched analysis (1:2) was performed to compare the outcomes following LLPE and laparoscopic distal pancreatectomy (LDP).

RESULTS

Patient demographics, BMI, ASA score and pathological characteristics were similar between the RLPE and LLPE groups. Operative time was slightly longer for RLPE [123 (53-320) vs 102 (50-373) min, P = 0.09]. The rates of severe morbidity (≥Accordion grade III) and clinically relevant pancreatic fistula (grades B/C) were comparable, although with a trend for higher rate of complications following LLPE (16.7 vs 33.3 %; P = 0.19 and 20.8 vs 33.3 %, P = 0.34, respectively). The hospital stay was similar between RLPE and LLPE [5 (2-80) vs 7 (2-52), P = 0.49]. A case-matched analysis demonstrated shorter operating time [145 (90-350) vs 103 (50-233) min, P = 0.02], but higher readmission rate following LLPE (25 vs 3.1 %, P = 0.037).

CONCLUSION

LLPE seems to be associated with a higher risk of postoperative morbidity and readmission rates than LDP. RLPE is a feasible, safe approach and a reasonable alternative to pancreatoduodenectomy in selected patients with pancreatic lesions.

Diagnosis and surgical management of insulinomas in 33 consecutive patients at a single institution

PURPOSE

The purpose of this study was to evaluate the diagnosis and surgical management of insulinomas in a single-center setting.

METHODS

Demographic details, clinical presentation, preoperative diagnosis, surgical strategy, and outcomes of 33 consecutive patients who underwent surgery for insulinoma were analyzed retrospectively.

RESULTS

The median time from the first onset of symptoms to diagnosis was 24 months (range 3 days to 50 years). All cases presented with Whipple's triad and had a fasting insulin to glucose ratio higher than 0.33. The preoperative detection rates of transabdominal ultrasonography, CT, MRI, and EUS were 22 % (2/9), 72 % (23/32), 75 % (9/12), and 80 % (4/5), respectively. Intraoperative manual palpation localized all cases. Enucleation was performed in 58 % of cases (19/33), partial pancreatic resection in 39 % (13/33), and enucleation plus partial resection in 3 % (1/33). Pancreatic fistula was the most common complication and occurred in 15 patients (45 %), including seven grade A, five grade B, and three grade C fistulas. There was no mortality. When compared with partial pancreatectomy, enucleation held a significant advantage in operative time and operative bleeding, with no significant differences in demographic data and postoperative complications. During a median follow-up period of 32 months, two patients were lost to follow-up and the remaining 31 patients were without evidence of recurrence.

CONCLUSIONS

A fasting insulin release index larger than 0.3 is a reliable indicator for the diagnosis of insulinoma. Intraoperative palpation by an experienced surgeon can effectively complement an uncertain preoperative localization. Compared with partial pancreatic resection, enucleation showed significant benefit in terms of intraoperative blood loss and operation time.

Propensity score-matched analysis of robotic versus open surgical enucleation for small pancreatic neuroendocrine tumours

BACKGROUND

Enucleation of pancreatic neuroendocrine tumours (pNETs) via robotic surgery has rarely been described. This study sought to assess the safety and efficiency of robotic surgery for the enucleation of small pNETs.

METHODS

A comparison was conducted of enucleation of pNETs smaller than 2 cm by robotic or open surgery between January 2000 and May 2015. Propensity score matching was used to balance sex, age, BMI, tumour location and tumour diameter. Pathological results, safety-related outcomes (postoperative pancreatic fistula (POPF) rate, estimated blood loss, and short-term mortality and morbidity) and efficiency-related outcomes (duration of surgery and postoperative length of hospital stay) were compared between the groups.

RESULTS

A cohort of 120 patients with pNET were enrolled in the study (1 : 1 matched for open or robotic surgery, 60 per group). Ninety-three patients (77·5 per cent) had a grade 1 tumour and 114 (95·0 per cent) had an insulinoma. Robotic surgery had a conversion rate of 5 per cent (3 of 60), and was not associated with an increased POPF rate (10 per cent versus 17 per cent after open surgery; P = 0·283) or grade III-V surgical complications according to the Dindo-Clavien classification (3 versus 10 per cent respectively; P = 0·272). Estimated blood loss was reduced with the robotic approach (32·5 versus 80·0 ml in the open group; P = 0·008), as was duration of surgery (117 versus 150 min; P < 0·001). Length of hospital stay after surgery was similar in the two groups (12·0 versus 13·5 days respectively; P = 0·071).

CONCLUSION

Robotic surgery for enucleation of pNETs smaller than 2 cm did not increase POPF or major complication rates, and reduced the duration of surgery and estimated blood loss, compared with open surgery.

REGISTRATION NUMBER

NCT02125929 ( https://www.clinicaltrials.gov/).

Differences and Similarities in the Clinicopathological Features of Pancreatic Neuroendocrine Tumors in China and the United States: A Multicenter Study

The presentation, pathology, and prognosis of pancreatic neuroendocrine tumors (PNETs) in Asian patients have not been studied in large cohorts. We hypothesized that the clinicopathological features of PNETs of Chinese patients might be different from those of US patients. The objectives of this study were to address whether PNETs in Chinese patients exhibit unique clinicopathological features and natural history, and can be graded and staged using the WHO/ENETS criteria. This is a retrospective review of medical records of patients with PNETs in multiple academic medical centers in China (7) and the United States (2). Tumor grading and staging were based on WHO/ENETS criteria. The clinicopathological features of PNETs of Chinese and US patients were compared. Univariate and multivariate analyses were performed to find associations between survival and patient demographics, tumor grade and stage, and other clinicopathological characteristics. A total of 977 (527 Chinese and 450 US) patients with PNETs were studied. In general, Chinese patients were younger than US patients (median age 46 vs 56 years). In Chinese patients, insulinomas were the most common (52.2%), followed by nonfunctional tumors (39.7%), whereas the order was reversed in US patients. Tumor grade distribution was similar in the 2 countries (G1: 57.5% vs 55.0%; G2: 38.5% vs 41.3%; and G3: 4.0% vs 3.7%). However, age, primary tumor size, primary tumor location, grade, and stage of subtypes of PNETs were significantly different between the 2 countries. The Chinese nonfunctional tumors were significantly larger than US ones (median size 4 vs 3 cm) and more frequently located in the head/neck region (54.9% vs 34.8%). The Chinese and US insulinomas were similar in size (median 1.5 cm) but the Chinese insulinomas relatively more frequently located in the head/neck region (48.3% vs 26.1%). Higher grade, advanced stage, metastasis, and larger primary tumor size were significantly associated with unfavorable survival in both countries. Several clinicopathological differences are found between Chinese and US PNETs but the PNETs of both countries follow a similar natural history. The WHO tumor grading and ENETS staging criteria are applicable to both Chinese and US patients.

Isoattenuating insulinomas at biphasic contrast-enhanced CT: frequency, clinicopathologic features and perfusion characteristics

OBJECTIVES

We aimed to determine the frequency of isoattenuating insulinomas, to investigate their clinicopathological features and to assess their regional pancreatic perfusion characteristics.

METHODS

Institutional review board approval was obtained, and patient informed consent was waived. From July 2010 to June 2014, 170 patients (66 male, 104 female) with endogenous hyperinsulinemic hypoglycemia underwent biphasic contrast-enhanced CT before surgery, and 129 of those patients also received preoperative whole-pancreas CT perfusion. A total of 181 tumours were proved histopathologically after surgery. Enhancement pattern and regional pancreatic perfusion characteristics were analyzed. Clinical features, tumour size and pathological grading were investigated.

RESULTS

The frequency of isoattenuating tumours was 24.9 %. Tumour size and WHO grading was not significantly different between isoattenuating and hyperattenuating tumours. Tumour-free regions had identical blood flow (BF) regardless of their location (p = 0.35). Isoattenuating tumour-harbouring regions had lower BF compared with hyperattenuating tumour-harbouring regions; both showed higher BF compared with tumour-free neighbourhood regions (all p < 0.01). For patients with isoattenuating tumours, the overall hospital stay was longer (p < 0.01).

CONCLUSIONS

A substantial subset of insulinomas were isoattenuating on biphasic CT. CT perfusion showed higher BF in tumour-harbouring regions compared to tumour-free regions, providing a clue for tumour regionalization.

KEY POINTS

• About a quarter of all insulinomas were isoattenuating on biphasic contrast-enhanced CT. • CT perfusion finds tumour-harbouring regions have higher blood-flow compared to tumour-free regions. • CT perfusion provides important information for tumour regionalization, for isoattenuating tumours.

Pancreatic insulinomas: Laparoscopic management

Insulinomas are rare pancreatic neuroendocrine tumors that are most commonly benign, solitary, and intrapancreatic. Uncontrolled insulin overproduction from the tumor produces neurological and adrenergic symptoms of hypoglycemia. Biochemical diagnosis is confirmed by the presence of Whipple’s triad, along with corroborating measurements of blood glucose, insulin, proinsulin, C-peptide, β-hydroxybutyrate, and negative tests for hypoglycemic agents during a supervised fasting period. This is accompanied by accurate preoperative localization using both invasive and non-invasive imaging modalities. Following this, careful preoperative planning is required, with the ensuing procedure being preferably carried out laparoscopically. An integral part of the laparoscopic approach is the application of laparoscopic intraoperative ultrasound, which is indispensable for accurate intraoperative localization of the lesion in the pancreatic region. The extent of laparoscopic resection is dependent on preoperative and intraoperative findings, but most commonly involves tumor enucleation or distal pancreatectomy. When performed in an experienced surgical unit, laparoscopic resection is associated with minimal mortality and excellent long-term cure rates. Furthermore, this approach confers equivalent safety and efficacy rates to open resection, while improving cosmesis and reducing hospital stay. As such, laparoscopic resection should be considered in all cases of benign insulinoma where adequate surgical expertise is available.

Clinical outcomes of 15 consecutive patients who underwent laparoscopic insulinoma resection: The usefulness of monitoring intraoperative blood insulin during laparoscopic pancreatectomy

BACKGROUND

Insulinoma is a very serious functional tumor. Surgeons should confirm complete resection of insulinomas before completing the operation, even in laparoscopic surgery.

METHODS

Between August 2007 and September 2014, 15 consecutive patients with biochemical evidence of an insulinoma underwent laparoscopic pancreatectomy. Intraoperatively, a peripheral arterial blood sample was taken, and insulin was measured by quick insulin assay. Insulin levels were determined before anesthesia induction, every 30 min thereafter, and every 30 min for at least 1 h after tumor resection to confirm insulin levels did not increase before surgery was completed.

RESULTS

All 15 patients (3 men and 12 women, average age 57.2 years) successfully underwent laparoscopic resection. One patient had two tumors, and the remaining 14 patients had one tumor each (three in the head, five in the body, and eight in the tail of the pancreas). Preoperative localization and regionalization studies identified the tumor correctly through CT (12/15 [80.0%]), MRI (9/12 [75.0%]), angiography (11/13 [84.6%]), endoscopic ultrasonography (7/10 [70.0%]), and selective arterial calcium injection (14/14 [100%]). Intraoperative ultrasonography detected 13 of 15 tumors (86.7%), and intraoperative blood insulin monitoring confirmed the complete resection of 16 of 16 tumors (100%). All patients were discharged with normal insulin levels and have been followed up for 3-88 months. There has been no recurrence of symptoms in any patients and none has died.

CONCLUSION

Complete removal of an insulinoma can be reliably predicted by intraoperative blood insulin monitoring even in laparoscopic pancreatectomies.

Determinants of surgical resection for pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) include functioning and non-functional tumors. Functioning tumors consist of tumors that produce a variety of hormones and their clinical effects. Therefore, determinants of resection of pNETs should be discussed for each group of tumors. Less than 10% of insulinomas are malignant, therefore more than 90% of the cases can be cured by surgical resection. Lymphadenectomy is generally not necessary in insulinoma operation. If preoperative localization of the insulinoma is completed, enucleation from the pancreatic body or tail, and distal pancreatectomy can be performed safely by laparoscopy. When preoperative localization of a sporadic insulinoma is not confirmed, surgical exploration is needed. Intraoperative localization of a tumor, intraoperative insulin sampling and frozen section are required. The crucial purpose of surgical resection is to control inappropriate insulin secretion by removing all insulinomas. Gastrinomas are usually located in the duodenum or pancreas, which secrete gastrin and cause Zollinger-Ellison syndrome (ZES). Duodenal gastrinomas are usually small, therefore they are not seen on preoperative imaging studies or endoscopic ultrasound, and can be found only at surgery if a duodenotomy is performed. In addition, lymph node metastasis is found in 40-60% of cases. Therefore, the experienced surgeons should direct operation for gastrinomas. Surgical exploration with duodenotomy should be performed at a laparotomy. Other functioning pNETs can occur in the pancreas or in other locations. Curative resection is always recommended whenever possible after optimal symptomatic control of the clinical syndrome by medical treatment. Indications for surgery depend on clinical symptom control, tumor size, location, extent, malignancy and presence of metastasis. A lot of non-functioning pNETs are found incidentally according to the quality improvement of imaging techniques. Localized, small, malignant non-functioning pNETs should be operated on aggressively, while in possibly benign tumors smaller than 2 cm the surgical risk-benefit ratio should be carefully weighted. Surgical liver resection is generally proposed in curative intent to all patients with operable metastases from G1 or G2 pNET. The benefits of surgical resection of liver metastases have been demonstrated in terms of overall survival and quality of life. Complete resection is associated with better long-term survival.

Long-term results of the surgical management of insulinoma patients with MEN1: a Groupe d'étude des Tumeurs Endocrines (GTE) retrospective study

OBJECTIVE

Management of insulinomas in the context of MEN1 remains poorly studied. The aim of this study was to evaluate long-term results of various surgical approaches in a large cohort of insulinoma-MEN1 patients.

DESIGN AND METHODS

Consecutive insulinoma-MEN1 patients operated on for a nonmetastatic insulinoma between 1957 and 2010 were retrospectively selected from the MEN1 database of the French Endocrine Tumor Group. The type of surgery was categorized as distal pancreatectomy (DP), total pancreatectomy/cephalic duodenopancreatectomy (TP/CDP), or enucleation (E). Primary endpoint was time until recurrence of hypoglycemia after initial surgery. Secondary endpoints were post-operative complications.

RESULTS

The study included 73 patients (median age=28 years). Surgical procedures were DP (n=46), TP/CDP (n=9), or E (n=18). After a median post-operative follow-up of 9.0 years (inter-quartile range (IQR): 2.5-16.5 years), 60/73 patients (82.2%) remained hypoglycemia free. E and TP/CDP were associated with a higher risk of recurrent hypoglycemia episodes (unadjusted hazard ratio: 6.18 ((95% CI: 1.54-24.8); P=0.010) for E vs DP and 9.51 ((95% CI: 1.85-48.8); P=0.007) for TP/CDP vs DP. After adjustment for International Union against Cancer pTNM classification, enucleation remained significantly associated with a higher probability of recurrence. Long-term complications had occurred in 20 (43.5%) patients with DP, five (55.6%) with TP/CDP, but in none of the patients who have undergone E (P=0.002).

CONCLUSION

In the French Endocrine database, DP is associated with a lower risk for recurrent hypoglycemia episodes. Due to lower morbidity, E alone might be considered as an alternative.