Pancreatic Neuroendocrine Tumors (panNETs): Analysis of Overall Survival of Nonsurgical Management Versus Surgical Resection

Surgical Management of Gastroenteropancreatic Neuroendocrine Tumors

BACKGROUND/OBJECTIVES

Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from enterochromaffin cells that can arise from the gastrointestinal (GI) tract and pancreas. Surgical management is the cornerstone of treatment, with the optimal approach tailored by tumor grade, size, location, and presence of metastasis. This review discusses the current strategies for the surgical management of NETs of the gastroenteropancreatic tract.

METHODS

A review of the available literature was conducted to evaluate surgical approaches to NETs. Consensus guidelines were incorporated to synthesize evidence-based recommendations.

RESULTS

For gastric NETs, surgical approach depends on Rindi Classification, WHO grade, and tumor size, with endoscopic approaches favored for smaller and low-grade lesions. Small bowel NETs can be multifocal and thus often require a surgical approach with careful evaluation of the entire intestine. Pancreatic NETs are categorized as functional or non-functional, with enucleation or formal resection strategies based on size, location, functional status, and risk of malignancy. Colorectal NETs are primarily treated with transanal localized or formal surgical resection, depending on lesion size and depth of invasion or presence of lymph node involvement. Appendiceal NETs are either treated with appendectomy or right hemicolectomy, depending on the size, location, and invasiveness of the lesions. For metastatic NETs, cytoreduction, liver transplantation, and targeted therapies offer symptom relief and possible survival benefits.

CONCLUSIONS

Surgical resection provides curative potential for localized NETs and symptom control in metastatic cases. Future research is essential to refine guidelines for intermediate-risk lesions and multifocal tumors, ensuring optimal outcomes for patients with gastroenteropancreatic NETs.

Management of Pancreatic Neuroendocrine Tumors: Surgical Strategies and Controversies

OBJECTIVE

Pancreatic neuroendocrine tumors (PNETs) are uncommon tumors which are increasing in incidence. The management of these tumors continues to evolve. This review examines the current role of surgery in the treatment of these tumors.

METHODS

Studies published over the past 10 years were identified using several databases including PubMed, MEDLINE, and Science Direct. Search terms included PNETs, treatment, and surgery. Clinical practice guidelines and updates from several major groups were reviewed.

RESULTS

Surgery continues to have a major role in the treatment of sporadic functional and nonfunctional PNETs. Pancreas-sparing approaches are increasingly accepted as alternatives to formal pancreatic resection in selected patients. Options such as watch and wait or endoscopic ablation may be reasonable alternatives to surgery for non-functional PNETs < 2 cm in size. Surgical decision-making in multiple endocrine neoplasia type 1 patients remains complex and in some situations such as gastrinoma quite controversial. The role of surgery has significantly diminished in patients with advanced disease due to the advent of more effective systemic and liver-directed therapies. However, the optimal treatments and sequencing in advanced disease remain poorly defined, and it has been suggested that surgery is underutilized in these patients.

CONCLUSIONS

Surgery remains a major treatment modality for PNETs. Given the plethora of available treatments, ongoing controversies and the changing landscape, management has become increasingly complex. An experienced multidisciplinary team which includes surgery is essential to manage these patients.

Oncogenic pathway signatures predict the risk of progression and recurrence in well-differentiated pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (pNETs) are genomically diverse tumors. The management of newly diagnosed well-differentiated pNETs is limited by a lack of sensitivity of existing biomarkers for prognostication. Our goal was to investigate the potential utility of genetic markers as a predictor of progression-free survival (PFS) and recurrence-free survival (RFS).

METHODS

Whole-exome sequencing of resected well-differentiated, low and intermediate-grade (G1 and G2) pNETs and normal adjacent tissue from patients who underwent resection from 2005 to 2015 was performed. Genetic alterations were classified using pan-genomic and oncogenic pathway classifications. Additional samples with genetic and clinicopathologic data available were obtained from the publicly available International Cancer Genome Consortium (ICGC) database and included in the analysis. The prognostic relevance of these genomic signatures on PFS and RFS was analyzed.

RESULTS

Thirty-one patients who underwent resection for pNET were identified. Genomic analysis of mutational, copy number, cytogenetic, and complex phenomena revealed similar patterns to prior studies of pNETs with relatively few somatic gene mutations but numerous instances of copy number changes. Analysis of genomic and clinicopathologic outcomes using the combined data from our study as well as the ICGC pNET cohort (n = 124 patients) revealed that the recurrent pattern of whole chromosome loss (RPCL) and metastatic disease were independently associated with disease progression. When evaluating patients with local disease at the time of resection, RPCL and alterations in the TGFβ oncogenic pathway were independently associated with the risk of recurrence.

CONCLUSIONS

Well-differentiated pNETs are genomically diverse tumors. Pathway signatures may be prognostic for predicting disease progression and recurrence.

Surgical Management and Long-Term Evaluation of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) arise from neuroendocrine cells and are a rare class of heterogenous tumors with increasing incidence. The diagnosis, staging, treatment, and prognosis of PNETs depend heavily on identifying the histologic features and biological mechanisms. Here, the authors provide an overview of the diagnostic workup (biomarkers and imaging), grade, and staging of PNETs. The authors also explore associated genetic mutations and molecular pathways and describe updated guidelines on surgical and systemic treatment modalities.

Long-Term Oncologic Outcome following Duodenum-Preserving Pancreatic Head Resection for Benign Tumors, Cystic Neoplasms, and Neuroendocrine Tumors: Systematic Review and Meta-analysis

BACKGROUND

Pancreatoduodenectomy (PD) has a considerable surgical risk for complications and late metabolic morbidity. Parenchyma-sparing resection of benign tumors has the potential to cure patients associated with reduced procedure-related short- and long-term complications.

MATERIALS AND METHODS

Pubmed, Embase, and Cochrane libraries were searched for studies reporting surgery-related complications following PD and duodenum-preserving total (DPPHRt) or partial (DPPHRp) pancreatic head resection for benign tumors. A total of 38 cohort studies that included data from 1262 patients were analyzed. In total, 729 patients underwent DPPHR and 533 PD.

RESULTS

Concordance between preoperative diagnosis of benign tumors and final histopathology was 90.57% for DPPHR. Cystic and neuroendocrine neoplasms (PNETs) and periampullary tumors (PATs) were observed in 497, 89, and 31 patients, respectively. In total, 34 of 161 (21.1%) patients with intraepithelial papillar mucinous neoplasm exhibited severe dysplasia in the final histopathology. The meta-analysis, when comparing DPPHRt and PD, revealed in-hospital mortality of 1/362 (0.26%) and 8/547 (1.46%) patients, respectively [OR 0.48 (95% CI 0.15-1.58); p = 0.21], and frequency of reoperation of 3.26 % and 6.75%, respectively [OR 0.52 (95% CI 0.28-0.96); p = 0.04]. After a follow-up of 45.8 ± 26.6 months, 14/340 patients with intraductal papillary mucinous neoplasms/mucinous cystic neoplasms (IPMN/MCN, 4.11%) and 2/89 patients with PNET (2.24%) exhibited tumor recurrence. Local recurrence at the resection margin and reoccurrence of tumor growth in the remnant pancreas was comparable after DPPHR or PD [OR 0.94 (95% CI 0.178-5.34); p = 0.96].

CONCLUSIONS

DPPHR for benign, premalignant neoplasms provides a cure for patients with low risk of tumor recurrence and significantly fewer early surgery-related complications compared with PD. DPPHR has the potential to replace PD for benign, premalignant cystic and neuroendocrine neoplasms.

Race and Odds of Surgery Offer in Small Bowel and Pancreas Neuroendocrine Neoplasms

BACKGROUND

Despite existing society guidelines, management of pancreatic (PanNEN) and small bowel (SBNEN) neuroendocrine neoplasms remains inconsistent. The purpose of this study was to identify patient- and/or disease-specific characteristics associated with increased odds of being offered surgery for PanNEN and SBNEN.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) Program database and the National Cancer Database (NCDB) were queried for patients with PanNEN/SBNEN. Demographic and pathologic data were compared between patients who were offered surgery and those who were not. Multivariate logistic regression was performed to identify factors independently associated with being offered surgery.

RESULTS

In SEER, there were 3641 patients with PanNEN (54.7% were offered surgery) and 5720 with SBNEN (86.0% were offered surgery). On multivariate analysis of SEER, non-white race was associated with decreased odds of surgery offer for SBNEN [odds ratio (OR) 0.58, p < 0.001], but not PanNEN (p = 0.187). In NCDB, there were 28,483 patients with PanNEN (57.5% were offered surgery) and 42,675 with SBNEN (86.9% were offered surgery). On multivariate analysis of NCDB, non-white race was also associated with decreased odds of surgery offer for SBNEN (OR 0.61, p < 0.001) but not PanNEN (p = 0.414).

CONCLUSIONS

This study's findings suggest that, in addition to previously reported disparities in surgical resection and surgery refusal rates, racial/ethnic disparities also exist earlier in the course of treatment, with non-white patients being less likely to be offered surgery for SBNEN but not for PanNEN; this is potentially due to discrepancies in rates of referral to academic centers for pancreas and small bowel malignancies.

Gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) - Current literature review of diagnostics and therapy. What has changed in the management?

<b>Introduction:</b> Gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) are malignancies originating from cells of the diffuse endocrine system. They are rare and localize in the upper and lower parts of the gastrointestinal tract and in the pancreas. Despite such a varied location, GEP-NENs are considered a common group of neoplasms due to the fact of their similar morphology and ability to secrete peptide hormones and biologically active amines. They are associated with clinical manifestations specific to the substances produced by a particular neoplasm. The classification of GEP-NENs is constantly systematized and updated based on their differentiation and grading. The development of available diagnostic and treatment methods for these tumors has made significant progress over the past 10 years and is still ongoing.<b>Aim:</b> In the following paper, we review the diagnostics and treatment of GEP-NENs, taking into account the latest molecular, immunological, or gene-based methods. Imaging methods using markers for receptors allow for high diagnostic sensitivity<b>Methods:</b> Medical databases were searched for the latest information. The authors also sought confirmation of the content of a particular publication in another publications, so as to present the most reliable information possible.<b>Results:</b> Research results revealed that the diagnostics and treatment of GEP-NENs have significantly advanced in recent years. Surgical interventions, especially minimally invasive techniques, have shown efficacy in treating GEP-NENs, with specific therapies such as somatostatin analogs, chemotherapy, and peptide receptor radionuclide therapy demonstrating promising outcomes. The evolution of diagnostic methods, including imaging techniques and biomarker testing, has contributed to improved patient care and prognosis.<b>Conclusions:</b> The increasing incidence of GEP-NENs is attributed to enhanced diagnostic capabilities rather than a rise in population prevalence. The study emphasizes the importance of ongoing research to identify specific markers for early detection and targeted therapies to further enhance the effectiveness of treating these rare and heterogeneous malignancies. The findings suggest a positive trajectory in the management of GEP-NENs, with future prospects focused on personalized and targeted treatment approaches.

Premalignant Lesions in the Kidney Transplant Candidate

End-stage kidney disease patients who are referred for transplant undergo an extensive evaluation process to ensure their health prior to transplant due in part to the shortage of available organs. Although management and surveillance guidelines exist for malignancies identified in the transplant and waitlist populations, less is written about the management of premalignant lesions in this population. This review covers the less common premalignant lesions (intraductal papillary mucinous neoplasm, gastrointestinal stromal tumor, thymoma, and pancreatic neuroendocrine tumor) that can be found in the transplant candidate population. High-level evidence for the management of these rarer premalignant lesions in the transplant population is lacking, and this review extrapolates evidence from the general population and should not be a substitute for a multidisciplinary discussion with medical and surgical oncologists.

Recurrence-Free Survival and Disease-Specific Survival in Patients with Pancreatic Neuroendocrine Neoplasms: A Single-Center Retrospective Study of 413 Patients

INTRODUCTION

The prognosis and impact of different prognostic factors in pancreatic neuroendocrine neoplasms (pNEN) remain controversial.

AIM

To investigate prognostic factors for recurrence-free survival and disease-specific survival in patients with pNEN, divided into three groups: patients undergoing surveillance (tumor size < 2 cm, group 1), patients followed after curative-intended surgery (group 2), and patients with unresectable disease or residual tumors after resection (group 3).

METHOD

A single-center retrospective study including consecutive patients over a 20-year period. Multivariate Cox regression analyses were performed to identify risk factors.

RESULTS

413 patients were included, with a mean (SD) age of 62 ± 14 years. In group 1 (n = 51), median (IQR) follow-up was 29 (21-34) months, and tumor size was 1.0 (0.8-1.4) cm. One progressed and had a tumor resection. In group 2 (n = 165), follow-up 59 (31-102) months, median tumor size 2 (1.2-3.4) cm, median Ki-67 index 5 (3-10)%, the 5-year recurrence rate was 21%. Tumor size (p < 0.001), Ki-67 index (p = 0.02), and location in the pancreatic head (p < 0.001) were independent risk factors. In group 3 (n = 197), follow-up 19 (6-46) months, median tumor size 4.2 (2.6-7.0) cm, Ki-67 index 17 (9-64)%, the median disease-specific survival was 22 (6-75) months-99 in NET G1; 54 in NET G2; 14 in NET G3; and 6 months in neuroendocrine carcinomas (NEC). Age (p = 0.029), plasma chromogranin A (p = 0.014), and proliferation, expressed by grade (p = 0.001) and Ki-67 index (p < 0.001), were risk factors.

CONCLUSION

Growth in pNET < 2 cm requiring surgery was observed in 1/51. Tumor size, Ki-67 index, and location in the head were prognostic factors for disease recurrence, while age, plasma chromogranin A, and proliferation predicted mortality in patients with unresectable disease or residual tumors after resection.

An Overview of Pancreatic Neuroendocrine Tumors and an Update on Endoscopic Techniques for Their Management

The growing importance of advanced endoscopy in the diagnosis and treatment of pancreatic neuroendocrine neoplasms (PanNETs) necessitates a comprehensive understanding of various biochemical markers, genetic testing methods, radiological techniques, and treatment approaches that encompass multiple disciplines within and beyond gastrointestinal oncology. This review aims to highlight key aspects of these topics, with a specific focus on emerging EUS-guided procedures for the management of PanNETs.

Observational study of surgical resection in small non-functional pancreatic neuroendocrine tumors: AS SEER-based study

The potential benefits of surgical resection for small non-functional pancreatic neuroendocrine tumors (NF-PNETs) in terms of survival remain uncertain. This study aimed to evaluate the impact of surgical treatment on patients with NF-PNETs. Using SEER data, we identified 1102 patients from 2004 to 2015 with well and moderately differentiated pancreatic neuroendocrine tumors (PNETs). The associations between continuous variables and receipt of surgery were assessed using Wilcoxon rank-sum tests. Kaplan-Meier survival curves for OS were compared using the log-rank test. We compared outcomes in patients who received surgical resection with those in patients who did not, using a univariable Cox model with inverse probability weighting according to the propensity score and propensity-score matching. Among the cohort of 1102 patients, a majority of 965 individuals (87%) underwent surgical intervention. Upon conducting univariate analysis, we observed that surgical treatment significantly prolonged patients' survival [HR = 0.41, 95% CI [0.26-0.65] P < 0.001]. However, the old [HR = 3.27, 95% CI (2.24-4.76), P 0.001], male gender [HR = 1.82, 95% CI (1.23-2.68), P = 0.003], and moderately well-differentiated factors [HR = 1.71, 95% CI (1.04-2.80), P = 0.034] were found to potentially decrease patients' survival time. In the multivariate analysis, male gender [HR = 1.73, 95% CI (1.15-2.61), P = 0.009] and the old factor [HR = 3.52, 95% CI (2.33-5.31), P < 0.001] emerged as influential predictors with higher hazard ratios. Notably, surgical treatment remained a significant factor associated with improved overall survival [HR = 0.53, 95% CI (0.33-0.84), P = 0.007]. Propensity-score matching and inverse probability weighting were employed as analytical techniques. The univariate analysis results showed favorable outcomes in the weight group [HR = 0.48, 95% CI (0.29-0.78), P = 0.003] and matched group [HR = 0.44, 95% CI (0.22-0.85), P = 0.015], respectively. Survival analysis further confirmed that surgical treatment contributed to increased overall survival (log rank, P < 0.05) in both the matching and weight groups. Patients diagnosed with small, non-functioning pancreatic neuroendocrine tumors who undergo surgical intervention exhibit improved overall survival (OS) outcomes. Therefore, surgery is strongly recommended for this patient population.

Surgical Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are relatively uncommon malignancies, characterized as either functional or nonfunctional secondary to their secretion of biologically active hormones. A wide range of clinical behavior can be seen, with the primary prognostic indicator being tumor grade as defined by the Ki67 proliferation index and mitotic index. Surgery is the primary treatment modality for PNETs. While functional PNETs should undergo resection for symptom control as well as potential curative intent, nonfunctional PNETs are increasingly managed nonoperatively. There is increasing data to suggest small, nonfunctional PNETs (less than 2 cm) are appropriate follow with nonoperative active surveillance. Evidence supports surgical management of metastatic disease if possible, and occasionally even surgical management of the primary tumor in the setting of widespread metastases. In this review, we highlight the evolving surgical management of local and metastatic PNETs.

The Surgical and Therapeutic Activities of Non-Functional Pancreatic Neuroendocrine Tumors at a High-Volume Institution

BACKGROUND

This study aimed to summarize the surgical and therapeutic activities of non-functional pancreatic neuroendocrine tumors (NF-PanNETs) and perform survival analyses of a 15-year single-institutional cohort of NF-PanNETs.

METHODS

In total, 1001 patients with neuroendocrine neoplasms treated at Fudan University Shanghai Cancer Center were screened for inclusion, and 509 patients with NF-PanNETs from 2006 to 2020 were included. For time trend analyses, the 15-year study period was randomly divided into three periods. Survival analyses used the Kaplan-Meier method and Cox regression models.

RESULTS

The total number of resected NF-PanNETs increased over the 15-year study period, from 5 resections in 2006 to 94 resections in 2020. A significant decrease in the tumor size was observed, from a mean of 4.0 cm to 3.3 cm, and to 3.0 cm in the most recent period (p = 0.006). Minimally invasive techniques gradually increased from 3.5% to 12.9%, and finally to 46.4% in the most recent period (p < 0.001). In non-metastatic and resected tumors, the tumor size (p < 0.001), positive lymph node (p < 0.001), adjuvant treatment (p = 0.048), and tumor grade (p < 0.001) were independent prognostic factors for recurrence-free survival (RFS). The microvascular invasion (p = 0.024) and tumor grade (p = 0.013) were independent prognostic factors for overall survival (OS). A malignant transformation from NET into neuroendocrine carcinoma was observed.

CONCLUSIONS

An increasing number of NF-PanNETs resection and minimally invasive surgery was shown. In non-metastatic and resected tumors NF-PanNETs, tumor size, positive lymph node, adjuvant treatment, and tumor grade were independent predictors of RFS. Microvascular invasion and tumor grade were independent prognostic factors for OS.

Management of Small Nonfunctioning Pancreatic Neuroendocrine Neoplasms: Current Opinion and Controversies

The incidence of small and asymptomatic pancreatic neuroendocrine neoplasms (PNENs) has increased due to the widespread use of high-resolution diagnostic imaging in screening programs. Most PNENs are slow-growing indolent neoplasms. However, a local invasion or metastasis can sometimes occur with PNENs, leading to a poor prognosis. The management of small, nonfunctioning PNENs remains under debate. The National Comprehensive Cancer Network guidelines recommend observation in selected cases of small PNENs less than 2 cm. Pancreatic surgery remains a high-risk operation with a 28-30% morbidity and 1% mortality. Therefore, the decision on how to manage small PNENs is challenging. This review focuses on the management of small nonfunctioning PNENs. We also highlight the malignant potential of small PNENs according to tumor size, tumor grade, and tumor biomarker. Endoscopic-ultrasound-guided biopsy is recommended to evaluate the potential risk of malignancy. Furthermore, we discuss the current guidelines and future directions for the management of small PNENs.

Pancreatic Neuroendocrine Tumor: Rationale for Centralization in an Integrated Health Care System

OBJECTIVES

Given the complex surgical management and infrequency of pancreatic neuroendocrine tumor, we hypothesized that treatment at a center of excellence improves survival.

METHODS

Retrospective review identified 354 patients with pancreatic neuroendocrine tumor treated between 2010 and 2018. Four hepatopancreatobiliary centers of excellence were created from 21 hospitals throughout Northern California. Univariate and multivariate analyses were performed. The χ2 test of clinicopathologic factors determined which were predictive for overall survival (OS).

RESULTS

Localized disease was seen in 51% of patients, and metastatic disease was seen in 32% of patients with mean OS of 93 and 37 months, respectively (P < 0.001). On multivariate survival analysis, stage, tumor location, and surgical resection were significant for OS (P < 0.001). All stage OS for patients treated at designated centers was 80 and 60 months for noncenters (P < 0.001). Surgery was more common across stages at the centers of excellence versus noncenters at 70% and 40%, respectively (P < 0.001).

CONCLUSIONS

Pancreatic neuroendocrine tumors are indolent but have malignant potential at any size with management often requiring complex surgeries. We showed survival was improved for patients treated at a center of excellence, where surgery was more frequently utilized.

[Highlights of pancreatic surgery: extended indications in pancreatic neuroendocrine tumors]

Advanced pancreatic neuroendocrine tumors (paNET) are mostly characterized by infiltration of vascular structures and/or neighboring organs. The indications for resection in these cases should be measured based on the possibility of an R0 resection. Although the data situation for this rare entity is limited, small case series have shown a significant survival advantage in patients who underwent a radical resection in locally advanced stages of paNET. Both vascular reconstruction and multivisceral resection, when performed at experienced centers, should be considered as curative treatment options. The very special biological behavior of the paNET and the often young patient age justify a much more aggressive approach compared to the pancreatic ductal adenocarcinoma.

Impact of Surgery on Non-Functional Pancreatic Neuroendocrine Tumors ≤2 cm: Analyses With Propensity Score–Based Inverse Probability of Treatment Weighting

Purpose

The impact of surgery on non-functional pancreatic neuroendocrine tumors (NF-PNETs) ≤2 cm is controversial. This study sought to demonstrate the impact of surgery on the prognosis of NF-PNETs ≤2 cm with different biological behaviors.

Methods

Patients with NF-PNETs ≤2 cm from 2004 to 2015 in the Surveillance, Epidemiology, and End Results database were included in this study. An inverse probability of treatment weighting (IPTW) method was used to reduce the selection bias. Kaplan–Meier survival analysis and Cox proportional hazards regression were used to evaluate the effect of surgery on the prognosis.

Results

In the IPTW-adjusted Cox proportional hazards regression analysis, surgery improved the cancer-specific survival (CSS) in the overall cohort (hazard ratio [HR], 0.187; 95% confidence interval [CI], 0.102–0.343; p < 0.001), patients with poorly differentiated or undifferentiated tumor grades (HR, 0.238; 95% CI, 0.105–0.64; p < 0.001), patients with distant metastasis (HR, 0.102; 95% CI, 0.021–0.496; p = 0.005), and patients with local invasion (HR, 0.059; 95% CI, 0.005–0.683; p = 0.002). Surgery did not improve the CSS in patients with lymph node metastasis only (HR, 0.26; 95% CI, 0.0462–1.461; p = 0.126) or patients with well or moderate differentiation while without distant and lymph node metastasis (HR, 0.387; 95% CI, 0.146–1.028; p = 0.057).

Conclusions

Among patients with NF-PNETs ≤2 cm, different biological behaviors correlate with different prognostic impacts of surgery. As long as distant metastasis does not occur and the grade is well–moderately differentiated, these patients will not benefit from surgery no matter whether lymph node metastasis occurs or not. However, when local invasion appears in this group of patients, surgery should be performed. Moreover, patients with a tumor grade of poorly differentiated or undifferentiated or those with distant metastases may benefit from surgery.

Survival Benefit of Surgical Resection for Pancreatic Neuroendocrine Tumors With Oligometastatic Liver Metastasis: A Retrospective and Propensity Score-Matching Analysis

Background

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of pancreatic malignancies. Surgical resection is the only curative treatment option for patients with localized PanNETs, yet the role of cancer-directed surgery (CDS) in the setting of oligometastatic liver metastasis remains a controversy.

Methods

All patients diagnosed with PanNETs and liver-only metastasis from 2010 to 2018 were identified from the SEER database. The biases of baseline characteristics between CDS and no-CDS cohorts were reduced by the propensity score-matching (PSM) method, and the prognostic role of CDS was estimated using the Kaplan–Meier method and Cox regression models. Logistic regression analysis was utilized to identify factors associated with patients who underwent CDS.

Results

A total of 1,270 PanNET patients with oligometastatic liver metastasis were included and analyzed. Of these patients, 283 (22.3%) patients underwent CDS of the primary tumor, while the remaining 987 (77.7%) did not. The OS and CSS were significantly better in the CDS cohort regardless of the propensity score analysis. Multivariate analysis revealed that age, tumor differentiation, tumor location, and lymph node status were significantly associated with patients who were more likely to receive CDS.

Conclusion

Our study demonstrated that CDS was associated with survival benefits in selected patients with PanNETs and liver-only metastasis based on a large population database.

Enucleation Is a Feasible Procedure for Well-Differentiated pNEN-A Matched Pair Analysis

The extent of surgical resection in the treatment of pancreatic neuroendocrine neoplasms (pNEN) is still controversial. This study aimed to evaluate the outcomes of enucleation for well-differentiated non-functional (nf) pNEN. Patients undergoing enucleation (2001−2020) were analyzed. Clinicopathological parameters, perioperative outcomes and survival were assessed. The analysis was performed as a nested case-control study and matched-pair analysis with formal resection. Sixty-one patients undergoing enucleation were identified. Compared to patients undergoing formal resection, enucleation was associated with a significantly shorter median length of operative time (128 (IQR 95−170) versus 263 (172−337) minutes, p < 0.0001) and a significantly lower rate of postoperative diabetes (2% versus 21%, p = 0.0020). There was no significant difference in postoperative pancreatic fistula rate (18% versus 16% type B/C, p = 1.0), Clavien−Dindo ≥ III complications (20% versus 26%, p = 0.5189), readmission rate (12% versus 15%, p = 0.6022) or length of hospital stay (8 (7−11) versus 10 (8−17) days, p = 0.0652). There was no 30-day mortality after enucleation compared to 1.6% (n = 1) after formal resection. 10-year overall survival (OS) and disease-free survival (DFS) was similar between the two groups (OS: 89% versus 77%, p = 0.2756; DFS: 98% versus 91%, p = 0.0873). Enucleation presents a safe surgical approach for well-differentiated nf-pNEN with good long-term outcomes for selected patients.

Current updates and future directions in diagnosis and management of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms are a heterogenous group of rare neoplasms that are increasingly being discovered, often incidentally, throughout the gastrointestinal tract with varying degrees of activity and malignant potential. Confusing nomenclature has added to the complexity of managing these lesions. The term carcinoid tumor and embryonic classification have been replaced with gastroenteropancreatic neuroendocrine neoplasm, which includes gastrointestinal neuroendocrine and pancreatic neuroendocrine neoplasms. A comprehensive multidisciplinary approach is important for clinicians to diagnose, stage and manage these lesions. While histological diagnosis is the gold standard, recent advancements in endoscopy, conventional imaging, functional imaging, and serum biomarkers complement histology for tailoring specific treatment options. In light of developing technology, our review sets out to characterize diagnostic and therapeutic advancements for managing gastroenteropancreatic neuroendocrine tumors, including innovations in radiolabeled peptide imaging, circulating biomarkers, and endoscopic treatment approaches adapted to different locations throughout the gastrointestinal system.

[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.

Current status of surgical management of patients with gastroenteropancreatic neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) of the gastroenteropancreatic system are rare and heterogeneous tumours, yet with increasing prevalence. The most frequent primary sites are the small intestine, rectum, pancreas, and stomach. For a localized disease, surgical resection with local lymph nodes is usually curative with good overall and disease free survival. More complex situation is the treatment of locally advanced lesions, liver metastases, and, surprisingly, small asymptomatic tumours of the rectum and pancreas. In this review, we focus on the current role of surgical management of gastroenteropancreatic NENs. We present surgical approach for the most frequent primary sites. We highlight the role of endoscopic surgery and the watch-and-wait strategy for selected cases. As liver metastases pose an important clinical challenge, we present current indications and contraindications for liver resection and a role of liver transplantation for metastatic NENs.

Facility type and size-stratified analysis of management patterns and outcomes of patients with localized non-functional pancreatic neuroendocrine tumors

BACKGROUND

Non-functional neuroendocrine tumors of the pancreas (NF-pNETs) are uncommon. Consensus guidelines have conflicting recommendations. We performed a nationwide analysis of patterns in management and outcomes based on facility type and tumor size.

METHODS

The National Cancer Database (2004-2016) was queried for patients with localized NF-pNETs (<1 cm, 1-2 cm, >2 cm) stratified by facility type. Management decisions, operative outcomes, and survival were compared.

RESULTS

A total of 7170 patients were included in the analysis (<1 cm = 916; 1-2 cm = 2180; >2 cm = 4074). Most patients were treated at academic facilities (62.8%). Over 67% of patients with tumors <1 cm underwent resection, independent of facility type (p = 0.443). There was no association between facility type and operative vs non-operative management of patients with NF-pNETs 1-2 cm in size. Patients treated at academic facilities were more likely to undergo resection for tumors >2 cm compared to other facility types. Resection was associated with improved survival among patients with tumors 1-2 cm (HR = 0.43,p < 0.001) and >2 cm (HR = 0.32,p < 0.001), but not <1 cm (HR = 0.64,p = 0.054), as compared to non-operative management.

CONCLUSION

There is heterogeneity in management of NF-pNETs across facility types. Treatment at academic facilities appears to be associated with higher resection rates for tumors >2 cm. There appears to be an independent association between operative management and improved survival for tumors ≥1 cm in size.

Pancreatic Neuroendocrine Tumors: The Effect of Facility Type on Patient Survival

OBJECTIVES

During the last decades, significant progress has been made in the management of patients with pancreatic neuroendocrine tumors (pNETs). It is unclear how the type of the treating health care facility alters patient outcomes.

METHODS

Data from pNETs reported to the National Cancer Database between 2004 and 2016 were examined. Types of institutions were as follows: academic/research cancer program (ARP), comprehensive community cancer program (CCCP), integrated network cancer program (INCP), and community cancer program (CCP).

RESULTS

A total of 17,887 patients with pNETs were analyzed. Treatment at ARPs was significantly associated with receipt of surgery (ARP, 61.9%; CCCP, 45.6%; CCP, 29.9%; INCP, 55.5%; P < 0.001), both for patients with very early tumors ≤2 cm (ARP, 74.7%; CCCP, 66.5%; CCP, 52.4%; INCP, 71.6%; P < 0.001) and for patients with liver metastases (ARP, 21.3%; CCCP, 10.6%; CCP, 5%; INCP, 16.8%; P < 0.001). Treatment at ARPs was associated with improved survival (median overall survival: ARP, 91 mo; CCCP, 47 mo; CCP, 24.5 mo; INCP, 72 mo; P < 0.001).

CONCLUSIONS

Treatment of pNETs at academic/research programs is associated with more frequent resections and best survival outcomes. This survival benefit exists for early and late stages and after adjusting for known cofactors.

Fate of Surgical Patients with Small Nonfunctioning Pancreatic Neuroendocrine Tumors: An International Study Using Multi-Institutional Registries

Simple Summary

No consensus has been reached regarding whether nonmetastatic nonfunctioning neuroendocrine tumors of the pancreas (NF-pNETs) ≤ 2 cm should be resected or observed. In this retrospective international multicenter study, 483 patients who underwent resection for NF-pNETs ≤ 2 cm in 18 institutions from 2000 to 2017 were enrolled and their medical records were reviewed. Tumor size > 1.5 cm, Ki-67 index ≥ 3%, and nodal metastasis were independent adverse prognostic factors for survival after multivariable analysis. NF-pNET patients with tumors ≤ 1.5 cm can be observed if the preoperative Ki-67 index is under 3%, and if nodal metastasis is not suspected in preoperative radiologic studies. These findings support the clinical use to make decisions about small NF-pNETs.

Abstract

Several treatment guidelines for sporadic, nonmetastatic nonfunctioning neuroendocrine tumors of the pancreas (NF-pNETs) have recommended resection, however, tumors ≤ 2 cm do not necessarily need surgery. This study aims to establish a surgical treatment plan for NF-pNETs ≤ 2 cm. From 2000 to 2017, 483 patients who underwent resection for NF-pNETs ≤ 2 cm in 18 institutions from Korea and China were enrolled and their medical records were reviewed. The median age was 56 (range 16–80) years. The 10-year overall survival rate (10Y-OS) and recurrence-free survival rate (10Y-RFS) were 89.8 and 93.1%, respectively. In multivariable analysis, tumor size (>1.5 cm; HR 4.28, 95% CI 1.80–10.18, p = 0.001) and nodal metastasis (HR 3.32, 95% CI 1.29–8.50, p = 0.013) were independent adverse prognostic factors for OS. Perineural invasion (HR 4.36, 95% CI 1.48–12.87, p = 0.008) and high Ki-67 index (≥3%; HR 9.06, 95% CI 3.01–27.30, p < 0.001) were independent prognostic factors for poor RFS. NF-pNETs ≤ 2 cm showed unfavorable prognosis after resection when the tumor was larger than 1.5 cm, Ki-67 index ≥ 3%, or nodal metastasis was present. NF-pNET patients with tumors ≤ 1.5 cm can be observed if the preoperative Ki-67 index is under 3%, and if nodal metastasis is not suspected in preoperative radiologic studies. These findings support the clinical use to make decisions about small NF-pNETs.

Reappraisal of a 2-cm Cutoff Size for the Management of Nonfunctional Pancreatic Neuroendocrine Tumors: A Population-Based Study

BACKGROUND

Expectant observation and aggressive surgery are both recommended for small nonfunctional pancreatic neuroendocrine tumors (NF-PanNETs). However, the optimal management of small NF-PanNETs remains disputable due to the heterogeneous clinical behavior.

METHODS

Patients who were diagnosed with pancreatic neuroendocrine neoplasms (PanNENs) between 2000 and 2018 were identified from the surveillance, epidemiology, and end results (SEER) database and reviewed retrospectively. Tumor aggressiveness was defined as poor differentiation, lymph node involvement, liver involvement, and advanced stage. The best cutoff of tumor size associated with tumor aggressiveness was determined through the receiver operating characteristic (ROC) curve analysis. Univariate and multivariate analyses were used to identify prognostic factors in patients with tumors of ≤2 cm.

RESULTS

A total of 5,172 patients with PanNENs were enrolled, including 1,760 (34.0%) tumors ≤2 cm and 3,412 (66.0%) tumors >2 cm. A 2.5-cm cutoff size was found to be associated with a satisfactory ability in predicting tumor aggressiveness. On multivariate analysis, age, gender, ethnicity, tumor grade, tumor number, and stage were independent prognostic factors for overall survival (OS) in patients with tumors less than or equal to 2 cm in size. A total of 1,621 patients were diagnosed with NF-PanNETs according to the WHO classification, of whom 1,350 underwent surgery, 271 performed active observation. The OS was significantly better in the surgery group compared to the observation group regardless of propensity score analysis. Additionally, a total of 407 patients were selected based on the multivariate Cox regression analysis, of whom 46 underwent observation, 361 underwent surgery, and the OS was comparable.

CONCLUSION

Expectant observation may be a reasonable alternative to aggressive surgical resection in highly selected small NF-PanNET patients. Also, the decision to observe versus surgery should not only be based on tumor size alone but also take into account other important clinicopathological factors.

Predicting Progression, Recurrence, and Survival in Pancreatic Neuroendocrine Tumors: A Single Center Analysis of 174 Patients

INTRODUCTION

The European Neuroendocrine Tumor Society, ENETS, reports variables of prognostic significance in pancreatic neuroendocrine tumors (PNET). However, studies have short follow-ups, and the optimal treatment remains controversial. We aimed to determine overall survival (OS), progression-free survival (PFS) after conservative treatment, and recurrence-free survival (RFS) after surgery and further to find predictors of aggressive PNET behavior to support treatment decisions.

METHODS

174 patients with PNET treated at Aarhus University Hospital from 2011 to 2021 were included in a retrospective cohort study. Patients were divided into surgically resected (SUR, n=91) and medically or conservatively treated (MED, n=83). Variables were tested in univariate and multivariate survival analysis. Median follow-up time was 3.4 years in the MED group and 4.5 years in the SUR group.

RESULTS

The 5-year OS was 95% and 65% for the SUR and MED groups, respectively. The 5-year RFS in the SUR group was 80% whereas the 5-year PFS in the MED group was 41%. Larger tumor size, Ki67 index, tumor grade, and stage were predictive of shorter OS, RFS, and PFS. Further, chromogranin A was a predictor of OS. Larger tumor size was associated with higher stage and grade. Only 1 of 28 patients with stage 1 disease and size ≤2 cm developed progression on a watch-and-wait strategy during a median follow-up of 36 months.

CONCLUSION

This study supported the ENETS staging and grading system to be useful to predict OS, PFS, and RFS in PNET. Further, our data support that small, localized, low-grade PNETS can be followed with active surveillance.

A novel tool for visualization and detection of pancreatic neuroendocrine tumours. A 'fluorescent' world is calling for exploration?

AIM OF THE STUDY

Pancreatic neuroendocrine tumours (pNETs) are rare tumours with a propensity to metastasize. Physicians frequently face a huge clinical challenge during the localization of these lesions. The aim of this study is to investigate whether fluorescence-guided localization techniques with indocyanine green (ICG) can be utilized as a detection tool in pNETs, along with any other clinical implications of this technique.

MATERIAL AND METHODS

A thorough literature search in PubMed and Google Scholar, under the terms 'ICG OR Indocyanine OR Fluorescence AND Neuroendocrine' until 31 June 2021, regarding the utilization of indocyanine-fluorescence in localization of pancreatic neuroendocrine, was conducted by the authors, and the associated results are presented.

RESULTS

Indocyanine fluorescence imaging may facilitate the efforts of surgeons to identify occult pancreatic neuroendocrine lesions, assisting them in the identification of resection margins and delineation of the surgical anatomy when it is difficult to clarify.

CONCLUSIONS

Indocyanine-fluorescence imaging might play a pivotal role in pancreatic surgery in terms of localization for neuroendocrine tumours. However, further large-scale clinical studies are needed to assess the absolute indications and optimal use of this technique.

Small pancreatic neuroendocrine tumours: observe and monitor or prompt surgical resection

Over recent decades there has been a significant increase in the annual incidence of neuroendocrine tumors of the pancreas (PanNets), from 0.4 to 0.8 per 100,000 inhabitants, due to the more widespread use of more sensitive imaging techniques (cross-sectional and functional imaging).

Clinical Prognosticators of Metastatic Potential in Patients with Small Pancreatic Neuroendocrine Tumors

BACKGROUND

While observation of T1(≤2cm) nonfunctioning pancreatic neuroendocrine tumors (NF-PanNETs) is an accepted practice, an ill-defined subgroup of patients with T1 tumors develops metastases. This study aimed to identify those patients via clinical factors.

METHODS

Patients from the Surveillance, Epidemiology, and End Results (SEER) registry who were diagnosed with NF-PanNET with size ≤2cm between 1998 and 2014 and who underwent primary tumor resection were identified. Binary logistic regression analyses were performed to evaluate factors associated with pathological nodal and systemic metastatic disease.

RESULTS

A total of 612 patients with T1 NF-PanNETs were identified. Of those, 72 (11.7%) developed nodal metastasis and 35 (5.7%) distant metastasis (M1). In the multivariable analysis, tumor location in the pancreatic body (OR 1.903, p=0.03) (OR 1.407, p=0.038) or tail (OR 1.258, p=0.04) (OR 1.612, p=0.021); tumor grade III-IV (OR 2.042, p=0.022) (OR 5.379, p≤0.001); and younger age (OR 0.963, p=0.01) (OR 0.919, p=0.009) were associated with nodal metastases and the presence of M1 disease, respectively.

CONCLUSION

While the low metastatic potential of ≤2cm NF-PanNET implies watchful waiting to be an appropriate strategy for most patients, the increased risk of metastatic disease in younger patients with high grade (III-IV) body/tail tumors suggests individualized risk stratification to be optimal.

Surgical Management of Pancreatic Neuroendocrine Tumors

Surgical management of pancreatic neuroendocrine tumors (PNETS) is steadily evolving and is influenced by multiple factors. Sporadic PNETs are generally managed more aggressively than those occurring in the background of hereditary syndromes, and functioning PNETs are almost always resected if they are not metastatic. Localized nonfunctioning PNETs less than 2 cm can often be observed. Surgical resection for localized PNET greater than 2 cm comprises parenchymal sparing pancreas resections, such as enucleations, or formal anatomic resection, such as distal pancreatectomy or pancreaticoduodenectomy. PNETs commonly metastasize to the liver, and several systemic and liver-directed options to treat hepatic metastases are available.

Prior Resection of the Primary Tumor Prolongs Survival After Peptide Receptor Radionuclide Therapy of Advanced Neuroendocrine Neoplasms

OBJECTIVE

The aim of the study was to compare impact on survival after resection of primary tumors (PTs) after peptide receptor radionuclide therapy (PRRT).

BACKGROUND

PRRT is a highly effective therapeutic option to treat locally advanced or metastatic neuroendocrine neoplasms (NENs).

METHODS

We retrospectively analyzed the data of 889 patients with advanced NEN (G1-G3, stage IV) treated with at least 1 cycle of PRRT. In 486 of 889 patients (55%, group 1), PT had been removed before PRRT. Group 2 constituted 403 patients (45%) with no prior PT resection. Progression-free survival (PFS) and overall survival (OS) was determined by 68Ga SSTR-PET/CT in all patients applying RECIST and EORTC.

RESULTS

Most patients had their PT in pancreas (n = 335; 38%) and small intestine (n = 284; 32%). Both groups received a mean of 4 cycles of PRRT (P = 0.835) with a mean cumulative administered radioactivity of 21.6 ± 11.7 versus 22.2 ± 11.2 GBq (P = 0.407). Median OS in group 1 was 134.0 months [confidence interval (CI): 118-147], whereas OS in group 2 was 67.0 months (CI: 60-80; hazard ratio 2.79); P < 0.001. Likewise, the median progression-free survival after first PRRT was longer in group 1 with 18.0 (CI: 15-20) months as compared to group 2 with 14.0 (CI: 15-18; hazard ratio 1.21) months; P = 0.012.

CONCLUSIONS

A previous resection of the PT before PRRT provides a significant survival benefit in patients with NENs stage IV.

Comparison of phenotypes and outcomes following resection of incidental versus symptomatic pancreatic neuroendocrine tumors

Background/Aim Fifty to 70 percent of pancreatic neuroendocrine tumors are diagnosed incidentally. The objective of this study is to compare the phenotype and oncological outcomes of incidental versus symptomatic pancreatic neuroendocrine tumors. Methods A retrospective study was conducted identifying all incidental and symptomatic tumors resected between 2000 and 2019. Baseline characteristics, symptoms, operative variables and pathological stage were all recorded. In both groups, patterns of recurrence and overall and disease-free survival were analyzed. Results Fifty-one incidental and 45 symptomatic pancreatic tumor resections were performed. Symptomatic tumors were more frequent in women (29 vs 17; p=0.005), in younger patients (median years; 50 vs 58; p=0.012) and were detected at a more advanced stage (p=0.027). There were no differences in location and most resections (n= 49; 51%) were performed laparoscopically. There were no operative mortalities and 17 (17.7%) severe complications (≥IIIb on the Clavien-Dindo classification) were recorded with no differences between the two groups. With a median follow-up of 64.4 months (range 13.5 - 90), overall survival at 5 and 10 years was 89.7% and 72.8% for the non-incidental tumors, and 80.9% and 54.6% for the incidental tumors (p=ns). Disease-free survival in both groups (excluding M1a) was 71.2% and 47.5%, and 93.7% and 78.1%, respectively (p= ns). Conclusions Symptomatic tumors are more frequent in women and present at higher pathological stages. There were no significant differences in overall and disease-free survival between the two groups. Resection of incidental tumors ≥1.5 - 2 cm seems advisable, although each case should assessed on an individual basis.

The clinicopathologic and operative characteristics of patients with small nonfunctioning pancreatic neuroendocrine tumors

BACKGROUND

Incidentally detected, small nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) are increasingly diagnosed on imaging modalities. This retrospective investigation evaluated the clinicopathologic characteristics and perioperative and oncologic outcomes in patients with small NF-PNETs undergoing curative resection.

METHODS

The medical records of 444 patients who underwent pancreatic resection for NF-PNETs at a single, large-volume institution between January 2000 and December 2018 were retrospectively reviewed. Patients were divided into those with small (≤2 cm) and large (>2 cm) tumors based on the largest tumor diameter on preoperative computed tomography (CT). Outcomes were also evaluated in subgroups of patients with small NF-PNET who did and did not undergo lymphadenectomy.

RESULTS

Of the 444 patients with NF-PNETs, 195 (43.9%) had small (≤2 cm) and 249 (56.1%) had large (>2 cm) NF-PNETs. The rate of parenchyma-preserving surgery (14.4% vs. 7.2%, p = 0.014) and the ratio of spleen preservation for left-sided pancreatectomy (65.6% vs. 38.3%, p < 0.001) were higher in the small NF-PNET group. Size on CT >2 cm (p < 0.001, hazard ratio [HR]: 5.836, 95% confidence interval [CI]: 2.474-13.769), presence of perineural invasion (p < 0.001, HR: 3.025, 95% CI: 1.640-5.577), World Health Organization (WHO) Grade 2 (p = 0.007, HR: 2.861, 95% CI: 1.325-6.176), and WHO Grade 3 (p < 0.001, HR: 11.537, 95% CI: 5.282-25.199) were independent predictors of disease-free survival (DFS). DFS did not differ significantly in patients with small NF-PNETs who did and did not undergo lymphadenectomy (p = 0.886).

CONCLUSIONS

Assessment of long-term oncologic outcomes suggests that surgical resection may cure small NF-PNETs. Minimally invasive surgery and organ-preserving surgery are acceptable treatment options for select patients with small NF-PNETs. The effect on survival outcomes of lymph node dissection for small NF-PNETs remains unclear.

Enucleation for benign or borderline tumors of the pancreas: comparing open and minimally invasive surgery

BACKGROUND

The feasibility and safety of minimally invasive enucleation (ME) for benign or borderline pancreatic tumors is still unclear. The aim of this study was to compare outcomes between ME and open enucleation (OE).

METHODS

All patients undergoing pancreatic enucleation between October 2001 and January 2020 were analyzed from a prospective database. Consecutive patients undergoing ME were compared with patients undergoing OE in a matched-pair analysis (1:2).

RESULTS

Of 358 patients, undergoing enucleation, 120 matched patients (ME n = 40, OE n = 80) were included. Patients undergoing ME had less blood loss (median 50 vs. 100 ml, P = 0.025) and had a higher proportion of patients discharged by 7 days, than patients undergoing OE (38% vs. 18%, P = 0.016). The rates of clinically relevant postoperative pancreatic fistula (POPF) and major complications (Clavien grade ≥ 3) were similar between both groups. Risk factor analysis for POPF B/C showed no significant parameters associated with POPF, including tumor size and proximity to the main pancreatic duct.

CONCLUSION

Compared with conventional OE, ME reduces the amount of bleeding and allows earlier postoperative discharge, without increasing the incidence of major complications. Thus, minimally invasive enucleation should be considered for benign tumors of the pancreas when technically and oncologically feasible.

Comparison of clinical outcomes between enucleation and regular pancreatectomy in patients with non-functional pancreatic neuroendocrine tumors: a retrospective multicenter and propensity score-matched study

OBJECTIVE

There are limited data from retrospective studies on whether therapeutic outcomes after regular pancreatectomy are superior to those after enucleation in patients with small, peripheral and well-differentiated non-functional pancreatic neuroendocrine tumors. This study aimed to compare the short- and long-term outcomes of regular pancreatectomy and enucleation in patients with non-functional pancreatic neuroendocrine tumors.

METHODS

Between January 2007 and July 2020, 227 patients with non-functional pancreatic neuroendocrine tumors who underwent either enucleation (n = 89) or regular pancreatectomy (n = 138) were included. Perioperative complications, disease-free survival, and overall survival probabilities were compared. Propensity score matching was performed to balance the baseline differences between the two groups.

RESULTS

The median follow-up period was 60.76 months in the enucleation group and 43.29 months in the regular pancreatectomy group. In total, 34 paired patients were identified after propensity score matching. The average operative duration in the enucleation group was significantly shorter than that in the regular pancreatectomy group (147.94 ± 42.39 min versus 217.94 ± 74.60 min, P < 0.001), and the estimated blood loss was also significantly lesser (P < 0.001). The matched patients who underwent enucleation displayed a similar overall incidence of postoperative complications (P = 0.765), and a comparable length of hospital stay (11.12 ± 3.90 days versus 9.94 ± 2.62 days, P = 0.084) compared with those who underwent regular pancreatectomy. There were no statistically significant differences between the two groups in disease-free survival and overall survival after propensity score matching.

CONCLUSION

Enucleation in patients with non-functional pancreatic neuroendocrine tumors was associated with shorter operative time, lesser intraoperative bleeding, similar overall morbidity of postoperative complications, and comparable 5-year disease-free survival and overall survival when compared with regular pancreatectomy.

Effects of pancreatic resection for benign pancreatic neoplasms on pancreatic volume and endocrine function: A long-term computed tomography-based study

BACKGROUND

Pancreatic surgery may result in changes in pancreatic volume and endocrine function. The effects of pancreatic resection for benign neoplasms on pancreatic volume and endocrine function have not been established yet. This study aimed to investigate the long-term results of different pancreatic surgeries for benign pancreatic neoplasms on pancreatic volume and endocrine function.

METHODS

The medical records of 30 patients who underwent pancreaticoduodenectomy (PD) and 30 patients who underwent left-sided pancreatectomy(LP) for benign pancreatic neoplasms between 2005 and 2012 were reviewed. The changes in pancreatic volume after pancreatic surgery were assessed using multi-detector row computed tomography volumetry. Endocrine pancreatic function was evaluated on the basis of fasting glucose level or oral glucose tolerance test result.

RESULTS

The median follow-up duration was 91.3 months (interquartile range, 75.7-119.1 months). Reduction in pancreatic volume after surgery was more pronounced in patients who underwent PD than in those who underwent LP (median percentage of volume reduction, 23.8% vs 5.1%, p < .001). Multivariable analysis of prognostic factors for endocrine insufficiency showed that PD to be significant factor. (HR 3.87, 95% CI 1.12-14.66, p = .037).

CONCLUSIONS

The surgical methods for benign pancreatic neoplasms affect the reduction in pancreatic volume. Furthermore, the methods of pancreatic surgery were associated with the risk of endocrine insufficiency. Further studies with a large number of patients are warranted to evaluate the association between the degree of volume reduction and the development of endocrine insufficiency.

A Survival Analysis of Patients with Localized, Asymptomatic Pancreatic Neuroendocrine Tumors: No Surgical Survival Benefit when Examining Appropriately Selected Outcomes

BACKGROUND

Surgical resection for asymptomatic, localized, well-differentiated pancreatic neuroendocrine tumors (PNETs) is common yet controversial. Studies using overall survival as an endpoint have shown a benefit for resection; however, these results may be due to treatment selection bias. We assessed the impact of surgery on both overall (OS) and cancer-specific survival (CSS) for asymptomatic patients with stage I PNETs (AJCC 8th edition).

METHODS

Using SEER data, we identified 709 patients from 2007 to 2015 with well- and moderately differentiated stage I PNETs. We performed Kaplan-Meier survival estimates and adjusted Cox regression for OS and CSS.

RESULTS

Among 709 patients, 628 (88.6%) underwent surgery. There were 37 overall deaths and 11 cancer-specific deaths. All cancer-specific deaths occurred within 3 years of diagnosis. Five-year OS and CSS rates were 89% and 98%, respectively, for the population. Five-year OS rates were 56% in the non-surgical cohort versus 92% in the surgical cohort (log rank, p < 0.001). However, the 5-year CSS rates were similar; 94% in the non-surgical group and 98% in the surgical group (log rank, p  = 0.207). On multivariable analysis, surgery predicted improved OS but not CSS.

CONCLUSION

Although OS is superior in surgically treated stage I PNETs, CSS is not improved, implying treatment selection bias towards surgery being performed in healthier patients. These data suggest that overall survival is a problematic endpoint for the study of asymptomatic, stage I PNETs. Surgery should be individualized for this cohort of patients as the primary cause of death is non-cancer related.

Laparoscopic enucleation of pancreatic tumours: a single-institution experience of 66 cases

BACKGROUND

Laparoscopic enucleation of pancreatic tumours is seemingly a simple procedure, but challenging as the tumour is deeply embedded in the pancreatic parenchyma. Our study reports a single-centre experience for these cases.

METHODS

Cases with a tumour underwent laparoscopic enucleation from January 2014 to March 2020 in our hospital were collected and analysed.

RESULTS

Sixty-six cases were enrolled, including 21 men and 45 women with an average age of 43.6 ± 16.7 years old. The mean size of tumours was 2.7 ± 1.8 cm. The tumours were mainly located at the pancreatic head and neck (63.6%). The most common pathological diagnoses were insulinomas, followed by solid pseudopapillary tumours. Incidences of overall complications and pancreatic fistula (PF, Grade B) were 24.2% and 19.7%, respectively. No patient developed PF (Grade C) or died. Cases were divided into two groups according to whether the tumour was deeply embedded in the pancreas. Compared to the group with a superficial tumour (n = 36), the group with an embedded tumour (n = 30) had a longer operation time and drainage duration and a smaller tumour size (P < 0.05), but did not increase the incidence of complications and PF (Grade B/C).

CONCLUSION

Laparoscopic enucleation of tumours that were deeply embedded in the pancreas was technically feasible and safe.

The Landmark Series: Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) comprise a heterogeneous group of neoplasms arising from pancreatic islet cells that remain relatively rare but are increasing in incidence worldwide. While significant advances have been made in recent years with regard to systemic therapies for patients with advanced disease, surgical resection remains the standard of care for most patients with localized tumors. Although formal pancreatectomy with regional lymphadenectomy is the standard approach for most PNETs, pancreas-preserving approaches without formal lymphadenectomy are acceptable for smaller tumors at low risk for lymph node metastases. Furthermore, observation of small, asymptomatic, low-grade PNETs is a safe, initial strategy and is generally recommended for tumors < 1 cm in size. In this Landmark Series review, we highlight the critical studies that have defined the surgical management of PNETs.

Multivisceral robotic resection: a glimpse into the future of minimally invasive abdominal surgery

A 62-year-old man was referred to the Hepato-Pancreato-Biliary (HPB) surgeons with left upper quadrant discomfort. The initial investigations and CT scans revealed a tumour in the pancreatic tail with liver metastases, confirmed on MRI. It was initially thought to be an adenocarcinoma; however, further investigations found that it was a grade 1 neuroendocrine tumour with Ki 67 at 1% and it was agreed that he would undergo a total robotic surgery involving resection of the locally advanced tumour of the tail of pancreas, with the involvement of the stomach, and splenic flexure of the colon with liver metastases. The resulting procedure was a total robotic distal pancreatectomy, splenectomy, sleeve resection of stomach, cholecystectomy, atypical resection of two liver lesions and microwave ablation of multiple liver lesions. Four days post-operatively, he was discharged from hospital and commenced adjuvant chemotherapy. He currently enjoys a good quality of life.

Surgical management of primary pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are the second most common malignancy of the pancreas, and their incidence is increasing. PanNETs are a diverse group of diseases which range from benign to malignant, can be sporadic or associated with genetic mutations, and be functional or nonfunctional. In as much, the treatment and management of PanNETs can vary from a "Wait and See" approach to orthotopic liver transplantation (OLT). Despite this, surgical resection is still the primary treatment modality to achieve cure. This review focuses on the surgical management of PanNETs.

Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of tumors with complicated treatment options that depend on pathological grading, clinical staging, and presence of symptoms related to hormonal secretion. With regard to diagnosis, remarkable advances have been made: Chromogranin A is recommended as a general marker for pNETs. But other new biomarker modalities, like circulating tumor cells, multiple transcript analysis, microRNA profile, and cytokines, should be clarified in future investigations before clinical application. Therefore, the currently available serum biomarkers are insufficient for diagnosis, but reasonably acceptable in evaluating the prognosis of and response to treatments during follow-up of pNETs. Surgical resection is still the only curative therapeutic option for localized pNETs. However, a debulking operation has also been proven to be effective for controlling the disease. As for drug therapy, steroids and somatostatin analogues are the first-line therapy for those with positive expression of somatostatin receptor, while everolimus and sunitinib represent important progress for the treatment of patients with advanced pNETs. Great progress has been achieved in the combination of systematic therapy with local control treatments. The optimal timing of local control intervention, planning of sequential therapies, and implementation of multidisciplinary care remain pending.

Specific Growth Rate as a Predictor of Survival in Pancreatic Neuroendocrine Tumors: A Multi-institutional Study from the United States Neuroendocrine Study Group

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are often indolent; however, identifying patients at risk for rapidly progressing variants is critical, particularly for those with small tumors who may be candidates for expectant management. Specific growth rate (SGR) has been predictive of survival in other malignancies but has not been examined in PNETs.

METHODS

A retrospective cohort study of adult patients who underwent PNET resection from 2000 to 2016 was performed utilizing the multi-institutional United States Neuroendocrine Study Group database. Patients with ≥ 2 preoperative cross-sectional imaging studies at least 30 days apart were included in our analysis (N = 288). Patients were grouped as "high SGR" or "low SGR." Demographic and clinical factors were compared between the groups. Kaplan-Meier and log-rank analysis were used for survival analysis. Cox proportional hazard analysis was used to assess the impact of various clinical factors on overall survival (OS).

RESULTS

High SGR was associated with higher T stage at resection, shorter doubling time, and elevated HbA1c (all P ≤ 0.01). Patients with high SGR had significantly decreased 5-year OS (63 vs 80%, P = 0.01) and disease-specific survival (72 vs 91%, P = 0.03) compared to those with low SGR. In patients with small (≤ 2 cm) tumors (N = 106), high SGR predicted lower 5-year OS (79 vs 96%, P = 0.01). On multivariate analysis, high SGR was independently associated with worse OS (hazard ratio 2.67, 95% confidence interval 1.05-6.84, P = 0.04).

CONCLUSION

High SGR is associated with worse survival in PNET patients. Evaluating PNET SGR may enhance clinical decision-making, particularly when weighing expectant management versus surgery in patients with small tumors.

Lymphovascular Invasion Predicts Lymph Node Involvement in Small Pancreatic Neuroendocrine Tumors

INTRODUCTION

Pancreatic neuroendocrine tumors (p-NETS) are increasing in incidence, and prognostic factors continue to evolve. The benefit of lymphadenectomy for p-NETS ≤2 cm remains unclear. We sought to determine the significance of lymphovascular invasion (LVI) for small p-NETS.

METHODS

The National Cancer Database was queried for patients with p-NETS ≤2 cm and with ≥1 evaluated lymph node (LN), years 2004-2015. Demographic, clinical, and treatment characteristics were analyzed. Multivariate logistic regression was performed to identify predictors of LN positivity.

RESULTS

Among 2,499 patients identified, tumor location was delineated as the head (26%), body (18%), tail (38%), or unspecified (18%); 74% were well-differentiated versus 10% moderate, 2% poor, and 14% unknown. LVI occurred in 11%. A median of 9 LNs were evaluated; overall positivity was 18%. Mean survival was significantly longer in node-negative patients (115 vs. 95 months, log-rank p < 0.0001). LVI was the strongest predictor of node involvement (OR 10.4, p < 0.0001) when controlling for tumor size, grade, and location. Subset analysis of patients with known LVI status, grade, location, and mitoses found that LVI was more likely in the setting of moderate-to-high tumor grade, 1-2 cm size, pancreatic head location, and high mitotic rate. Among patients with ≥2 of these 4 factors, 25% were node-positive.

CONCLUSIONS

Presence of LVI was the strongest predictor of node positivity. LVI on endoscopic biopsy should prompt resection and regional LN dissection to fully stage patients with small p-NETS. Patients with other high-risk factors should also be considered for resection and regional lymphadenectomy.

The North American Neuroendocrine Tumor Society Consensus Paper on the Surgical Management of Pancreatic Neuroendocrine Tumors

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the surgical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The group reviewed a series of questions of specific interest to surgeons taking care of patients with pancreatic neuroendocrine tumors, and for each, the available literature was reviewed. What follows are these reviews for each question followed by recommendations of the panel.

Prognostic and predictive factors on overall survival and surgical outcomes in pancreatic neuroendocrine tumors: recent advances and controversies

Introduction: Recent advances in diagnostic modalities and therapeutic agents have raised the importance of prognostic factors in predicting overall survival, as well as predictive factors for surgical outcomes, in tailoring therapeutic strategies of patients with pancreatic neuroendocrine neoplasms (panNENs).Areas covered: Numerous recent studies of panNEN patients report the prognostic values of a number of clinically related factors (clinical, laboratory, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors on long-term survival. In addition, an increasing number of studies showed the usefulness of various factors, specifically biomarkers and molecular makers, in predicting recurrence and mortality related to surgical treatment. Recent findings (from the last 3 years) in each of these areas, as well as recent controversies, are reviewed.Expert commentary: The clinical importance of prognostic and predictive factors for panNENs is markedly increased for both overall outcome and post resection, as a result of recent advances in all aspects of the diagnosis, management and treatment of panNENs. Despite the proven prognostic utility of routinely used tumor grading/classification and staging systems, further studies are required to establish these novel prognostic factors to support their routine clinical use.

Exploratory Study of Apparent Diffusion Coefficient Histogram Metrics in Assessing Pancreatic Malignancy

PURPOSE

To evaluate whole-lesion 3D-histogram apparent diffusion coefficient (ADC) metrics for assessment of pancreatic malignancy.

METHODS

Forty-two pancreatic malignancies (36 pancreatic adenocarcinoma [PDAC], 6 pancreatic neuroendocrine [PanNET]) underwent abdominal magnetic resonance imaging (MRI) with diffusion-weighted imaging before endoscopic ultrasound biopsy or surgical resection. Two radiologists independently placed 3D volumes of interest to derive whole-lesion histogram ADC metrics. Mann-Whitney tests and receiver operating characteristic analyses were used to assess metrics' diagnostic performance for lesion histology, T-stage, N-stage, and grade.

RESULTS

Whole-lesion ADC histogram metrics lower in PDACs than PanNETs for both readers (P ≤ .026) were mean ADC (area under the curve [AUC] = 0.787-0.792), mean of the bottom 10th percentile (mean_0-10) (AUC = 0.787-0.880), mean of the 10th-25th percentile (mean_10-25) (AUC = 0.884-0.917) and mean of the 25th-50th percentile (mean_25-50) (AUC = 0.829-0.829). For mean_10-25 (metric with highest AUC for identifying PDAC), for reader 1 a threshold > 0.94 × 10^-3 mm²/s achieved sensitivity 94% and specificity 83%, and for reader 2 a threshold > 0.82 achieved sensitivity 97% and specificity 67%. Metrics lower in nodal status ≥ N₁ than N₀ for both readers (P ≤ .043) were mean_0-10 (AUC = 0.789-0.822) and mean_10-25 (AUC = 0.800-0.822). For mean_10-25 (metric with highest AUC for identifying N₀), for reader 1 a threshold <1.17 achieved sensitivity 87% and specificity 67%, and for reader 2 a threshold <1.04 achieved sensitivity 87% and specificity 83%. No metric was associated with T-stage (P > .195) or grade (P > .215).

CONCLUSION

Volumetric ADC histogram metrics may serve as non-invasive biomarkers of pancreatic malignancy. Mean_10-25 outperformed standard mean for lesion histology and nodal status, supporting the role of histogram analysis.