Complications of surgery for gastro-entero-pancreatic neuroendocrine neoplasias

Novel Surgical Initiatives in Gastroenteropancreatic Neuroendocrine Tumours

PURPOSE OF REVIEW

Neuroendocrine tumours (NET) are rare entities arising from hormone producing cells in the gastroentero-pancreatic (GEP) tract. Surgery is the most common treatment of GEP-NETs.

RECENT FINDINGS

Improvements in surgical techniques allow for more locally advanced and metastasised GEP-NETs to be resected. Laparoscopic and robotically--assisted approaches are increasingly being utilised in the resection of selected GEP-NETs and are facilitated by novel intraoperative tumour localisation tools and parenchyma-sparing methods. At the same time, some authors suggest that indications for formal resections of small well differentiated non-functioning pancreatic NETs and appendiceal NETs should be more restrictive. Advancements in surgery allows for tissue-sparing resections of GEP-NETs. Indications for surgical resection and the extent of the procedure are highly dependent on GEP-NET size, localisation and grading. Robotically assisted surgeries with intraoperative ultrasound and visualisation methods as well as vessel-sparing radical retrograde lymphadenectomies for small intestinal NETs seem to be the future of GEP-NET surgery.

Gastroenteropancreatic neuroendocrine neoplasms: epidemiology, genetics, and treatment

The incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) is increasing at a rapid pace and is becoming an increasingly important consideration in clinical care. Epidemiological data from multiple countries indicate that the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) exhibits regional, site-specific, and gender-based variations. While the genetics and pathogenesis of some GEP NEN, particularly pancreatic NENs, have been investigated, there are still many mechanisms that require further investigation. The management of GEP NEN is diverse, but surgery remains the primary option for most cases. Peptide receptor radionuclide therapy (PRRT) is an effective treatment, and several clinical trials are exploring the potential of immunotherapy and targeted therapy, as well as combination therapy.

Neoadjuvant 177Lu-DOTATATE for non-functioning pancreatic neuroendocrine tumours (NEOLUPANET): multicentre phase II study

BACKGROUND

Resection of non-functioning pancreatic neuroendocrine tumours (NF-PanNETs) is curative in most patients. The potential benefits of neoadjuvant treatments have, however, never been explored. The primary aim of this study was to evaluate the safety of neoadjuvant 177Lu-labelled DOTA0-octreotate (177Lu-DOTATATE) followed by surgery in patients with NF-PanNETs.

METHODS

NEOLUPANET was a multicentre, single-arm, phase II trial of patients with sporadic, resectable or potentially resectable NF-PanNETs at high-risk of recurrence; those with positive 68Ga-labelled DOTA PET were eligible. All patients were candidates for neoadjuvant 177Lu-DOTATATE followed by surgery. A sample size of 30 patients was calculated to test postoperative complication rates against predefined cut-offs. The primary endpoint was safety, reflected by postoperative morbidity and mortality within 90 days. Secondary endpoints included rate of objective radiological response and quality of life.

RESULTS

From March 2020 to February 2023, 31 patients were enrolled, of whom 26 completed 4 cycles of 177Lu-DOTATATE. A partial radiological response was observed in 18 of 31 patients, and 13 patients had stable disease. Disease progression was not observed. Twenty-four R0 resections and 4 R1 resections were performed in 29 patients who underwent surgery. One tumour was unresectable owing to vascular involvement. There was no postoperative death. Postoperative complications occurred in 21 of 29 patients. Severe complications were observed in seven patients. Quality of life remained stable after 177Lu-DOTATATE and decreased after surgery.

CONCLUSION

Neoadjuvant treatment with 177Lu-DOTATATE is safe and effective for patients with NF-PanNETs.

Comparative Analysis of Complications Following Distal Resections for Neuroendocrine Tumors and Adenocarcinoma: Unveiling the Differences

BACKGROUND Adenocarcinomas and pancreatic neuroendocrine tumors (pNETs) display some similarities and differences. The aim of this study was to compare preoperative data and morphological parameters, and to assess postoperative complications after resection. MATERIAL AND METHODS Data of 162 patients who underwent distal pancreatic resection for neuroendocrine or adenocarcinoma tumor were retrospectively analyzed. After applying inclusion and exclusion criteria, 131 patients were included in the study. The preoperative data analyzed included age, sex, and ASA-PS (American Society of Anesthesiologists Physical Status) grade. The diameter of the pancreatic duct and the texture of the pancreas were analyzed. Postoperative data included grading (G1-G3), the presence of PanIN (pancreatic intraepithelial neoplasia), infiltration of structures, and postoperative complications. RESULTS Patients with adenocarcinoma were statistically older and had a higher ASA-PS class than patients with NET (P<0.001). Statistically significantly more patients with adenocarcinoma had a histopathological diagnosis of G3 (p<0.001). In patients with adenocarcinomas infiltration of structures occurred more frequently. Pancreatic duct diameter ≥3 mm was more common in patients with adenocarcinoma (P=0.045). Clinically significant pancreatic fistulas were more frequent in patients with neuroendocrine tumors (P=0.044). CONCLUSIONS Adenocarcinomas in the pancreatic body and tail are more aggressive, they cause more frequent infiltration of structures, and more often metastasize to lymph nodes compared to NETs. NETs tend to have softer pancreatic texture and higher incidence of clinically significant pancreatic fistulas, but postoperative complications of Clavien-Dindo grade ≥III occur at a similar rate in both groups.

Surgery for advanced neuroendocrine tumours of the small bowel: recommendations based on a consensus meeting of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Small bowel neuroendocrine tumours often present with locally advanced or metastatic disease. The aim of this paper is to provide evidence-based recommendations regarding (controversial) topics in the surgical management of advanced small bowel neuroendocrine tumours.

METHODS

A working group of experts was formed by the European Society of Endocrine Surgeons. The group addressed 11 clinically relevant questions regarding surgery for advanced disease, including the benefit of primary tumour resection, the role of cytoreduction, the extent of lymph node clearance, and the management of an unknown primary tumour. A systematic literature search was performed in MEDLINE to identify papers addressing the research questions. Final recommendations were presented and voted upon by European Society of Endocrine Surgeons members at the European Society of Endocrine Surgeons Conference in Mainz in 2023.

RESULTS

The literature review yielded 1223 papers, of which 84 were included. There were no randomized controlled trials to address any of the research questions and therefore conclusions were based on the available case series, cohort studies, and systematic reviews/meta-analyses of the available non-randomized studies. The proposed recommendations were scored by 38-51 members and rated 'strongly agree' or 'agree' by 64-96% of participants.

CONCLUSION

This paper provides recommendations based on the best available evidence and expert opinion on the surgical management of locally advanced and metastatic small bowel neuroendocrine tumours.

[Indication and Surgical Procedures for MEN1-associated Duodenopancreatic Neuroendocrine Neoplasms]

The optimal therapy of duodenopancreatic neuroendocrine neoplasia (dpNEN), which occurs in the context of multiple endocrine neoplasia type 1, is still a major challenge and is controversial. Due to the rarity of the disease, there is a lack of prospective randomised studies, so that most recommendations regarding the surgical indication and procedure are based on retrospective case series. In summary, surgical therapy is indicated for non-functional dpNEN > 2 cm, suspected malignancy and functionally active dpNEN. Enucleation or formal pancreatic resections with or without lymphadenectomy may be considered. The aim of therapy should be to eliminate hormone-associated symptoms and prevent an aggressive metastatic disease. At the same time, pancreatic function and quality of life should be preserved in the mostly young patients by resections that save as much parenchyma as possible.

Optimal surgical approach for digestive neuroendocrine neoplasia primaries: Oncological benefits versus short and long-term complications

The rising incidence and the accumulating prevalence of neuroendocrine neoplasia (NEN) in the population makes this a common, prevalent and a clinically relevant disease group. Surgical resection represents the only potentially curative treatment for digestive NENs. Thus, resection should in principle be considered for all patients with NEN, although taking the patients age, relevant comorbidity, and performance status into account for operability. Patients with insulinomas, NEN of the appendix and rectal NENs are usually cured by surgery alone. However, less than a third of patients are amendable to curative surgery alone at time of diagnosis. Furthermore, recurrence is common and may occur years after primary surgery, hence the long follow-up time recommended in most NENs (>10 years). As many patients with NENs present with locoregional or metastatic disease, there is considerable debate regarding the role of debulking surgery in these settings. However, good long-term survival can be achieved in a considerable proportion of patients, with 50-70% alive up to 10 years after surgery. Location and grade are the main determinants of long-term survival. Here we present considerations to surgery for primary neuroendocrine tumors in the digestive tract.

Hereditary Endocrine Tumor Registries

Context

Endocrine neoplasia syndromes are phenotypically complex, and there is a misconception that they are universally rare. Genetic alterations are increasingly recognized; however, true prevalence is unknown. The purpose of a clinical registry is to monitor the quality of health care delivered to a specified group of patients through the collection, analysis, and reporting of relevant health-related information. This leads to improved clinical practice, decision-making, patient satisfaction, and outcome.

Objective

This review aims to identify, compare, and contrast active registries worldwide that capture data relevant to hereditary endocrine tumors (HETs).

Methods

Clinical registries were identified using a systematic approach from publications (Ovid MEDLINE, EMBASE) peer consultation, clinical trials, and web searches. Inclusion criteria were hereditary endocrine tumors, clinical registries, and English language. Exclusion criteria were institutional audits, absence of clinical data, or inactivity. Details surrounding general characteristics, funding, data fields, collection periods, and entry methods were collated.

Results

Fifteen registries specific for HET were shortlisted with 136 affiliated peer-reviewed manuscripts.

Conclusion

There are few clinical registries specific to HET. Most of these are European, and the data collected are highly variable. Further research into their effectiveness is warranted. We note the absence of an Australian registry for all HET, which would provide potential health and economic gains. This review presents a unique opportunity to harmonize registry data for HET locally and further afield.

Utility of fistula risk score in assessing the risk of postoperative pancreatic fistula occurrence and other significant complications after different types of pancreatic neuroendocrine tumor resections

Purpose

This study was performed to evaluate the utility of the fistula risk score (FRS) and its components in predicting the occurrence of postoperative pancreatic fistula and other significant postoperative complications after resections of pancreatic neuroendocrine tumors.

Methods

Retrospective analysis of 131 patients operated on for pancreatic neuroendocrine tumors between 2015 and 2021 was performed. The correlation of the FRS scale with the occurrence of postoperative pancreatic fistulas and postoperative complications according to the Clavien-Dindo classification was analyzed; only in 109 cases of distal resections and pancreatoduodenectomies (PD).

Results

Soft pancreatic texture and intraoperative blood loss of >700 mL are risk factors for clinically significant pancreatic fistula (P = 0.001 and P = 0.001, respectively) and significant postoperative complications (P = 0.016 and P = 0.001, respectively). Wirsung duct diameter (WDD) was associated only with the occurrence of postoperative pancreatic fistula (P = 0.013). FRS scale is associated with the occurrence of pancreatic fistulas and clinically significant postoperative complications in cases of distal resections and PDs (P < 0.001 and P = 0.005, respectively). Postoperative complications are correlated with the occurrence of fistula type B or C (P < 0.001).

Conclusion

Soft pancreatic texture, intraoperative blood loss of >700 mL, and a WDD of ≤3 mm are risk factors for clinically significant postoperative pancreatic fistula. FRS may be applied not only in PDs but also in distal pancreatectomies. Unfortunately, it is not used in total pancreatic resections and enucleations since FRS takes into account the WDD.

Predictive value of the preoperative prognostic nutritional index for postoperative progression in patients with pancreatic neuroendocrine neoplasms

Objective

The preoperative nutritional status of cancer patients is closely related to prognosis. The prognostic nutritional index (PNI) has been shown to predict the prognosis of a variety of tumors, but its study in pancreatic neuroendocrine neoplasms (pNENs) is lacking. The aim of the present study is to investigate the predictive value of the preoperative PNI for postoperative progression in patients with pNENs.

Methods

The medical records of 181 patients with pNENs, who underwent surgery, were retrospectively analyzed. A time-dependent receiver operating characteristic (ROC) curve was plotted to determine the optimal cut-off value of the preoperative PNI. Correlations between the preoperative PNI and clinicopathological parameters were analyzed using multiple linear regression. A Kaplan-Meier curve was applied to assess the progression-free survival (PFS) rate, which was tested using a log rank. Univariate and multivariate Cox proportional risk regression models were used to analyze the predictive value of the preoperative PNI on prognosis.

Results

The optimal cut-off value of the preoperative PNI was 48.275. The patients were divided into a high PNI group (PNI > 48.275, n = 92) and a low PNI group (PNI ≤ 48.275, n = 89). The proportion of patients with tumor progression after surgery was significantly higher in the low PNI group compared with that in the high PNI group (P = 0.004). The Kaplan-Meier curve showed that the PFS rate after surgery was significantly lower in the low PNI group compared with that in the high PNI group (P = 0.026). The preoperative PNI was an independent predictor of PFS (HR: 2.727, 95% CI: 1.174∼6.333, P = 0.020).

Conclusion

The preoperative PNI has a predictive value for postoperative progression in patients with pNENs.

Advances in the Diagnosis and Therapeutic Management of Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs)

Neuroendocrine neoplasms (NENs) are an increasingly common cause of neoplastic diseases. One of the largest groups of NENs are neoplasms localized to the gastroenteropancreatic system, which are known as gastroenteropancreatic NENs (GEP-NENs). Because of nonspecific clinical symptoms, GEP-NEN patient diagnosis and, consequently, their treatment, might be difficult and delayed. This situation has forced researchers all over the world to continue progress in the diagnosis and treatment of patients with GEP-NENs. Our review is designed to present the latest reports on the laboratory diagnostic techniques, imaging tests and surgical and nonsurgical treatment strategies used for patients with these rare neoplasms. We paid particular attention to the nuclear approach, the use of which has been applied to GEP-NEN patient diagnosis, and to nonsurgical and radionuclide treatment strategies. Recent publications were reviewed in search of reports on new strategies for effective disease management. Attention was also paid to those studies still in progress, but with successful results. A total of 248 papers were analyzed, from which 141 papers most relevant to the aim of the study were selected. Using these papers, we highlight the progress in the development of diagnostic and treatment strategies for patients with GEP-NENs.

Management of incidentally discovered appendiceal neuroendocrine tumors after an appendicectomy

Appendiceal neuroendocrine tumors (aNETs) are an uncommon neoplasm that is relatively indolent in most cases. They are typically diagnosed in younger patients than other neuroendocrine tumors and are often an incidental finding after an appendectomy. Although there are numerous clinical practice guidelines on management of aNETs, there is continues to be a dearth of evidence on optimal treatment. Management of these tumors is stratified according to risk of locoregional and distant metastasis. However, there is a lack of consensus regarding tumors that measure 1-2 cm. In these cases, some histopathological features such as size, tumor grade, presence of lymphovascular invasion, or mesoappendix infiltration must also be considered. Computed tomography or magnetic resonance imaging scans are recommended for evaluating the presence of additional disease, except in the case of tumors smaller than 1 cm without additional risk factors. Somatostatin receptor scintigraphy or positron emission tomography with computed tomography should be considered in cases with suspected residual or distant disease. The main point of controversy is the indication for performing a completion right hemicolectomy after an initial appendectomy, based on the risk of lymph node metastases. The main factor considered is tumor size and 2 cm is the most common threshold for indicating a colectomy. Other factors such as mesoappendix infiltration, lymphovascular invasion, or tumor grade may also be considered. On the other hand, potential complications, and decreased quality of life after a hemicolectomy as well as the lack of evidence on benefits in terms of survival must be taken into consideration. In this review, we present data regarding the current indications, outcomes, and benefits of a colectomy.

Effect of primary tumour resection without curative intent in patients with metastatic neuroendocrine tumours of the small intestine and right colon: meta-analysis

Background

Patients with small intestinal neuroendocrine tumours (siNETs) usually present with advanced disease. Primary tumour resection without curative intent is controversial in patients with metastatic siNETs. The aim of this meta-analysis was to investigate survival after primary tumour resection without curative intent compared with no resection in patients with metastatic siNETs.

Methods

A systematic literature search was performed, using MEDLINE® (PubMed), Embase®, Web of Science, and the Cochrane Library up to 25 February 2021. Studies were included if survival after primary tumour resection versus no resection in patients with metastatic siNETs was reported. Results were pooled in a random-effects meta-analysis, and are reported as hazard ratios (HRs) with 95 per cent confidence intervals. Sensitivity analyses were undertaken to enable comment on the impact of important confounders.

Results

After screening 3659 abstracts, 16 studies, published between 1992 and 2021, met the inclusion criteria, with a total of 9428 patients. Thirteen studies reported HRs adjusted for important confounders and were included in the meta-analysis. Median overall survival was 112 (i.q.r. 82–134) months in the primary tumour resection group compared with 60 (74–88) months in the group without resection. Five-year overall survival rates were 74 (i.q.r. 67–77) and 44 (34–45) per cent respectively. Primary tumour resection was associated with improved survival compared with no resection (HR 0.55, 95 per cent c.i. 0.47 to 0.66). This effect remained in sensitivity analyses.

Conclusion

Primary tumour resection is associated with increased survival in patients with advanced, metastatic siNETs, even after adjusting for important confounders.

Resection of Non-Functional Pancreatic Neuroendocrine Neoplasms-A Single-Center Retrospective Outcome Analysis

Surgery remains the only curative treatment of pancreatic neuroendocrine neoplasms (pNEN). Here, we report the outcome after surgery for non-functional pNEN at a European Neuroendocrine Tumor Society (ENETS) center in Germany between 2000 and 2019; cases were analyzed for surgical (Clavien–Dindo classification; CDc) and oncological outcomes. Forty-nine patients (tumor grading G1 n = 25, G2 n = 22, G3 n = 2), with a median age of 56 years, were included. Severe complications (CDc ≥ grade 3b) occurred in 11 patients (22.4%) and type B/C pancreatic fistulas (POPFs) occurred in 5 patients (10.2%); in-hospital mortality was 2% (n = 1). Six of seven patients with tumor recurrence (14.3%) had G2 tumors in the pancreatic body/tail. The median survival was 5.7 years (68 months; [1–228 months]). Neither the occurrence (p = 0.683) nor the severity of complications had an influence on the relapse behavior (p = 0.086). This also applied for a POPF (≥B, p = 0.609). G2 pNEN patients (n = 22) with and without tumor recurrence had similar median tumor sizes (4 cm and 3.9 cm, respectively). Five of the six relapsed G2 patients (83.3%) had tumor-positive lymph nodes (N+); all G2 pNEN patients with recurrence had initially been treated with distal pancreatic resection. Pancreatic resections for pNEN are safe but associated with relevant postoperative morbidity. Future studies are needed to evaluate suitable resection strategies for G2 pNEN.

Postoperative morbidity and mortality after surgical resection of small bowel neuroendocrine neoplasms: A systematic review and meta-analysis

Although small bowel resection is generally considered a low risk gastrointestinal procedure, this might not be true for small bowel neuroendocrine neoplasms (SB-NEN) as a result of potential central mesenteric involvement. We aimed to determine the reported morbidity and mortality after resection of SB-NEN in the literature and assess the effect of hospital volume on postoperative morbidity and mortality. A systematic review was performed by searching MEDLINE and Embase in March 2021. All studies reporting morbidity and/or mortality after SB-NEN resection were included. Pooled proportions of overall morbidity (Clavien-Dindo I-IV), severe morbidity (Clavien-Dindo III-IV), 30-day mortality, 90-day mortality and in-hospital mortality were calculated, as well as the association with hospital volume (high volume defined as the fourth quartile). Thirteen studies were included, with a total of 1087 patients. Pooled proportions revealed an overall morbidity of 13% (95% confidence interval [CI] = 7%-24%, I²  = 90%), severe morbidity of 7% (95% CI = 4%-14%, I²  = 70%), 30-day mortality of 2% (95% CI = 1%-3%, I²  = 0%), 90-day mortality of2% (95% CI = 2%-4%, I²  = 35%) and in-hospital mortality of 1% (95% CI = 0%-2%, I²  = 0%). An annual hospital volume of nine or more resections was associated with lower overall and severe morbidity compared to lower volume: 10% vs 15% and 4% vs 9%, respectively. Thirty-day mortality was similar (2% vs 1%) and 90-day mortality was higher in high-volume hospitals: 4% vs 1%. This systematic review with meta-analyses showed severe morbidity of 7% and low mortality rates after resection of SB-NEN. The currently available literature suggests a certain impact of hospital volume on postoperative outcomes, although heterogeneity among the included studies constrains interpretation.

Fluorescence angiography guided resection of small bowel neuroendocrine neoplasms with mesenteric lymph node metastases

BACKGROUND

Surgery for small bowel neuroendocrine neoplasms (SB-NEN) might result in vascular compromise of the remaining bowel due to resection of lymph node metastases in close proximity to main mesenteric vessels. Fluorescence angiography (FA) has been described as a safe technique to assess perfusion during gastro-intestinal surgery. This study aimed to evaluate the potential value of intraoperative FA during surgery for SB-NEN.

METHODS

This study included patients undergoing surgery for SB-NEN of any stage. The planned level of transection was marked by the surgeon, after which FA using indocyanine green (ICG) was performed. The primary study outcome was change in management due to FA.

RESULTS

Ten consecutive patients with SB-NEN were included, all with metastatic lymph nodes close to main mesenteric vessels. FA use led to management changes in eight patients (80%); four patients had less bowel resected with a preserved length of 5-35 cm. The other four patients had more extended bowel resections with an additional length varying from 3 to 25 cm. The median postoperative stay was 4 days (interquartile range 4-6). No anastomotic leakage occurred.

CONCLUSION

This is the first known series describing preliminary results of FA during SB-NEN surgery. FA led to a management change in 80% of patients with better tailoring the extent of resection of small bowel. Structural implementation of FA to assess small bowel perfusion after dissection for small bowel NET results in change of management, either by preserving small bowel or resecting ill-perfused small bowel.