Treatment of liver metastases from neuroendocrine tumours in relation to the extent of hepatic disease

[Gastroenteropancreatic neuroendocrine neoplasms-Surgery in a multimodal concept]

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) are mainly found in the small intestine and pancreas. The course of the disease in patients is highly variable and depends on the degree of differentiation (G1-G3) of the neoplasm. The potential for metastasis formation of GEP-NEN is high even with good differentiation (G1). Lymph node metastases and, in many cases, liver metastases are also often found. Less common are bone metastases or peritoneal carcinomas. The treatment of these GEP-NENs is surgical, whenever possible. If an R0 resection with removal of all lymph node and liver metastases is successful, the prognosis of the patients is excellent. Patients with diffuse liver or bone metastases can no longer be cured by surgery alone. The long-term survival of these patients is nowadays possible due to the availability of drugs (e.g., somatostatin analogues, tyrosine kinase inhibitors), peptide receptor radionuclide therapy (PRRT) and liver-directed procedures, with a good quality of life.

Current Management of Neuroendocrine Tumour Liver Metastases

PURPOSE OF REVIEW

This article aims to illustrate the current state of investigations and management of liver metastases in patients with Neuroendocrine Neoplasms. Neuroendocrine tumours (NETs) are rising in incidence globally and have become the second most prevalent gastrointestinal malignancy in UK and USA. Frequently, patients have metastatic disease at time of presentation. The liver is the most common site of metastases for gastro-enteropancreatic NETs. Characterisation of liver metastases with imaging is important to ensure disease is not under-staged.

RECENT FINDINGS

Magnetic resonance imaging and positron emission tomography are now becoming standard of care for imaging liver metastases. There is an increasing armamentarium of therapies available for management of NETs and loco-regional therapy for liver metastases. The data supporting surgical and loco-regional therapy is reviewed with focus on role of liver transplantation. It is important to use appropriate imaging and classification of NET liver metastases. It is key that decisions regarding approach to treatment is undertaken in a multidisciplinary team and that individualised approaches are considered for management of patients with metastatic NETs.

Long-Term Survival Outcomes After Minimally Invasive Surgery for Ileal Neuroendocrine Tumors

BACKGROUND

Ileal neuroendocrine tumors (i-NETs) are characterized by their multifocality and bulky mesenteric mass. Having shown that minimally invasive surgery (MIS) utilizing a hand-access port device has favorable short-term outcomes and achieves the goals of surgery for i-NETs, we sought to analyze long-term survival outcomes of MIS.

METHODS

One hundred and sixty-eight patients who underwent resection of primary i-NETs at a single institution between January 2007 and February 2023 were retrospectively studied. Patients were categorized into the MIS or open surgery cohorts on an intention-to-treat basis. Open surgery was selected mainly based on the need for hepatectomy or bulky mesenteric mass resection. Overall survival was analyzed using log-rank tests with propensity score matching (PSM) and Cox proportional hazards regression. PSM was performed to reduce standardized mean differences of the variables to <0.2.

RESULTS

Overall, 129 (77%) patients underwent MIS and 39 (23%) underwent open surgery. Twenty-seven MIS patients were converted to an open procedure. The median follow-up time was 49 months (interquartile range 23-87 months). In the PSM cohorts, overall survival did not differ significantly between the MIS and open surgery cohorts {median 99 months (95% confidence interval [CI] 91-not applicable [NA]) vs. 103 months (95% CI 86-NA), p = 0.77; hazard ratio 0.87 (95% CI 0.33-2.2), p = 0.77}.

CONCLUSIONS

MIS is an alternative to open surgery for i-NETs, achieving similar short- and long-term oncological outcomes. Bulky mesenteric mass and a plan for concurrent liver resection are potential criteria for open surgery.

Impact of primary tumor resection in the management of metastatic well-differentiated neuroendocrine tumors of the small bowel and pancreas

Patients with gastroenteropancreatic (GEP) neuroendocrine tumors (NET) often present with advanced disease. Primary tumor resection (PTR) in the setting of unresectable metastatic disease is controversial. Most studies evaluating the impact of PTR on overall survival (OS) have been performed using large population-based databases, with limited treatment related data. This study aims to determine whether PTR improves OS and progression-free survival (PFS) in patients with metastatic well-differentiated GEP-NET. This is a retrospective single-institution study of patients with metastatic well-differentiated GEP-NET between 1978 and 2021. The primary outcome was OS. The secondary outcome was PFS. Chi-squared tests and Cox regression were used to perform univariate and multivariate analyses (MVA). OS and PFS were estimated using the Kaplan-Meier method and log-rank test. Between 1978 and 2021, 505 patients presented with metastatic NET, 151 of whom had well-differentiated GEP-NET. PTR was performed in 31 PNET and 77 SBNET patients. PTR was associated with improved median OS for PNET (136 vs. 61 months, p = .003) and SBNET (not reached vs. 79 months, p<.001). On MVA, only higher grade (HR 3.70, 95%CI 1.49-9.17) and PTR (HR 0.21, 95%CI 0.08-0.53) influenced OS. PTR resulted in longer median PFS for patients with SBNET (46 vs. 28 months, p = .03) and a trend toward longer median PFS for patients with PNET (20 vs. 13 months, p = .07). In patients with metastatic well-differentiated GEP-NET, PTR is associated with improved OS and may be associated with improved PFS and should be considered in a multidisciplinary setting. Future prospective studies are needed to validate these findings.

Liver-Directed Locoregional Therapies for Neuroendocrine Liver Metastases: Recent Advances and Management

Neuroendocrine tumors (NETs) are a heterogeneous class of cancers, predominately occurring in the gastroenteropancreatic system, which pose a growing health concern with a significant rise in incidence over the past four decades. Emerging from neuroendocrine cells, these tumors often elicit paraneoplastic syndromes such as carcinoid syndrome, which can manifest as a constellation of symptoms significantly impacting patients' quality of life. The prognosis of NETs is influenced by their tendency for metastasis, especially in cases involving the liver, where the estimated 5-year survival is between 20 and 40%. Although surgical resection remains the preferred curative option, challenges emerge in cases of neuroendocrine tumors with liver metastasis (NELM) with multifocal lobar involvement, and many patients may not meet the criteria for surgery. Thus, minimally invasive and non-surgical treatments, such as locoregional therapies, have surfaced. Overall, these approaches aim to prioritize symptom relief and aid in overall tumor control. This review examines locoregional therapies, encompassing catheter-driven procedures, ablative techniques, and radioembolization therapies. These interventions play a pivotal role in enhancing progression-free survival and managing hormonal symptoms, contributing to the dynamic landscape of evolving NELM treatment. This review meticulously explores each modality, presenting the current state of the literature on their utilization and efficacy in addressing NELM.

Cinematic Rendering of Pancreatic Neuroendocrine Tumours: Opportunities for Clinical Implementation: Part 2: Preoperative Planning and Evaluation of Metastatic Disease

Pancreatic neuroendocrine tumours (PNETs) are a rare subset of pancreatic tumours that have historically comprised up to 3% of all clinically detected pancreatic tumours. In recent decades, however, advancements in imaging have led to an increased incidental detection rate of PNETs and imaging has played an increasingly central role in the initial diagnostics and surgical planning of these tumours. Cinematic rendering (CR) is a 3D post-processing technique that generates highly photorealistic images through more realistically modelling the path of photons through the imaged volume. This allows for more comprehensive visualization, description, and interpretation of anatomical structures. In this 2-part review article, we present the first description of the various CR appearances of PNETs in the reported literature while providing commentary on the unique clinical opportunities afforded by the adjunctive utilization of CR in the workup of these rare tumours. This second instalment focuses on the applications of CR in optimizing preoperative planning of PNETs.

The Role of Liver Transplantation in the Treatment of Liver Metastases from Neuroendocrine Tumors

OPINION STATEMENT

Transplant oncology is a new field of medicine referred to the use of solid organ transplantation, particularly the liver, to improve prognosis and quality of life in cancer patients. In unresectable, liver-only metastases from neuroendocrine tumors (NETs) of the digestive tract, liver transplantation represents a competitive chance of cure. Due to the limited resource of donated organs, accurate patients' selection is crucial in order to maximize transplant benefit. Several tumor- and patient-related factors should be considered. Among them, primary tumors with a low grade of differentiation (G1-G2 or Ki67 < 10%), located in a region drained by the portal system and removed before transplantation with at least 3-6 months period of disease stability observed before transplant listing, can be considered for transplantation. In case of NET located in the pancreas, extended lymphadenectomy should complement curative pancreatic resection. A number of other features are described in this review of liver transplantation for NET metastases. Comprehensive approach including various forms of non-surgical treatment and detailed planning and timing of total hepatectomy are discussed. Open issues remain on possible expansion of current criteria while maintaining the same long-term benefit demonstrated with the Milan NET criteria with respect to other non-transplant options, with particular reference to liver resection, peptide receptor radionuclide therapy, and locoregional and systemic treatments.

Long-Term Outcomes of Liver Transplantation for the Management of Neuroendocrine Neoplasms: A Systematic Review

Liver transplantation is an uncommonly used, controversially debated therapeutic approach for highly selected individuals with neuroendocrine liver metastases. Synthesising evidence regarding outcomes from this approach is crucial to understand its position within the broad neuroendocrine liver metastases armamentarium. In this narrative systematic review of studies published in PubMed, Scopus and OVID until 1 July 2021, we summarise and critically appraise the existing literature regarding this modality, with a special focus on long-term outcomes data where possible. Fourteen studies were identified that reported outcomes from the use of liver transplantation for metastatic neuroendocrine neoplasms. No randomised trials were identified. Generally, indications and selection criteria were poorly articulated, with the notable exception of studies using the Milan criteria. The median 5-year overall survival was 65% (ranging from 36% to 97.2%, 11 studies), and the median 10-year overall survival was 50% (ranging from 46.1% to 88.8%, 3 studies). One additional study focussed on treatments and outcomes following post-transplant recurrence. No studies reported outcomes past 10 years. Further follow-up of the largest series with explicit selection criteria will deepen our understanding of the role that transplantation has to play in this setting.

Management of Small Bowel Neuroendocrine Tumours: 10 Years' Experience at a Tertiary Referral Centre

BACKGROUND

Neuroendocrine tumours (NET) arising from the small bowel are clinically challenging and are often diagnosed at advanced stages. Disease control with surgery alone can be demanding. Multimodal treatment concepts integrating surgery and non-surgical modalities could be of benefit.

METHOD

Retrospective review of consecutive adult patients with SB NET treated at Imperial College Healthcare NHS Trust between 1 January 2010 and 31 December 2019. Data regarding clinicopathological characteristics, treatments, and disease trajectory were extracted and summarised. Overall and progression/recurrence-free survival were estimated at 5 and 10 years.

RESULTS

154 patients were identified, with a median age of 64 years (range 33-87); 135/154 (87.7%) had stage III/IV disease at diagnosis. Surgery was used in 125 individuals (81.2%), typically with either segmental small bowel resection (60.8%) or right hemicolectomy (33.6%) and mesenteric lymphadenectomy for the primary tumour. Systemic and/or liver-directed therapies were used in 126 (81.8%); 60 (47.6%) had more than one line of non-surgical treatment. Median follow-up was 67.2 months (range 3.1-310.4); overall survival at 5 and 10 years was 91.0% (95% CI: 84.9-94.7%) and 82.5% (95% CI: 72.9-88.9%), respectively. Imaging-based median progression-free survival was 42.7 months (95% CI: 24.7 to 72.4); 5-year progression-free survival was 63.4% (95% CI: 55.0-70.6%); 10-year progression-free survival was 18.7% (95% CI: 12.4-26.1). Nineteen patients (12.3%) reached 10 years follow-up without disease recurrence and therefore were considered cured.

CONCLUSIONS

Most patients with SB NET present in a metastasised stage. Multimodal treatment concepts may be associated with excellent clinical outcomes. Future work should explore optimal approaches to treatment sequencing and patient selection.

Developments in interventional management of hepatic metastases from neuroendocrine tumours

Neuroendocrine tumours commonly metastasise to the liver, particularly those arising from the intestinal tract and pancreas. Whilst surgery offers the only approach with intent to cure, the vast majority of patients with neuroendocrine liver metastases are ineligible. Liver-directed interventional therapies seek to exploit the patho-anatomy of the blood supply of hepatic metastases to deliver therapy to liver deposits. This may involve percutaneous ablation, bland embolization, or the selective infusion of chemotherapeutics, targeted agents or radiolabelled embolic material. Retrospective case series evidence has characterised objective response rates, disease control rates, and longer-term outcomes associated with each approach. Recent advances in this field include ongoing comparative trials of different techniques, but more importantly, combinations of interventional liver-directed therapies and other systemic therapy in multimodal treatment concepts.

A Comprehensive Review on Neuroendocrine Neoplasms: Presentation, Pathophysiology and Management

Neuroendocrine neoplasms (NENs) are a group of heterogeneous tumors with neuroendocrine differentiation that can arise from any organ. They account for 2% of all malignancies in the United States. A significant proportion of NEN patients experience endocrine imbalances consequent to increased amine or peptide hormone secretion, impacting their quality of life and prognosis. Over the last decade, pathologic categorization, diagnostic techniques and therapeutic choices for NENs-both well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs)-have appreciably evolved. Diagnosis of NEN mostly follows a suspicion from clinical features or incidental imaging findings. Hormonal or non-hormonal biomarkers (like serum serotonin, urine 5-HIAA, gastrin and VIP) and histology of a suspected NEN is, therefore, critical for both confirmation of the diagnosis and classification as an NET or NEC. Therapy for NENs has progressed recently based on a better molecular understanding, including the involvement of mTOR, VEGF and peptide receptor radionuclide therapy (PRRT), which add to the growing evidence supporting the possibility of treatment beyond complete resection. As the incidence of NENs is on the rise in the United States and several other countries, physicians are more likely to see these cases, and their better understanding may support earlier diagnosis and tailoring treatment to the patient. We have compiled clinically significant evidence for NENs, including relevant changes to clinical practice that have greatly updated our diagnostic and therapeutic approach for NEN patients.

Transplantation for metastatic liver disease

The liver is a common site of metastases from many cancers, particularly those originating in the gastrointestinal tract. Liver transplantation is an uncommonly used but promising and at times controversial treatment option for neuroendocrine and colorectal liver metastases. Transplantation with meticulous patient selection has been associated with excellent long-term outcomes in individuals with neuroendocrine liver metastases, but questions remain regarding the role of transplantation in those who could also be eligible for hepatectomy, the role of neoadjuvant/adjuvant treatments in minimising recurrence, and the optimal timing of the procedure. A prospective pilot study of liver transplantation for unresectable colorectal liver metastases that reported a 5-year overall survival rate of 60% reinvigorated interest in this area following initially dismal outcomes. This has been followed by larger studies, and prospective trials are ongoing to quantify the potential benefits of liver transplantation over palliative chemotherapy. This review provides a critical summary of currently available knowledge on liver transplantation for neuroendocrine and colorectal liver metastases, and highlights avenues for further study to address gaps in the evidence base.

Controversy Over Liver Transplantation or Resection for Neuroendocrine Liver Metastasis: Tumor Biology Cuts the Deal

BACKGROUND

In patients with neuroendocrine liver metastasis (NELM), liver transplantation (LT) is an alternative to liver resection (LR), although the choice of therapy remains controversial. In this multicenter study, we aim to provide novel insight in this dispute.

METHODS

Following a systematic literature search, 15 large international centers were contacted to provide comprehensive data on their patients after LR or LT for NELM. Survival analyses were performed with the Kaplan-Meier method, while multivariable Cox regression served to identify factors influencing survival after either transplantation or resection. Inverse probability weighting and propensity score matching was used for analyses with balanced and equalized baseline characteristics.

RESULTS

Overall, 455 patients were analyzed, including 230 after LR and 225 after LT, with a median follow-up of 97 months [95% confidence interval (CI): 85-110 months]. Multivariable analysis revealed G3 grading as a negative prognostic factor for LR [hazard ratio (HR)=2.22, 95% CI: 1.04-4.77, P =0.040], while G2 grading (HR=2.52, 95% CI: 1.15-5.52, P =0.021) and LT outside Milan criteria (HR=2.40, 95% CI: 1.16-4.92, P =0.018) were negative prognostic factors in transplanted patients. Inverse probability-weighted multivariate analyses revealed a distinct survival benefit after LT. Matched patients presented a median overall survival (OS) of 197 months (95% CI: 143-not reached) and a 73% 5-year OS after LT, and 119 months (95% CI: 74-133 months) and a 52.8% 5-year OS after LR (HR=0.59, 95% CI: 0.3-0.9, P =0.022). However, the survival benefit after LT was lost if patients were transplanted outside Milan criteria.

CONCLUSIONS

This multicentric study in patients with NELM demonstrates a survival benefit of LT over LR. This benefit depends on adherence to selection criteria, in particular low-grade tumor biology and Milan criteria, and must be balanced against potential risks of LT.

Diagnostic performance of PET/CT in the detection of liver metastases in well-differentiated NETs

BACKGROUND

The aim of this retrospective study was to compare the diagnostic accuracy of somatostatin receptor (SSR)-PET/CT to liver MRI as reference standard in the evaluation of hepatic involvement in neuroendocrine tumors (NET).

METHODS

An institutional database was screened for "SSR" imaging studies between 2006 and 2021. 1000 NET Patients (grade 1/2) with 2383 SSR-PET/CT studies and matching liver MRI in an interval of +3 months were identified. Medical reports of SSR-PET/CT and MRI were retrospectively evaluated regarding hepatic involvement and either confirmed by both or observed in MRI but not in SSR-PET/CT (false-negative) or in SSR-PET but not in MRI (false-positive).

RESULTS

Metastatic hepatic involvement was reported in 1650 (69.2%) of the total 2383 SSR-PET/CT imaging studies, whereas MRI detected hepatic involvement in 1685 (70.7%) cases. There were 51 (2.1%) false-negative and 16 (0.7%) false-positive cases. In case of discrepant reports, MRI and PET/CT were reviewed side by side for consensus reading. SSR-PET/CT demonstrated a sensitivity of 97.0% (95%CI: 96.0%, 97.7%), a specificity of 97.7% (95%CI: 96.3%, 98.7%), a PPV of 99.0% (95%CI: 98.4%, 99.4%) and NPV of 93.0% (95%CI: 91.0, 94.8%) in identifying hepatic involvement. The most frequent reason for false-negative results was the small size of lesions with the majority < 0.6 cm.

CONCLUSION

This study confirms the high diagnostic accuracy of SSR-PET/CT in the detection of hepatic involvement in NET patients based on a patient-based analysis of metastatic hepatic involvement with a high sensitivity and specificity using liver MRI imaging as reference standard. However, one should be aware of possible pitfalls when a single imaging method is used in evaluating neuroendocrine liver metastases in patients.

Neuroendocrine Tumor Diagnosis: PET/MR Imaging

Imaging plays a critical role in the diagnosis and management of neuroendocrine tumors (NETs). The initial workup of the primary tumor, including its characterization, local and distant staging, defines subsequent treatment decisions. Functional imaging using hybrid systems, such as PET combined with computed tomography, has become the gold standard. As NETs majorly arise from the gastrointestinal system and metastasize primarily to the liver, simultaneous PET and MR imaging with its high soft tissue contrast might be a valuable clinical one-stop-shop whole-body imaging tool. This review presents the current status and challenges of PET/MR imaging for diagnosis of NETs.

Tumour Heterogeneity and the Consequent Practical Challenges in the Management of Gastroenteropancreatic Neuroendocrine Neoplasms

Tumour heterogeneity is a common phenomenon in neuroendocrine neoplasms (NENs) and a significant cause of treatment failure and disease progression. Genetic and epigenetic instability, along with proliferation of cancer stem cells and alterations in the tumour microenvironment, manifest as intra-tumoural variability in tumour biology in primary tumours and metastases. This may change over time, especially under selective pressure during treatment. The gastroenteropancreatic (GEP) tract is the most common site for NENs, and their diagnosis and treatment depends on the specific characteristics of the disease, in particular proliferation activity, expression of somatostatin receptors and grading. Somatostatin receptor expression has a major role in the diagnosis and treatment of GEP-NENs, while Ki-67 is also a valuable prognostic marker. Intra- and inter-tumour heterogeneity in GEP-NENS, however, may lead to inaccurate assessment of the disease and affect the reliability of the available diagnostic, prognostic and predictive tests. In this review, we summarise the current available evidence of the impact of tumour heterogeneity on tumour diagnosis and treatment of GEP-NENs. Understanding and accurately measuring tumour heterogeneity could better inform clinical decision making in NENs.

Pancreatic Neuroendocrine Neoplasms Larger than 4 cm: A Retrospective Observational Study of Surgery, Histology, and Outcome

BACKGROUND

Pancreatic neuroendocrine neoplasms (pNENs) are often detected as large primary lesions, even with distant metastases, and their prognosis may be difficult to predict.

METHODS

In this retrospective study, we retrieved data of patients treated for a large pNEN in our Surgical Unit (1979-2017) to evaluate the possible prognostic role of clinic-pathological features and surgery. Cox-proportional hazard regression models were used to find possible associations among some variables (clinical features, surgery, and histology) and survival at univariate and multivariate analyses.

RESULTS

Among 333 pNENs, we identified 64 patients (19%) with a lesion > 4 cm. Patients' median age was 61 years, median tumor size was 6.0 cm, and 35 (55%) patients had distant metastases at diagnosis. There were 50 (78%) nonfunctioning pNENs, and 31 tumors localized in the body/tail region of the pancreas. Overall, 36 patients underwent a standard pancreatic resection (with 13 associated liver resection/ablation). Regarding histology, 67% of pNENs were N1, and 34% were grade 2. After a median follow-up of 48 months (up to 33 years), 42 patients died of disease. Median survival after surgery was 79 months, and six patients experienced recurrence (median DFS 94 months). At multivariate analysis, distant metastases were associated with a worse outcome, while having undergone radical tumor resection was a protective factor.

CONCLUSIONS

In our experience, about 20% of pNENs have a size > 4 cm, 78% are nonfunctioning, and 55% show distant metastases at diagnosis. Nevertheless, a long-term survival of more than five years may be achieved after surgery.

Treatment strategies for neuroendocrine liver metastases: a systematic review

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors are often diagnosed when metastatic. The liver is the main site of metastases. Unfortunately, optimal management of neuroendocrine liver metastases remains a topic of debate. The aim of this study was to make a systematic review of the current literature about the results of the different treatments of neuroendocrine liver metastases.

METHODS

A systematic review was conducted for English language publications from 1995 to 2021. Outcomes were analyzed according to survival, disease-free survival, and in the case of systemic therapies, progression-free survival.

RESULTS

5509 patients were analyzed in the review. 67% of patients underwent surgery achieving 5 years overall survival despite only 30% percent without a recurrence. 60% of patients that had received a transplant reached 5 years survival with a low disease-free survival rate (20%). Five-year survival rate was 36.2% for patients undergoing loco-regional therapies.

CONCLUSION

Surgical resection is the best treatment when metastases are resectable, with the highest rate of survival, although liver transplantation shows good results for patients not eligible for surgery. Loco-regional therapies may be useful when surgical resection is contraindicated, or selectively used as a bridge to surgery or transplantation. Systemic therapies are indicated in patients for whom curative treatment cannot be obtained.

Maximum Value on Arterial Phase Computed Tomography Predicts Prognosis and Treatment Efficacy of Sunitinib for Pancreatic Neuroendocrine Tumours

PURPOSE

This study was designed to assess the computed tomography maximum (CTmax) value on pretherapeutic arterial phase computed tomography (APCT) images to predict pancreatic neuroendocrine tumours (pNETs) recurrence and clarify its role in predicting the outcome of tumour therapy.

METHODS

This retrospective study enrolled 250 surgical patients and 24 nonsurgical patients with sunitinib-based treatment in our hospital from 2008 to 2019. CT images were assessed, the maximum value was defined as "CTmax," and recurrence-free survival (RFS) or progression-free survival (PFS) was compared between a high-CTmax group and a low-CTmax group among patients who underwent surgical resection or nonsurgical, sunitinib-based treatment according to the CTmax cutoff value.

RESULTS

In ROC curve analysis, a CTmax of 108 Hounsfield units, as the cutoff value, achieved an AUC of 0.796 in predicting recurrence. Compared with the low-CTmax group, the high-CTmax group had a longer RFS (p < 0.001). Low CTmax was identified as an independent factor for RFS (p < 0.001) in multivariate analysis; these results were confirmed using the internal validation set. The CTmax value was significantly correlated with the microvascular density (MVD) value (p < 0.001) and the vascular endothelial growth factor receptor 2 (VEGFR2) score (p < 0.001). Furthermore, the high-CTmax group had a better PFS than the low-CTmax group among the sunitinib treatment group (p = 0.007).

CONCLUSIONS

The tumour CTmax on APCT might be a potential and independent indicator for predicting recurrence in patients who have undergone surgical resection and assessing the efficacy of sunitinib for patients with advanced metastatic pNETs.

The Antiproliferative Activity of High-Dose Somatostatin Analogs in Gastro-Entero-Pancreatic Neuroendocrine Tumors: A Systematic Review and Meta-Analysis

Background: The antiproliferative activity of a high dose of somatostatin analogs (HD-SSA) in treating gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) remains under debate. Methods: A systematic review and proportion meta-analysis were made. The primary endpoint was the efficacy measured as incidence density ratio (IDR) at one year. The secondary endpoints were the disease control rate (DCR) and severe adverse events (SAEs). The heterogeneity (I2), when high (>50%), was interpreted by performing a univariate metaregression analysis, analyzing as covariates: type and design of the study, location (Europe or USA), sample size, grading according to 2017 WHO, the metastatic disease rate, previous therapy including surgery, and quality of the study. Results: A total of 11 studies with 783 patients were included. The IDR was 62 new progressions of 100 patients treated with HD-SSA every one year. The heterogeneity was high. The study’s year, type and design, primary tumor, grading, previous treatments, and quality of the studies did not influence the IDR. The IDR was significantly higher in USA centers and studies with more than 50 patients. The IDR was lower when a high rate of metastatic patients was present in the studies. The DCR was 45%. The heterogeneity was high. The DCR was lower in USA studies and in prospective trials. Conclusion: Given the limited efficacy of HD-SSA in preventing the disease progression in unresectable GEP-NENs after failure of standard dose SSA, the use of this therapeutic approach is advisable in selected cases when other antiproliferative treatments are not feasible.

Analysis of Tumor Burden as a Biomarker for Patient Survival with Neuroendocrine Tumor Liver Metastases Undergoing Intra-Arterial Therapies: A Single-Center Retrospective Analysis

PURPOSE

To assess the value of quantitative analysis of tumor burden on baseline MRI for prediction of survival in patients with neuroendocrine tumor liver metastases (NELM) undergoing intra-arterial therapies.

MATERIALS AND METHODS

This retrospective single-center analysis included 122 patients with NELM who received conventional (n = 74) or drug-eluting beads, (n = 20) chemoembolization and radioembolization (n = 28) from 2000 to 2014. Overall tumor diameter (1D) and area (2D) of up to 3 largest liver lesions were measured on baseline arterially contrast enhanced MR images. Three-dimensional quantitative analysis was performed using the qEASL tool (IntelliSpace Portal Version 8, Philips) to calculate enhancing tumor burden (the ratio between enhancing tumor volume and total liver volume). Based on Q-statistics, patients were stratified into low tumor burden (TB) or high TB.

RESULTS

The survival curves were significantly separated between low TB and high TB groups for 1D (p < 0.001), 2D (p < 0.001) and enhancing TB (p = 0.008) measurements, with, respectively, 2.7, 2.6 and 2.2 times longer median overall survival (MOS) in the low TB group (p < 0.001, p < 0.001 and p = 0.008). Multivariate analysis showed that 1D, 2D, and enhancing TB were independent prognostic factors for MOS, with respective hazard ratios of 0.4 (95%CI: 0.2-0.6, p < 0.001), 0.4 (95%CI: 0.3-0.7, p < 0.001) and 0.5 (95%CI: 0.3-0.8, p = 0.003).

CONCLUSION

The overall tumor diameter, overall tumor area, and enhancing tumor burden are strong prognostic factors of overall survival in patients with neuroendocrine tumor liver metastases undergoing intra-arterial therapies.

[Liver metastases of neuroendocrine tumors]

Neuroendocrine liver metastases (NELM) are very heterogeneous with respect to the clinical presentation and the prognosis. The treatment of NELMs requires a multidisciplinary approach and patients with NELM should be referred to a specialized center. When possible, the resection of NELMs provides the best long-term results. The general selection criteria for liver resection include an acceptable general physical condition for a large liver operation, tumors with a favorable differentiation grade 1 or 2, a lack of extrahepatic lesions, a sufficient residual liver volume and the possibility to resect at least 70% of the metastases. Supplementary treatment, including simultaneous liver ablation, are generally safe and can increase the number of patients who can be considered for surgery. For patients with resectable NELM, the resection of the primary tumor is recommended either in a 2-stage or combined procedure. In selected patients with nonresectable NELM a liver transplantation can be carried out, which can be associated with excellent long-term results.

Differenzierte Therapiestrategie bei Lebermetastasen gastro-entero-pankreatischer Neuroendokriner Neoplasien

Neuroendokrine Neoplasien (NEN) bilden eine heterogene Gruppe maligner Tumoren, die überwiegend dem gastro-entero-pankreatischen System (GEP) zuzuordnen sind. Hierbei sind Dünndarm und Pankreas die häufigsten Organe für Primärtumoren, die Leber stellt den dominanten Metastasierungsort dar. Da viele Patient*innen lange asymptomatisch bleiben, führen oftmals zufällig diagnostizierte Lebermetastasen oder ein Ileus zur Diagnose. Die einzige kurative Therapieoption stellt die komplette Entfernung von Primarius und Metastasen dar. Besonders im Falle der metastasierten Erkrankung sollten die vorhandenen Therapieoptionen immer im interdisziplinären Tumorboard mit Spezialisten*innen aus Gastroenterologie, (Leber-)Chirurgie, Radiologie, Nuklearmedizin, Radiotherapie, Pathologie und Endokrinologie evaluiert werden. Durch die Kombination der verschiedenen Therapieverfahren kann auch für Patient*innen mit fortgeschrittener Erkrankung eine jahrelange Prognose bei guter Lebensqualität erreicht werden. Wichtig für die Therapieentscheidung sind neben patientenindividuellen Faktoren der Differenzierungsgrad des Tumors, dessen hormonelle Sekretion, das Metastasierungsmuster und der Erkrankungsverlauf. Die Behandlung von Lebermetastasen umfasst neben den unterschiedlichen chirurgischen Strategien die lokal-ablativen radiologischen und nuklearmedizinischen Verfahren, die als Ergänzung zu den systemischen Therapien zur Verfügung stehen.

[Importance of surgery in distant metastatic pancreatic neuroendocrine neoplasms]

The majority of patients with pancreatic neuroendocrine neoplasms (pNEN) already present with distant metastases at diagnosis. The heterogeneity of pNEN and the broad spectrum of treatment options make adequate patient selection and an evidence-based strategy essential. In metastatic pNEN both primary resection and resection of liver metastases have been shown to improve overall survival. Surgical treatment of liver metastases can also be carried out with palliative intent, especially for symptomatic pNEN and can have a positive effect on disease-free survival and overall survival. Classical hepatectomy techniques and innovative techniques (two-stage resections, liver transplantation) are available to the surgeon. In complex growth types of liver metastases, there is increasing evidence for a combination of surgery and ablative methods. Due to a relevant risk of recurrence following liver resection, pNEN patients need to be included in multimodal treatment concepts. Current areas of interest in the treatment of metastatic pNEN are the use of adjuvant/neoadjuvant chemotherapy and surgery in G3-NEN and G3-NEC patients. The aim of this review is to give an overview on the impact of surgery in the situation of distant metastatic NEN of the pancreas.

Orchestrating Treatment Modalities in Metastatic Pancreatic Neuroendocrine Tumors-Need for a Conductor

Simple Summary

Pancreatic neuroendocrine tumors (pNET) are a heterogeneous and challenging entity, and today’s guidelines offer a variety of treatment modalities, while surgery has a clear role for patients with resectable tumors and early stages, advanced, or metastatic pNET may benefit from treatments that were evaluated in randomized controlled studies during the last year. With this review, we aim to provide an updated view on treatment options for metastatic pNET.

Abstract

Pancreatic neuroendocrine tumors (pNETs) are a vast growing disease. Over 50% of these tumors are recognized at advanced stages with lymph node, liver, or distant metastasis. An ongoing controversy is the role of surgery in the metastatic setting as dedicated systemic treatments have emerged recently and shown benefits in randomized trials. Today, liver surgery is an option for advanced pNETs if the tumor has a favorable prognosis, reflected by a low to moderate proliferation index (G1 and G2). Surgery in this well-selected population may prolong progression-free and overall survival. Optimal selection of a treatment plan for an individual patient should be considered in a multidisciplinary tumor board. However, while current guidelines offer a variety of modalities, there is so far only a limited focus on the right timing. Available data is based on small case series or retrospective analyses. The focus of this review is to highlight the right time-point for surgery in the setting of the multimodal treatment of an advanced pancreatic neuroendocrine tumor.

Prolonged progression-free survival achieved by octreotide LAR plus transarterial embolization in low-to-intermediate grade neuroendocrine tumor liver metastases with high hepatic tumor burden

Objective

To evaluate the efficacy and outcome of transarterial embolization (TAE) plus octreotide long‐acting repeatable (LAR) on patients with low‐to‐intermediate neuroendocrine tumor liver metastases (NETLM).

Methods

One hundred and sixteen patients with G1/G2 NETLM treated with TAE plus octreotide LAR at the First Affiliated Hospital, Sun Yat‐sen University between January 12, 2016 and September 24, 2020 were reviewed. Radiological response was evaluated according to response evaluation criterion in solid tumor version 1.1. Overall progression‐free survival (PFS) was assessed. Intrahepatic and extrahepatic PFS were evaluated in the whole cohort and in patients with the extrahepatic disease (EHD), respectively. Factors affecting treatment response and overall PFS were analyzed using the logistic regression model and Cox proportional hazard model. Adverse events were recorded and evaluated according to Common Terminology Criteria for Adverse Events 5.0.

Results

The median overall PFS of the whole cohort was 13.6 months. For the patients with EHD, the median intrahepatic PFS and extrahepatic PFS were 13.6 and 26.1 months, respectively. The median overall PFS of patients with hepatic tumor burden (HTB) <10%, 10%–25%, 25%–50%, and >50% were 25.2, 13.6, 11.2, and 12.3 months, respectively. Ki67 >10%, HTB >50%, and bone metastasis were independently associated with overall PFS. The objective response rate was 78.4%. In patients with HTB 25%–50% and >50%, responders (complete response or partial response) had significant prolonged PFS compared with nonresponders (stable disease or progression disease). Ki67 >10%, bone metastasis, and clear tumor margin were independently associated with response to TAE. The most frequent adverse events that occurred after TAE were postembolization syndrome, and no treatment‐associated death occurred during the perioperative period.

Conclusion

Transarterial embolization plus octreotide LAR can significantly prolong the PFS of neuroendocrine tumor liver metastases, especially with high HTB over 50%. Selected patients with HTB >25% (ki67 ≤10%, absence of bone metastasis, clear tumor margin) could derive prognostic advantage from the combined treatment.

Early Complications of Radioisotope Therapy with Lutetium-177 and Yttrium-90 in Patients with Neuroendocrine Neoplasms-A Preliminary Study

Neuroendocrine neoplasms (NENs) constitute a heterogenous group of tumors originating from neuroendocrine cells scattered throughout the body. Peptide Receptor Radionuclide Therapy (PRRT) is a treatment of choice of unresectable metastasized progressive and well-differentiated NENs. The aim of the study was to assess early bone marrow and kidney injury after administration of Lutetium-177 or Lutetium-177 combined with Yttrium-90. Thirty-one patients received treatment with [¹⁷⁷Lu]Lu-DOTATATE with the activity of 7.4 GBq. Eleven patients received tandem treatment with [⁹⁰Y]Y-DOTATATE with the activity of 1.85 GBq + [¹⁷⁷Lu]Lu-DOTATATE with the activity of 1.85 GBq. After PRRT a significant decrease in leukocyte, neutrophil, and lymphocyte counts was noted. Tandem treatment demonstrated a more marked decrease in white blood cell count compared to Lutetium-177 therapy only. Conversely, no significant influence on glomerular filtration was found in this assessment. However, PRRT triggered acute renal tubule dysfunction, regardless of the treatment type. Regarding the acute complications, PRRT appeared to be a safe modality in the treatment of patients with NEN.

OUP accepted manuscript

Background

Peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin receptor (SSR) analogs is now an established systemic treatment for neuroendocrine tumors (NET). However, more short- and long-term data about renal and hepatotoxicity is needed. Here we present our experience in this clinical scenario.

Methods

Eighty-six patients with progressive SSR-expressing malignancies underwent PRRT with Lu-177 Dotatate and were followed up for up to 2 years. Laboratory tests were done 1 week before each cycle and every 2 months at follow-up. Hepatic and renal toxicity was determined based on NCI CTCAE V5.0.

Results

55/86 (64%) patients completed all 4 cycles of PRRT; 18/86 (20.9%) are currently being treated; 13/86 (15.1%) had to discontinue PRRT: 4/13 (31%) due to hematologic toxicity, 9/13 (69%) due to non-PRRT-related comorbidities. Out of the patients who finished treatment, only transient grade 2 toxicities were observed during PRRT: hypoalbuminemia in 5.5% (3/55), and renal toxicity (serum creatinine and estimated glomerular filtration rate) in 1.8% (1/55). No grade 3 or 4 liver and renal toxicity occurred. Patients presenting with impaired liver or renal function prior to PRRT, either improved or had stable findings. No deterioration was observed.

Conclusion

Peptide receptor radionuclide therapy does not have a negative impact on liver and renal function, even in patients with pre-existing impaired parameters. No grade 3 or 4 hepatic or renal toxicity was identified. Only transient grade 2 hypoalbuminemia in 5.5% and nephrotoxicity in 1.8% of patients were seen during PRRT.

Is Long-Term Survival in Metastases from Neuroendocrine Neoplasms Improved by Liver Resection?

Background and Objectives: Although many of the neuroendocrine neoplasms (NEN) have a typically prolonged natural history compared with other gastrointestinal tract cancers, at least 40% of patients develop liver metastases. This study aims to identify whether liver resection improves the overall survival of patients with liver metastases from NEN. Materials and Methods: We conducted a retrospective study at “Fundeni” Clinical Institute over a time period of 15 years; we thereby identified a series of 93 patients treated for NEN with liver metastases, which we further divided into 2 groups as follows: A (45 patients) had been subjected to liver resection complemented by systemic therapies, and B (48 patients) underwent systemic therapy alone. To reduce the patient selection bias we performed at first a propensity score matching. This was followed by a bootstrapping selection with Jackknife error correction, with the purpose of getting a statistically illustrative sample. Results: The overall survival of the matched virtual cohort under study was 41 months (95% CI 37–45). Group A virtual matched patients showed a higher survival rate (52 mo., 95% CI: 45–59) than B (31 mo., 95% CI: 27–35), (p < 0.001, Log-Rank test). Upon multivariate analysis, seven independent factors were identified to have an influence on survival: location (midgut) and primary tumor grading (G3), absence of concomitant LM, number (2–4), location (unilobar), grading (G3) of LM, and 25–50% hepatic involvement at the time of the metastatic disease diagnosis. Conclusions: Hepatic resection is nowadays the main treatment providing potential cure and prolonged survival, for patients with NEN when integrated in a multimodal strategy based on systemic therapy.

What Are the Place and Modalities of Surgical Management for Pancreatic Neuroendocrine Neoplasms? A Narrative Review

Pancreatic neuroendocrine neoplasms (panNENs) are a heterogeneous group of tumors derived from cells with neuroendocrine differentiation. They are considered malignant by default. However, their outcomes are variable depending on their presentation in the onset of hereditary syndromes, hormonal secretion, grading, and extension. Therefore, although surgical treatment has long been suggested as the only treatment of pancreatic neuroendocrine neoplasms, its modalities are an evolving landscape. For selected patients (small, localized, non-functional panNENs), a "wait and see" strategy is suggested, as it is in the setting of multiple neuroendocrine neoplasia type 1, but the accurate size cut-off remains to be established. Parenchyma-sparring pancreatectomy, aiming to limit pancreatic insufficiency, are also emerging procedures, which place beyond the treatment of insulinomas and small non-functional panNENs (in association with lymph node picking) remains to be clarified. Furthermore, giving the fact that the liver is generally the only metastatic site, surgery keeps a place of choice alongside medical therapies in the treatment of metastatic disease, but its modalities and extensions are still a matter of debate. This narrative review aims to describe the current recommended surgical management for pancreatic NENs and controversies in light of the actual recommendations and recent literature.

Surgical Feasibility, Determinants, and Overall Efficacy of Neoadjuvant 177Lu-DOTATATE PRRT for Locally Advanced Unresectable Gastroenteropancreatic Neuroendocrine Tumors

We assessed 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) in the neoadjuvant setting in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). We also evaluated the variables associated with resectability of the primary tumor after PRRT. Methods: This study included 57 GEP-NET patients who had a primary tumor that was unresectable (because of vascular involvement as defined using the pancreatic ductal adenocarcinoma criteria of the National Comprehensive Cancer Network) and who underwent 177Lu-DOTATATE therapy without any prior surgery. They were categorized into 2 groups: 23 patients without liver metastases (group 1) and 34 patients with potentially resectable liver metastases (group 2). 177Lu-DOTATATE was administered with mixed amino acid-based renal protection at a dose of 7.4 GBq (200 mCi) per cycle. Surgical resectability was evaluated using triphasic contrast-enhanced abdominal CT imaging at 3 different time points during the PRRT course. Four broad categories of overall PRRT response were evaluated. The Kaplan-Meier product-limit method was used to calculate progression-free survival (PFS) and overall survival (OS). Associations between variables and a resectable primary tumor after PRRT were analyzed using the χ2 test, with a P value of less than 0.05 considered statistically significant. Results: After 177Lu-DOTATATE therapy, the unresectable primary tumor became resectable in 15 of 57 (26.3%) patients (7 patients in group 1 and 8 patients in group 2). A complete or partial response to PRRT was seen in 48 patients (84%), 23 patients (40%), 18 patients (31%), and 23 patients (40%) using symptomatic, biochemical, molecular imaging, and anatomic imaging criteria, respectively. Estimated rates of PFS were 95% and 90% at 2 y in groups 1 and 2, respectively. The 2-y OS of the 2 groups combined was 92.1%. The rate at which the primary tumor was resectable after PRRT was significantly higher in patients who had duodenal neuroendocrine tumors, patients who had GEP-NETs with no regional lymph node involvement, patients for whom the primary tumor was smaller than 5 cm, patients for whom liver metastases were no larger than 1.5 cm, patients for whom there were no more than 3 liver metastases, and patients for whom 18F-FDG uptake in the primary tumor had an SUVmax of less than 5. Conclusion: In a moderate fraction of GEP-NET patients, with or without liver metastases, whose primary tumor was unresectable because of vascular involvement, the primary tumor converted from unresectable to resectable after 177Lu-DOTATATE therapy, signifying that neoadjuvant PRRT can be considered in such patients. The effective control of symptoms, favorable morphologic and functional imaging response, and durable PFS and OS that we observed after 177Lu-DOTATATE PRRT may lead to less morbidity and mortality in these patients.

Management of Primary Hepatopancreatobiliary and Ampulla Large Cell Neuroendocrine Carcinoma

Background: Large cell neuroendocrine carcinoma (LCNEC) of the liver, gallbladder, pancreas, and ampulla is rare and usually arises in case reports, and thus to date, no studies have well described the treatment options and outcomes of those patients. Methods: The data of 108 patients diagnosed as hepatopancreatobiliary and ampulla LCNEC between 2004 and 2015 were retrieved from the surveillance, epidemiology, and final results. Results: In the entire cohort, the median overall survival (OS) was 10 months. For nonmetastatic patients, the median OS was 32 months for surgery of the primary tumor alone (n = 17), 19 months for surgery of the primary tumor and adjuvant therapy (n = 19), and 1 month for nonsurgical treatment (n = 8). For metastatic patients, the median OS was 14 months for patients who received surgery of the primary tumor with and without adjuvant therapy (n = 16), 9 months for patients undergoing adjuvant treatment alone (n = 30), and 1 month for patients who had no treatment (n = 16). Multivariate analysis revealed that surgery of the primary tumor was an independent factor for improved survival. Conclusions: This disease offers a very poor prognosis despite aggressive treatment. Radical resection is the first choice for resectable tumors, whereas surgical resection of the primary tumor plus adjuvant therapy might represent a valid option for metastatic disease. However, further studies are needed to confirm this.

Surgery after sunitinib administration to improve survival of patients with advanced pancreatic neuroendocrine neoplasms

BACKGROUND

Little research is available regarding the treatments combining surgical resection with systemic chemotherapy for advanced pancreatic neuroendocrine neoplasm patients. We retrospectively elucidated whether sunitinib administration before surgery in advanced pancreatic neuroendocrine neoplasm (Pan-NEN) patients increases survival.

METHODS

This study included 106 of 326 Pan-NEN patients with distant metastases and/or unresectable locally advanced tumors who visited our department to receive sunitinib for more than 1 mo during April 2002 to December 2019. Risk factors for overall survival (OS) and disease-free survival (DFS) were analyzed.

RESULTS

The median duration of preoperative sunitinib administration and observation time after sunitinib were 6 and 26.5 mo, respectively. Of 106 patients, 31 (29.2%) underwent surgery following sunitinib administration. Hepatectomy, synchronous hepatopancreatectomy, pancreatectomy, and lymphadenectomy were performed for 13, 12, 5, and 1 patient, respectively. The 5-y OS rates in the resected and nonresected groups were 88.9% and 14.1%, respectively (P < .001). In the multivariate analysis, the absence of surgical resection following sunitinib (hazard ratio [HR], 13.1; P = .001), poor differentiation (HR, 5.5; P = .007), and bilateral liver metastases (HR, 3.7; P = .048) were independent risk factors for OS, although large liver tumor volumes were more evident in the nonresected group, as patient characteristics. The median DFS was 16.1 mo in 22 patients who underwent R0/1 resections, and risk factors for postoperative recurrence were Ki-67 index >7.8% (HR, 7.4; P = .02) and R1 resection (HR, 4.4; P = .04).

CONCLUSION

Surgical resection after sunitinib administration improved OS in advanced Pan-NENs.

How to Manage Small Intestine (Jejunal and Ileal) Neuroendocrine Neoplasms Presenting with Liver Metastases?

PURPOSE OF REVIEW

Small intestinal neuroendocrine neoplasms (siNENs) are slowly growing tumours with a low malignant potential. However, more than half of the patients present with distant metastases (stage IV) and nearly all with locoregional lymph node (LN) metastases at the time of surgery. The value of locoregional treatment is discussed controversially.

RECENT FINDINGS

In stage I to III disease, locoregional surgery was currently shown to be curative prolonging survival. In stage IV disease, surgery may prolong survival in selected patients with the chance to cure locoregional disease besides radical/debulking liver surgery. It may improve the quality of life and may prevent severe local complications resulting in a state of chronic malnutrition and severe intestinal ischaemia or bowel obstruction. Locoregional tumour resection offers the opportunity to be curative or to focus therapeutically on liver metastasis, facilitating various other therapeutic modalities. Risks and benefits of the surgical intervention need to be balanced individually.

Hormonal tumor mapping for liver metastases of gastroenteropancreatic neuroendocrine neoplasms: a novel therapeutic strategy

PURPOSE

In patients with metastatic functional gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), it is unknown what degree of tumor reduction is required to eliminate hormonal symptoms. We aimed to reduce hormonal symptoms derived from advanced GEP-NENs by efficient minimal intervention, constructing a hormonal tumor map of liver metastases.

METHODS

Between 2013 and 2019, we treated 12 insulinoma or gastrinoma patients with liver metastases. Liver segments containing hormone-producing tumors were identified by injecting calcium gluconate via the hepatic arteries and monitoring the change in serum hormone concentration in the three hepatic veins. A greater-than-twofold increase in hormone concentration indicated a tumor-feeding vessel.

RESULTS

Cases included eight insulinomas and four gastrinomas. Primary lesions were functional in three patients and nonfunctional in 9. Nine patients showed hormonal step-up indicating the presence of functional lesions; eight showed step-up in tumor-bearing liver segments, while one with synchronous liver metastases showed step-up only in the pancreatic region. Five patients underwent surgery. Serum hormone concentration decreased markedly after removing the culprit lesions in 3; immediate improvement in hormonal symptoms was achieved in all patients. Three patients with previous surgical treatment who showed step-up underwent transcatheter arterial embolization, achieving temporary improvement of hormonal symptoms. Four patients showed unclear localization of the hormone-producing tumors; treatment options were limited, resulting in poor outcomes.

CONCLUSION

Hormonal tumor mapping demonstrated heterogeneity in hormone production among primary and metastatic tumors of GEP-NENs. Minimally invasive treatment based on hormonal mapping may be a viable alternative to conventional cytoreduction.

Liver-Directed Therapies for Neuroendocrine Neoplasms

PURPOSE OF REVIEW

To comprehensively synthesise and appraise the available evidence regarding therapies for metastatic neuroendocrine neoplasms that exploit the hepatic vasculature to deliver therapy to liver metastases.

RECENT FINDINGS

Various techniques including transarterial embolisation/chemoembolisation (TAE/TACE) and selective internal radiotherapy (SIRT, also termed radioembolisation [RE]) have been examined in patents with neuroendocrine liver metastases. Variations in the radioactive agents for selective internal radiotherapy (SIRT) have been explored, such as the use of Holmium-166, in addition to more established agents such as Yttrium-90. Recent trials have examined the safety and efficacy of combining liver-targeted therapy with systemic treatments, such as peptide receptor radionuclide therapy. More retrospective case series of liver-directed modalities will not provide additional knowledge. Randomised clinical trials have begun to compare the efficacy of different forms of liver-directed therapies, and also their combination with systemic treatment. Their results are expected to guide optimal treatment sequencing within multimodal concepts.

Outcomes of Simultaneous Resection of Small Bowel Neuroendocrine Tumors with Synchronous Liver Metastases

BACKGROUND

This study evaluated the short- and long-term outcomes of synchronous resection of liver metastases (LM) from small bowel neuroendocrine tumors (SB-NET).

METHODS

A retrospective review of patients undergoing resection for LMs from SB-NETs from January 1997 and December 2018 was performed.

RESULTS

There were 44 patients with synchronous SB-NET and LMs. Perioperative and 90-day mortality values were zero, and the morbidity rate was 27%. The median overall survival (OS) was 128.4 months (CI 95% 74.0-161.5 months) with 1-, 3-, 5-, and 10-year survival rates of 100%, 83%, 79%, and 60%, respectively. Not achieving surgical treatment for LM was the unique independent factor for survival (HR 6.50; CI 95% 1.54-27.28; p = 0.01) in patients with unresected LMs having OS and 10-year survival rates (42 months, 33%) versus patients undergoing liver resection (152 months, 66%)(p = 0.0008). The recurrence rate was 81.8% and associated with longer OS and 5-year survival rates when limited to the liver [223 months (61%) vs 94 months (87%)].

CONCLUSIONS

Simultaneous resection of SB-NETs with synchronous LMs was safe and associated with considerable long-term survival even in the presence of bilobar disease. However, recurrence after resection was common (81%) but associated with longer survival rates when limited to the liver.

Currently available treatment options for neuroendocrine liver metastases

Neuroendocrine neoplasms (NEN) are frequently characterized by a high propensity for metastasis to the liver, which appears to be a dominant site of distant-stage disease, affecting quality of life and overall survival. Liver surgery with the intention to cure is the treatment of choice for resectable neuroendocrine liver metastases (NELM), aiming to potentially prolong survival and ameliorate hormonal symptoms refractory to medical control. Surgical resection is indicated for patients with NELM from well-differentiated NEN, while its feasibility and complexity are largely dictated by the degree of liver involvement. As a result of advances in surgical techniques over the past decades, complex 1- and 2-stage, or repeat liver resections are performed safely and effectively by experienced surgeons. Furthermore, liver transplantation for the treatment of NELM should be anchored in a multimodal and multidisciplinary therapeutic strategy and restricted only to highly selected individual cases. A broad spectrum of interventional radiology treatments for NELM have recently been available, with expanding indications that are more applicable, as they are less limited by patient- and tumor-related parameters, being therefore important adjuncts or alternatives to surgery. Overall, liver-targeted treatment modalities may precede the administration of systemic molecular targeted agents and chemotherapy for patients with liver-dominant metastatic disease; these appear to be a crucial component of multimodal management of patients with NEN. In the present review, we discuss surgical and non-surgical liver-targeted treatment approaches for NELM, each complementing the other, with a view to assisting physicians in optimizing multimodal NEN patient care.

A literature-based treatment algorithm for low-grade neuroendocrine liver metastases

BACKGROUND

The optimal timing of treatment of liver metastases from low-grade neuroendocrine tumors (LG-NELM) varies significantly due to numerous treatment modalities and the literature supporting various treatment(s). This study sought to create and validate a literature-based treatment algorithm for LG-NELM.

METHODS

A treatment algorithm to maximize overall survival (OS) was designed using peer-reviewed articles evaluating treatment of LG-NELM. This algorithm was retrospectively applied to patients treated for LG-NELM at our institution. Deviation was determined based on whether or not a patient received treatment consistent with that recommended by the algorithm. Patients who did and did not deviate from the algorithm were compared with respect to OS and number of treatments.

RESULTS

Applying our algorithm to a 149-patient cohort, 57 (38%) deviated from recommended treatment. Deviation occurred in the form of alternative (28, 49%) versus additional procedures (29, 51%). Algorithm deviators underwent significantly more procedures than non-deviators (median 1 vs. 2, p < 0.001). Cox model indicated no difference in OS associated with algorithm deviation (HR 1.19, p = 0.58) when controlling for age and tumor characteristics.

CONCLUSION

This literature-based algorithm helps standardize treatment protocols in patients with LG-NELM and can reduce cost and risk by minimizing unnecessary procedures. Prospective implementation and validation is required.

The Revolution in Indication for Liver Transplantation: Will Liver Metastatic Disease Overcome the End-Stage Liver Disease in the Next Future?

Indications for liver transplantation (LT) have constantly been evolving during the last few decades due to a better understanding of liver diseases and innovative therapies. Likewise, also the underlying causes of liver disease have changed. In the setting of transplant oncology, recent developments have pushed the boundaries of oncological indications for LT outside hepatocellular carcinoma (HCC), especially for secondary liver tumors, such as neuroendocrine and colorectal cancer. In the next years, as more evidence emerges, LT could become the standard treatment for well-selected metastatic liver tumors. In this manuscript, we review and summarize the available evidence for LT in liver tumors beyond HCC with a focus on metastatic liver malignancies, highlighting the importance of these new concepts for future implications.

Distinct Expression Patterns of VEGFR 1-3 in Gastroenteropancreatic Neuroendocrine Neoplasms: Supporting Clinical Relevance, but not a Prognostic Factor

INTRODUCTION

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are an increasing tumor entity. Since many patients are diagnosed at an advanced stage, treatment is still challenging and dependent on many tumor and patient specific factors. Therefore, the aim of the present study was to elucidate the expression rates and the prognostic value of vascular endothelial growth factor receptor (VEGFR) 1-3 in GEP-NENs. A potential association to immune checkpoint markers was further investigated.

MATERIAL AND METHODS

The expression levels of VEGFR 1-3 were analyzed by immunohistochemistry and correlated with the expression of the checkpoint markers PD-1 and PD-L1. Furthermore, the tumor samples of 249 GEP-NEN patients were studied and correlated with overall survival rates and clinicopathological features. Kaplan-Meier analyses and the log rank test were used for survival analyses. Categorical variables were compared by the χ2 test.

RESULTS

The most common primary tumor site was the small intestine (50.6%), followed by the pancreas (25.7%). VEGFR 1 was highly expressed in 59%, VEGFR 2 in 6.4%, and VEGFR 3 in 61.8% of the analyzed samples. The expression of VEGFR 1-3 was not significantly associated with survival rates. Pancreatic NENs had the highest expression of VEGFR 1 and 3 in 80% of the cases. VEGFR 1-3 positivity correlated with the expression levels of immune checkpoint markers.

DISCUSSION

VEGFR 1-3 show a distinct expression pattern in different subgroups of neuroendocrine neoplasias indicating a conceivable target. Moreover, there was a substantial association between VEGFRs and immune checkpoint markers. Taken together, anti-VEGFR therapy represents a promising therapeutic approach in GEP-NEN patients and should be addressed in future studies.

Pattern of disease recurrence and treatment after surgery for nonfunctioning well-differentiated pancreatic neuroendocrine tumors

BACKGROUND

The risk of recurrence after curative surgery for pancreatic neuroendocrine tumors is reported to be between 10% and 30%. Among the available locoregional and systemic treatments, there are no specific recommendations regarding the best option for treating recurrent disease. The aims of this study were to evaluate the pattern of recurrence after surgery performed with curative intent for nonfunctioning pancreatic neuroendocrine tumors and to analyze the impact of treatment on disease progression.

METHODS

All patients submitted to curative surgery for sporadic, well-differentiated, nonfunctioning pancreatic neuroendocrine tumors at 2 Italian centers between 2001 and 2018, with evidence of disease recurrence during follow-up, were included (n = 46).

RESULTS

The most frequent type of recurrence was distant metastases (n = 38, 83%), located in the liver in 100% of cases, whereas 8 patients (17%) had an isolated local recurrence. Therapy for first disease recurrence included both locoregional (n = 14) and systemic treatments (n = 32). A second disease recurrence/progression occurred in 28 patients (61%). Patients who underwent systemic treatment after the first disease recurrence had better progression-free survival (1-year progression-free survival 78%) compared with those submitted to a locoregional procedure (1-year progression-free survival 50%; P = .007). Independent predictors of shortened progression-free survival after the first disease recurrence were the type of treatment (locoregional, hazard ratio 4.452, P = .001), the presence of necrosis (hazard ratio 2.732, P = .022) and age (>60 year, hazard ratio 2.494, P = .040).

CONCLUSION

Upfront locoregional treatment of the first recurrence of nonfunctioning pancreatic neuroendocrine tumors after curative surgery should be avoided in favor of systemic therapy.

Liver Tumor Burden in Pancreatic Neuroendocrine Tumors: CT Features and Texture Analysis in the Prediction of Tumor Grade and 18F-FDG Uptake

Pancreatic neuroendocrine tumors (p-NETs) are a rare group of neoplasms that often present with liver metastases. Histological characteristics, metabolic behavior, and liver tumor burden (LTB) are important prognostic factors. In this study, the usefulness of texture analysis of liver metastases in evaluating the biological aggressiveness of p-NETs was assessed. Fifty-six patients with liver metastases from p-NET were retrospectively enrolled. Qualitative and quantitative CT features of LTB were evaluated. Histogram-derived parameters of liver metastases were calculated and correlated with the tumor grade (G) and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) standardized uptake value (SUV). Arterial relative enhancement was inversely related with G (−0.37, p = 0.006). Different metastatic spread patterns of LTB were not associated with histological grade. Arterial_entropy was significantly correlated to G (−0.368, p = 0.038) and to Ki67 percentage (−0.421, p = 0.018). The ROC curve for the Arterial_entropy reported an area under the curve (AUC) of 0.736 (95% confidence interval 0.545–0.928, p = 0.035) in the identification of G1–2 tumors. Arterial_uniformity values were correlated to G (0.346, p = 0.005) and Ki67 levels (0.383, p = 0.033). Arterial_entropy values were directly correlated with the SUV (0.449, p = 0.047) which was inversely correlated with Arterial_uniformity (−0.499, p = 0.025). Skewness and kurtosis reported no significant correlations. In conclusion, histogram-derived parameters may predict adverse histological features and metabolic behavior of p-NET liver metastases.

Long-term outcome of surgical resection in patients with gastroenteropancreatic neuroendocrine neoplasia: results from a German nation-wide multi-centric registry

BACKGROUND

Neuroendocrine neoplasia (NEN) are rare and heterogenous tumours. Few data exist on the impact of surgical therapy.

MATERIALS AND METHODS

This is a retrospective analysis of prospectively collected data of gastroenteropancreatic NEN in the German NET-Registry (1999-2012). It focuses on patients without distant metastases (limited disease, LD, stage I-IIIB).

RESULTS

Data of 2239 patients with NEN were recorded. Median age was 59 years, the gender ratio was 1:1.3 (f:m). A total of 986 patients (44%) had LD, and the 5-year survival rate (5 years) was 77% for all and 90% for patients with LD. A total of 1635 patients (73%) received a surgical therapy (1st to 6th line); the 5 and 10 ysr were 83/65% after and 59/35% without surgery for all patients (p < .001). The resection margins in the LD patients were 76%, 16%, and 3% for R0, R1 and R2, respectively. The 10 ysr was 84%, 59% and 42% for R0, R1 and R2 resections, respectively (p = .021 R0/R1, p < .001 R0/R2). The R0 resection rate was 75% for G1/G2 NET and 67% for G3 NEC.

CONCLUSION

The rate of complete tumour resection (R0) in LD is independent of tumour grading, and R0 resection is the key determinant of long-term survival, as demonstrated by the 10 ysr. of 84%. All NEN patients with limited disease should be considered for operation, if possible, as the best 10-year survival is shown after an R0 resection.

ALPPS in neuroendocrine liver metastases not amenable for conventional resection - lessons learned from an interim analysis of the International ALPPS Registry

BACKGROUND

Surgery is the most effective treatment option for neuroendocrine liver metastases (NELM). This study investigated the role of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) as a novel strategy in treatment of NELM.

METHODS

The International ALPPS Registry was reviewed to study patients who underwent ALPPS for NELM.

RESULTS

From 2010 to 2017, 954 ALPPS procedures from 135 international centers were recorded in the International ALPPS Registry. Of them, 24 (2.5%) were performed for NELM. Twenty-one patients entered the final analysis. Overall grade ≥3b morbidity was 9% after stage 1 and 27% after stage 2. Ninety-day mortality was 5%. R0 resection was achieved in 19 cases (90%) at stage 2. Median follow-up was 28 (19-48) months. Median disease free survival (DFS) was 17.3 (95% CI: 7.1-27.4) months, 1-year and 2-year DFS was 73.2% and 41.8%, respectively. Median overall survival (OS) was not reached. One-year and 2-year OS was 95.2% and 95.2%, respectively.

CONCLUSIONS

ALPPS appears to be a suitable strategy for inclusion in the multimodal armamentarium of well-selected patients with neuroendocrine liver metastases. In light of the morbidity in this initial series and a high rate of disease-recurrence, the procedure should be taken with caution.