A multimodal approach to the management of neuroendocrine tumour liver metastases

Role of neoadjuvant peptide receptor radionuclide therapy in unresectable and metastatic gastro-entero-pancreatic neuroendocrine neoplasms: A scoping review

Peptide receptor radionuclide therapy (PRRT) is an established therapy for metastatic neuroendocrine neoplasms (NEN). The role of PRRT as a neoadjuvant treatment prior to surgery or other local therapies is uncertain. This scoping review aimed to define the landscape of evidence available detailing the utility of PRRT in the neo-adjuvant setting, including the clinical contexts, efficacy, and levels of evidence. A comprehensive literature search of PUBMED, SCOPUS, and EMBASE through to December 2022 was performed to identify reports of PRRT use as neoadjuvant therapy prior to local therapies. Observational studies and clinical trials were included. A total of 369 records were identified by the initial search, and 17 were included in the final analysis, comprising 179 patients treated with neoadjuvant PRRT. Publications included case reports, retrospective cohort series and a phase 2 trial. Definitions of unresectable disease were variable. Radioisotopes used included 177Lu (n = 142) and 90Y (n = 36), used separately (n = 178) or in combination (n = 1). A combination of PRRT with chemotherapy was also explored (n = 2). Toxicity data was reported in 11/17 studies. Survival analysis was reported in 3/17 studies. Surgical resection following PRRT was reported for both the primary tumor (n = 71) and metastases (n = 12). Resection rates could not be calculated as not all publications reported whether resection was completed. Published literature exploring the use of PRRT in the neoadjuvant setting is mostly limited to case reports and retrospective cohort studies. From these limited data there is reported to be a role of PRRT in neoadjuvant setting in the literature. However, the low quality of evidence precludes any definite conclusion on the grade of disease, site of primary, isotope used or use of concomitant chemotherapy that can benefit from this application. Further prospective studies will require collaboration between multiple centers to gain sufficient high-quality evidence.

The Surgical Management of Lung Neuroendocrine Neoplasms

This review summarizes key recent developments relevant to the surgical management of lung neuroendocrine neoplasms (L-NENs), including typical and atypical carcinoids, large cell neuroendocrine carcinoma, and small cell lung carcinoma. This review includes recent insights into the classification, clinical presentation, diagnostic workup, treatment options, and follow-up. Highlighted topics include general principles of surgery in localized or locally advanced or metastatic L-NENs, lung-sparing surgery for small, peripheral typical carcinoids, adjuvant and systemic therapies for typical and atypical carcinoids, and surgery and adjuvant therapies for large cell neuroendocrine carcinoma and small cell lung carcinoma.

Perioperative Carcinoid Crisis: A Systematic Review and Meta-Analysis

Simple Summary

Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication for patients with neuroendocrine tumors (NET). Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting the use of perioperative octreotide to prevent CC. The aim of our meta-analysis was to evaluate the existing evidence characterizing CC and the efficacy of prophylactic octreotide. We found that CC occurs frequently in patients having midgut NETs surgery, specifically those with NET liver metastasis, and is associated with worse postoperative outcomes. Our findings did not show a decreased risk in CC with prophylactic octreotide and questioned the advantage of routine prophylactic octreotide.

Abstract

Background: Surgery is the only curative option for patients with neuroendocrine tumors (NET) and is also indicated for debulking of liver metastasis. Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication. Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting its use. We sought to evaluate existing evidence characterizing CC and evaluating the efficacy of prophylactic octreotide. Methods: A systematic review was performed on studies including patients having surgery for well-differentiated NET and/or NET liver metastasis (2000–2021), and reporting data on the incidence, risk factors, or prognosis of CC, and/or use of prophylactic octreotide. Meta-analysis was performed using random-effects models. Results: Eight studies met inclusion criteria (n = 943 operations). The pooled incidence of CC was 19% (95% CI [0.06–0.36]). Liver metastasis (odds ratio 2.85 [1.49–5.47]) and gender (male 0.58 [0.34–0.99]) were the only significant risk factors. The occurrence of CC was associated with increased risk of major postoperative complications (2.12 [1.03–4.35]). The use of prophylactic octreotide was not associated with decreased risk of CC (0.73 [0.32–1.66]). Notably, there was no standard prophylactic octreotide strategy used. Conclusions: Intraoperative carcinoid crisis is a common complication occurring in up to 20% of patients with midgut NET and/or liver metastasis undergoing surgery. Prophylactic octreotide may not provide an efficient way to prevent this complication. Future studies should focus on prospective evaluation of well-defined prophylactic protocols using a standardized definition for CC.

Human Immunocompetent Model of Neuroendocrine Liver Metastases Recapitulates Patient-Specific Tumour Microenvironment

Neuroendocrine liver metastases (LM-NEN) develop in a considerable proportion of patients with gastroenteropancreatic neuroendocrine neoplasms. There is a paucity of experimental models that accurately recapitulate this complex metastatic human liver microenvironment precluding scientific and clinical advancements. Here, we describe the development of a novel personalised immunocompetent precision cut tumour slice (PCTS) model for LM-NEN using resected human liver tissue. The histological assessment throughout the culture demonstrated that slices maintain viability for at least 7 days and retain the cellular heterogeneity of the original tumour. Essential clinical features, such as patient-specific histoarchitecture, tumour grade, neuroendocrine differentiation and metabolic capacity, are preserved in the slices. The PCTS also replicate the tumor-specific immunological profile as shown by the innate and adaptive immunity markers analysis. Furthermore, the study of soluble immune checkpoint receptors in the culture supernatants proves that these immunomodulators are actively produced by LM-NEN and suggests that this process is epithelium-dependent. This model can be employed to investigate these pathways and provides a powerful platform for mechanistic, immunological and pre-clinical studies.

Y90 selective internal radiation therapy and peptide receptor radionuclide therapy for the treatment of metastatic neuroendocrine tumors: combination or not?

BACKGROUND

Peptide receptor radionuclide therapy and selective internal radiation therapy are effective radionuclide therapy modalities for unresectable metastatic neuroendocrine tumor patients that cannot be controlled with somatostatin analogs. The present study is intended to evaluate the therapeutic efficacy and toxicity of the combined therapy of selective internal radiation therapy and peptide receptor radionuclide therapy and stand-alone selective internal radiation therapy in patients with neuroendocrine tumor, a liver-dominant disease.

METHODS

This cohort consists of 27 patients with metastatic neuroendocrine tumor and liver-dominant disease. They were grouped as the patients who were treated with selective internal radiation therapy for unresectable liver metastasis (n = 15) and the patients who received a combination of selective internal radiation therapy and peptide receptor radionuclide therapy (n = 12) for hepatic and extrahepatic metastasis. Treatment efficacy and treatment-associated toxicity were retrospectively assessed in both groups.

RESULTS

The objective treatment response and stable disease were found in 13 patients (86.6%) in the selective internal radiation therapy group and eight patients (66.6%) in the selective internal radiation therapy + peptide receptor radionuclide therapy group. The median overall survival rate was found to be 34.9 months, in the selective internal radiation therapy group and 67.5 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.217). The median progression-free survival data was not reached, and the mean values of progression-free survival were 53.1 ± 9.9 months in the selective internal radiation therapy group, and 27.2 ± 5.9 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.561). Temporary lymphopenia was the most common side effect. Grade 1-2 hepatotoxicity was observed to be 6.6% in the selective internal radiation therapy group, while it was not observed in selective internal radiation therapy + peptide receptor radionuclide therapy group.

CONCLUSIONS

In the neuroendocrine tumors with liver-dominant metastatic disease, personalized selective internal radiation therapy and peptide receptor radionuclide therapy and their combinations result in increased survival rates. Selective internal radiation therapy alone could be an effective treatment in patients with liver-limited and -dominant disease.

Efficacy of Galium-68 DOTATATE PET/CT in the Detection of Metastasis Rate of Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors

Objective(s):

The aim of this study was to determine metastasis rate in patients with well-differentiated grade1 (G1) and grade 2 (G2) gastroenteropancreatic neuroendocrine tumors (GEP NETs) using the gallium-68 DOTATATE positron emission tomography/computed tomography (⁶⁸Ga-DOTATATE PET/CT). This study was also targeted toward investigating the relationship of maximum standardized uptake value (SUV_max) with mitotic count, histological grade, and Ki-67 index.

Methods:

This retrospective study included 38 patients (i.e., 17 males and 21 females) with G1 or G2 GEP NETs who underwent ⁶⁸Ga-DOTATATE PET/CT in Diyarbakir Gazi Yasargil training and research hospital between November 2014 and March 2018. The patients had at least one positive lesion that was approved by two nuclear medicine specialists with a minimum of 10 years of experience.

Results:

The median age of the patients was 50 years (age range: 27-80 years), and their mean age was 52±15 years. Out of 38 patients, 1 (2.6%), 2 (5.2%), 2 (5.2%), 3 (7.8%), 10 (28.5%), and 19 (50%) patients had primary hepatic, primary mesenteric, colon, duodenal, gastric, and pancreatic NETs, respectively. In addition, the liver metastasis, local lymph node invasions, distant lymph node metastasis, bone metastasis, peritoneal involvement, and lung metastasis were observed in 42%, 21%, 15.7%, 13%, 7.8%, and 5% of the cases, respectively. The SUV_max median values of G1 and G2 tumors were 9.45 (range: 4.2-43.6) and 34.9 (range: 4.1-103), respectively (P=0.003). The Ki-67 index showed a negative correlation with the SUV_max value of the liver metastases and the highest SUV_max value (P=0.001 and P=0.002, respectively). There was also a negative correlation between mitosis count and the highest SUV_max value (P=0.011).

Conclusion:

Based on the findings, although [⁶⁸Ga]DOTATATE PET/CT is successfully used to diagnose primary GEP NETs and their metastases, the SUV_max value obtained from DOTATATE PET/CT showed a negative correlation with Ki-67 and mitotic count.

Systemic treatment for lung carcinoids: from bench to bedside

In the huge spectrum of lung neuroendocrine neoplasms, typical and atypical carcinoids should be considered as a separate biological entity from poorly differentiated forms, harboring peculiar molecular alterations. Despite their indolent behavior, lung carcinoids correlate with a worse survival. To date, only limited therapeutic options are available and novel drugs are strongly needed. In this work, we extensively reviewed scientific literature exploring available therapeutic options, new molecular targets and future perspectives in the management of well differentiated neoplasms of bronchopulmonary tree. Systemic therapy represents the main option in advanced and unresectable disease; accepted choices are somatostatin analogs, peptide receptor radionuclide therapy, everolimus and chemotherapy. To date, an univocal treatment strategy has not been identified yet, thus tailored therapeutic algorithms should consider treatment efficacy as well as safety profiles. Several molecular alterations found in carcinoid tumors might act as molecular targets leading to development of new therapeutic options. Further studies are necessary to identify new potential “druggable” molecular targets in the selected subset of low-grade lung carcinoids. Furthermore, evaluating the available therapies in more homogeneous population might improve their efficacy through a perfect tailoring of treatment options.

Outcome after hepatic resection for isolated non-colorectal, non-neuroendocrine liver metastases in 100 patients - the role of the embryologic origin of the primary tumor

Background

The indication for hepatic resection (HR) in patients suffering from liver metastases (LM) other than colorectal and neuroendocrine tumors is one focus of current multidisciplinary, oncologic considerations. This study retrospectively analyzes outcome after HR for non-colorectal, non-neuroendocrine (NCNNE) LM in the absence of distant or extrahepatic metastases.

Methods

We included 100 consecutive patients undergoing HR for isolated NCNNE LM from a prospective database in our institution, including postoperative follow-up. Primary tumors were of mesodermal origin in 44%, of ectodermal origin in 29% and of entodermal origin in 27%. Survival analysis was performed by univariate and multivariable methods. Mean follow-up after hepatic surgery was 3.6 years (0.25–16).

Results

Median age at the time of HR was 59.5 years. Kaplan-Meier-estimated survival after liver resection was 56.8%, 34.3% and 24.5% after 5, 10 and 15 years, respectively. Univariate analysis after HR revealed residual disease (hepatic or primary; p = 0.02), female gender (p = 0.013), entodermal origin (p = 0.009) and early onset of metastatic disease (≤24 months, p = 0.002), as negative prognostic factors. Multivariable survival analysis confirmed residual disease, female gender, entodermal embryologic origin and early onset of metastatic disease (≤24 months) as independent negative prognostic factors.

Conclusion

Overall outcome after HR of NCNNE LM results in acceptable long-term outcome. Although individual decision-making today mostly relies on clinical experience for this type of disease, risk factors derived from the embryologic origin of the tumor might help in patient selection.

Nothing But NET: A Review of Neuroendocrine Tumors and Carcinomas

This review covers the diverse topic of neuroendocrine neoplasms (NENs), a relatively rare and heterogeneous tumor type, comprising ~2% of all malignancies, with a prevalence of <200,000 in the United States, which makes it an orphan disease (Basu et al., 2010).1 For functional purposes, NENs are divided into two groups on the basis of clinical behavior, histology, and proliferation rate: well differentiated (low grade to intermediate grade) neuroendocrine tumors and poorly differentiated (high grade) neuroendocrine carcinoma (Bosman et al., 2010)2; this histological categorization/dichotomization is highly clinically relevant with respect to impact on treatment and prognosis even though it is not absolute since a subset of tumors with a low-grade appearance behaves similarly to high-grade lesions. Given the relative dearth of evidenced-based literature about this orphan disease as a whole (Modlin et al., 2008),3 since the focus of most articles is on particular anatomic subtypes of NENs (i.e., gastroenteropancreatic or pulmonary), the purpose of this review is to summarize the presentation, pathophysiology, staging, current standard of care treatments, and active areas of current research.

Neuroendocrine Tumors

Neuroendocrine tumors are increasingly diagnosed, either incidentally as part of screening processes, or for symptoms, which have commonly been mistaken for other disorders initially. The diagnostic workup to characterize tumor behaviour and prognosis focuses on histologic, anatomic, and functional imaging assessments. Several therapeutic options exist for patients ranging from curative and debulking surgery through to liver-directed therapies and systemic treatments. Multimodal therapies are often required over the patient's disease history. The management paradigm can be complex but should be focused on curative resections and then on controlling symptoms and limiting disease progression. There are several new systemic therapies that have completed phase 3 studies with new compounds being studied in phase 2. Genetic and epigenetic markers may lead to a new era of personalised therapy in the future.

The First Case Report of Robotic Multivisceral Resection for Synchronous Liver Metastasis from Pancreatic Neuroendocrine Tumor: A Case Report and Literature Review

INTRODUCTION

Surgery for liver metastases in pancreatic neuroendocrine tumor (PNET) improves overall survival rate. We present the first case report for robotic multivisceral resection of distal pancreas, spleen, and left liver for metastatic PNET.

MATERIALS AND METHODS

We present a case of 52-year-old female diagnosed with PNET in the pancreatic neck metastatic to the liver, responding to somatostatin and bland embolization, who underwent surgical debulking using da Vinci robotic platform. Intraoperative Doppler ultrasound was used to define the vascular distribution and tumor extension. The parenchymal liver transection was performed with vessel sealer. The distal pancreas and the spleen were approached medial to lateral and resected in an en-bloc fashion. The left liver inflow, outflow, and splenic artery and vein were transected with vascular stapler device.

RESULTS

Da Vinci robot-assisted multivisceral resection has been performed with good postoperative outcome. Operative time was 369 minutes and the estimated blood loss was 100 mL. The patient had a short hospital stay with quick recovery and good outcome at 5 months follow-up after the surgery.

DISCUSSION

Liver metastases in PNETs are considered an adverse factor. Aggressive surgical management is a mainstay. The laparoscopic approach to pancreatic or hepatic surgery is difficult in inexperienced hands with steep learning curve. The recent robotic system seems to overcome many limitations. This is the first case of robotic multivisceral resection for synchronous liver metastasis from PNET. Concurrent primary tumor resection with hepatectomy offers potential curative intention.

Incidental Detection of Neuroendocrine Carcinoma of Rectum During Staging Workup of Renal Cell Carcinoma

Malignancies of rectum and kidneys are common pathologies in clinical practice; however, the incidence of these malignancies coexisting together is unclear. The main purpose of this article was to show the usefulness of computed tomography (CT) in diagnosing these rare synchronous tumors. We report a case of neuroendocrine carcinoma of the rectum in a 57-year-old male patient who came for staging workup of renal cell carcinoma (RCC) of the left kidney. To our knowledge, this is the first case of synchronous RCC and rectal neuroendocrine carcinoma coexisting in the same patient.

Molecular response assessed by (68)Ga-DOTANOC and survival after (90)Y microsphere therapy in patients with liver metastases from neuroendocrine tumours

PURPOSE

We investigated the prognostic role of (68)Ga-DOTANOC in patients affected by hepatic metastases from neuroendocrine tumours (NET) undergoing (90)Y radioembolization ((90)Y-RE).

METHODS

A group of 15 consecutive patients with unresectable NET liver metastases underwent (68)Ga-DOTANOC PET at baseline and 6 weeks after (90)Y-RE. Molecular response was defined as a reduction of >50% in the tumour-to-spleen ratio (ΔT/S). The patients were divided into two groups (responders with ΔT/S >50% and nonresponders with ΔT/S <50%) Patients were followed up by imaging and laboratory tests every 3 months until death or for at least 36 months following (90)Y-RE. Statistical analysis was performed to identify factors predicting overall survival (OS) and progression-free survival (PFS).

RESULTS

A decrease in T/S ratio was seen in all patients on (68)Ga-DOTANOC PET scans performed after (90)Y-RE. Nine patients were classified as responders and six as nonresponders. The mean OS in all patients was 31.0 months. Responders had a significantly (p < 0.001) longer OS (mean 36.0 ± 2.5 months) and PFS (mean 29.7 ± 3.4 months) than nonresponders. In a multivariate analysis, none of the other examined variables including age, unilobar vs. bilobar locations, bilirubin levels, radiological response or the presence of extrahepatic disease significantly predicted patient outcome.

CONCLUSION

Molecular response assessed with (68)Ga-DOTANOC PET might be a useful predictor of survival in patients affected by NET liver metastases treated with (90)Y-RE.

Diagnosis and treatment of bronchopulmonary neuroendocrine tumours: State of the art

Bronchopulmonary neuroendocrine tumours (BP-NET) are a heterogeneous population of neoplasms with different pathology, clinical behaviour and prognosis compared to the more common lung cancers. The management of BP-NET patients is largely based on studies with a low level of evidence and extrapolation of data obtained from more common types of neuroendocrine tumours. This review reflects our view of the current state of the art of diagnosis and treatment of patients with BP-NET.

Surgical treatment of liver metastases in patients with neuroendocrine tumors

Liver metastases occur in 75% to 80% of patients with neuroendocrine tumors (NETs), and are considered significant adverse prognostic indicators. Management of NETs liver metastases is challenging and requires aggressive therapy. Currently, there are many therapeutic options for metastatic NETs. However, there is considerable controversy regarding the optimal management. Although complete surgical resection remains the optimal therapy, a variety of other minimally invasive surgical and medical options are available, this includes thermal ablative techniques (e.g., radiofrequency ablation, microwave ablation, cryotherapy), embolization using transcatheter embolization, chemoembolization, or radioembolization, and medical therapy (e.g., chemotherapy, biotherapy with somatostatin analogues and interferon). Currently there is no evidence-based data directly comparing surgical versus alternative liver-directed treatment options. An aggressive surgical approach, coupled with additional liver-directed procedures is often recommended as it extends the overall survival. Optimal patient care should be directed by a multidisciplinary team to assure that all treatment options are explored for decision-making while treating this aggressive disease.

Role of surgery and transplantation in the treatment of hepatic metastases from neuroendocrine tumor

Neuroendocrine tumors (NET) are a heterogeneous group of cancers, with indolent behavior. The most common primary origin is the gastro-intestinal tract but can also appear in the lungs, kidneys, adrenals, ovaries and other organs. In general, NET is usually discovered in the metastatic phase (40%-80%). The liver is the most common organ involved when metastases occur (40%-93%), followed by bone (12%-20%) and lung (8%-10%).A number of different therapeutic options are available for the treatment of hepatic metastases including surgical resection, transplantation, ablation, trans-arterial chemoembolization, chemotherapy and somatostatin analogues. Recently, molecular targeted therapies have been used, usually in combination with other treatment options, to improve outcomes in patients with metastases. This article emphasizes on the role of surgery in the treatment of liver metastases from NET.

Sequential Use of (90)Y Microspheres Radioembolization and (177)Lu-Dotatate in Pluri-Metastatic Neuroendocrine Tumors: A Case Report

(90)Y radioembolization and peptide-receptor radionuclide therapy (PRRT) with(177)Lu-DOTATATE are both effective treatments for patients with inoperable neuroendocrine metastatic tumors (NET). We report the case of a 72-year-old man with severe functional syndrome due to a metastatic NET. (68)Ga-DOTATOC positron-emission tomography (PET) revealed high somatostatin receptor expression in a gross liver metastasis, in one abdominal lymph node and in several skeletal lesions. The patient underwent liver radioembolization with (90)Y-resin microspheres followed by four cycles of PRRT with(177)Lu-DOTATATE. After 3 months, a complete remission of the functional syndrome was observed. (68)Ga-DOTATOC PET demonstrated a complete response for skeletal and lymph nodal lesions with a residual bulky mass in the liver. Therefore a further (90)Y radioembolization was performed as consolidation treatment for the hepatic lesion. Six months after these combined treatments, (68)Ga-DOTATOC PET demonstrated complete metabolic response in liver and stable extrahepatic lesions. No significant long-term adverse reactions were registered. To our knowledge, the sequential use of (90)Y radiembolization before and after PRRT in a liver-dominant advanced NET has not been reported in the literature and this case suggests that these combined treatments can be safe and effective.

Review article: the investigation and management of gastric neuroendocrine tumours

BACKGROUND

Gastric carcinoids (GCs) or neuroendocrine tumours (NETs) are increasingly identified at endoscopy, and account for 0.6-2% of all gastric polyps identified. The SEER database in the US has demonstrated a rising incidence of gastric NETs amongst all NETs; from 2.2% between 1950 and 1969 to 6.0% between 2000 and 2007.

AIM

To review the literature and assist clinicians in managing patients with GCs.

METHODS

A literature search was conducted through MEDLINE using search terms: gastric, carcinoid, neuroendocrine tumour, therapy, endoscopy, mucosal resection, submucosal dissection. Relevant articles were identified through manual review. The reference lists of these articles were reviewed to include further appropriate articles.

RESULTS

There are three types of GCs with important epidemiological, pathophysiological, histological and endoscopic differences that affect prognosis and management. Type 1 and 2 GCs develop in the context of hypergastrinaemia that originates from achlorhydria in atrophic gastritis and a gastrinoma, respectively. Type 3 GCs occur sporadically and independent of gastrin. The histological type, grade and Ki67 index are used to determine prognosis and direct clinical management. Type 1 GCs >1 cm in size and type 2 GCs should be assessed for invasion beyond the submucosa with EUS prior to endoscopic resection with EMR or ESD. Type 3 GCs should be managed as per recommendations for gastric adenocarcinoma. The treatment of advanced disease is multimodal.

CONCLUSIONS

Patients with gastric carcinoids should be discussed in a specialist neuroendocrine tumour multidisciplinary meeting to ensure all treatment options are explored in localised and advanced disease. Areas of controversy exist that need further research.

Nonsurgical Strategies in Patients With NET Liver Metastases: A Protocol of Four Systematic Reviews

BACKGROUND

Patients diagnosed with neuroendocrine tumors (NETs) with hepatic metastases generally have a worse prognosis as compared with patients with nonmetastasized NETs. Due to tumor location and distant metastases, a surgical approach is often not possible and nonsurgical therapeutic strategies may apply.

OBJECTIVE

The aim of these systematic reviews is to evaluate the role of nonsurgical therapy options for patients with nonresectable liver metastases of NETs.

METHODS

An objective group of librarians will provide an electronic search strategy to examine the MEDLINE, EMBASE, and The Cochrane Library (Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials [CENTRAL]) databases. There will be no restriction concerning language and publication date. The qualitative and quantitative synthesis of the systematic review will be conducted with randomized controlled trials (RCT), prospective, and retrospective comparative cohort, and case-control studies. Case series will be collected in a separate database and only used for descriptive purposes.

RESULTS

This study is ongoing and presents a protocol of four systematic reviews to assess the role of nonsurgical treatment options in patients with neuroendocrine liver metastases.

CONCLUSIONS

These systematic reviews, performed according to this protocol, will assess the value of noninvasive therapy options for patients with nonresectable liver metastases of NETs in combination with invasive techniques, such as percutaneous liver-directed techniques and local ablation techniques.

TRIAL REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO): CRD42012002657; http://www.metaxis.com/PROSPERO/full_doc.asp?RecordID=2657 (Archived by WebCite at http://www.webcitation.org/6NDlYi37O); CRD42012002658; http://www.metaxis.com/PROSPERO/full_doc.asp?RecordID=2658 (Archived by WebCite at http://www.webcitation.org/6NDlfWSuD); CRD42012002659; www.metaxis.com/PROSPERO/full_doc.asp?RecordID=2659 (Arichived by Webcite at http://www.webcitation.org/6NDlmWAFM); and CRD42012002660; http://www.metaxis.com/PROSPERO/full_doc.asp?RecordID=2660 (Archived by WebCite at http://www.webcitation.org/6NDmnylzp).

Diagnostic Value of (68)Ga-DOTATATE PET/CT in Liver Metastases of Neuroendocrine Tumours of Unknown Origin

PURPOSE

In neuroendocrine liver metastases of unknown primary, a multimodality approach is usually adopted and consists of transabdominal ultrasound, endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine techniques, endoscopy and exploratory surgery. The purpose of the study is to evaluate the diagnostic value of (68)Ga-DOTATATE positron emission tomography (PET)/CT as part of a multimodality approach in neuroendocrine liver metastases of unknown primary.

MATERIALS AND METHODS

Six patients (M:F = 5:1, age range 28-56 years) with immunohistochemically proven neuroendocrine liver metastases but inconclusive initial CT work-up were retrospectively analysed. Clinical finding, histopathology, comparative imaging and follow-up were used to validate the results when ethically justified.

RESULTS

(68)Ga-DOTATATE PET/CT identified the primary tumour in five out of six (83.3 %) patients: pancreas (n = 4) and stomach (n = 1). Out of three patients with indeterminate primary on initial CT, two patients were confirmed by (68)Ga-DOTATATE PET/CT. Absence of uptake in indeterminate primary of one patient was later confirmed negative by histopathology. In another three patients with undetected primary on initial CT, primary site was demonstrated in all patients with unsuspected metastases in two patients on (68)Ga-DOTATATE PET/ CT. No further work-up was done to confirm the primary in patients with distant metastases. Change of management was observed in three out of six (50 %) patients.

CONCLUSION

Our small study indicates that (68)Ga-DOTATATE PET/CT is a promising diagnostic option in the multimodality approach to neuroendocrine liver metastases of unknown primary origin.

Imaging features of carcinoid tumors of the gastrointestinal tract

OBJECTIVE

Recent studies have provided a better understanding of the biologic behavior of gastrointestinal carcinoid tumors. This article focusing on imaging of gastrointestinal carcinoids will emphasize epidemiology, molecular biology, taxonomy, histopathology, and management.

CONCLUSION

Gastrointestinal carcinoids are a biologically heterogeneous group of tumors, with variable clinical presentation and biologic behavior. Imaging can play an important role in multidisciplinary identification and management of this disease.

Molecular and therapeutic advances in the diagnosis and management of malignant pheochromocytomas and paragangliomas

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare catecholamine-secreting tumors derived from chromaffin cells originating in the neural crest. These tumors represent a significant diagnostic and therapeutic challenge because the diagnosis of malignancy is frequently made in retrospect by the development of metastatic or recurrent disease. Complete surgical resection offers the only potential for cure; however, recurrence can occur even after apparently successful resection of the primary tumor. The prognosis for malignant disease is poor because traditional treatment modalities have been limited. The last decade has witnessed exciting discoveries in the study of PCCs and PGLs; advances in molecular genetics have uncovered hereditary and germline mutations of at least 10 genes that contribute to the development of these tumors, and increasing knowledge of genotype-phenotype interactions has facilitated more accurate determination of malignant potential. Elucidating the molecular mechanisms responsible for malignant transformation in these tumors has opened avenues of investigation into targeted therapeutics that show promising results. There have also been significant advances in functional and radiological imaging and in the surgical approach to adrenalectomy, which remains the mainstay of treatment for PCC. In this review, we discuss the currently available diagnostic and therapeutic options for patients with malignant PCCs and PGLs and detail the molecular rationale and clinical evidence for novel and emerging diagnostic and therapeutic strategies.

Therapy of metastatic pancreatic neuroendocrine tumors (pNETs): recent insights and advances

Neuroendocrine tumors (NETs) [carcinoids, pancreatic neuroendocrine tumors (pNETs)] are becoming an increasing clinical problem because not only are they increasing in frequency, but they can frequently present with advanced disease that requires diagnostic and treatment approaches different from those used in the neoplasms that most physicians are used to seeing and treating. In the past few years there have been numerous advances in all aspects of NETs including: an understanding of their unique pathogenesis; specific classification systems developed which have prognostic value; novel methods of tumor localization developed; and novel treatment approaches described. In patients with advanced metastatic disease these include the use of newer chemotherapeutic approaches, an increased understanding of the role of surgery and cytoreductive methods, the development of methods for targeted delivery of cytotoxic agents, and the development of targeted medical therapies (everolimus, sunitinib) based on an increased understanding of the disease biology. Although pNETs and gastrointestinal NETs share many features, recent studies show they differ in pathogenesis and in many aspects of diagnosis and treatment, including their responsiveness to different therapies. Because of limited space, this review will be limited to the advances made in the management and treatment of patients with advanced metastatic pNETs over the past 5 years.