Update on the management of gastroenteropancreatic neuroendocrine tumors with emphasis on the role of imaging

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

Methodology of the SORENTO clinical trial: a prospective, randomised, active-controlled phase 3 trial assessing the efficacy and safety of high exposure octreotide subcutaneous depot (CAM2029) in patients with GEP-NET

BACKGROUND

The current standard of care (SoC) for the initial treatment of unresectable or metastatic well-differentiated gastroenteropancreatic neuroendocrine tumours (GEP-NET) requires initiation of first-generation somatostatin receptor ligand (SRL) therapy, octreotide and lanreotide, which provide safe and efficacious tumour/symptom control in most patients. However, disease progression can occur with SoC SRL treatment and the optimal dose response of SRL remains unknown. Octreotide subcutaneous depot (CAM2029) is a novel, long-acting, high-exposure formulation that has shown greater bioavailability and improved administration than octreotide long-acting release (LAR) with a well-tolerated safety profile. Retrospective data have highlighted a potential benefit of high-exposure SRL for improved disease control in patients who did not adequately respond to the current SoC SRL treatment. This trial will investigate the efficacy and tolerability of CAM2029 compared to the current SoC, including octreotide LAR and lanreotide autogel (ATG).

METHODS

SORENTO is a prospective, multicentre, randomised, active-controlled, open-label phase 3 trial aiming to demonstrate superiority of treatment with 20 mg octreotide subcutaneous depot (CAM2029) every 2 weeks (Q2W) compared to treatment with the Investigator's choice of SRL therapy at standard doses for tumour control (octreotide LAR 30 mg or lanreotide ATG 120 mg every 4 weeks [Q4W]) as assessed by progression-free survival (PFS) in approximately 300 patients with unresectable/metastatic and well-differentiated GEP-NET. Upon confirmation of disease progression (determined by a Blinded Independent Review Committee [BIRC] and defined as per RECIST 1.1), patients may enter an open-label extension treatment period with once weekly dosing, to investigate the effects of higher frequency dosing. Overall survival follow-up will end a maximum of 2 years after primary analysis. The primary endpoint will be analysed after 194 confirmed PFS events.

DISCUSSION

This is the first trial investigating the efficacy of CAM2029 versus SoC SRL therapy using a head-to-head, superiority trial design. It is expected to be the first trial to investigate the efficacy of increased dosing frequency of a high-exposure SRL. A BIRC will limit bias and measurement variability and ensure high-quality efficacy data. Additionally, inclusion of patients with well-differentiated Grade 3 NET may elucidate treatment strategies for this rarely investigated patient population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05050942. Registered on 21st September 2021.

Lanreotide Depot to Treat Gastroenteropancreatic Neuroendocrine Tumors in a US Community Oncology Setting: A Prospective, Observational Study

INTRODUCTION

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can result in symptoms such as diarrhea, flushing, abdominal pain, and fatigue and are often associated with a significant disease burden and poor prognosis. This non-interventional, prospective, observational study evaluated the real-world safety and effectiveness of lanreotide depot, a somatostatin analog (SSA) used to treat GEP-NETs, in a community setting.

METHODS

In this prospective, non-interventional study (NCT02730104), adult patients with locally advanced (inoperable), metastatic GEP-NETs treated with lanreotide depot were evaluated by their physician every 6 months from enrollment for 24 months. Clinically defined time to disease progression (TTDP) and overall survival (OS) were estimated for the total population and by primary tumor type (gastrointestinal [GI], pancreatic, unknown origin), and an exploratory analysis determined the rate of progression-free survival (PFS) at 12 and 24 months. Patient satisfaction was evaluated via the Treatment Satisfaction Questionnaire for Medication (TSQM-9), and safety information was recorded.

RESULTS

Of 99 patients, the 24-month PFS rate was 73.7% (95% confidence interval [CI] 63.1-81.7) and 24-month OS rate was 84.2% (95% CI 74.0-90.7). Median TTDP was not reached because few patients experienced disease progression during the study period. The majority of responding patients expressed satisfaction with treatment on each domain of the TSQM-9. Treatment-related adverse events (AEs) occurred in 19.2% of patients, while no serious AEs (SAEs) were related to the study drug.

CONCLUSIONS

Lanreotide depot is an effective and well-tolerated treatment for GEP-NETs in the real-world community setting.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02730104.

Risk of Radiation Exposure to Clinical Staff from Paracenteses of Large-Volume Chylous Ascites Following 177Lu-DOTATATE Infusion

¹⁷⁷Lu-DOTATATE has gained wide clinical acceptance for the treatment of advanced gastroenteropancreatic neuroendocrine tumors; however, little is known regarding its accumulation in ascites. As such, clinical staff performing paracenteses shortly after a treatment dose may be concerned about their potential radiation exposure, or the risk of contamination. Methods: In this report, therapeutic paracenteses were performed on a patient with metastatic intestinal carcinoid complicated by recurrent chylous ascites at various time intervals following a standard 7.4 GBq dose of ¹⁷⁷Lu-DOTATATE. Samples of the fluid were analyzed in a scintillation counter to estimate the concentration of radioactivity. Results: The concentration of activity in the ascitic fluid obtained 3 days after an infusion was exceptionally low (175.3 ± 25.9 Bq/mL). Conclusion: Our findings suggest that paracenteses conducted as soon as 3 days after a standard dose of ¹⁷⁷Lu-DOTATATE pose little to no risk in terms of radiation safety to staff performing the procedure.

Gastrointestinal neuroendocrine neoplasms (GI-NENs): hot topics in morphological, functional, and prognostic imaging

Neuroendocrine neoplasms (NENs) are heterogeneous tumours with a common phenotype descended from the diffuse endocrine system. NENs are found nearly anywhere in the body but the most frequent location is the gastrointestinal tract. Gastrointestinal neuroendocrine neoplasms (GI-NENs) are rather uncommon, representing around 2% of all gastrointestinal tumours and 20–30% of all primary neoplasms of the small bowel. GI-NENs have various clinical manifestations due to the different substances they can produce; some of these tumours appear to be associated with familial syndromes, such as multiple endocrine neoplasm and neurofibromatosis type 1. The current WHO classification (2019) divides NENs into three major categories: well-differentiated NENs, poorly differentiated NENs, and mixed neuroendocrine-non-neuroendocrine neoplasms. The diagnosis, localization, and staging of GI-NENs include morphology and functional imaging, above all contrast-enhanced computed tomography (CECT), and in the field of nuclear medicine imaging, a key role is played by ⁶⁸Ga-labelled-somatostatin analogues (⁶⁸Ga-DOTA-peptides) positron emission tomography/computed tomography (PET/TC). In this review of recent literature, we described the objectives of morphological/functional imaging and potential future possibilities of prognostic imaging in the assessment of GI-NENs.

A novel classification of portal venous tumor invasion to predict residual tumor status after surgery in patients with pancreatic neuroendocrine neoplasms

PURPOSE

To elucidate whether portal venous tumor invasion (PVTI) is a prognostic factor for patients with pancreatic neuroendocrine neoplasms (Pan-NENs).

METHODS

From 2002 to 2019, 240 patients with Pan-NEN were included to examine prognostic factors. PVTI based on computed tomography (CT) images are classified into four types: no PVTI (Vp0/1), PVTI not invading the superior mesenteric vein (Vp2), PVTI invading the superior mesenteric vein or portal vein (Vp3), and PVTI invading the portal bifurcation (Vp4).

RESULTS

Simultaneous liver metastases (SLM) determined the overall survival (OS) in 240 patients. The 5-year OS rates with and without SLM were 46% and 92%, respectively (P < 0.001). PVTIs were observed in 56 of the 240 patients (23%). Among such patients, 39, 11, and 6 had Vp2, Vp3, and Vp4, respectively. The 5-year OS rates with and without PVTI were 62% and 82%, respectively (P < 0.001). Severity of PVTI did not decide PFS and OS after R0/1 resection. There was significant difference in the prognoses between Vp0/1 and Vp2-4. In 161 patients without SLM, 21 had PVTI (13%). According to a multivariate analysis, PVTI and Ki-67 index were independent prognostic factors for progression-free survival (PFS) in patients without SLM. The 5-year PFS rates with and without PVTI were 18% and 77%, respectively (P < 0.001). The 5-year OS rates with and without PVTI were 76% and 95%, respectively (P = 0.02). PVTI was associated with tumor functionality, high serum NSE, and high Ki-67 index.

CONCLUSIONS

PVTI may be a predictor for postoperative recurrence.

Radiology of the neuroendocrine neoplasms of the gastrointestinal tract: a comprehensive review

Neuroendocrine neoplasms (NENs) are a group of neoplasms arising from the diffuse endocrine system (DES). The gastrointestinal tract (GIT) is the most common site of NEN. The WHO classification divides NEN into three broad categories viz. well-differentiated NENs, poorly differentiated NENs, and mixed neuroendocrine-non-neuroendocrine neoplasms. All GIT NEN have the potential to synthesize and secrete various bioactive substances which may lead to various clinical syndromes. The NEN may occur anywhere in the GIT and exhibit varying clinical presentation, prognosis, and metastatic potential. Further, some tumors show association with familial syndromes like multiple endocrine neoplasia type 1 and neurofibromatosis type 1. Ultrasonography, computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT are the imaging modalities useful in the diagnosis, localization, and staging of GIT NEN. Management depends on the site, size, grade, and stage of the tumor with interventional radiology playing a significant role in some cases. This imaging review describes the role of a radiologist in the management of GIT NEN.

Anatomic and Functional Imaging of Neuroendocrine Tumors

OPINION STATEMENT

Neuroendocrine tumors (NETs) can occur in a wide variety of organs and display a spectrum of pathologic behavior. Accurate and effective imaging is paramount to the diagnosis, staging, therapy, and surveillance of patients with NET. There have been continuous advancements in the imaging of NET which includes anatomic and functional techniques.

Tumour-to-liver ratio determined by [68Ga]Ga-DOTA-TOC PET/CT as a prognostic factor of lanreotide efficacy for patients with well-differentiated gastroenteropancreatic-neuroendocrine tumours

Abstract

Background

Lanreotide is a long-acting somatostatin analogue with proven antitumour effects against well-differentiated (WD) gastroenteropancreatic-neuroendocrine tumours (GEP-NETs). However, there are no globally established prognostic factors associated with the efficacy of lanreotide as a treatment for GEP-NETs. We investigated the prognostic value of [⁶⁸Ga]Ga-DOTA-TOC positron emission tomography (PET)/computed tomography (CT) somatostatin receptor imaging for patients with WD GEP-NETs treated with lanreotide.

Methods

In this retrospective study, we included 31 patients with unresectable or metastatic WD GEP-NETs who received lanreotide and underwent [⁶⁸Ga]Ga-DOTA-TOC PET/CT before receiving lanreotide. We captured the following clinicopathological variables: Eastern Cooperative Oncology Group (ECOG) performance status, primary tumour site, NET World Health Organization grade, existence of carcinoid symptoms, previous surgery, previous chemotherapy, and hepatic tumour volume assessed by CT or magnetic resonance imaging (MRI). We also assessed the following [⁶⁸Ga]Ga-DOTA-TOC PET/CT variables: Krenning score, tumour-to-liver ratio (TLR), maximum standardized uptake value (SUVmax), whole tumour volume (WTV), and total receptor expression (TRE, WTV multiplied by SUVmean). The associations between these markers and progression-free survival (PFS) with lanreotide were analysed.

Results

The mean age was 55.1 ± 15.5 years (range 16.0–81.0). The most common primary tumour site was the pancreas, followed by the stomach, and rectum. The median PFS interval with lanreotide was 14.4 months (range 1.3–34.9), with identified disease progression in 20 patients (64.5%). Among the [⁶⁸Ga]Ga-DOTA-TOC PET/CT variables, TLR (< 8.1 vs. ≥ 8.1; p = 0.013), SUVmax (< 42.9 vs. ≥ 42.9; p = 0.037), and WTV (≥ 58.9 cm³ vs. < 58.9 cm³; p = 0.030) were significantly associated with PFS in the univariate analyses, but only TLR (hazard ratio 3.182 [95% CI 1.189–8.514], p = 0.021) remained an independent factor for PFS in the multivariate analysis.

Conclusions

Low TLR, determined via [⁶⁸Ga]Ga-DOTA-TOC PET/CT, can be a factor of worse prognosis in patients with advanced WD GEP-NETs treated with lanreotide.

Correlation Between Apparent Diffusion Coefficient Value on MRI and Histopathologic WHO Grades of Neuroendocrine Tumors

Background

The correlation of diffusion-weighted MRI and tumor aggressiveness has been established for different tumor types, which leads to the question if it could also apply for neuroendocrine tumors (NET).

Purpose

To investigate the possible correlation between apparent diffusion coefficient (ADC) value on magnetic resonance imaging (MRI) and histopathologic WHO-grades of NET.

Material and Methods

Electronic patient records from patients presented at the multidisciplinary neuro-endocrine tumor board between November 2017 and April 2019 were retrospectively reviewed. Patients with both available MR imaging (primary tumor or metastasis) and known WHO tumor grade were included (n = 47). Average and minimum ADC values (avgADC; minADC) were measured by drawing a freehand ROI excluding only the outermost border of the lesion. The largest axial size (primary tumor) or most clearly delineated lesion (metastasis) was used.

Results

Forty seven patients met the inclusion criteria (mean age 59 ± 12 SD; 24F/23M). Twenty one patients (45%) were diagnosed with WHO G1 tumor, 17 seventeen with G2 (36%) and nine with G3 (19%) tumor. Twenty eight primary tumors and 19 metastases were measured. A significant difference was found between low-grade (G1+G2) and high-grade (G3) tumors (Mann-Whitney; avgADC: p < 0,001; minADC: p = 0,001). There was a moderate negative correlation between WHO-grade and avgADC/minADC (Spearman; avgADC: -0,606; 95% CI [-0,773; -0,384]; minADC: -0,581; 95% CI [-0.759; -0.353]).

Conclusion

Our data show a significant difference in both average and minimum ADC values on MRI between low and high grade NET. A moderate negative correlation was found between histopathologic WHO grade and ADC value.

The multidisciplinary team for gastroenteropancreatic neuroendocrine tumours: the radiologist's challenge

Background

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are a heterogeneous group of tumours. An effective diagnosis requires a multimodal approach that combines evaluation of clinical symptoms, hormonelevels, radiological and nuclear imaging, and histological confirmation. Imaging plays a critical role in NETs diagnosis, prognosis and management, so the radiologists are important members of the multidisciplinary team. During diagnostic work-up two critical issues are present: firstly the need to identify tumor presence and secondly to define the primary site and assess regional and distant metastases.

Conclusions

The most appropriate imaging technique depends on the type of neuroendocrine tumour and the availability of specialized imaging techniques and expertise. There is no general consensus on the most efficient imaging pathway, reflecting the challenge in reliably detection of these tumours.

Neuroendocrine Tumors in Pediatrics

Neuroendocrine cells are dispersed diffusely throughout many organ systems in the body and hence neuroendocrine tumors (NETs) can arise from almost anywhere in the body. NETs are considered rare tumors, and the current incidence is reported to be about 6 cases in 100 000 in adults and about 2.8 cases per million in the pediatric age group. Despite the indolent nature of these tumors, they have the potential for metastasis and significant morbidity. NETs can be asymptomatic at the time of diagnosis or can present with flushing, diarrhea, wheezing, weight loss, and fatigue among other symptoms. Due to the ambiguity of presenting symptoms, it is not uncommon for NETs to be diagnosed late in the disease course. Despite low incidence, the prevalence of the disease is high since patients live for many years and sometimes decades. Early detection of well-differentiated NETs has excellent outcomes with the majority of early-stage diseases being cured with surgical resection alone. There have been recent advancements in the management of metastatic progressive NETs with approval of peptide receptor radionuclide therapy, telotristat, and everolimus. Awareness of these rare tumors and its management is crucial for optimal management. This article will focus on pediatric NETs and current advances in its management.

What Is New in the 2017 World Health Organization Classification and 8th American Joint Committee on Cancer Staging System for Pancreatic Neuroendocrine Neoplasms?

The diagnosis and management of pancreatic neuroendocrine neoplasms (NENs) have evolved significantly in recent years. There are several diagnostic and therapeutic challenges and controversies regarding the management of these lesions. In this review, we focus on the recent significant changes and controversial issues regarding the diagnosis and management of NENs and discuss the role of imaging in the multidisciplinary team approach.

Intra-caval Percutaneous Radiofrequency Ablation for a Neuroendocrine Tumor (NET) Metastasis in Transplanted Liver

Less than 1% of patients with liver metastases from neuroendocrine tumors (NETs) are susceptible to liver transplantation. We report a case of a patient transplanted 13 years ago for NET metastases, with a lesion histologically proved for NET metastasis located at the cava vein anastomosis. He was treated with percutaneous radiofrequency ablation (RFA) after a first failed attempt of endovascular approach. The vascular heat sink, which RFA is susceptible to, was considered an advantage in this case, since it restricted the propagation of heat only to the tissue located in the very proximity of the RFA antenna, protecting the inferior vena cava vessel walls. This positive result may suggest an additional use of RFA in selected challenging cases.

Consensus document on the progression and treatment response criteria in gastroenteropancreatic neuroendocrine tumors

PURPOSE

Gastroenteropancreatic neuroendocrine tumors are a heterogeneous group of low incidence neoplasms characterized by a low proliferative activity and slow growth. Their response to targeted therapies is heterogeneous and often does not lead to tumor shrinkage. Thus, evaluation of the therapeutic response should differ from other kind of tumors.

METHODS

To answer relevant questions about which techniques are best in the assessment of progression or treatment response a RAND/UCLA-based consensus process was implemented. Relevant clinical questions were listed followed by a systematic search of the literature. The expert panel answered all questions with recommendations, combining available evidence and expert opinion. Recommendations were validated through a questionnaire and a participatory meeting.

RESULTS

Expert recommendations regarding imaging tools for tumor assessment and evaluation of progression were agreed upon. Available imaging techniques were reviewed and recommendations for best patient monitoring practice and the best way to evaluate treatment response were formulated.

Solid non-functioning endocrine tumors of the pancreas: correlating computed tomography and pathology

BACKGROUND

Since prognosis and treatment of pancreatic endocrine tumors (pNET) are based on tumor grade, contrast-enhanced multidetector computed tomography (MDCT) features of solid non-functioning pNETs were studied and correlated with pathology tumor grading.

METHODS

MDCTs of diagnosed pNETs were reviewed retrospectively. Each tumor was analyzed for location, size, homogeneity, margins, arterial and venous phase enhancement, main pancreatic duct diameter, calcifications, vascular invasion, lymph-nodes enlargement, and liver metastases.

RESULTS

Of 154 pNETs presenting between January 2000 and May 2016 with available histology from resected specimen or biopsy, there were 65 G1, 72 G2 and 17 G3 pNETs. Tumor diameter varied significantly between the three groups. Tumors >20 mm were more frequently malignant and non-homogeneous than smaller tumors. G1 tumors were more commonly hypervascular and G3 tumors more often non-hypervascular in the arterial phase. Arterial phase non-hyperdensity and tumor non-homogeneity had a higher rate of metastatic lesions. Vascular invasion correlated with presence of metastases and histological grade. G3 tumors were all >20 mm (p = 0.007), more often non-hypervascular in the arterial phase (p = 0.0025), and non-hyperdense in the venous phase (p = 0.009), and showed more often vascular invasion (p = 0.0198).

CONCLUSION

CT correlated with tumor grade; differentiating low-grade and high-grade pNETs through routine CT imaging might improve patient management.

Magnetic Resonance Imaging of Neuroendocrine Tumor Hepatic Metastases: Does Hepatobiliary Phase Imaging Improve Lesion Conspicuity and Interobserver Agreement of Lesion Measurements?

OBJECTIVE

The aim of this study was to determine if magnetic resonance imaging (MRI) performed with hepatobiliary phase imaging results in higher lesion conspicuity and produces lesion measurements with higher interobserver agreement than other MRI sequences when imaging neuroendocrine hepatic metastases.

METHODS

Patients who had MRIs with both gadoxetate disodium and gadopentetate dimeglumine contrast within a 6-month span were identified, and 23 hepatic lesions were selected. Three radiologists and 1 oncologist measured the greatest diameter of each lesion on the following sequences: T2 weighted, T1 weighted, postcontrast (dynamic, delayed, and hepatobiliary phase), and diffusion weighted. Signal intensity ratio (SIlesion/SIliver) and contrast-to-noise ratio ([SIlesion - SIliver]/noise) were calculated for all lesions on each sequence. The interobserver agreement of measurements on each sequence was calculated using concordance correlation coefficient.

RESULTS

Diffusion-weighted sequences had the highest signal intensity ratio ranging from 147% to 187% (vs other sequences range of 19.6%-130%). One hepatobiliary sequence had the highest contrast-to-noise ratio with a value of 41 (vs other sequences range of 3.2-28.1). Lesion measurements on all sequences showed high-interobserver agreement, with hepatobiliary sequences showing some of the highest levels of agreement.

CONCLUSIONS

Our results support the use of contrast agents with hepatobiliary excretion when imaging neuroendocrine tumors metastatic to liver.

The Surgical Management of Small Bowel Neuroendocrine Tumors: Consensus Guidelines of the North American Neuroendocrine Tumor Society

Small bowel neuroendocrine tumors (SBNETs) have been increasing in frequency over the past decades, and are now the most common type of small bowel tumor. Consequently, general surgeons and surgical oncologists are seeing more patients with SBNETs in their practices than ever before. The management of these patients is often complex, owing to their secretion of hormones, frequent presentation with advanced disease, and difficulties with making the diagnosis of SBNETs. Despite these issues, even patients with advanced disease can have long-term survival. There are a number of scenarios which commonly arise in SBNET patients where it is difficult to determine the optimal management from the published data. To address these challenges for clinicians, a consensus conference was held assembling experts in the field to review and discuss the available literature and patterns of practice pertaining to specific management issues. This paper summarizes the important elements from these studies and the recommendations of the group for these questions regarding the management of SBNET patients.

Pediatric Neuroendocrine Carcinoid Tumors: Review of Diagnostic Imaging Findings and Recent Advances

OBJECTIVE

Although rare, pediatric neuroendocrine tumors including carcinoid tumor have increased in incidence over the past few decades. Despite increased recognition, survival rates have not significantly improved. Earlier detection of these tumors is necessary to improve clinical outcomes. This article discusses imaging approaches for detecting pediatric carcinoid tumors including anatomic imaging methods such as CT and MRI as well as functional imaging methods targeting the somatostatin receptor including ¹¹¹In-labeled octreotide and newer ⁶⁸Ga-based radiotracers that may hold promise in hybrid PET/CT or PET/MRI.

CONCLUSION

Improvements in functional imaging with novel somatostatin receptor-specific radiotracers along with fused functional and anatomic imaging have substantially improved the clinical detection of carcinoid tumors. Although rare, these tumors are encountered in children, and an awareness of the appropriate use of various imaging methods is essential for pediatric specialists. Further research is needed to ascertain the diagnostic value of newer imaging methods and radiotracer-based treatment approaches, especially in the pediatric population.

Mesenteric changes in an ultrasound examination can facilitate the diagnosis of neuroendocrine tumors of the small intestine

Neuroendocrine tumors make up an interesting pathology of a variable clinical picture, prognosis, localization, endocrine activity and degree of malignancy.

Prognostic value of CT findings to predict survival outcomes in patients with pancreatic neuroendocrine neoplasms: a single institutional study of 161 patients

OBJECTIVES

To evaluate the prognostic value of CT to predict recurrence-free and overall survival in patients with pancreatic neuroendocrine neoplasms (PanNENs).

METHODS

Between January 2004 and December 2012, 161 consecutive patients who underwent preoperative triphasic CT and surgical resection with curative intent for PanNENs were identified. The tumour consistency, margin, presence of calcification, pancreatic duct dilatation, bile duct dilatation, vascular invasion, and hepatic metastases were evaluated. The tumour size, arterial enhancement ratio, and portal enhancement ratio were measured. The Cox proportional hazard model was used to determine the association between CT features and recurrence-free survival and overall survival.

RESULTS

By multivariate analysis, tumour size (>3 cm) (hazard ratio, 3.314; p = 0.006), portal enhancement ratio (≤1.1) (hazard ratio, 2.718; p = 0.006), and hepatic metastases (hazard ratio, 4.374; p = 0.003) were independent significant variables for worse recurrence-free survival. Portal enhancement ratio (≤1.1) (hazard ratio, 5.951; p = 0.001) and hepatic metastases (hazard ratio, 4.122; p = 0.021) were independent significant variables for worse overall survival.

CONCLUSIONS

Portal enhancement ratio (≤1.1) and hepatic metastases assessed on CT were common independent prognostic factors for worse recurrence-free survival and overall survival in patients with PanNENs.

KEY POINTS

• CT is useful to predict survival outcomes in patients with PanNENs. • Survival outcomes are associated with portal enhancement ratio and hepatic metastases. • Portal enhancement ratio is prognostic CT biomarker in patients with PanNENs.

Hormonal therapy in oncology: a primer for the radiologist

OBJECTIVE

The purpose of this article is to provide a comprehensive imaging review of the common hormonal therapies used in oncology and the side effects associated with them.

CONCLUSION

Commonly used hormones in oncology include corticosteroids, somatostatin analogues, progestins, gonadotropin-releasing hormone agonists and antagonists, antiandrogens, aromatase inhibitors, and selective estrogen receptor modulators. Familiarity with these hormones and their side effects can help radiologists to be vigilant for the side effects and complications of these agents.

In vitro and in vivo application of radiolabeled gastrin-releasing peptide receptor ligands in breast cancer

Breast cancer (BC) consists of multiple subtypes defined by various molecular characteristics, for instance, estrogen receptor (ER) expression. Methods for visualizing BC include mammography, MR imaging, ultrasound, and nuclear medicine-based methods such as (99m)Tc-sestamibi and (18)F-FDG PET, unfortunately all lacking specificity. Peptide receptor scintigraphy and peptide receptor radionuclide therapy are successfully applied for imaging and therapy of somatostatin receptor-expressing neuroendocrine tumors using somatostatin receptor radioligands. On the basis of a similar rationale, radioligands targeting the gastrin-releasing peptide receptor (GRP-R) might offer a specific method for imaging and therapy of BC. The aim of this study was to explore the application of GRP-R radioligands for imaging and therapy of BC by introducing valid preclinical in vitro and in vivo models.

METHODS

GRP-R expression of 50 clinical BC specimens and the correlation with ER expression was studied by in vitro autoradiography with the GRP-R agonist (111)In-AMBA. GRP-R expression was also analyzed in 9 BC cell lines applying (111)In-AMBA internalization assays and quantitative reverse transcriptase polymerase chain reaction. In vitro cytotoxicity of (177)Lu-AMBA was determined on the GRP-R-expressing BC cell line T47D. SPECT/CT imaging and biodistribution were studied in mice with subcutaneous and orthotopic ER-positive T47D and MCF7 xenografts after injection of the GRP-R antagonist (111)In-JMV4168.

RESULTS

Most of the human BC specimens (96%) and BC cell lines (6/9) were found to express GRP-R. GRP-R tumor expression was positively (P = 0.026, χ(2)(4) = 12,911) correlated with ER expression in the human BC specimens. Treatment of T47D cells with 10(-7) M/50 MBq of (177)Lu-AMBA resulted in 80% reduction of cells in vitro. Furthermore, subcutaneous and orthotopic tumors from both BC cell lines were successfully visualized in vivo by SPECT/CT using (111)In-JMV4168; T47D tumors exhibited a higher uptake than MCF7 xenografts.

CONCLUSION

Targeting GRP-R-expressing BC tumors using GRP-R radioligands is promising for nuclear imaging and therapy, especially in ER-positive BC patients.

Management of pancreatic neuroendocrine tumors

Abstract: 

Despite the rarity of the disease, there has been significant recent progress in the management of pancreatic neuroendocrine tumors (PNETs). Arterial phase imaging and somatostatin scintigraphy are important parts of the diagnostic and staging work-up of PNETs. The slow growth rate of PNETs can make observation a reasonable initial option in low volume asymptomatic disease or allow debulking surgery in selected patients with advanced disease. Somatostatin analogs, angiogenesis and mTOR inhibitors have proven benefit for PNET patients in randomized trials while retrospective and single-arm trials using chemotherapy or peptide receptor radiation therapy also appear promising. This review summarizes key aspects in the management of PNETs with emphasis on the most recent advances in systemic therapy.

The status of neuroendocrine tumor imaging: from darkness to light?

Diagnostic imaging plays a pivotal role in the diagnosis, staging, treatment selection and follow-up for neuroendocrine tumors. The available diagnostic strategies are morphologic imaging, including computed tomography, magnetic resonance imaging (MRI) and ultrasound techniques, and molecular imaging, including scintigraphy with (111)In-pentetreotide and positron emission tomography with (68)Ga-DOTA-peptides, (18)F-DOPA and (11)C-5-HTP. A combination of anatomic and functional techniques is routinely performed to optimize sensitivity and specificity. The introduction of diffusion-weighted MRI and dynamic contrast-enhanced techniques represents a promising advance in radiologic imaging, whereas new receptor-binding peptides, including somatostatin agonists and antagonists, represent the recent most favorable innovation in molecular imaging. Future development includes the short-term validation of these techniques, but in extension also a more comprehensive multilevel integration of biologic information pertaining to a specific tumor and patient, possibly encompassing genomic considerations, currently evolving as a new entity denoted 'precision medicine'. The ideal is a diagnostic sequence that captures the global status of an individual's tumor and encompasses a multidimensional characterization of tumor location, metabolic performance and target identification. To date, advances in imagery have focused on increasing resolution, discrimination and functional characterization. In the future, the fusion of imagery with the parallel analysis of biological and genomic information has the potential to considerably amplify diagnosis.

Neuroendocrine neoplasms of the pancreas at dynamic enhanced CT: comparison between grade 3 neuroendocrine carcinoma and grade 1/2 neuroendocrine tumour

OBJECTIVES

To identify the CT features in differentiating grade 3 neuroendocrine carcinomas from grade 1/2 neuroendocrine tumours.

METHODS

This study included 161 patients with surgically confirmed pancreatic neuroendocrine neoplasms. Pathology slides were reviewed to determine the tumour grade. CT image analysis included size, pattern, calcification, margin, pancreatic duct dilatation, bile duct dilatation, vascular invasion, arterial enhancement ratio, and portal enhancement ratio. We used 2 cm, 3 cm, and 4 cm as cutoff values of tumour size and 0.9 and 1.1 of enhancement ratio to determine the sensitivity and specificity.

RESULTS

Pathology analysis identified 167 lesions in 161 patients. 154 lesions (92 %) were grade 1/2 and 13 (8 %) were grade 3. Portal enhancement ratio (< 1.1) showed high sensitivity and specificity 92.3 % and 80.5 %, respectively in differentiating grade 3 from grade 1/2. It showed the highest odds ratio (49.60), followed by poorly defined margin, size (> 3 cm), bile duct dilatation, and vascular invasion. When at least two of these five criteria were used in combination, the sensitivity and specificity for diagnosing grade 3 were 92.3 % (12/13) and 87.7 % (135/154), respectively.

CONCLUSIONS

By using specific CT findings, grade 3 can be differentiated from grade 1/2 with a high diagnostic accuracy leading to an appropriate imaging staging.

KEY POINTS

• Neuroendocrine carcinomas should be differentiated from neuroendocrine tumours. • Neuroendocrine carcinomas can be differentiated from neuroendocrine tumours on dynamic CT. • Neuroendocrine carcinomas show iso- or hypo-enhancement on portal venous phase CT.