Dosimetry and pharmacokinetics of [177Lu]Lu-satoreotide tetraxetan in patients with progressive neuroendocrine tumours

PURPOSE

To evaluate the dosimetry and pharmacokinetics of the novel radiolabelled somatostatin receptor antagonist [177Lu]Lu-satoreotide tetraxetan in patients with advanced neuroendocrine tumours (NETs).

METHODS

This study was part of a phase I/II trial of [177Lu]Lu-satoreotide tetraxetan, administered at a median cumulative activity of 13.0 GBq over three planned cycles (median activity/cycle: 4.5 GBq), in 40 patients with progressive NETs. Organ absorbed doses were monitored at each cycle using patient-specific dosimetry; the cumulative absorbed-dose limits were set at 23.0 Gy for the kidneys and 1.5 Gy for bone marrow. Absorbed dose coefficients (ADCs) were calculated using both patient-specific and model-based dosimetry for some patients.

RESULTS

In all evaluated organs, maximum [177Lu]Lu-satoreotide tetraxetan uptake was observed at the first imaging timepoint (4 h after injection), followed by an exponential decrease. Kidneys were the main route of elimination, with a cumulative excretion of 57-66% within 48 h following the first treatment cycle. At the first treatment cycle, [177Lu]Lu-satoreotide tetraxetan showed a median terminal blood half-life of 127 h and median ADCs of [177Lu]Lu-satoreotide tetraxetan were 5.0 Gy/GBq in tumours, 0.1 Gy/GBq in the bone marrow, 0.9 Gy/GBq in kidneys, 0.2 Gy/GBq in the liver and 0.8 Gy/GBq in the spleen. Using image-based dosimetry, the bone marrow and kidneys received median cumulative absorbed doses of 1.1 and 10.8 Gy, respectively, after three cycles.

CONCLUSION

[177Lu]Lu-satoreotide tetraxetan showed a favourable dosimetry profile, with high and prolonged tumour uptake, supporting its acceptable safety profile and promising efficacy.

TRIAL REGISTRATION

NCT02592707. Registered October 30, 2015.

Risk of treatment-altering haematological toxicity and its dependence on bone marrow doses in peptide receptor radionuclide therapy

BACKGROUND

Peptide receptor radionuclide therapy is effective in treating neuroendocrine tumours, but treatment may be limited by kidney and bone marrow toxicity. In this work, the absorbed dose burden to the bone marrow was estimated using image-based dosimetry and its potential use for predicting treatment-altering toxicity was studied. Peripheral blood samples taken before and after 229 treatments with 177Lu-DOTATATE in 59 patients were studied. In connection to the treatments, a total of 940 blood sample occasions provided data on white blood cell, neutrophil granulocyte, platelet, erythrocyte and haemoglobin concentrations. SPECT/CT image data were collected at two or three time points after each treatment. Absorbed doses to bone marrow were calculated from the activity concentration in a metastasis-free lumbar vertebra. The rate of delayed and aborted treatments was analysed based on medical records.

RESULTS

The average absorbed dose to the bone marrow was 0.42 Gy (median 0.33 Gy, SD 0.27 Gy) per treatment. Dose-response relationships between white blood cells, neutrophil granulocytes and haemoglobin concentrations were observed, most prominently at 31-45 days after each treatment. The correlations were stronger in patients with skeletal metastases. The rates of haematological toxicity-related delays and aborted treatments were 6% and 12%, respectively. None of the studied bone marrow dosimetric parameters could clearly predict treatment-related toxicity. However, patients with skeletal metastases had higher risk of treatment-altering toxicity (odds ratio = 6.0).

CONCLUSIONS

Treatment-altering haematological toxicity in peptide receptor radionuclide therapy is relatively rare and appears difficult to fully predict from post-therapeutic image-based dosimetry. However, for patients with skeletal metastases, the haematological dose-response relationships are stronger. Future studies may focus on this patient group, to further investigate the usefulness of dosimetry in predicting decreases in blood values.

An international simulated-use study to assess nurses' preferences between two lanreotide syringes for patients with neuroendocrine tumours or acromegaly (PRESTO 3)

PURPOSE

PRESTO 3 evaluated nurses' preference for the Somatuline® Autogel® syringe versus the Lanreotide Pharmathen syringe after injection-pad testing.

METHODS

This international simulated-use study included oncology/endocrinology nurses with ≥ 1 years' experience in managing neuroendocrine tumours (NETs) and/or acromegaly. Each nurse tested both syringes twice in a randomised order before completing an electronic survey. The primary objective was to assess overall preference (%, 95% confidence interval [CI]) for the Somatuline Autogel syringe versus the Lanreotide Pharmathen syringe. Secondary objectives included rating syringe performance and ranking the importance of syringe attributes.

RESULTS

Ninety-four nurses were enrolled: mean age, 41.0 (SD, 11.5) years. The percentage of nurses stating a preference ("strong" or "slight") for the Somatuline Autogel syringe (86.2% [95% CI 77.5-92.4%]) was significantly higher than 50% (p < 0.0001). Performance rating was significantly higher for the Somatuline Autogel syringe versus Lanreotide Pharmathen syringe for 10 of the 11 attributes tested (p < 0.05). The syringe attributes considered most important when injecting patients in routine clinical practice were "easy to use from preparation to injection" (30.9%) and "comfortable to handle during use from preparation to injection" (16.0%). The attribute most commonly rated as least important was "fast administration from preparation to injection" (26.6%).

CONCLUSION

Nurses strongly preferred the user experience of the Somatuline Autogel syringe over the Lanreotide Pharmathen syringe. "Ease of use" and "comfortable to handle" were the most important syringe attributes, and performance rating was significantly higher with Somatuline Autogel versus Lanreotide Pharmathen syringe for all but one attribute.

The cycle effect quantified: reduced tumour uptake in subsequent cycles of [177Lu]Lu-HA-DOTATATE during peptide receptor radionuclide therapy

BACKGROUND

Clear evidence regarding the effect of reduced tumour accumulation in later peptide receptor radionuclide therapy (PRRT) cycles is lacking. Therefore, we aimed to quantify potential cycle effects for patients treated with [177Lu]Lu-HA-DOTATATE using a population pharmacokinetic (PK) modelling approach.

METHODS

A population PK model was developed using imaging data from 48 patients who received multiple cycles of [177Lu]Lu-HA-DOTATATE. The five-compartment model included a central, kidney, spleen, tumour and lumped rest compartment. Tumour volume and continued use of long-acting somatostatin analogues (SSAs) were tested as covariates in the model. In addition, the presence of a cycle effect was evaluated by relating the uptake rate in a specific cycle as a fraction of the (tumour or organ) uptake rate in the first cycle.

RESULTS

The final PK model adequately captured observed radioactivity accumulation in kidney, spleen and tumour. A higher tumour volume was identified to increase the tumour uptake rate, where a twofold increase in tumour volume resulted in a 2.3-fold higher uptake rate. Also, continued use of long-acting SSAs significantly reduced the spleen uptake rate (68.4% uptake compared to SSA withdrawal (10.5% RSE)). Lastly, a cycle effect was significantly identified, where tumour uptake rate decreased to 86.9% (5.3% RSE) in the second cycle and even further to 79.7% (5.6% RSE) and 77.6% (6.2% RSE) in the third and fourth cycle, respectively, compared to cycle one.

CONCLUSIONS

Using a population PK modelling approach, the cycle effect of reduced tumour uptake in subsequent PRRT cycles was quantified. Our findings implied that downregulation of target receptors is probably not the major cause of the cycle effect, due to a plateau in the decrease of tumour uptake in the fourth cycle.

Sarcopenia and Neuroendocrine Neoplasms

PURPOSE OF THE REVIEW

To summarise the current literature regarding the presence of sarcopenia in patients with neuroendocrine neoplasms (NENs). These are uncommon cancers separated into well-differentiated neuroendocrine tumours (NETs) and poorly differentiated neuroendocrine carcinoma (NECs). For the diagnosis of sarcopenia, there needs to be low muscle strength and low muscle quantity/quality.

RECENT FINDINGS

Five studies exist describing either low muscle strength or low muscle quantity in patients with NETs. The studies used different techniques to analyse muscle strength and muscle quantity, included heterogeneous populations, and performed the analysis at different time points following the diagnosis of the NET. Only 2 studies regarding patients with NECs could be found, both included mainly patients with a mixed adenoneuroendocrine carcinoma (MiNEN) and are, therefore, difficult to interpret for patients with a NEC. The main findings of this review are to describe the presence of sarcopenia in patients with NENs. However, results should be interpreted with caution, and future research should focus on the correct technique, homogenous population and same time point.

Dual-energy CT improves differentiation of non-hypervascular pancreatic neuroendocrine neoplasms from CA 19-9-negative pancreatic ductal adenocarcinomas

PURPOSE

To evaluate the utility of dual-energy CT (DECT) in differentiating non-hypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs) with negative carbohydrate antigen 19-9 (CA 19-9).

METHODS

This retrospective study included 26 and 39 patients with pathologically confirmed non-hypervascular PNENs and CA 19-9-negative PDACs, respectively, who underwent contrast-enhanced DECT before treatment between June 2019 and December 2021. The clinical, conventional CT qualitative, conventional CT quantitative, and DECT quantitative parameters of the two groups were compared using univariate analysis and selected by least absolute shrinkage and selection operator regression (LASSO) analysis. Multivariate logistic regression analyses were performed to build qualitative, conventional CT quantitative, DECT quantitative, and comprehensive models. The areas under the receiver operating characteristic curve (AUCs) of the models were compared using DeLong's test.

RESULTS

The AUCs of the DECT quantitative (based on normalized iodine concentrations [nICs] in the arterial and portal venous phases: 0.918; 95% confidence interval [CI] 0.852-0.985) and comprehensive (based on tumour location and nICs in the arterial and portal venous phases: 0.966; 95% CI 0.889-0.995) models were higher than those of the qualitative (based on tumour location: 0.782; 95% CI 0.665-0.899) and conventional CT quantitative (based on normalized conventional CT attenuation in the arterial phase: 0.665; 95% CI 0.533-0.797; all P < 0.05) models. The DECT quantitative and comprehensive models had comparable performances (P = 0.076).

CONCLUSIONS

Higher nICs in the arterial and portal venous phases were associated with higher blood supply improving the identification of non-hypervascular PNENs.

The molecular biology of midgut neuroendocrine neoplasms

Midgut neuroendocrine neoplasms (NENs) are one of the most common subtypes of NEN, and their incidence is rising globally. Despite being the most frequently diagnosed malignancy of the small intestine, little is known about their underlying molecular biology. Their unusually low mutational burden compared to other solid tumours, and the unexplained occurrence of multi-focal tumours makes the molecular biology of midgut NENs a particularly fascinating field of research. This review provides an overview of recent advances in the understanding of the interplay of the genetic, epigenetic and transcriptomic landscape in the development of midgut NENs; a topic which is critical to understanding their biology and improving treatment options and outcomes for patients.

A phase I/II study of the safety and efficacy of [177Lu]Lu-satoreotide tetraxetan in advanced somatostatin receptor-positive neuroendocrine tumours

PURPOSE

We present the results of an open-label, phase I/II study evaluating the safety and efficacy of the novel somatostatin receptor (SSTR) antagonist [177Lu]Lu-satoreotide tetraxetan in 40 patients with previously treated, progressive neuroendocrine tumours (NETs), in which dosimetry was used to guide maximum administered activity.

METHODS

This study was conducted in two parts. Part A consisted of 15 patients who completed three cycles of [177Lu]Lu-satoreotide tetraxetan at a fixed administered activity and peptide amount per cycle (4.5 GBq/300 µg). Part B, which included 25 patients who received one to five cycles of [177Lu]Lu-satoreotide tetraxetan, evaluated different administered activities (4.5 or 6.0 GBq/cycle) and peptide amounts (300, 700, or 1300 μg/cycle), limited to a cumulative absorbed radiation dose of 23 Gy to the kidneys and 1.5 Gy to the bone marrow.

RESULTS

Median cumulative administered activity of [177Lu]Lu-satoreotide tetraxetan was 13.0 GBq over three cycles (13.1 GBq in part A and 12.9 GBq in part B). Overall, 17 (42.5%) patients experienced grade ≥ 3 treatment‑related adverse events; the most common were lymphopenia, thrombocytopenia, and neutropenia. No grade 3/4 nephrotoxicity was observed. Two patients developed myeloid neoplasms considered treatment related by the investigator. Disease control rate for part A and part B was 94.7% (95% confidence interval [CI]: 82.3-99.4), and overall response rate was 21.1% (95% CI: 9.6-37.3).

CONCLUSION

[177Lu]Lu-satoreotide tetraxetan, administered at a median cumulative activity of 13.0 GBq over three cycles, has an acceptable safety profile with a promising clinical response in patients with progressive, SSTR-positive NETs. A 5-year long-term follow-up study is ongoing.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02592707. Registered October 30, 2015.

Key Device Attributes for Injectable Somatostatin Receptor Ligand Therapy in Acromegaly and Neuroendocrine Tumours

INTRODUCTION

People living with acromegaly and neuroendocrine tumours (NETs) may be treated with injectable somatostatin receptor ligands (SRLs), administered by either a caregiver or as self-injection via a proprietary or generic device. Injection device attributes that contribute to ease of use and storage, minimise preparation requirements, and reduce injection pain are associated with improved adherence and more favourable therapeutic outcomes. The aim of this study was to assess current opinion surrounding favourable SRL device attributes for people living with acromegaly and NETs as well as that of their caregivers.

METHODS

Participants (healthcare professionals [HCPs] and patients/non-HCP caregivers) from 11 countries were invited to answer survey questions related to their demographic, experience, and preferences as they relate to the real-world use of injectable SRL devices. Questions were developed based on review of available literature and meetings with a Scientific Committee.

RESULTS

Device attributes preferred by the patient/non-HCP caregiver group (n = 211) included confidence that the correct drug amount is delivered (76%), quick administration with minimal pain/discomfort (68%), and device safety (needle-safety and low risk of contamination; 53%). Device attributes preferred by HCPs (n = 52) were quick administration with minimal pain/discomfort (69%), correct use is easy to learn, confidence in handling the device (63%), and confidence that the correct drug amount is delivered (62%).

CONCLUSION

The results identified key features of injection devices for SRL therapy which merit consideration for optimal management and underscore the importance of patient partnership in treatment decisions.

Appendiceal neuroendocrine neoplasms and resection of the mesoappendix: a retrospective comparative study

PURPOSE

Incidental appendiceal neoplasms are identified in approximately 1% of the specimens of suspected appendicitis. The current institutional policy is to perform en bloc mesoappendix resection during routine laparoscopic appendicectomy allowing for staging, reducing the need for oncological right hemicolectomy (ORH). Herein, we review en bloc mesoappendicectomy in clinical practice and its effects on the rate of ORH.

METHODS

We reviewed all cases of appendicectomy performed at the Auckland City Hospital between 1 May 2014 and 31 May 2019. Clinical notes and histopathological reports were reviewed. All neoplasms, surgical techniques and the need for further surgery were analysed.

RESULTS

A total of 2455 appendicectomies were performed with an approximately similar number of procedures between the sexes and an overall median age of 31 years. Overall, 86% (n = 2098) of the specimens included resection of the mesoappendix, and 58 (2.4%) appendiceal neoplasms were identified. Of them, 33 (1.3%) specimens included neuroendocrine appendiceal neoplasms. Eleven (33%) patients with appendiceal neuroendocrine neoplasms were recommended ORH. One of these patients may have avoided additional surgery, whereas 3 (9.1%) patients with tumours of 10-20 mm avoided ORH because their mesoappendix was resected.

CONCLUSION

At our centre, there has been a significant change in the practice of mesoappendix resection, and we support resection of the mesoappendix during appendicectomy. The procedure is technically straightforward and safe, incurs no increases in costs or time, allows for accurate tumour staging and guides decisions regarding further surgical interventions.

Health care resource use and costs among patients with carcinoid syndrome in France: Analysis of the National Health Insurance Database

OBJECTIVES

Carcinoid syndrome (CS) develops in approximately 20% of patients with neuroendocrine tumours (NET). This study described healthcare resource utilization and its associated costs among patients with NET and CS, using the French national health care data system.

METHODS

Patients were included if they had a hospital stay associated with the code E34.0 "CS" and at least one delivery of a somatostatin analogue (SSA) between 01/01/2012 and 31/12/2016. The end of the analysis was either 31/12/2017 or the date of death, whichever occurred first. Mean overall costs were described by item of expenditure and by periods.

RESULTS

646 patients were included: 64yo, 55% men, 64% and 15% had NET from the small-intestine or lung, respectively. Among them, 309 patients were incident and 271 died during the study period. Mean overall cost per person per month (PPPM) was €2,892: €3,273 for the first year following diagnosis, €2,574 in "middle-years" and €5,039 within the year preceding death. The two most costly expenditure items were drugs (€1,695 PPPM) and hospital stays (€870 PPPM).

CONCLUSION

The first year following diagnosis and the year preceding death are the two periods representing the highest costs for CS care in France. Successful disease management may contribute to lower costs in the intermediate period.

Sex differences on multikinase inhibitors toxicity in patients with advanced gastroenteropancreatic neuroendocrine tumours

PURPOSE

There is an increasing interest in the role of sex and gender in cancer patients. The impact of sex differences in oncological systemic therapies is still unknown, and there is a lack of evidence specially in uncommon neoplasms like neuroendocrine tumours (NET). In the present study, we combine the differential toxicities by sex in five published clinical trials with multikinase inhibitors (MKI) in gastroenteropancreatic (GEP) NET.

METHODS

We performed a pooled univariate analysis of reported toxicity in patients treated in five phase 2 and phase 3 clinical trials with MKI in the GEP NET setting: sunitinib (SU11248, SUN1111), Pazopanib (PAZONET), sorafenib-bevacizumab (GETNE0801) and Lenvatinib (TALENT). Differential toxicities between male and female patients were evaluated considering relationship with study drug and different weights of each trial by random effect adjustment.

RESULTS

We found nine toxicities which were more frequent in female patients (leukopenia, alopecia, vomiting, headache, bleeding, nausea, dysgeusia, neutrophil count decreased and dry mouth) and two toxicities being more frequent in male patients (Anal Symptoms and Insomnia). Asthenia and diarrhoea were the only severe (Grade 3-4) toxicities more frequent in female patients.

CONCLUSIONS

Sex-related differences in toxicity with the MKI treatment require targeted information and individualised management of patients with NET. Differential reporting of toxicity should be promoted when clinical trials are published.

Indications for genetic study in gastro-entero-pancreatic and thoracic neuroendocrine tumors

Gastro-entero-pancreatic (GEP-NET) and thoracic neuroendocrine tumours (NETs) are one of the most heritable groups of neoplasms in the body, being multiple endocrine neoplasia syndrome type 1 (MEN1), the genetic syndrome most frequently associated with this type of tumours. Moreover, Von Hippel Lindau syndrome, tuberous sclerosis, type 4 multiple neoplasia syndrome, and type 1 neurofibromatosis are associated with an increased risk of developing GEP-NETs. Another important aspect in GEP-NETs and thoracic NETs is the knowledge of the molecular background since the molecular profile of these tumours may have implications in the prognosis and in the response to specific treatments. This review summarizes the main indications for performing a genetic study in patients with GEP-NETs and thoracic NETs, and the methods used to carry it out. Moreover, it offers a description of the main hereditary syndromes associated with these NETs and their molecular background, as well as the clinical implications of the molecular profile.

Efficacy and toxicity of anti-vascular endothelial growth receptor tyrosine kinase inhibitors in patients with neuroendocrine tumours - A systematic review and meta-analysis

AIM

Although anti-vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitors (RTKIs) have been tested in patients with neuroendocrine tumours (NETs) over the last two decades, no study to date has benchmarked efficacy and toxicity of these drugs in this patient population.

METHODS

All phase II and phase III studies of anti-VEGF RTKIs in patients with NETs, published between January 1, 2000 andJuly 31, 2021, across major trial databases, were searched in August 2021 for relevant studies. The primary objectives of the meta-analysis were to compare objective response rate (ORR) and progression-free survival (PFS) between patients with pancreatic NETs (pNETs) and extra-pancreatic NETs (epNETs), and the incidence rate ratio (IRR) of adverse events between patients receiving anti-VEGF RTKIs and control.

RESULTS

1611 patients were available for the meta-analysis; 1194 received anti-VEGF RTKIs. ORR in pNETs was 18% (95% confidence interval (CI) 13-25%), while ORR in epNETs was 8% (95% CI 5-12%); test for differences between pNETs and epNETs (x12 = 8.38, p < .01). Median PFS in pNETs was 13.9 months (95% CI 11.43-16.38 months), while median PFS in epNETs was 12.71 months (95% CI 9.37-16.05 months); test for differences between pNETs and epNETs (x12 = .35, p = .55). With regards to common grade 3/4 adverse events , patients who received anti-VEGF RTKIs were more likely to experience hypertension (IRR 3.04, 95% CI 1.63-5.65) and proteinuria (IRR 5.79, 95% CI 1.09-30.74) in comparison to those who received control.

CONCLUSIONS

Anti-VEGF RTKIs demonstrate anti-tumour effect in both pNETs and epNETs, supporting their development in both populations. These agents also appear to be safe in patients with NETs.

Where Are We Now with Liver Transplantation in Neuroendocrine Neoplasms? The Place of Liver Transplantation for Grades 1 and 2 Well-Differentiated Unresectable Liver Metastatic Neuroendocrine Tumours

PURPOSE OF REVIEW

This review outlines the role of liver transplantation in selected patients with unresectable neuroendocrine tumour liver metastases. It discusses the international consensus on eligibility criteria and outlines the efforts taking place in the UK and Ireland to develop effective national liver transplant programmes for neuroendocrine tumour patients.

RECENT FINDINGS

In the early history of liver transplantation, indications included cancer metastases to the liver as well as primaries of liver origin. Often, liver transplantation was a salvage procedure. The early results were disappointing, including in patients with neuroendocrine tumours. These data discouraged the widespread adoption of liver transplantation for neuroendocrine tumour liver metastases (NET LM). A few centres persisted in performing liver transplantation for patients with NET LM and in determining parameters predictive of good outcomes. Their work has provided evidence for benefit of liver transplantation in a selected group of patients with NET LM. Liver transplantation for NET LM is now accepted as a valid indication by many professional bodies, including the European Neuroendocrine Tumour Society (ENETS) and the United Network for Organ Sharing (UNOS). It is nevertheless rarely utilised. The UK and the Republic of Ireland are commencing a pilot programme of liver transplantation in selected patients. This programme will help develop the expertise and infrastructure to make liver transplantation for NET LM a routine procedure.

Relationships between uptake of [68Ga]Ga-DOTA-TATE and absorbed dose in [177Lu]Lu-DOTA-TATE therapy

BACKGROUND

Somatostatin receptor ⁶⁸Ga PET imaging is standard for evaluation of a patient's suitability for ¹⁷⁷Lu peptide receptor radionuclide therapy of neuroendocrine tumours (NETs). The ⁶⁸Ga PET serves to ensure sufficient somatostatin receptor expression, commonly evaluated qualitatively. The aim of this study is to investigate the quantitative relationships between uptake in ⁶⁸Ga PET and absorbed doses in ¹⁷⁷Lu therapy.

METHOD

Eighteen patients underwent [⁶⁸Ga]Ga-DOTA-TATE PET imaging within 20 weeks prior to their first cycle of [¹⁷⁷Lu]Lu-DOTA-TATE. Absorbed doses for therapy were estimated for tumours, kidney, spleen, and normal liver parenchyma using a hybrid SPECT/CT-planar method. Gallium-68 activity concentrations were retrieved from PET images and also used to calculate SUVs and normalized SUVs, using blood and tissue for normalization. The ⁶⁸Ga activity concentrations per injected activity, SUVs, and normalized SUVs were compared with ¹⁷⁷Lu activity concentrations 1 d post-injection and ¹⁷⁷Lu absorbed doses. For tumours, for which there was a variable number per patient, both inter- and intra-patient correlations were analysed. Furthermore, the prediction of ¹⁷⁷Lu tumour absorbed doses based on a combination of tumour-specific ⁶⁸Ga activity concentrations and group-based estimates of the effective half-lives for grade 1 and 2 NETs was explored.

RESULTS

For normal organs, only spleen showed a significant correlation between the ⁶⁸Ga activity concentration and ¹⁷⁷Lu absorbed dose (r = 0.6). For tumours, significant, but moderate, correlations were obtained, with respect to both inter-patient (r = 0.7) and intra-patient (r = 0.45) analyses. The correlations to absorbed doses did not improve when using ⁶⁸Ga SUVs or normalized SUVs. The relationship between activity uptakes for ⁶⁸Ga PET and ¹⁷⁷Lu SPECT was stronger, with correlation coefficients r = 0.8 for both inter- and intra-patient analyses. The ¹⁷⁷Lu absorbed dose to tumour could be predicted from the ⁶⁸Ga activity concentrations with a 95% coverage interval of - 65% to 248%.

CONCLUSIONS

On a group level, a high uptake of [⁶⁸Ga]Ga-DOTA-TATE is associated with high absorbed doses at ¹⁷⁷Lu-DOTA-TATE therapy, but the relationship has a limited potential with respect to individual absorbed dose planning. Using SUV or SUV normalized to reference tissues do not improve correlations compared with using activity concentration per injected activity.

Preparation of Patient Doses of [177Lu]Lu-DOTATATE and [177Lu]Lu-PSMA-617 with Carrier Added (CA) and No Carrier Added (NCA) 177Lu

Purpose

[177Lu]Lu-DOTATATE and [177Lu]Lu-PSMA-617 used for targeted radionuclide therapy are very often prepared in the hospital radiopharmacy. The preparation parameters vary depending upon the specific activity of the 177Lu used. The aim of this study was to develop optimized protocols to be used in the nuclear medicine department for the preparation of patient doses of the above radiopharmaceuticals.

Method

177Lu (CA and NCA) were used for radiolabeling DOTATATE and PSMA-617. Parameters studied are 177Lu of different specific activity and different peptide concentrations and two different buffer systems. Paper and thin layer chromatography systems were used for estimating the radiochemical yield as well as radiochemical purity. Solid-phase extraction was used for the purification of the labeled tracers.

Results

[177Lu]Lu-DOTATATE was prepared with CA 177Lu (n = 13) and NCA177Lu (n = 6). Four batches each of [177Lu]Lu-PSMA-617 were prepared using CA and NCA 177Lu. Radiochemical yields > 80% and final product with less than < 1% radiochemical impurity could be obtained in all batches which were used for therapy.

Conclusion

Robust protocols for the preparation of clinical doses of [177Lu]Lu-DOTATATE and [177Lu]Lu-PSMA-617 were developed and used for the preparation of clinical doses. The quality of the SPECT images of both the tracers are consistent with the expected uptake in respective diseases.

S-1/temozolomide versus S-1/temozolomide plus thalidomide in advanced pancreatic and non-pancreatic neuroendocrine tumours (STEM): A randomised, open-label, multicentre phase 2 trial

BACKGROUND

There are currently limited systemic treatment options for patients with advanced neuroendocrine tumours (NETS) and the efficacy of existing treatments is sub-optimal. We evaluated the efficacy and safety of Tegafur/gimeracil/oteracil/potassium capsules (S-1)/Temozolomide with or without thalidomide for the treatment of NETS (STEM trial).

METHODS

A randomised, controlled, open-label, phase 2 trial conducted at eight hospitals in China. Adults (≥18 years) with unresectable/metastatic, pancreatic or non-pancreatic NETS, with an Eastern Cooperative Oncology Group (ECOG) PS of 0-1, and progression on ≤2 previous therapies were randomised (1:1, using hierarchical block randomization with block length 4, stratified by pancreatic/non-pancreatic disease to receive S-1 40-60 mg orally twice daily on days 1-14 plus temozolomide 200 mg orally daily on days 10-14 in a 21-day cycle OR S-1 and temozolomide plus thalidomide orally nightly (100 mg on days 1-7, 200 mg on days 8-14, and 300 mg from day 15), until disease progression, death, intolerable toxicity, withdrawal of informed consent or at the investigator's discretion. The primary endpoint was objective response rate (ORR) by RECIST 1.1 in an intention-to-treat population. Safety was assessed in all patients who received treatment. The study was registered at ClinicalTrials.gov: NCT03204019 (pancreatic group) and NCT03204032 (non-pancreatic group).

FINDINGS

Between March 23, 2017 and November 16, 2020, 187 patients were screened and 140 were randomly assigned to S-1/temozolomide plus thalidomide (n = 69) or S-1/temozolomide (n =71). After a median follow-up of 12·1 months (IQR: 8·4-16·6), the ORR was comparable in the S-1/temozolomide plus thalidomide and S-1/temozolomide groups 26·1% [95% CI 17·2-37·5] versus 25·4% [95% CI 16·7-36·6]; odds ratio: 1·03 [95% CI 0·48-2·22]; P = 0·9381). In the S-1/temozolomide plus thalidomide group, the most common grade 3-4 treatment-related adverse event was fatigue (2/68, 3%), and in the control group were thrombocytopenia and diarrhea (both 1/71, 2%). There were no treatment-related deaths in either group.

INTERPRETATION

S-1/temozolomide with or without thalidomide leads to a comparable treatment response in patients with advanced/metastatic NETS.

FUNDING

This work was supported by CAMS Innovation Fund for Medical Sciences (CIFMS,2021-I2M-1-066, 2017-I2M-4-002, 2021-I2M-1-019, 2017-I2M-1-001), the National Natural Science Foundation of China (81972311, 82141127, 31970794,), the State Key Project on Infection Diseases of China (2017ZX10201021-007-003), the Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences (2019PT310026), Sanming Project of Medicine in Shenzhen (SZSM202011010), and the State Key Laboratory Special fund from the Ministry of Science (2060204).

Epigenetic potentiation of somatostatin-2 by guadecitabine in neuroendocrine neoplasias as a novel method to allow delivery of peptide receptor radiotherapy

BACKGROUND

Somatostatin receptor-2 (SSTR2) is expressed on cell surface of neuroendocrine neoplasias; its presence is exploited for the delivery of peptide receptor radionuclide therapy (PRRT). Patients with no or low expression of SSTR2 are not candidates for PRRT. SSTR2 promotor undergoes epigenetic modification, known to regulate gene expression. We investigated whether the demethylation agent, guadecitabine, could enhance the expression of SSTR2 in NET models, using radioligand uptake/PET imaging as a biomarker of epigenetic modification.

METHODS

The effects of guadecitabine on the transcriptional, translational, and functional regulation of SSTR2 both in vitro and in vivo using low (QGP-1) and high (BON-1) methylated neuroendocrine neoplasia models was characterised. Promotor region methylation profiling of clinical samples (n = 61) was undertaken. Safety of combination guadecitabine and PRRT was assessed in vivo.

RESULTS

Pyrosequencing of cell lines illustrated differential methylation indices - BON: 1 94%, QGP: 1 21%. Following guadecitabine treatment, a dose-dependent increase in SSTR2 in BON-1 at a transcriptional, translational, and functional levels using the SSTR2-directed radioligand, ¹⁸F-FET-βAG-TOCA ([¹⁸F]-FETO) (150% increase [¹⁸F]-FETO uptake, p < 0.05) was observed. In vivo, guadecitabine treatment resulted in a 70% increase in [¹⁸F]-FETO uptake in BON-1 tumour models compared models with low baseline percentage methylation (p < 0.05). No additive toxicity was observed with the combination treatment of PRRT and guadecitabine in vivo. Methylation index in clinical samples was 10.5% compared to 5.2% in controls (p = 0.03) and correlated with SSTR2 expression (Wilcoxon rank sign -3.75,p < 0.01).

CONCLUSION

Guadecitabine increases SSTR2 expression both in vitro and in vivo. The combination of demethylation agents with PRRT warrants further investigation.

Recommendations for the diagnosis and radiological follow-up of pituitary neuroendocrine tumours

Pituitary neuroendocrine tumours (PitNETs) constitute a heterogeneous group of tumours with a gradually increasing incidence, partly accounted for by more sensitive imaging techniques and more extensive experience in neuroradiology in this regard. Although most PitNETs are indolent, some exhibit aggressive behaviour, and recurrence may be seen after surgical removal. The changes introduced in the WHO classification in 2017 and terminological debates in relation to neuroendocrine tumours warrant an update of the guidelines for the diagnosis, preoperative and postoperative management, and follow-up of response to treatment of PitNETs. This multidisciplinary document, an initiative of the Neuroendocrinology area of the Sociedad Española de Endocrinología y Nutrición [Spanish Society of Endocrinology and Nutrition] (SEEN), focuses on neuroimaging studies for the diagnosis, prognosis and follow-up of PitNETs. The basic requirements and elements that should be covered by magnetic resonance imaging are described, and a minimum radiology report to aid clinicians in treatment decision-making is proposed. This work supplements the consensus between the Neuroendocrinology area of the SEEN and the Sociedad Española de Anatomía Patológica [Spanish Society of Pathology] (SEAP) for the pathological study of PitNETs.

Primary Neuroendocrine Carcinoma of the Larynx: A Case Report

Neuroendocrine tumours can originate from any part of the body. The most common site in the head and neck is the larynx, accounts for less than 0.6%. The neuroendocrine carcinomas (NECs) of the larynx are rare tumours with high incidence of widespread metastases and poor prognosis. Here we report a 50-year-old male with localised primary moderately differentiated NEC of the larynx. He was treated with surgery followed by adjuvant chemotherapy and concurrent chemoradiation. He is free of his disease and is doing well.

Lanreotide as maintenance therapy after first-line treatment in patients with non-resectable duodeno-pancreatic neuroendocrine tumours: An international double-blind, placebo-controlled randomised phase II trial - Prodige 31 REMINET: An FFCD study

BACKGROUND

Following European guidelines, patients with aggressive metastatic or locally advanced, non-resectable, duodeno-pancreatic (DP) neuroendocrine tumours (NETs) should receive systemic combination chemotherapy until progression. Aggressive disease is defined as progressive and/or symptomatic metastases with or without significant hepatic invasion (>30-50%), and/or bone metastases.

METHODS

This academic randomised, double-blind, placebo-controlled phase II study aims to evaluate lanreotide autogel 120 mg (LAN) as maintenance treatment after at least 2 months of first-line treatment (L1) in aggressive G1-G2 DP-NET. Patients were randomly assigned in a 1:1 ratio to receive LAN or placebo (PBO), every 28 days, until progression or toxicity. The primary end-point was progression-free survival (PFS) at 6 months.

RESULTS

Among the 118 planned patients, 53 were included. Of these, 81.1% had a G2 tumour, and 90.6% had metastatic disease. L1 therapy consisted of chemotherapy (96.8%). Median duration of L1 was 4.6 months (range: 2.0-7.7). At the time of randomisation, 81.1% of patients had stable disease. Median follow-up was 27.0 months (95% CI: 19.5; 31.2). PFS at 6 months was 73.1% (90% CI: 55.3; 86.6) in LAN versus 54.2% (90% CI: 35.8; 71.8) in PBO. Median PFS was 19.4 months (95% CI: 7.6; 32.6) and 7.6 months (95% CI: 3.0; 9.0), respectively. Median overall survival was 41.9 months in PBO and was not reached in LAN. The toxicity profile was mainly grade 1-2 expected toxicities.

CONCLUSIONS

The encouraging results of lanreotide autogel 120 mg as a maintenance treatment after L1 in aggressive G1/2 DP-NET should be confirmed.

TRIAL REGISTRATION

NCT02288377 (clinicaltrials.gov).

Lurbinectedin in patients with pretreated neuroendocrine tumours: Results from a phase II basket study

BACKGROUND

Patients with neuroendocrine tumours (NETs) need alternative therapies after failure of first-line therapy.

PATIENTS AND METHODS

This phase II trial evaluated lurbinectedin, a selective inhibitor of oncogenic transcription, at 3.2 mg/m² as a 1-h intravenous infusion every 3 weeks in 32 NETs patients treated in the second- or third-line setting. The primary efficacy endpoint was overall response rate (ORR) according to RECIST v1.1 assessed by the investigators. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

Two of 31 evaluable patients had confirmed partial responses (ORR = 6.5%; 95%CI, 0.8-21.4%). Median DoR was 4.7 months (95% CI, 4.0-5.4 months), median PFS was 1.4 months (95% CI, 1.2-3.0 months) and median OS was 7.4 months (95% CI, 3.4-16.2 months). Lurbinectedin showed an acceptable, predictable and manageable safety profile. The most common grade 3/4 toxicity was neutropenia (40.6%; grade 4, 12.4%; febrile neutropenia, 3.1%).

CONCLUSIONS

Considering the exploratory aim of this trial that evaluated a heterogeneous population of NETs patients, and the signs of antitumour activity observed (two confirmed partial responses and seven long disease stabilisations), further development of lurbinectedin is warranted in a more selected NETs population.

TRIAL REGISTRATION NUMBER

Sponsor Study Code: PM1183-B-005-14. EudraCT number: 2014-003773-42.

CLINICALTRIALS

gov reference: NCT02454972.

Long-term survival in patients with gastroenteropancreatic neuroendocrine neoplasms: A population-based study

BACKGROUND

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) comprise a group of rare malignant tumours with heterogeneous behaviour. This study aimed to assess long-term survival and prognostic factors associated with survival, in order to optimise counselling.

PATIENTS AND METHODS

This population-based study included all GEP-NENs diagnosed between 1989 and 2016 in the Netherlands, selected from the Netherlands Cancer Registry. Overall survival (OS) and relative survival (RS) were calculated. A Cox Proportional Hazard analysis was used to identify prognostic factors (gender, age, tumour stage, location and treatment) for OS. Analyses were stratified by metastatic disease status and tumour grade.

RESULTS

In total, 9697 patients were included. In grade 1, 2 and 3 non-metastatic GEP-NENs (N = 6544), 5-year OS and RS were 81% and 88%, 78% and 83%, and 26% and 30%, respectively. In grade 1 non-metastatic GEP-NENs 10-year OS and RS were 68% and 83%. In grade 1, 2 and 3 metastatic GEP-NENs (N = 3153), 5-year OS and RS rates were 47% and 52%, 38% and 41%, and 5% and 5%, respectively. The highest (relative) survival rates were found in appendicular and rectal NENs, demonstrating 10-year OS and RS of 87% and 93%, and 81% and 95%, respectively.

CONCLUSIONS

These long-term follow-up data demonstrate significant differences in survival for different grades, tumour stage, and primary origin of GEP-NENs, with the most favourable overall and RS rates in patients with non-metastatic grade 1 appendicular and rectal NENs. This study demonstrates unique long-term OS and RS rates using combined stratification by tumour site, grade and stage.

Management of type-I gastric neuroendocrine neoplasms: A 10-years prospective single centre study

BACKGROUND

This study aimed to evaluate the outcome of patients with type 1 gastric neuroendocrine neoplasia (T1gNENs) treated with different endoscopic approaches.

METHODS

Patients were managed with endoscopic surveillance at regular intervals. Resection was performed by forceps or cold snare in tumours < 10 mm, otherwise mucosal resection (EMR) or submucosal dissection (ESD) were done.

RESULTS

127 T1gNENs, detected in 80 patients, were included. 87.4% of them were <5 mm, whereas 8.7% were 6-10 mm, 3.1% were 11-20 mm, and 0.8% was >20 mm. Ki67 <3%% was found in 85.8% tumours, whereas it was 3%-20% in the remaining 14.2% lesions. Noninterventional management (surveillance without radical resection) was performed in 15 patients (18.7%) with T1gNENs <5 mm. None of them underwent disease progression during follow-up. among the 65 patients treated by radical endoscopic resection, 37 patients (56.9%) had disease recurrence. 48.5% T1gNENs were removed by forceps, 16.8% by cold snare, 31.7% by EMR and 3% by ESD. The recurrence rate was similar among the different endoscopic techniques used.

CONCLUSIONS

The management of T1gNENs may be planned based on tumour size. T1gNENs < 5 mm for which the initial removal is not radical could be followed up by noninterventional endoscopic surveillance.

Sex differences in carcinoid syndrome: A gap to be closed

The incidence of neuroendocrine neoplasms and related carcinoid syndrome (CS) has markedly increased over the last decades and women seem to be more at risk than men for developing CS. Nevertheless, very few studies have investigated sex differences in clinical presentation and outcomes of CS. However, as per other tumours, sex might be relevant in influencing tumour localization, delay in diagnosis, clinical outcomes, prognosis and overall survival in CS. The present review was aimed at evaluating sex differences in CS, as they emerge from an extensive search of the recent literature. It emerged that CS occurs more frequently in female than in male patients with NENs and women seem to have a better prognosis and a slight advantage in overall survival and response to therapy. Moreover, the disease likely impacts differently the quality of life of men and women, with different psychological and social consequences. Nevertheless, sex differences, even if partially known, are deeply underestimated in clinical practice and data from clinical trials are lacking. There is urgent need to increase our understanding of the sex-related differences of CS, in order to define tailored strategies of management of the disease, improving both the quality of life and the prognosis of affected patients.

New insights in diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare epithelial neoplasms derived from pluripotent endocrine cells along the gastrointestinal tract and pancreas. GEP-NENs are classified into well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas. Despite overlapping morphological features, GEP-NENs vary in molecular biology, epigenetic, clinical behavior, treatment response, and prognosis features and remain an unmet clinical challenge. In this review, we introduce recent updates on the histopathologic classification, including the tumor grading and staging system, molecular genetics, and systemic evaluation of the diagnosis and treatment of GEP-NENs at different anatomic sites, together with some insights into the diagnosis of challenging and unusual cases. We also discuss the application of novel therapeutic approaches for GEP-NENs, including peptide receptor radionuclide therapy, targeted therapy, and immunotherapy with immune checkpoint inhibitors. These findings will help improve patient care with precise diagnosis and individualized treatment of patients with GEP-NENs.

New PET Radiotracers for the Imaging of Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NEN) are a heterogeneous group of tumours derived from cells of neuroendocrine origin and can potentially arise everywhere in the human body. The diagnostic assessment of NEN can be performed using a variety of PET radiopharmaceuticals. Well-differentiated NEN (NET) present a high expression of SSTR (somatostatin receptors) and can therefore be studied with 68Ga-DOTA-peptides ([68Ga]Ga-DOTANOC, [68Ga]Ga-DOTATOC, [68Ga]Ga-DOTATATE). Current guidelines recommend the use of SSTR imaging to assess disease extension at staging/restaging, follow-up, assessment of response to therapy and selection of patients who may benefit from radionuclide therapy (PRRT). [18F]F-FDG is used for the assessment of high-grade tumours (high-grade G2, G3 and NEC) and in every case, there is one or more mismatched lesions between diagnostic CT (positive) and SSTR-PET/CT (negative). [18F]F-DOPA is currently used for the assessment of medullary thyroid carcinoma, neuroblastoma, primary pheochromocytoma and abdominal paraganglioma. In recent years, however, several new tracers were designed exploiting the many potential targets of the neuroendocrine cell and were employed in clinical trials for both imaging and therapy. Currently, the real-life clinical impact of these tracers is still mostly not known; however, the favourable biodistribution (e.g. [68Ga]Ga-FAPI, SSTR antagonists) and the possibility to use new theranostic pairs may provide novel diagnostic as well as therapeutic options (e.g. [68Ga]Ga-PSMA, [64Cu]Cu-SARTATE, [68Ga]Ga-CXCR4) for NEN patients.

Highly aggressive neuroendocrine neoplasm of the ascending colon: a wolf in sheep's clothing

Neuroendocrine neoplasms represent a broad group of uncommon tumours, comprising neuroendocrine tumours, mixed neuroendocrine non-endocrine neoplasms and neuroendocrine carcinomas. While most neuroendocrine neoplasms are well differentiated and exhibit indolent disease biology with excellent treatment response, neuroendocrine carcinomas represent a rare subtype with much more aggressive tumour behaviour, minimal response to adjuvant therapy and extremely poor prognosis. Herein, we report the case of a 47-year-old man who presented with a phlegmonous ascending colonic mass and associated calcified ileocolic lymphadenopathy. He underwent emergent right hemicolectomy, which diagnosed a T4aN2b neuroendocrine carcinoma. Within a week the patient displayed rapidly progressive locoregional nodal disease and he succumbed to disease within 5 weeks. We discuss the significance of calcified abdominal lymphadenopathy on computed tomography scans of the abdomen and review the literature surrounding this rare and highly fatal malignancy.

Time to give up traditional methods for the management of gastrointestinal neuroendocrine tumours

Neuroendocrine tumors (NETs) are a rare and heterogeneous disease group and constitute 0.5% of all malignancies. The annual incidence of NETs is increasing worldwide. The reason for the increase in the incidence of NETs is the detection of benign lesions, incidental detection due to the highest use of endoscopic and imaging procedures, and higher recognition rates of pathologists. There have been exciting developments regarding NET biology in recent years. Among these, first of all, somatostatin receptors and downstream pathways in neuroendocrine cells have been found to be important regulatory mechanisms for protein synthesis, hormone secretion, and proliferation. Subsequently, activation of the mammalian target of rapamycin pathway was found to be an important mechanism in angiogenesis and tumor survival and cell metabolism. Finally, the importance of proangiogenic factors (platelet-derived growth factor, vascular endothelial growth factor, fibroblastic growth factor, angiopoietin, and semaphorins) in the progression of NET has been determined. Using the combination of biomarkers and imaging methods allows early evaluation of the appropriateness of treatment and response to treatment.

Efficacy and safety of high-dose lanreotide autogel in patients with progressive pancreatic or midgut neuroendocrine tumours: CLARINET FORTE phase 2 study results

INTRODUCTION

This prospective, single-arm, phase 2 study assessed the efficacy and safety of lanreotide autogel (LAN) administered at a reduced dosing interval in patients with progressive neuroendocrine tumours (NETs) after LAN standard regimen.

METHODS

Patients had metastatic or locally advanced, grade 1 or 2 midgut NETs or pancreatic NETs (panNETs) and centrally assessed disease progression on LAN 120 mg every 28 days. They were treated with LAN 120 mg every 14 days for up to 96 weeks (midgut cohort) or 48 weeks (panNET cohort). The primary end-point was centrally assessed progression-free survival (PFS). PFS by Ki-67 categories was analysed post hoc. Secondary end-points included quality of life (QoL) and safety.

RESULTS

Ninety-nine patients were enrolled (midgut, N = 51; panNET, N = 48). Median (95% CI) PFS was 8.3 (5.6-11.1) and 5.6 (5.5-8.3) months, respectively. In patients with Ki-67 ≤ 10%, median (95% CI) PFS was 8.6 (5.6-13.8) and 8.0 (5.6-8.3) months in the midgut and panNET cohorts, respectively. Patients' QoL did not deteriorate during the study. There were no treatment-related serious adverse events and only two withdrawals for treatment-related adverse events (both in the panNET cohort).

CONCLUSIONS

In patients with progressive NETs following standard-regimen LAN, reducing the dosing interval to every 14 days provided encouraging PFS, particularly in patients with a Ki-67 ≤ 10% (post hoc); no safety concerns and no deterioration in QoL were observed. Increasing LAN dosing frequency could therefore be considered before escalation to less well-tolerated therapies.

Pituitary metastases from neuroendocrine neoplasms: case report and narrative review

PURPOSE

Pituitary metastases (PM) are uncommon findings and are mainly derived from breast and lung cancers. No extensive review of PM from neuroendocrine neoplasms (NENs) is on record. Here we describe a clinical case of PM from pancreatic NEN and review the clinical features of PM from NENs reported in the literature.

METHODS

A case of PM from a pancreatic NEN followed at our institution is described. We also reviewed the 43 cases of PM from NENs reported in the literature.

RESULTS

A 59-year old female patient, previously submitted to duodeno-cephalo-pancreasectomy for a well-differentiated pancreatic NEN, with known hepatic metastases, underwent a ⁶⁸ Ga-DOTATOC PET/CT that revealed an uptake in the pituitary gland. A subsequent MRI displayed a pituitary lesion, with suprasellar extension. After a hormonal and genetic diagnostic workup that excluded the diagnosis of MEN 1, the worsening of headache and visual impairment and the growth of the lesion lead to its surgical removal. A pituitary localization of the pancreatic NEN was identified. Regarding the published cases of PM from NENs, the most common tumour type was small cell lung cancer (SCLC), accounting for nearly half of the cases, followed by bronchial and pancreatic well differentiated NENs. The most frequent symptom was a variable degree of visual impairment, while headache was reported in half of the cases. Partial or total anterior hypopituitarism was present in approximately three quarters of the cases, while diabetes insipidus was less common. The most frequent treatment for PM was surgical resection, followed by radiotherapy and chemotherapy. The clinical outcome was in line with previous reports of PM from solid tumours, with a median survival of 14 months. Surgery of PM was associated with prolonged survival.

CONCLUSIONS

PM from NENs have clinical features similar to metastases derived from other solid tumours, albeit the involvement of the anterior pituitary seems more frequent; a thorough pituitary hormonal evaluation is mandatory, after focused radiological studies, particularly if a surgical approach is considered. The optimal management of PM remains disputed and seems mainly driven by the aggressiveness of the primary tumour and the presence of symptoms. In well-differentiated NENs, particularly in the case of symptomatic PM, surgical removal may be a reasonable approach.

A novel read methodology to evaluate the optimal dose of 68Ga-satoreotide trizoxetan as a PET imaging agent in patients with gastroenteropancreatic neuroendocrine tumours: a phase II clinical trial

BACKGROUND

⁶⁸Ga-satoreotide trizoxetan is a novel somatostatin receptor antagonist exhibiting higher tumour-to-background ratios and sensitivity compared to ⁶⁸Ga-DOTATOC. This randomised, 2 × 3 factorial, phase II study aimed to confirm the optimal peptide mass and radioactivity ranges for ⁶⁸Ga-satoreotide trizoxetan, using binary visual reading. To that end, 24 patients with metastatic gastroenteropancreatic neuroendocrine tumours received 5-20 µg of ⁶⁸Ga-satoreotide trizoxetan on day 1 of the study and 30-45 µg on day 16-22, with one of three gallium-68  radioactivity ranges (40-80, 100-140, or 160-200 MBq) per visit. Two ⁶⁸Ga-satoreotide trizoxetan PET/CT scans were acquired from each patient post-injection, and were scored by experienced independent blinded readers using a binary system (0 for non-optimal image quality and 1 for optimal image quality). For each patient pair of ⁶⁸Ga-satoreotide trizoxetan scans, one or both images could score 1.

RESULTS

Total image quality score for ⁶⁸Ga-satoreotide trizoxetan PET scans was lower in the 40-80 MBq radioactivity range (56.3%) compared to 100-140 MBq (90.6%) and 160-200 MBq (81.3%). Both qualitative and semi-quantitative analysis showed that peptide mass (5-20 or 30-45 µg) did not influence ⁶⁸Ga-satoreotide trizoxetan imaging. There was only one reading where readers diverged on scoring; one reader preferred one image because of higher lesion conspicuity, and the other reader preferred the alternative image because of the ability to identify more lesions.

CONCLUSIONS

Binary visual reading, which was associated with a low inter-reader variability, has further supported that the optimal administered radioactivity of ⁶⁸Ga-satoreotide trizoxetan was 100-200 MBq with a peptide mass up to 50 µg. Trial registration ClinicalTrials.gov, NCT03220217. Registered 18 July 2017, https://clinicaltrials.gov/ct2/show/NCT03220217.

Paraneoplastic Cushing Syndrome in Gastrointestinal Neuroendocrine Tumour

Ectopic production of adrenocorticotropic hormone (ACTH) by gastrointestinal neuroendocrine tumours (NETs) is relatively uncommon. We report a rare case of a liver metastatic G1 low-grade NET of the intestine that induced hypercortisolism after surgical resection. A 50-year-old man was admitted for an intestinal obstruction caused by a tumour of the intestine. Paraneoplastic Cushing syndrome was diagnosed more than a year later following the appearance of cushingoid symptoms, despite stable disease according to RECIST criteria but chromogranin A increase. Ketoconazole and sandostatin medical treatment and liver chemoembolization never managed to control the hypercortisolism unlike the bilateral adrenalectomy. The identification and effective management of this uncommon statement of ectopic ACTH secretion is important to improve the patient's prognosis and quality of life.

Tunneled biopsy is an underutilised, simple, safe and efficient method for tissue acquisition from subepithelial tumours

BACKGROUND

Tissue acquisition from subepithelial lesions is often attempted by endoscopic ultrasound (EUS)-sampling as conventional endoscopic biopsy usually fails to reach deeper layers of the gastrointestinal wall.

AIM

To investigate the utilisation, safety and diagnostic yield of an intensified “bite-on-bite” tunnel biopsy technique.

METHODS

In this retrospective cohort study, all patients presenting with subepithelial masses in the upper gastrointestinal tract from March 2013 to July 2019 were included. Data were analysed for size and location of the subepithelial mass, use of intensified tunnel biopsy protocol (more than 10 double bite-on-bite biopsies) or superficial conventional biopsies, histology and imaging results, occurrence of readmission and adverse events after endoscopy.

RESULTS

Two hundred and twenty-nine patients with subepithelial lesions were included. Superficial conventional biopsies were taken in 117 patients and were diagnostic only in one lipoma (0.9 %). Tunnel biopsies taken in 112/229 (48.9%) patients were significantly more likely to provide histological diagnosis (53.6%; P < 0.001). For lesions ≥ 10mm the diagnostic yield of tunnel biopsies further increased to 41/67 (61.2%). No immediate or delayed complications were reported. Only 8 of the 51 endoscopists (15.7%) regularly attempted tunnel biopsies.

CONCLUSION

Tunnel biopsy is a simple, safe and efficient but underutilised diagnostic modality for tissue acquisition in subepithelial masses. It should be routinely attempted at the initial endoscopy.

Clinicopathological features and current treatment outcomes of neuroendocrine thymic tumours

OBJECTIVES

Neuroendocrine thymic tumours (NETTs) are a distinct subgroup of rare malignancies. An international, multicentre retrospective analysis was used to study the clinicopathological features, current pattern of diagnosis, treatment and outcomes of patients with NETT.

METHODS

One hundred and forty-six NETT treated from 1989 to 2016 at 21 centres in China, Europe and North America were retrospectively collected and reclassified according to the World Health Organization histological type and International Thymic Malignancy Interest Group (ITMIG)/International Association for Studies in Lung Cancer (IASLC)/Union for International Cancer Control (UICC) staging. Clinicopathological features, diagnostic and therapeutic approaches and outcomes were investigated. Results in the earlier and latter halves of the study period were also compared.

RESULTS

The pretreatment work-up relied exclusively on computed tomography in 85.6% (125/146) of cases. Most patients had advanced disease, with 32.2% (47/146) having lymph node involvement. Higher-grade histological type was associated with more advanced disease (P < 0.05). Induction therapies and surgical procedures were used more often in the latter half of the study. However, the complete resection rate remained unchanged, being 71.5% (98/137) in the whole group. Complete resection was associated with significantly longer 5-year overall survival (77.2% vs 51.2%; P < 0.001) than incomplete or no resection. Significant survival differences were seen with the T, N and M categories of ITMIG/IASLC/UICC staging. Poorly differentiated carcinoma, ITMIG/IASLC/UICC stage IIIa or above and incomplete or no resection were independent risk factors for worse survival. No survival difference was noted between the earlier and the latter halves of the study (58.2% vs 71.9%; P = 0.299).

CONCLUSIONS

Current management similar to that for thymomas is unsatisfactory in providing disease control or long-term survival for patients with NETT. Specific diagnostic tools and novel therapeutic agents are needed to improve management outcomes of this disease.

Coronavirus disease 2019 in patients with neuroendocrine neoplasms: Preliminary results of the INTENSIVE study

Background

Specific data regarding coronavirus disease 2019 (COVID-19) in patients with neuroendocrine neoplasms (NENs) are lacking. The aim of this study is to describe the characteristics of patients with NENs who tested severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive.

Material and methods

This is a worldwide study collecting cases of patients with NENs along with a positive nasopharyngeal swab reverse transcriptase-polymerase chain reaction (RT-PCR) test for SARS-CoV-2 between June 1, 2020, and March 31, 2021. Centres treating patients with NENs were directly contacted by the principal investigator. Patients with NENs of any primary site, grade and stage were included, excluding small-cell lung carcinoma and mixed adenoneuroendocrine carcinoma.

Results

Among 81 centres directly contacted, 88.8% responded and 48.6% of them declined due to lack of cases or interest. On March 31^st, 2021, eight recruiting centres enrolled 89 patients. The median age was 64 years at the time of COVID-19 diagnosis. Most patients had metastatic, non-functioning, low-/intermediate-grade gastroenteropancreatic NENs on treatment with somatostatin analogues and radioligand therapy. Most of them had comorbidities. Only 8% of patients had high-grade NENs and 12% were receiving chemotherapy. Most patients had symptoms or signs of COVID-19, mainly fever and cough. Only 3 patients underwent sub-intensive treatment, whereas most of them received medical therapies, mostly antibiotics. In two third of cases, no changes occurred for the anti-NEN therapy. More than 80% of patients completely recovered without sequelae, whereas 7.8% patients died due to COVID-19.

Conclusions

Patients included in this study reflect the typical NEN population regardless of SARS-CoV-2. In most cases, they overcome COVID-19 without need of intensive care, short-term sequelae and discontinuation of systemic oncological therapy.

Multiple endocrine neoplasia type 1 (MEN-1) and neuroendocrine neoplasms (NENs)

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms with 6.4-times increasing age-adjusted annual incidence during the last four decades. NENs arise from neuroendocrine cells, which release hormones in response to neuronal stimuli and they are distributed into organs and tissues. The presentation and biological behaviour of the NENs are highly heterogeneous, depending on the organ. The increased incidence is mainly due to increased awareness and improved detection methods both in the majority of sporadic NENs (non-inherited), but also the inherited groups of neoplasms appearing in at least ten genetic syndromes. The most important one is multiple endocrine neoplasia type 1 (MEN-1), caused by mutations in the tumour suppressor gene MEN1. MEN-1 has been associated with different tumour manifestations of NENs e.g. pancreas, gastrointestinal tract, lungs, thymus and pituitary. Pancreatic NENs tend to be less aggressive when arising in the setting of MEN-1 compared to sporadic pancreatic NENs. There have been very important improvements over the past years in both genotyping, genetic counselling and family screening, introduction and validation of various relevant biomarkers, as well as newer imaging modalities. Alongside this development, both medical, surgical and radionuclide treatments have also advanced and improved morbidity, quality of life and mortality in many of these patients. Despite this progress, there is still space for improving insight into the genetic and epigenetic factors in relation to the biological mechanisms determining NENs as part of MEN-1. This review gives a comprehensive update of current evidence for co-occurrence, diagnosis and treatment of MEN-1 and neuroendocrine neoplasms and highlight the important progress now finding its way to international guidelines in order to improve the global management of these patients.

177Lu-DOTATATE in older patients with metastatic neuroendocrine tumours: safety, efficacy and health-related quality of life

PURPOSE

The safety and efficacy of ¹⁷⁷Lu-DOTATATE in older patients with advanced neuroendocrine tumours (NET) are not well understood.

METHODS

Patients ≥70 years of age and treated with ¹⁷⁷Lu-DOTATATE were included. Toxicity, health-related quality of life (HRQoL), objective response, progression-free survival (PFS) and overall survival (OS) were assessed. The relationship between baseline characteristics and PFS and OS was analysed using the Kaplan-Meier method. Univariate analyses were performed using the Cox proportional hazards model.

RESULTS

In total, 71 patients were included (76.1% midgut primary). The median age at diagnosis and age at ¹⁷⁷Lu-DOTATATE treatment were 70 and 74 years, respectively. The majority (78.9%) of patients completed 4 cycles of ¹⁷⁷Lu-DOTATATE. Clinically significant myelosuppression was rare (2.8%). There was no deterioration in HRQoL and 'disease-specific worries' significantly improved (P = 0.029). Radiological response assessment was available in 66 patients. Partial response, stable disease and progression of disease were found in 10 (15.2%), 52 (78.8%) and 4 patients (6.1%), respectively. Median PFS and OS were 36.0 and 47.0 months, respectively. Increased baseline alkaline phosphatase was associated with poorer PFS (P = 0.002) and OS (P = 0.006).

CONCLUSION

Patients ≥70 years of age with advanced NET treated with ¹⁷⁷Lu-DOTATATE have efficacy and toxicity profiles similar to the wider NET population, without deterioration of HRQoL.

Current Oncologic Standards for Surgery of Small Bowel Cancers

PURPOSE

The last 2 decades has witnessed efforts towards standardization of surgery for small bowel cancers. The proposed recent guidelines/recommendations pertaining to choice of procedure and extent of lymphadenectomy are based on analysis of data from high volume centres of excellence. We evaluated whether these recently proposed oncologic recommendations can be replicated in the setting of single centre/team.

METHODS

This was a retrospective analysis of consecutive adult patients (age ≥ 18 years) who underwent surgery for tumours of small intestine (duodenum, jejunum, and ileum) by the same team of surgeons from 01/01/2010 to 12/31/2019. The procedure performed and lymph nodes harvested during pathologic examination were compared with recent recommendations.

RESULTS

Of the 32 patients (20 males and 12 females), mean age was 52.4 (range 31-77) years. Twenty-nine (90.6%) patients underwent surgery for small bowel cancers. Duodenum was the most common site, while NET was the commonest cancer. Whipple's procedure was performed for tumours of II part of duodenum, while for the rest, segmental resection was performed. The median number of lymph nodes examined for duodenal adenocarcinoma and NET was 14 and 9, respectively. For jejunal/ileal adenocarcinoma, median lymph node number examined was 11.

CONCLUSION

Our study shows that these recently proposed standards for surgery of small bowel cancers are achievable if basic principles of oncologic surgery are followed.

Gastroenteropancreatic neuroendocrine neoplasms: A clinical snapshot

Our understanding about the epidemiological aspects, pathogenesis, molecular diagnosis, and targeted therapies of neuroendocrine neoplasms (NENs) have drastically advanced in the past decade. Gastroenteropancreatic (GEP) NENs originate from the enteroendocrine cells of the embryonic gut which share common endocrine and neural differentiation factors. Most NENs are well-differentiated, and slow growing. Specific neuroendocrine biomarkers that are used in the diagnosis of functional NENs include insulin, glucagon, vasoactive intestinal polypeptide, gastrin, somatostatin, adrenocorticotropin, growth hormone releasing hormone, parathyroid hormone-related peptide, serotonin, histamine, and 5-hydroxy indole acetic acid (5-HIAA). Biomarkers such as pancreatic polypeptide, human chorionic gonadotrophin subunits, neurotensin, ghrelin, and calcitonin are used in the diagnosis of non-functional NENs. 5-HIAA levels correlate with tumour burden, prognosis and development of carcinoid heart disease and mesenteric fibrosis, however several diseases, medications and edible products can falsely elevate the 5-HIAA levels. Organ-specific transcription factors are useful in the differential diagnosis of metastasis from an unknown primary of well-differentiated NENs. Emerging novel biomarkers include circulating tumour cells, circulating tumour DNA, circulating micro-RNAs, and neuroendocrine neoplasms test (NETest) (simultaneous measurement of 51 neuroendocrine-specific marker genes in the peripheral blood). NETest has high sensitivity (85%-98%) and specificity (93%-97%) for the detection of gastrointestinal NENs, and is useful for monitoring treatment response, recurrence, and prognosis. In terms of management, surgery, radiofrequency ablation, symptom control with medications, chemotherapy and molecular targeted therapies are all considered as options. Surgery is the mainstay of treatment, but depends on factors including age of the individual, location, stage, grade, functional status, and the heredity of the tumour (sporadic vs inherited). Medical management is helpful to alleviate the symptoms, manage inoperable lesions, suppress postoperative tumour growth, and manage recurrences. Several molecular-targeted therapies are considered second line to somatostatin analogues. This review is a clinical update on the pathophysiological aspects, diagnostic algorithm, and management of GEP NENs.

Gastroenteropancreatic neuroendocrine neoplasms: A clinical snapshot

Our understanding about the epidemiological aspects, pathogenesis, molecular diagnosis, and targeted therapies of neuroendocrine neoplasms (NENs) have drastically advanced in the past decade. Gastroenteropancreatic (GEP) NENs originate from the enteroendocrine cells of the embryonic gut which share common endocrine and neural differentiation factors. Most NENs are well-differentiated, and slow growing. Specific neuroendocrine biomarkers that are used in the diagnosis of functional NENs include insulin, glucagon, vasoactive intestinal polypeptide, gastrin, somatostatin, adrenocorticotropin, growth hormone releasing hormone, parathyroid hormone-related peptide, serotonin, histamine, and 5-hydroxy indole acetic acid (5-HIAA). Biomarkers such as pancreatic polypeptide, human chorionic gonadotrophin subunits, neurotensin, ghrelin, and calcitonin are used in the diagnosis of non-functional NENs. 5-HIAA levels correlate with tumour burden, prognosis and development of carcinoid heart disease and mesenteric fibrosis, however several diseases, medications and edible products can falsely elevate the 5-HIAA levels. Organ-specific transcription factors are useful in the differential diagnosis of metastasis from an unknown primary of well-differentiated NENs. Emerging novel biomarkers include circulating tumour cells, circulating tumour DNA, circulating micro-RNAs, and neuroendocrine neoplasms test (NETest) (simultaneous measurement of 51 neuroendocrine-specific marker genes in the peripheral blood). NETest has high sensitivity (85%-98%) and specificity (93%-97%) for the detection of gastrointestinal NENs, and is useful for monitoring treatment response, recurrence, and prognosis. In terms of management, surgery, radiofrequency ablation, symptom control with medications, chemotherapy and molecular targeted therapies are all considered as options. Surgery is the mainstay of treatment, but depends on factors including age of the individual, location, stage, grade, functional status, and the heredity of the tumour (sporadic vs inherited). Medical management is helpful to alleviate the symptoms, manage inoperable lesions, suppress postoperative tumour growth, and manage recurrences. Several molecular-targeted therapies are considered second line to somatostatin analogues. This review is a clinical update on the pathophysiological aspects, diagnostic algorithm, and management of GEP NENs.

The emerging clinical relevance of genomic profiling in neuroendocrine tumours

Background

Neuroendocrine tumours (NETs) arise from hormone-producing or nervous system cells and can develop from anywhere in the body. They have heterogeneous origins from skin to gastrointestinal track and a complicated histology. Thus, there is an inevitable need for genomic profiling to determine the exact genetics of each tumour for prognosis and treatment strategies to overcome the disease’s complexity. For this purpose, next-generation-sequencing (NGS) is the most reliable methodology for both germ-line and somatic studies to make a clinical diagnosis. In this study, we analyse liquid biopsies, formalin fixed paraffin embedded (FFPE) tissues, and peripheral blood samples for their ability to provide information for actionability.

Methods

A customized multi-gene panel comprised of Succinate Dehydrogenase Complex Iron Sulfur Subunit B (SDHB), Succinate Dehydrogenase Complex Subunit C (SDHC), Cell Division Cycle 73(CDC73), Calcium Sensing Receptor (CASR), Platelet Derived Growth Factor Receptor Alpha (PDGFRA), Succinate Dehydrogenase Complex Flavoprotein Subunit A (SDHA), Ret Proto-Oncogene (RET), Succinate Dehydrogenase Complex Assembly Factor 2(SDHAF2), Menin 1(MEN1), Succinate Dehydrogenase Complex Subunit D (SDHD), MYC Associated Factor X (MAX) and Protein Kinase CAMP-Dependent Type I Regulatory Subunit Alpha (PRKAR1A) genes was constructed to assess multiple specimen types including: 3 liquid biopsies, 6 FFPE tissues, and 26 peripheral blood samples from 35 unique NET patients. Quality-control and bioinformatics analyses were performed using QCI-Analyze and QCI-Interpret.

Results

The three liquid biopsies and the 6 FFPE tissue samples were evaluated for somatic mutations; while the 26 peripheral blood samples were analysed using the germ-line pipeline. Five (55.6%) of the nine patients that were studied for somatic changes carried actionable mutations related to therapy sensitivities. Through the germ-line studies, we observed a 50% positivity rate for disease predisposition with 16 variants classified according to ACMG (American College of Medical Genetics) Standards and Guidelines.

Conclusions

Genomic profiling medicine is an emerging area of clinical oncology and has become crucial for disease and patient management by providing a precision approach; this is especially true for rare diseases including rare cancers such as NETs. Notably, this study emphasized the relevance of multiple distinctive biological sample types for use in the genetic testing of cancers to help with the choice of therapy to maximize the likelihood of a positive clinical outcome.

Lanreotide autogel/depot in advanced enteropancreatic neuroendocrine tumours: final results of the CLARINET open-label extension study

PURPOSE

In the phase III CLARINET study (NCT00353496), lanreotide autogel/depot (lanreotide) significantly improved progression-free survival (PFS) vs placebo in patients with non-functioning intestinal or pancreatic neuroendocrine tumours (NETs). The aim of CLARINET open-label extension (OLE) (NCT00842348) was to evaluate long-term safety and efficacy of lanreotide in these patients.

METHODS

Patients from the CLARINET study were eligible for the OLE if they had stable disease (irrespective of treatment group) or progressive disease (PD) (placebo-treated patients only). All patients in the OLE received lanreotide 120 mg every 28 days. Computed tomography or magnetic resonance imaging scans were conducted every 6 months and assessed locally for PD (the final scan was also assessed centrally).

RESULTS

Overall, 89 patients took part in the OLE (lanreotide, n = 42; placebo, n = 47). Median (range) exposure to lanreotide in patients who received lanreotide in the core study and OLE (LAN-LAN group) was 59.0 (26.0-102.3) months. In this group, the overall incidences of adverse events (AEs) and treatment-related AEs were lower in the OLE than in the core study. Median [95% CI] PFS in the LAN-LAN group was 38.5 [30.9; 59.4] months. In placebo-treated patients with PD at the end of the core study, time to death or subsequent PD during the OLE was 19 [10.1; 26.7] months.

CONCLUSIONS

This study provides new evidence on the long-term safety profile and sustained anti-tumour effects of lanreotide autogel/depot in indolent and progressive metastatic intestinal or pancreatic NETs.

Physician-perceived utility of the EORTC QLQ-GINET21 questionnaire in the treatment of patients with gastrointestinal neuroendocrine tumours: a multicentre, cross-sectional survey (QUALINETS)

Background and objective

Patient-reported outcome measures can provide clinicians with valuable information to improve doctor-patient communication and inform clinical decision-making. The aim of this study was to evaluate the physician-perceived utility of the QLQ-GINET21 in routine clinical practice in patients with gastrointestinal neuroendocrine tumours (GI-NETs). Secondary aims were to explore the patient, clinician, and/or centre-related variables potentially associated with perceived clinical utility.

Methods

Non-interventional, cross-sectional, multicentre study conducted at 34 hospitals in Spain and Portugal (NCT02853422). Patients diagnosed with GI-NETs completed two health-related quality of life (HRQoL) questionnaires (QLQ-C30, QLQ-GINET21) during a single routine visit. Physicians completed a 14-item ad hoc survey to rate the clinical utility of QLQ-GINET21 on three dimensions: 1)therapeutic and clinical decision-making, 2)doctor-patient communication, 3)questionnaire characteristics.

Results

A total of 199 patients at 34 centres were enrolled by 36 participating clinicians. The highest rated dimension on the QLQ-GINET21 was questionnaire characteristics (86.9% of responses indicating “high utility”), followed by doctor-patient communication (74.4%), and therapeutic and clinical decision-making (65.8%). One physician-related variable (GI-NET patient volume > 30 patients/year) was associated with high clinical utility and two variables (older age/less experience treating GI-NETs) with low clinical utility.

Conclusions

Clinician-perceived clinical utility of QLQ-GINET21 is high. Clinicians valued the instruments’ capacity to provide a better understanding of patient perspectives and to identify the factors that had the largest influence on patient HRQoL.

Contribution of Immune-Mediated Paraneoplastic Syndromes to Neurological Manifestations of Neuroendocrine Tumours: A Retrospective Study

INTRODUCTION

Neurological symptoms associated with neuroendocrine tumours (NETs) may be related to metastatic disease or paraneoplastic syndromes (PNSs); these last are often associated with autoantibodies targeting various onconeural antigens. To better characterize neurological PNSs related to NETs, we report the largest case-series study to date.

METHODS

We retrospectively reviewed the charts of all patients diagnosed with NETs of the gastrointestinal tract who presented with neurological symptoms at either of 2 tertiary academic hospitals (Henri Mondor and Beaujon, France) between 1994 and 2016. All patients underwent extensive neurological tests including clinical, laboratory, and radiological investigations. The clinical response to immunomodulating agents was recorded.

RESULTS

In the 13 identified patients, the most common presentations were peripheral neuropathy (46.2%) and encephalopathy (26.6%). Of the 6 (53.3%) patients whose serum anti-neuronal antibodies were assayed, 5 had high titres. Short-term oral corticosteroid and immunosuppressant drug therapy was given to 4 of these patients, of whom 3 had a clinical response and 1 no response. Repeated high-dose intravenous immunoglobulin therapy induced a complete clinical response in 1 patient. Encephalopathy resolved fully after hepatectomy or intrahepatic chemoembolization for liver metastases in another 2 patients.

DISCUSSION

The neurological symptoms associated with NETs may be due in part to autoimmune PNS. Based on experience at our 2 centres, we estimate that autoimmune PNS occurs in about 1% of patients with NETs. Early symptom recognition allows the initiation of effective treatments including corticosteroids, immunosuppressive drugs, and/or intravenous immunoglobulins.

Programmed Cell Death Ligand Expression Drives Immune Tolerogenesis across the Diverse Subtypes of Neuroendocrine Tumours

INTRODUCTION

A comprehensive characterization of the tumour microenvironment is lacking in neuroendocrine tumours (NETs), where programmed cell death-1 receptor-ligand (PD-1/PD-L1) inhibitors are undergoing efficacy testing.

OBJECTIVE

We investigated drivers of cancer-related immunosuppression across NETs of various sites and grades using multi-parameter immunohistochemistry and targeted transcriptomic profiling.

METHODS

Tissue microarrays (n = 102) were stained for PD-L1 and 2 and indoleamine deoxygenase-1 (IDO-1) and evaluated in relationship to functional characteristics of tumour-infiltrating T-lymphocytes (TILs) and biomarkers of hypoxia/angiogenesis. PD-L1 expression was tested in circulating tumour cells (CTCs, n = 12) to evaluate its relationship with metastatic dissemination.

RESULTS

PD-L1 expression was highest in lung NETs (n = 30, p = 0.007), whereas PD-L2 was highest in pancreatic NETs (n = 53, p < 0.001) with no correlation with grade or hypoxia/angiogenesis. PD-L1+ NETs (n = 26, 25%) had greater CD4+/FOXP3+ and CD8+/PD1+ TILs (p < 0.001) and necrosis (p = 0.02). CD4+/FOXP3+ infiltrate had the highest PD-L1/IDO-1 co-expressing tumours (p = 0.006). Grade 3 well-differentiated NETs had lower CD4+/FOXP3+ and CD8+/PD1+ TIL density (p < 0.001), and NanoString immune profiling revealed enrichment of macrophage-related transcripts in cases with poorer prognosis. We identified PD-L1(+) CTC subpopulations in 75% of evaluated patients (n = 12).

CONCLUSIONS

PD-L1 expression correlates with T-cell exhaustion independent of tumour hypoxia and is enhanced in a subpopulation of CTCs, suggesting its relevance to the progression of NETs. These findings support a potential therapeutic role for PD-L1 inhibitors in a subset of NETs.