Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

Clinical application of targeted α-emitter therapy in gastroenteropancreatic neuroendocrine neoplasms

Effective therapeutic strategies for advanced gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) remain challenging, including a lack of response to therapy and post-treatment relapse. The rapid development of targeted radionuclide therapy (TRT) offers promising data for patients with somatostatin receptor (SSTR)-expressing tumors. This approach exhibits more advantages than somatostatin analog (SSA) therapy, which is primarily effective for well-differentiated and slow-growing GEP-NENs. Fortunately, some clinical studies on peptide receptor radionuclide therapy (PRRT) labeled with α-emitting radionuclides for GEP-NENs patients showed effective results for those with more advanced GEP-NENs, or those with malignant metastasis. For the improvement of clinical efficacy and the decline in the incidence of treatment-related relapse, recent progress in developing novel techniques and effective disease management strategies for optimal targeting has led to the emergence of targeted alpha therapy (TAT) in GEP-NENs patients. For instance, labeled technology and combination therapy could contribute to significantly improved long-term outcomes. However, the exact dosimetry for precision oncology, the shortage of radionuclides, and the stability of disease control are still under careful consideration. More high-quality, large-scale prospective studies are essential for obtaining valuable evidence on challenging problems and for further exploration.

Rare Malignant Liver Tumors: Current Insights and Imaging Challenges

Rare malignant liver tumors (RMLTs) comprise a diverse group of neoplasms with distinct imaging features and significant diagnostic challenges due to their low prevalence and overlap with more common hepatic lesions. This review highlights the main radiologic characteristics of selected RMLTs-including fibrolamellar hepatocellular carcinoma, hepatic lymphoma, hepatocellular carcinoma in non-cirrhotic liver, mucinous cystic neoplasm, intraductal papillary neoplasm of the bile duct, epithelioid hemangioendothelioma, angiosarcoma, malignant hepatic adenoma, neuroendocrine tumor, hepatocholangiocarcinoma, hepatoblastoma, undifferentiated embryonal sarcoma, and infantile hepatic hemangioendothelioma-focusing on their presentation in CT and MRI. Recognizing specific imaging findings, such as arterial hyperenhancement, biliary communication, target and lollipop signs, and tumor morphology, can help narrow differential diagnoses and guide appropriate clinical management. Despite advancements in imaging, histopathologic confirmation is often required due to nonspecific features. Improved radiologic awareness of these rare entities is essential to facilitate early diagnosis and individualized treatment planning.

Non-hypervascular pancreatic neuroendocrine neoplasms differentiation from CA19-9 negative pancreatic ductal adenocarcinomas based on contrast CT: A large sample series

PROPOSE

This study aims to evaluate the effectiveness of contrast-enhanced computed tomography (CT) in distinguishing non-hypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs) with a normal serum level of carbohydrate antigen 19-9 (CA19-9) levels.

METHODS

This retrospective study included 134 patients with pathologically confirmed non-hypervascular PNENs and 128 patients with CA19-9-negative PDACs, all of whom underwent contrast-enhanced CT prior to surgery between January 2015 and March 2024. Following independent evaluation by two radiologists, qualitative features from both groups were extracted in the arterial and portal venous phase and subsequently compared using univariate and multivariate analysis.

RESULTS

Patients with CA19-9 negative PDACs were significantly older than those with non-hypervascular PNENs (p < 0.001), and the majority of PDACs were located in the head of the pancreas (p < 0.01).Univariate analysis showed that non-hypervascular PNENs exhibited a higher frequency of well-defined tumor margins (p < 0.001) and calcification (p = 0.032) and a lower frequency of local invasion (p < 0.001), peripancreatic vascular invasion (p = 0.001), intra- or extrahepatic bile duct dilatation (p < 0.001), distal main pancreatic duct dilatation (p < 0.001), regional lymphadenopathy (p < 0.001) and tumor homogeneity (p < 0.001) when compared to CA19-9 negative PDACs. Multivariate analysis identified the absence of local invasion (Odds Ratio (OR) = 0.233; 95 % Confidence Internals (95 % CI):0.114-0.476; p < 0.001), absence of peripancreatic vascular invasion (OR = 0.434; 95 % CI:0.217-0.870; p = 0.019), a normal distal main pancreatic duct diameter (OR = 0.398; 95 % CI:0.202-0.785; p = 0.008), absence of regional lymphadenopathy (OR = 0.455; 95 % CI:0.238-0.870; p = 0.017) and tumor heterogeneity (OR = 0.240; 95 % CI:0.126-0.456; p < 0.001) as significant predictors of non-hypervascular PNENs. The area under the receiver operating characteristic curve for the radiological feature model was 0.829 based on logistic regression.

CONCLUSIONS

Qualitative features in contrast-enhanced CT images could be beneficial in differentially diagnosing non-hypervascular PNENs and CA19-9 negative PDACs.

Characterizing SSTR2 expression and modulation for targeted imaging and therapy in preclinical models of triple-negative breast cancer

Patients with breast cancer which lack molecular targets, such as human epidermal growth factor receptor 2 (HER2) or hormone receptors, have limited access to targeted therapies. Somatostatin receptor 2 (SSTR2) is overexpressed in some cancers, and SSTR2-targeted radiopharmaceuticals are FDA-approved for theranostic targeted imaging and therapy in neuroendocrine tumors (NETs). Importantly, histone deacetylase (HDAC) inhibitors can epigenetically modulate SSTR2 expression in NETs with low or variable basal expression. The goal of this study is to characterize SSTR2 basal expression and induction via HDAC inhibition as a potential target for imaging and therapy in preclinical models of triple-negative breast cancer (TNBC). SSTR2 expression in mouse samples was assessed via Western blot and immunohistochemistry. Real-time quantitative PCR (qRT-PCR), flow cytometry, and cell binding assays were utilized to determine if HDAC inhibition can upregulate SSTR2 expression. [68Ga]Ga-DOTATATE positron emission tomography (PET) imaging, which targets SSTR2, was used to non-invasively characterize SSTR2 expression and variability in the EO771 and 4T1 TNBC models before and after HDAC inhibition. These studies demonstrate that HDAC inhibition can upregulate SSTR2 at the transcriptional, translational, and functional levels in breast cancer. Importantly, SSTR2 expression can be characterized non-invasively via PET imaging and modulation with HDAC inhibitors can be monitored longitudinally. Our findings highlight SSTR2 as a promising therapeutic molecular target in TNBC.

Organ-specific response to [177Lu]DOTATATE peptide receptor radionuclide therapy (PRRT) assessed by sequential [68Ga]DOTATOC PET/CT in patients with metastatic small intestine neuroendocrine tumors

PURPOSE

To evaluate organ-specific response to [177Lu]DOTATATE Peptide Receptor Radionuclide Therapy (PRRT) in patients with small intestine neuroendocrine tumor (SiNET) through [68Ga]DOTATOC PET/CT, and to analyze tumor uptake and functional volume variations at different metastatic sites in relation to disease progression during clinical follow-up after treatment.

METHODS

A retrospective analysis was conducted on 33 metastatic patients. PET/CT were performed pre-treatment (PET0), mid-treatment after two PRRT cycles (PET2), and post-treatment (PET4). SUVmax and somatostatin receptor-expressing tumor volume (SRETV) were measured in liver, lymph node, peritoneum/mesentery, and bone metastases.

RESULTS

Liver metastases showed significant reduction in both SUVmax and SRETV from PET0 to PET4, with early response evident after two PRRT cycles. Nodal lesions exhibited a delayed response, with significant reductions at PET4. Peritoneal and bone metastases showed a continuous decline in SUVmax, but no significant changes in SRETV. Objective response rates were highest in liver metastases after treatment completion with lesser responses in nodal, peritoneal, and bone lesions. At a median follow-up of 24.3 months, 70% of patients experienced disease progression, while 30% did not. Liver metastases showed no significant changes in SUVmax or SRETV regardless of progression. Conversely, in non-progressing patients, peritoneal/mesenteric lesions showed a significant reduction in SUVmax, with unchanged SRETV, and nodal metastases exhibited reduced SRETV. Bone lesions in non-progressing patients showed significant decreases in both SUVmax and SRETV.

CONCLUSION

[177Lu]DOTATATE PRRT effectively reduces tumor functional activity in patients with SiNETs, with organ-specific responses highlighting the need for personalized treatment strategies to optimize efficacy and minimize toxicity.

Current status of peptide receptor radionuclide therapy in grade 1 and 2 gastroenteropancreatic neuroendocrine tumours

Peptide receptor radionuclide therapy (PRRT) using [177Lu-DOTA0,Tyr3]octreotate (177Lu-DOTATATE) represents an established treatment modality for somatostatin receptor-positive, locally advanced or metastatic gastroenteropancreatic neuroendocrine tumours (GEP NET) of grade 1 or 2. The studies have demonstrated that four cycles of PRRT with 177Lu-DOTATATE prolongs progression-free survival and preserves quality of life, in patients with grade 1 and 2 advanced GEP NET. Notably, first-line PRRT using 177Lu-DOTATATE in grade 2 and 3 GEP NET patients has also shown efficacy and safety. Furthermore, PRRT can ameliorate symptoms in patients with NET-associated functioning syndromes. Although various studies have explored alternative radionuclides for PRRT, none currently meet the criteria for routine clinical implementation. Ongoing research aims to further enhance PRRT, and the results from large clinical trials comparing PRRT with other NET treatments are anticipated, potentially leading to significant modifications in NET treatment strategies and PRRT protocols. The results of these studies are likely to help address existing knowledge gaps in the coming years. This review describes the clinical practice, recent developments and future treatment options of PRRT in patients with grade 1 and 2 GEP NET.

Developing a peripheral blood RNA-seq based NETseq ensemble classifier: A potential novel tool for non-invasive detection and treatment response assessment in neuroendocrine tumor patients receiving 177Lu-DOTATATE PRRT

Neuroendocrine tumors (NETs) are presented with metastases due to delayed diagnosis. We aimed to identify NET-related biomarkers from peripheral blood. The development and validation of a multi-gene NETseq ensemble classifier using peripheral blood RNA-Seq is reported. RNA-Seq was performed on peripheral blood samples from 178 NET patients and 73 healthy donors. Distinguishing gene features were identified from a learning cohort (59 PRRT-naïve GEP-NET patients and 38 healthy donors). Ensemble classifier combining the output of five machine learning algorithms viz. Random Forest (RF), Extreme Gradient Boosting (XGBOOST), Gradient Boosting Machine (GBM), Support Vector Machine (SVM), and Logistic Regression (LR) were trained and independently validated in the evaluation cohort (n = 106). The response to PRRT was evaluated in the PRRT cohort (n = 46) and the PRRT response monitoring cohort (n = 16). The response to 177Lu-DOTATATE PRRT was assessed using RECIST 1.1 criteria. The Ensemble classifier trained on 61 gene features, distinguished NET from healthy samples with 100% accuracy in the learning cohort. In an evaluation cohort, the classifier achieved 93% sensitivity (95% CI: 87.8%-98.03%) and 91.4% specificity (95% CI: 82.1%-100%) for PRRT-naïve GEP-NETs (AUROC = 95.4%). The classifier returned >87.5% sensitivity across different tumor characteristics and outperformed serum Chromogranin A sensitivity (χ2 = 21.89, p = 4.161e-6). In the PRRT cohort, RECIST 1.1 responders showed significantly lower NETseq prediction scores after 177Lu-DOTATATE PRRT, in comparison to the non-responders. In an independent response monitoring cohort, paired samples (before PRRT and after 2nd or 3rd cycle of PRRT) were analyzed. The NETseq prediction score significantly decreased in partial responders (p = .002) and marginally reduced in stable disease (p = .068). The NETseq ensemble classifier identified PRRT-naïve GEP-NETs with high accuracy (≥92%) and demonstrated a potential role in early treatment response monitoring in the PRRT setting. This blood-based, non-invasive, multi-analyte molecular method could be developed as a valuable adjunct to conventional methods in the detection and treatment response assessment in NET patients.

Efficacy and Safety of Peptide Receptor Radionuclide Therapy for the Treatment of Pancreatic Neuroendocrine Tumors: A Systematic Review and Meta-Analysis of Comparative Studies

Peptide receptor radionuclide therapy (PRRT) showed promising potential in the management of patients with pancreatic neuroendocrine tumors (pNETs). However, there is still a lack of evidence on its relative efficacy and safety compared with other treatment options. This review aims to synthesize the existing evidence on the efficacy and safety of PRRT for pNETs compared to different treatments. An electronic search was conducted from inception to May 2024. Comparative studies, including randomized controlled trials (RCTs), cohort studies, and case-control studies, that focused on the use of PRRT for treating pNETs were included. Efficacy outcomes included disease control rate (DCR), complete response (CR), partial response (PR), stable disease (SD), progression-free survival (PFS), and overall survival (OS). Safety outcomes were grade 3-4 hematological and renal toxicity and adverse events (AEs). Nine studies met the inclusive criteria. Among them, only one (11.1%) study was an RCT. Meta-analysis between full and reduced dosages of 177Lu-DOTATATE for G1-G2 pNETs revealed no significant differences in DCR, CR, PR, SD, and PFS between the groups. However, the full dosage group showed superior efficacy in some outcomes (DCR, CR, and PR). When PRRT was compared to other treatments such as surgery, chemotherapy, and targeted agents, it was associated with longer PFS and OS. Additionally, PRRT combined with capecitabine and salvage PRRT also showed efficacy in advanced cases. Safety analysis indicated that PRRT is well-tolerated, with minimal severe toxicity reported. PRRT is a promising therapeutic option for patients with advanced pNETs, offering a balance of efficacy and safety compared to other available treatments based on the low quality of evidence. Full-dosage PRRT may provide better outcomes than reduced dosages, and salvage PRRT remains effective for progressive disease. However, further high-quality RCTs are needed to confirm these findings and optimize PRRT usage in pNETs.

177Lu-DOTATATE Plus Capecitabine Versus 177Lu-DOTATATE Alone in Patients with Advanced Grade 1/2 Gastroenteropancreatic Neuroendocrine Tumors (LuCAP): A Randomized, Phase 2 Trial

177Lu-DOTATATE has emerged as a viable treatment strategy for advanced well-differentiated grade 1/2 gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Few retrospective studies have shown concomitant 177Lu-DOTATATE with radiosensitizing low-dose capecitabine to be effective in advanced NETs. However, this has not been validated in prospective randomized-controlled trials. Methods: In this investigator-initiated, parallel-group, open-label, phase 2 trial, patients with grade 1/2 GEP-NETs, having progressive somatostatin receptor-positive, locally advanced, or metastatic disease on 68Ga-DOTANOC PET/CT, were randomly assigned in a 1:1 ratio to 177Lu-DOTATATE plus capecitabine (experimental arm) or 177Lu-DOTATATE only (control arm). 177Lu-DOTATATE was administered at approximately 7.4 GBq/cycle intravenously, for up to 4 cycles, at 8 wk intervals, whereas capecitabine was given at 1,250 mg/m2/d orally from day 0 to day 14 of each cycle of 177Lu-DOTATATE. The primary endpoint was the objective response rate. Secondary endpoints included the disease control rate, progression-free survival, overall survival, and adverse events. Results: Seventy-two patients (median age, 53 y; range, 18-79 y) were enrolled. The objective response rate was 33.3% (95% CI, 18.6-50.9%) in the experimental arm versus 30.6% (95% CI, 16.4-48.1%) in the control arm (P = 0.800). The disease control rate was 88.9% (95% CI, 73.9-96.9%) and 91.7% (95% CI, 77.5-98.2%) in the experimental and control arms, respectively (P = 1.000). The estimated median progression-free survival in the experimental arm was 29 mo (95% CI, 22-29 mo) versus 31 mo (95% CI, 29-32 mo) in the control arm (P = 0.401). The median overall survival was not reached in either arm (P = 0.876). Overall, adverse events of at least grade 3 were noted in 7 patients in the experimental arm versus 6 patients in the control arm (P = 0.759). Conclusion: Based on the results of this trial, the addition of low-dose capecitabine to 177Lu-DOTATATE in advanced grade 1/2 GEP-NETs did not lead to superior radiographic responses. Further studies are needed to evaluate its potential role in high-grade NETs.

Everolimus in pituitary tumor: a review of preclinical and clinical evidence

Although pituitary tumors (PTs) are mostly benign, some PTs are characterized by low surgical resection rates, high recurrence rates, and poor response to conventional treatments and profoundly affect patients' quality of life. Everolimus (EVE) is the only FDA-approved mTOR inhibitor, which can be used for oral treatment. It effectively inhibits tumor cell proliferation and angiogenesis. It has been administered for various neuroendocrine tumors of the digestive tract, lungs, and pancreas. EVE not only suppresses the growth and proliferation of APT cells but also enhances their sensitivity to radiotherapy and chemotherapy. This review introduces the role of the PI3K/AKT/mTOR pathway in the development of APTs, comprehensively explores the current status of preclinical and clinical research of EVE in APTs, and discusses the blood-brain barrier permeability and safety of EVE.

Treatment and management of duodenal gangliocytic paraganglioma: A case report

Gangliocytic paraganglioma (GP) is a rare neuroendocrine tumor primarily found in the duodenum, most commonly in the second and third sections of the duodenum. Diagnosis of GP is based on its distinctive histopathological characteristics, which include three types of tumor cells in varying proportions: i) Epithelioid, ii) spindle-like and iii) ganglion-shaped cells. The distribution of the three tumor cell components varies from case to case and a patient may be easily misdiagnosed if one of the components is predominant. Endoscopic submucosal dissection (ESD) or surgical resection is the ideal treatment for duodenal GP (DGP); however, biotherapy, nuclide therapy, chemotherapy, targeted therapy and immunotherapy can be selected individually for patients with postoperative recurrence, metastasis or not suitable for surgery. In the present study, a male patient with DGP experienced recurrence after ESD surgery, and so received octreotide (Novartis; 30 mg/28 days) for 12 consecutive cycles. The patient had no further symptoms of gastrointestinal bleeding and no new lesions or metastases were observed after 47 months of follow-up.

Current Status of Immunotherapy in Management of Small Bowel Neuroendocrine Tumors

PURPOSE OF REVIEW

This study aims to present the current landscape of immunotherapy in the management of small bowel neuroendocrine tumors and identify ongoing and future targets for improved response.

RECENT FINDINGS

Somatostatin analogs and mTOR inhibitors remain cornerstones of non-surgical treatment, and applications of PRRT in SBNET are promising. Several efforts to replicate the success of immunotherapies in other solid tumors have been attempted in SBNET, with limited responses observed with current immune targets, such as PD-1/PD-L1 and CTLA-4. Epigenetic analyses have suggested a potential role for methylation and histone acetylation in SBNET tumorigenesis that warrant greater exploration. While the incidence of SBNET continues to increase, the number of effective therapies is few. Further elucidation of targetable components of the SBNET immune microenvironment with greater modulatory effects is necessary to improve outcomes in this growing patient population.

Management of Pancreatic Neuroendocrine Tumors: Surgical Strategies and Controversies

OBJECTIVE

Pancreatic neuroendocrine tumors (PNETs) are uncommon tumors which are increasing in incidence. The management of these tumors continues to evolve. This review examines the current role of surgery in the treatment of these tumors.

METHODS

Studies published over the past 10 years were identified using several databases including PubMed, MEDLINE, and Science Direct. Search terms included PNETs, treatment, and surgery. Clinical practice guidelines and updates from several major groups were reviewed.

RESULTS

Surgery continues to have a major role in the treatment of sporadic functional and nonfunctional PNETs. Pancreas-sparing approaches are increasingly accepted as alternatives to formal pancreatic resection in selected patients. Options such as watch and wait or endoscopic ablation may be reasonable alternatives to surgery for non-functional PNETs < 2 cm in size. Surgical decision-making in multiple endocrine neoplasia type 1 patients remains complex and in some situations such as gastrinoma quite controversial. The role of surgery has significantly diminished in patients with advanced disease due to the advent of more effective systemic and liver-directed therapies. However, the optimal treatments and sequencing in advanced disease remain poorly defined, and it has been suggested that surgery is underutilized in these patients.

CONCLUSIONS

Surgery remains a major treatment modality for PNETs. Given the plethora of available treatments, ongoing controversies and the changing landscape, management has become increasingly complex. An experienced multidisciplinary team which includes surgery is essential to manage these patients.

Gastroenteropancreatic neuroendocrine neoplasms: epidemiology, genetics, and treatment

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

Repeat Peptide Receptor Radionuclide Therapy in Neuroendocrine Tumors: A NET Center of Excellence Experience

INTRODUCTION

The available data for the safety and efficacy of repeat peptide receptor radionuclide therapy (PRRT) are almost exclusively from European centers. We present an updated experience with repeat PRRT in a cohort of US patients with neuroendocrine tumors (NETs) at our NET center of excellence.

METHODS

We used our single-center longitudinal NET registry to identify patients who had been previously treated with at least one dose of PRRT (PRRT 1, either 177Lu DOTATATE or 90Y DOTATOC) and following radiographic disease progression were re-treated with a second course of PRRT (PRRT 2). We reviewed patient, tumor and treatment characteristics, objective response rates, and toxicities after PRRT 1 and PRRT 2.

RESULTS

A total of 11 patients were included in the analysis. 45.5% (5/11) of patients received 177Lu DOTATATE PRRT only, both for PRRT1 and PRRT 2, while 54.5% (6/11) of patients received 90Y DOTATOC PRRT for PRRT1. At first restaging scan after PRRT2 (3-6 months), 18.2% (2/11), 36.4% (4/11), and 27.3% (3/11) of patients had PR, SD, and PD, respectively; 2/11 patients (18.2%) died before the first restaging scan. Therefore, 5/11 (45.5%) patients were noted to have disease progression. Median PFS for PRRT1 was 25.4 months and median PFS for PRRT2 was 13.1 months (p = 0.0001). We did not find a statistically significant difference between the occurrence of short and long-term hematological toxicities as well as renal toxicity after PRRT1 and PRRT2.

CONCLUSION

We show that repeat PRRT may benefit select patients and have an acceptable safety profile. In our cohort, PFS was significantly lower after PRRT2 as compared to PRRT1.

Comparative analysis of international guidelines on the management of advanced non-functioning well-differentiated pancreatic neuroendocrine tumors

This review presents a comprehensive comparative analysis of international guidelines for managing advanced, non-functioning, well-differentiated pancreatic neuroendocrine tumors (panNETs). PanNETs, which represent a significant proportion of pancreatic neuroendocrine neoplasms, exhibit diverse clinical behaviors and prognoses based on differentiation, grading, and other molecular markers. The varying therapeutic strategies proposed by different guidelines reflect their distinct emphases and regional considerations, such as the ESMO guideline's focus on advanced disease management and the ENETS guidance paper's multidisciplinary approach. This review examines the most recent guidelines from ESMO, NCCN, ASCO, ENETS, and NANETS, analyzing the recommendations for first-line therapies and subsequent treatment pathways in different clinical scenarios. Significant variations are observed in the recommendations, particularly concerning the choice and sequence of systemic therapies, the role of tumor grading and the Ki-67 index in therapeutic decisions, and the integration of regional regulatory and clinical practices. The analysis highlights the need for a tailored approach to managing advanced NF panNETs, advocating for flexibility in applying guidelines to account for individual patient circumstances and the evolving evidence base. This work underscores the complexities of managing this patient population and the critical role of a multidisciplinary team in optimizing treatment outcomes.

Surgical Management and Long-Term Evaluation of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) arise from neuroendocrine cells and are a rare class of heterogenous tumors with increasing incidence. The diagnosis, staging, treatment, and prognosis of PNETs depend heavily on identifying the histologic features and biological mechanisms. Here, the authors provide an overview of the diagnostic workup (biomarkers and imaging), grade, and staging of PNETs. The authors also explore associated genetic mutations and molecular pathways and describe updated guidelines on surgical and systemic treatment modalities.

Critical updates in neuroendocrine tumors: Version 9 American Joint Committee on Cancer staging system for gastroenteropancreatic neuroendocrine tumors

The American Joint Committee on Cancer (AJCC) staging system for all cancer sites, including gastroenteropancreatic neuroendocrine tumors (GEP-NETs), is meant to be dynamic, requiring periodic updates to optimize AJCC staging definitions. This entails the collaboration of experts charged with evaluating new evidence that supports changes to each staging system. GEP-NETs are the second most prevalent neoplasm of gastrointestinal origin after colorectal cancer. Since publication of the AJCC eighth edition, the World Health Organization has updated the classification and separates grade 3 GEP-NETs from poorly differentiated neuroendocrine carcinoma. In addition, because of major advancements in diagnostic and therapeutic technologies for GEP-NETs, AJCC version 9 advocates against the use of serum chromogranin A for the diagnosis and monitoring of GEP-NETs. Furthermore, AJCC version 9 recognizes the increasing role of endoscopy and endoscopic resection in the diagnosis and management of NETs, particularly in the stomach, duodenum, and colorectum. Finally, T1NXM0 has been added to stage I in these disease sites as well as in the appendix.

Presacral Neuroendocrine Neoplasms: A Multi-site Review of Surgical Outcomes

INTRODUCTION

Presacral neuroendocrine neoplasms (PNENs) are rare tumors, with limited data on management and outcomes.

METHODS

A retrospective review of institutional medical records was conducted to identify all patients with PNENs between 2008 and 2022. Data collection included demographics, symptoms, imaging, surgical approaches, pathology, complications, and long-term outcomes.

RESULTS

Twelve patients were identified; two-thirds were female, averaging 44.8 years of age, and, for the most part, presenting with back pain, constipation, and abdominal discomfort. Preoperative imaging included computed tomography scans and magnetic resonance images, with somatostatin receptor imaging and biopsies being common. Half of the patients had metastatic disease on presentation. Surgical approach varied, with anterior, posterior, and combined techniques used, often involving muscle transection and coccygectomy. Short-term complications affected one-quarter of patients. Pathologically, PNENs were mainly well-differentiated grade 2 tumors with positive synaptophysin and chromogranin A. Associated anomalies were common, with tail-gut cysts prevalent. Mean tumor diameter was 6.3 cm. Four patients received long-term adjuvant therapy. Disease progression necessitated additional interventions, including surgery and various chemotherapy regimens. Skeletal, liver, thyroid, lung, and pancreatic metastases occurred during follow-up, with no mortality reported. Kaplan-Meier analysis showed a 5-year local recurrence rate of 23.8%, disease progression rate of 14.3%, and de novo metastases rate of 30%.

CONCLUSION

The study underscores the complex management of PNENs and emphasizes the need for multicenter research to better understand and manage these tumors. It provides valuable insights into surgical outcomes, recurrence rates, and overall survival, guiding future treatment strategies for PNEN patients.

[177Lu]Lu-DOTA-TATE plus long-acting octreotide versus high‑dose long-acting octreotide for the treatment of newly diagnosed, advanced grade 2-3, well-differentiated, gastroenteropancreatic neuroendocrine tumours (NETTER-2): an open-label, randomised, phase 3 study

BACKGROUND

There are currently no standard first-line treatment options for patients with higher grade 2-3, well-differentiated, advanced, gastroenteropancreatic neuroendocrine tumours. We aimed to investigate the efficacy and safety of first-line [177Lu]Lu-DOTA-TATE (177Lu-Dotatate) treatment.

METHODS

NETTER-2 was an open-label, randomised, parallel-group, superiority, phase 3 trial. We enrolled patients (aged ≥15 years) with newly diagnosed higher grade 2 (Ki67 ≥10% and ≤20%) and grade 3 (Ki67 >20% and ≤55%), somatostatin receptor-positive (in all target lesions), advanced gastroenteropancreatic neuroendocrine tumours from 45 centres across nine countries in North America, Europe, and Asia. We used interactive response technologies to randomly assign (2:1) patients to receive four cycles (cycle interval was 8 weeks ± 1 week) of intravenous 177Lu-Dotatate plus intramuscular octreotide 30 mg long-acting repeatable (LAR) then octreotide 30 mg LAR every 4 weeks (177Lu-Dotatate group) or high-dose octreotide 60 mg LAR every 4 weeks (control group), stratified by neuroendocrine tumour grade (2 vs 3) and origin (pancreas vs other). Tumour assessments were done at baseline, week 16, and week 24, and then every 12 weeks until disease progression or death. The primary endpoint was progression-free survival by blinded, independent, central radiology assessment. We did the primary analysis at 101 progression-free survival events as the final progression-free survival analysis. NETTER-2 is registered with ClinicalTrials.gov, NCT03972488, and is active and not recruiting.

FINDINGS

Between Jan 22, 2020, and Oct 13, 2022, we screened 261 patients, 35 (13%) of whom were excluded. We randomly assigned 226 (87%) patients (121 [54%] male and 105 [46%] female) to the 177Lu-Dotatate group (n=151 [67%]) and control group (n=75 [33%]). Median progression-free survival was 8·5 months (95% CI 7·7-13·8) in the control group and 22·8 months (19·4-not estimated) in the 177Lu-Dotatate group (stratified hazard ratio 0·276 [0·182-0·418]; p<0·0001). During the treatment period, adverse events (of any grade) occurred in 136 (93%) of 147 treated patients in the 177Lu-Dotatate group and 69 (95%) of 73 treated patients in the control group. There were no study drug-related deaths during the treatment period.

INTERPRETATION

First-line 177Lu-Dotatate plus octreotide LAR significantly extended median progression-free survival (by 14 months) in patients with grade 2 or 3 advanced gastroenteropancreatic neuroendocrine tumours. 177Lu-Dotatate should be considered a new standard of care in first-line therapy in this population.

FUNDING

Advanced Accelerator Applications, a Novartis Company.

Advances in Radionuclide Therapies for Patients with Neuro-endocrine Tumors

PURPOSE OF REVIEW

To provide insights into the role of peptide receptor radionuclide therapy (PRRT) in patients with advanced neuroendocrine tumors (NET) and an overview of possible strategies to combine PRRT with locoregional and systemic anticancer treatments.

RECENT FINDINGS

Research on combining PRRT with other treatments encompasses a wide variety or treatments, both local (transarterial radioembolization) and systemic therapies, chemotherapy (i.e., capecitabine and temozolomide), targeted therapies (i.e., olaparib, everolimus, and sunitinib), and immunotherapies (e.g., nivolumab and pembrolizumab). Furthermore, PRRT shows promising first results as a treatment prior to surgery. There is great demand to enhance the efficacy of PRRT through combination with other anticancer treatments. While research in this area is currently limited, the field is rapidly evolving with numerous ongoing clinical trials aiming to address this need and explore novel therapeutic combinations.

Neuroendocrine Neoplasia: From Pathophysiology to Novel Therapeutic Approaches

Neuroendocrine neoplasia (NEN) represents a sensational field of modern medicine; immense progress in emerging biochemical, molecular, endocrine, immunohistochemical, and serum tumour markers of disease, respectively, which are part of early diagnosis, genetic testing, and multidisciplinary approaches [...].

Diagnostic and Therapeutic Management of Primary Orbital Neuroendocrine Tumors (NETs): Systematic Literature Review and Clinical Case Presentation

BACKGROUND

The ocular involvement of neuroendocrine neoplasms (NENs) is uncommon and mainly represented by metastases from gastrointestinal and lung neuroendocrine tumors. Primary orbital NENs are even less common and their diagnostic and therapeutic management is a challenge.

METHODS

A systematic review of the literature was conducted from 1966 to September 2023 on PubMed to identify articles on orbital NENs and to summarize their clinical-pathological features, diagnosis and therapeutic management. Furthermore, we presented a case of a locally advanced retro-orbital primary neuroendocrine tumor that was referred to the certified Center of Excellence of Sant'Andrea Hospital, La Sapienza University of Rome, Italy.

RESULTS

The final analysis included 63 records on orbital NENs and 11 records focused on primary orbital NENs. The localization was mostly unilateral and in the right orbit; proptosis or exophthalmos represented the initial symptoms. The diagnostic work-up and therapeutic management was discussed and a diagnostic algorithm for the suspicion of primary orbital NENs was proposed.

CONCLUSIONS

A multidisciplinary approach is required for the management of primary orbital NENs, emphasizing the importance of early referral to dedicated centers for prompt differential diagnosis, tailored treatment, and an improved quality of life and survival.