Pancreatic Neuroendocrine Tumors Research Articles

Multicenter validation study of a treatment selection MAP for pancreatic neuroendocrine tumors.

Somatostatin analogs, molecular-targeted agents and cytotoxic anticancer agents are available as therapeutic agents for the systemic treatment of pancreatic neuroendocrine tumors, and we have developed a first-line treatment selection MAP to enable selection of the optimal treatment strategy for pancreatic neuroendocrine tumors. The purpose of this study was to validate the usefulness of the treatment selection MAP. Patients who had received systemic therapy for a pancreatic neuroendocrine tumor between January 2017 and December 2020 were compared according to whether they had been treated as recommended by the MAP (matched patients) or not (unmatched patients) to determine whether better outcomes were achieved by the matched patients. The primary endpoint was progression-free survival of the matched group and unmatched groups in the somatostatin analog, molecular-targeted agent and cytotoxic anticancer agents areas of the MAP. There were 41 (55%) MAP-matched patients in all areas among the 74 patients registered at seven hospitals. The MAP-matched rates were 100, 77 and 38% in the somatostatin analog area, molecular-targeted agent area and cytotoxic anticancer agents area, respectively. All of the unmatched patients had been selected for less intensive treatment. The median progression-free survival in the matched group and unmatched group in the molecular-targeted agent area of the MAP were 46.6 and 15.4months, respectively, and a multivariate analysis identified MAP-matched (hazard ratio 0.18 [95% confidence interval: 0.04-0.87], P=0.032) as the only significant independent favorable predictive factor. The usefulness of the MAP for treatment selection was validated in the molecular-targeted agent area of the MAP.

HER2 Overexpression in Periampullary Tumors According to Anatomical and Histological Classification-A Systematic Review.

Pancreatic cancer is one of the most aggressive, heterogeneous, and fatal types of human cancer; therefore, more effective therapeutic drugs are urgently needed. Human epidermal growth factor receptor 2 (HER2) overexpression and amplification have been identified as a cornerstone in this pathology. The aim of this review is to identify HER2 membrane overexpression in relation to pancreatic cancer pathways that can be used in order to develop a targeted therapy. After searching the keywords, 174 articles were found during a time span of 10 years, between 2013 and 2023, but only twelve scientific papers were qualified for this investigation. The new era of biomolecular research found a significant relationship between HER2 overexpression and pancreatic cancer cells in 25-30% of cases. The variables are dependent on tumor-derived cells, with differences in receptor overexpression between PDAC (pancreatic ductal adenocarcinoma), BTC (biliary tract cancer), ampullary carcinoma, and PNETs (pancreatic neuroendocrine tumors). HER2 overexpression is frequently encountered in human pancreatic carcinoma cell lines, and the ERBB family is one of the targets in the near future of therapy, with good results in phase I, II, and III studies evaluating downregulation and tumor downstaging, respectively.

Impressive Response to TANDEM Peptide Receptor Radionuclide Therapy with 177Lu/225AcDOTA-LM3 Somatostatin Receptor Antagonist in a Patient with Therapy-Refractory, Rapidly Progressive Neuroendocrine Neoplasm of the Pancreas.

The present report describes the history of a 58-year-old woman with a rapidly progressing neuroendocrine pancreatic tumor (initially G2) presenting with extensive liver, bone, and lymph node metastases. Previous treatments included chemotherapy, hemithyroidectomy for right lobe metastasis, Peptide Receptor Radionuclide Therapy (PRRT) with [177Lu]Lu-DOTATATE, Lanreotide, Everolimus, and liver embolization. Due to severe disease progression, after a liver biopsy revealing tumor grade G3, PRRT with the somatostatin receptor antagonist LM3 was initiated. [68Ga]GaDOTA-LM3 PET/CT showed intense tracer uptake in the liver, pancreatic tumor, lymph nodes, and bone metastases. Three TANDEM-PRRT cycles using [177Lu]LuDOTA-LM3 and [225Ac]AcDOTA-LM3, administered concurrently, resulted in significant improvement, notably in liver metastases, hepatomegaly reduction, the complete regression of bone and lymph node metastases, and primary tumor improvement. Partial remission was confirmed by positron emission tomography/computed tomography, chest-abdomen-pelvis contrast-enhanced computed tomography, and magnetic resonance of the abdomen, with marked clinical improvement in pain, energy levels, and quality of life, enabling full resumption of physical activity.

Consensus on the clinical diagnosis and treatment of grade 3 pancreatic neuroendocrine tumors

The World Health Organization (WHO) 2017 classifications for neuroendocrine neoplasms (NENs) subdivided grade 3 pancreatic neuroendocrine neoplasms (pNENs) into G3 well-differentiated pancreatic neuroendocrine tumors (G3 pNETs) and poorly differentiated pancreatic neuroendocrine carcinomas (pNECs), according to the mitotic count, Ki-67 index, and cell differentiation. As a new category, G3 pNETs remain a challenging group of tumors to manage by lacking large randomized trials and consensus to support its clinical practice. Therefore, the Chinese Pancreatic Surgery Association, Chinese Society of Surgery, Chinese Medical Association gathered experts in this field to formulate this consensus for the diagnosis and treatment of G3 pNETs.

Germline Testing Identifies Pathogenic/Likely Pathogenic Variants in Patients with Pancreatic Neuroendocrine Tumors.

Ten percent of pancreatic neuroendocrine tumors (pNET) are related to inherited syndromes (MEN1, MEN4, VHL, NF1, and TSC). Growing evidence suggests that clinically sporadic pNETs can also harbor germline pathogenic variants. In this study, we report the prevalence of pathologic/likely pathologic (P/LP) germline variants in a high-risk cohort and an unselected cohort. We collected clinical data of patients with pNETs seen at MD Anderson Cancer Center and Johns Hopkins Hospital. The high-risk cohort included (n = 132) patients seen at MD Anderson Cancer Center who underwent germline testing for high-risk criteria (early onset, personal or family history of cancer, and syndromic features) between 2013 and 2019. The unselected cohort included (n = 106) patients seen at Johns Hopkins Hospital who underwent germline testing following their diagnosis of pNETs between 2020 and 2022. In the high-risk cohort (n = 132), 33% (n = 44) had P/LP variants. The majority of the patients had P/LP variants in MEN1 56% (n = 25), followed by DNA repair pathways 18% (n = 8), and 7% (n = 3) in MSH2 (Lynch syndrome). Patients with P/LP were younger (45 vs. 50 years; P = 0.002). In the unselected cohort (n = 106), 21% (n = 22) had P/LP. The majority were noted in DNA repair pathways 40% (n = 9) and MEN1 36% (n = 8). Multifocal tumors correlated with the presence of P/LP (P = 0.0035). MEN1 germline P/LP variants correlated with younger age (40 vs. 56 years; P = 0.0012), presence of multifocal tumors (P < 0.0001), and World Health Organization grade 1 histology (P = 0.0078). P/LP variants are prevalent in patients with clinically sporadic pNET irrespective of high-risk features. The findings support upfront universal germline testing in all patients with pNET. Prevention Relevance: Here, we present germline data from the largest reported cohort of patients with pNET (n = 238), comprising both a high-risk cohort and an unselected cohort. In both cohorts, we identify a high number of P/LPs, including those in the DNA repair pathway. Our findings support universal germline testing in patients with pNET.

A comparative study of INSM1 (clone MRQ70) immunoreactivity on CytoLyt® pretreated cytology and resection specimens of pancreatic neuroendocrine tumors.

Insulinoma-associated protein 1 (INSM1) is a newly characterized sensitive and specific immunohistochemical marker for neuroendocrine (NE) tumors. Whereas more traditional NE markers, such as chromogranin A and synaptophysin, are cytoplasmic, INSM1 is uniquely nuclear and thus could serve as a useful addition to NE tumor workup. While application of immunohistochemical studies to cytology specimens is becoming increasingly relevant, knowledge of the effects of the certain fixatives as well as the pattern and intensity of immunoexpression are important considerations. Sixteen cases of pancreatic neuroendocrine tumor (PanNET) diagnosed between 2015 and 2021 underwent both fine-needle aspiration, which was subsequently prepared in CytoLyt®-fixed cytology cell block (CCB), and surgical resection, in which specimens were prepared into formalin-fixed paraffin embedded blocks (FFPE). For all samples, INSM1 immunoreactivity was classified according to staining intensity and extent, then compared between CCBs and matched FFPEs. All 16 FFPE specimens demonstrated strong and diffuse INSM1 immunoreactivity, while only 10/16 (62.5%) CCBs were positive. Of those 10, only 2/10 (20%) demonstrated strong and diffuse reactivity. The choice of fixative has a demonstrable effect on the immunoreactivity of INSM1 in PanNET. Even though the sensitivity is lower in CytoLyt®-fixed cell block specimens, the addition of INSM1 is useful, especially in challenging cases that may be negative for one or more of the traditional NE markers.

Contemporary Approaches to the Surgical Management of Pancreatic Neuroendocrine Tumors.

The incidence of pancreatic neuroendocrine tumors (PNETs) is on the rise primarily due to the increasing use of cross-sectional imaging. Most of these incidentally detected lesions are non-functional PNETs with a small proportion of lesions being hormone-secreting, functional neoplasms. With recent advances in surgical approaches and systemic therapies, the management of PNETs have undergone a paradigm shift towards a more individualized approach. In this manuscript, we review the histologic classification and diagnostic approaches to both functional and non-functional PNETs. Additionally, we detail multidisciplinary approaches and surgical considerations tailored to the tumor's biology, location, and functionality based on recent evidence. We also discuss the complexities of metastatic disease, exploring liver-directed therapies and the evolving landscape of minimally invasive surgical techniques.

Factors Affecting Nonfunctioning Small Pancreatic Neuroendocrine Neoplasms and Proposed New Treatment Strategies

Despite previously reported treatment strategies for nonfunctioning small (≤20 mm) pancreatic neuroendocrine neoplasms (pNENs), uncertainties persist. We aimed to evaluate the surgically resected cases of nonfunctioning small pNENs (NF-spNENs) in a large Japanese cohort to elucidate an optimal treatment strategy for NF-spNENs. In this Japanese multicenter study, data were retrospectively collected from patients who underwent pancreatectomy between January 1996 and December 2019, were pathologically diagnosed with pNEN, and were treated according to the World Health Organization 2019 classification. Overall, 1490 patients met the eligibility criteria, and 1014 were included in the analysis cohort. In the analysis cohort, 606 patients (59.8%) had NF-spNENs, with 82% classified as grade 1 (NET-G1) and 18% as grade 2 (NET-G2) or higher. The incidence of lymph node metastasis (N1) by grade was significantly higher in NET-G2 (G1: 3.1% vs G2: 15.0%). Independent factors contributing to N1 were NET-G2 or higher and tumor diameter ≥15 mm. The predictive ability of tumor size for N1 was high. Independent factors contributing to recurrence included multiple lesions, NET-G2 or higher, tumor diameter ≥15 mm, and N1. However, the independent factor contributing to survival was tumor grade (NET-G2 or higher). The appropriate timing for surgical resection of NET-G1 and NET-G2 or higher was when tumors were >20 and >10 mm, respectively. For neoplasms with unknown preoperative grades, tumor size >15 mm was considered appropriate. NF-spNENs are heterogeneous with varying levels of malignancy. Therefore, treatment strategies based on tumor size alone can be unreliable; personalized treatment strategies that consider tumor grading are preferable.

Combined deletion of MEN1, ATRX and PTEN triggers development of high-grade pancreatic neuroendocrine tumors in mice

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of tumors that exhibit an unpredictable and broad spectrum of clinical presentations and biological aggressiveness. Surgical resection is still the only curative therapeutic option for localized PanNET, but the majority of patients are diagnosed at an advanced and metastatic stage with limited therapeutic options. Key factors limiting the development of new therapeutics are the extensive heterogeneity of PanNETs and the lack of appropriate clinically relevant models. In that context, genomic sequencing of human PanNETs revealed recurrent mutations and structural alterations in several tumor suppressors. Here, we demonstrated that combined loss of MEN1, ATRX, and PTEN, tumor suppressors commonly mutated in human PanNETs, triggers the development of high-grade pancreatic neuroendocrine tumors in mice. Histopathological evaluation and gene expression analyses of the developed tumors confirm the presence of PanNET hallmarks and significant overlap in gene expression patterns found in human disease. Thus, we postulate that the presented novel genetically defined mouse model is the first clinically relevant immunocompetent high-grade PanNET mouse model.

Endoscopic ultrasound-guided radiofrequency ablation of pancreatic tumors.

Surgery is a cornerstone in the management of pancreatic cancer and precancerous pancreatic lesions. However, many patients are not suitable candidates for surgery at the time of diagnosis for various reasons. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) appears to be a promising treatment option for patients who are ineligible for surgery for management of pancreatic adenocarcinoma (PDAC), and pancreatic neuroendocrine tumors (PNETs), and pancreatic cystic lesions (PCLs). EUS-RFA may serve as an adjunct to chemotherapy or palliative measures for inoperable cases of PDAC. Given its feasibility and efficacy, EUS-RFA has an evolving niche as a minimally invasive and potentially definitive treatment for PNETs and high-risk PCLs such as intraductal papillary mucinous neoplasms (IPMNs). EUS-RFA is a generally well tolerated procedure, with abdominal pain and acute pancreatitis being the most common adverse effects, though the risk can be mitigated through prophylactic measures. There is an increasing body of evidence to support the use of EUS-RFA in managing pancreatic lesions, either as definitive, adjunctive, or palliative treatment, depending on lesion type.

Cinematic Rendering: A New Look at Pancreatic Neuroendocrine Tumour Imaging.

Cinematic Rendering: A New Look at Pancreatic Neuroendocrine Tumour Imaging.

Prevalence of metastases outside the liver and abdominal lymph nodes on 68Ga-DOTATOC-PET/CT in patients with small intestinal and pancreatic neuroendocrine tumours.

Metastases outside the liver and abdominal/retroperitoneal lymph nodes are nowadays detected frequently in patients with neuroendocrine tumours (NETs), owing to the high sensitivity of positron emission tomography (PET) with Gallium-68-DOTA-somatostatin analogues (68Ga-SSA) and concomitant diagnostic computed tomography (CT). Our aim was to determine the prevalence of extra-abdominal metastases on 68Ga-DOTATOC-PET/CT in a cohort of patients with small intestinal (Si-NET) and pancreatic NET (Pan-NET), as well as that of pancreatic metastasis in patients with Si-NET. Among 2090 patients examined by 68Ga-DOTATOC-PET/CT at two tertiary referral centres, a total of 1177 patients with a history of Si- or Pan-NET, were identified. The most recent 68Ga-DOTATOC-PET/CT report for each patient was reviewed, and the location and number of metastases of interest were recorded. Lesions outside the liver and abdominal nodes were found in 26% of patients (n = 310/1177), of whom 21.5% (255/1177) were diagnosed with Si-NET and 4.5% (55/1177) Pan-NET. Bone metastases were found in 18.4% (215/1177), metastases to Virchow's lymph node in 7.1% (83/1177), and lung/pleura in 4.8% (56/1177). In the subset of 255 Si-NET patients, 5.4% (41/255) manifested lesions in the pancreas, 1.5% in the breast (18/255), 1.3% in the heart (15/255) and 1% in the orbita (12/255). In Si-NET patients, the Ki-67 proliferation index was higher in those with ≥2 metastatic sites of interest, than with 1 metastatic site, (p <0.001). Overall, extra-abdominal or pancreatic metastases were more often found in patients with Si-NET (34%) than in those with Pan-NET (13%) (p <0.001). Bone metastases were 2.6 times more frequent in patients with Si-NET compared to Pan-NET patients (p <0.001). Lesions to the breast and orbita were encountered in almost only Si-NET patients. In conclusion, lesions outside the liver and abdominal nodes were detected in as many as 26% of the patients, with different prevalence and metastatic patterns in patients with Si-NET compared to Pan-NET. The impact of such metastases on overall survival and clinical decision-making needs further evaluation.

INSM1 is a useful neuroendocrine marker to differentiate pancreatic serous cystadenoma from pancreatic well-differentiated neuroendocrine tumors in cytology and surgical specimens

IntroductionDifferentiating pancreatic serous cystadenoma (SCA) from well-differentiated neuroendocrine tumors (WDNETs) based on histomorphology is critical yet challenging, particularly in small biopsy samples. Our study aimed to examine the expression profile of INSM1 in cytologic and surgical resection specimens from pancreatic SCA to evaluate its potential as a discriminative marker against pancreatic WDNET. MethodsWe characterized INSM1 immunohistochemistry in 34 patients with pancreatic SCA, comprising 23 surgical resections and 11 cytology specimens. As a control, we used 28 cytology specimens from pancreatic WDNET. Clinical information was retrieved through a review of electronic medical records. ResultsAll 11 pancreatic SCA cytology specimens and 15 of 23 pancreatic SCA surgical resections exhibited absent INSM1 immunostaining. Each of the remaining eight surgical resection specimens demonstrated 1 % immunoreactivity. In contrast, 27 out of 28 (96 %) pancreatic WDNET cytology specimens were positive for INSM1 immunostaining, with a median immunoreactivity of 90 % and a range of 30–90 %. Overall, INSM1 immunostains perform similarly to chromogranin and synaptophysin in pancreatic SCA. ConclusionsThe results indicate that INSM1 immunohistochemistry staining may serve as a useful neuroendocrine marker to differentiate pancreatic SCA from pancreatic WDNET in clinical practice. To our knowledge, this represents the first large-scale study to evaluate INSM1 immunostaining in surgical and cytology specimens from pancreatic SCA.

Prognostic marker of immunohistochemistry-based somatostatin receptors 2 and 5 H-scores in patients with pancreatic neuroendocrine neoplasms

ObjectivePancreatic neuroendocrine neoplasms (pNENs) are histologically classified as well-differentiated, poorly-differentiated, or mixed neuroendocrine-non-neuroendocrine neoplasms. There are unresectable pNENs owing to metastases or invasion in not only functional pNENs but also non-functional. However, the exact origin of pNENs has not been elucidated. This study aims to characterize the molecular biology of pNENs based on clinical information and histopathological analysis and identify prognostic biomarkers. MethodsWe investigated the relationship between the biological characteristics and immunostaining of pathological tissues in 75 patients. Staining density was evaluated on a 4-point scale from 0 to 3, and the percentage of tumor cells was calculated and scored from 0 to 300 (H-score). We performed receiver operating characteristic (ROC) curve analysis of the H-score. Progression-free survival and overall survival analyses were performed based on the Kaplan–Meier curves. ResultsThe H-score showed that patients who died of pNEN had high Ki-67 and low somatostatin receptor (SSTR) 2 levels, and those who relapsed had high Ki-67 and low SSTR5 levels. The ROC showed that the SSTR2 H-score > 80.25 was associated with lower mortality, which was further confirmed by Kaplan–Meier curves [hazard ratio (HR): 6.039, 95 % confidence interval (CI): 1.233–29.59, P = 0.0006). SSTR5 H-score > 93.9 had less recurrence, which was confirmed using Kaplan–Meier curves (HR: 3.321, 95 % CI: 1.426–7.734, P = 0.0336). ConclusionKi-67 > 4.95 is associated with a significantly increased risk of death. Quantification of SSTR2 and SSTR5 immunostaining using the H-score may serve as prognostic markers.

Abstract CT221: Belzutifan, a hypoxia-inducible factor-2α (HIF-2α) inhibitor, for von Hippel-Lindau (VHL) disease-associated neoplasms: Long-term results of the phase 2 LITESPARK-004 study

Abstract Introduction: Belzutifan is a first-in-class HIF-2α inhibitor approved for patients (pts) with VHL disease-associated renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas (HB), or pancreatic neuroendocrine tumors (pNET) not requiring immediate surgery based on initial results from the phase 2 LITESPARK-004 study (NCT03401788). We present results from pts with more than 4 years of follow-up from LITESPARK-004. Methods: Adults with germline VHL alteration, ≥1 measurable nonmetastatic RCC tumor, no RCC tumor &amp;gt;3 cm requiring immediate surgery, and no prior systemic anticancer therapy received oral belzutifan 120 mg once daily until disease progression, unacceptable toxicity, or withdrawal. The primary end point was objective response rate (ORR) in VHL-associated RCC per RECIST v1.1 by independent review. Secondary end points included ORR in CNS HB and pNET; duration of response (DOR), time to response (TTR), progression-free survival (PFS), and time to surgery (TTS) in RCC, CNS HB, and pNET; and safety. Results: As of April 3, 2023, 36 of 61 pts (59%) were continuing treatment. Median follow-up was 49.9 mo (range, 48.2-58.1). Efficacy data are shown in the table. In the 4 years preceding belzutifan treatment, 46 pts (75%) underwent a total of 86 VHL-related tumor reduction procedures (surgery or radiation therapy). Since starting belzutifan, 16 pts (26%) underwent 18 tumor reduction procedures (RCC, n = 13; CNS HB, n = 3; retinal HB, n = 2). Safety profile remained unchanged with long-term follow-up. Conclusions: With a median follow-up of more than 4 years, belzutifan continues to demonstrate clinically meaningful ORR and durable responses in VHL-associated RCC, CNS HBs, and pNET. Fewer tumor reduction procedures were observed after pts started belzutifan treatment. These results support belzutifan as a standard of care for this pt population. Citation Format: Ramaprasad Srinivasan, Othon Iliopoulos, Kathryn E. Beckermann, Vivek Narayan, Benjamin L. Maughan, Stephane Oudard, Tobias Else, Jodi K. Maranchie, Ane B. Iversen, Jerry Cornell, Rodolfo F. Perini, Yanfang Liu, W. Marston Linehan, Eric Jonasch. Belzutifan, a hypoxia-inducible factor-2α (HIF-2α) inhibitor, for von Hippel-Lindau (VHL) disease-associated neoplasms: Long-term results of the phase 2 LITESPARK-004 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT221.

ABCD1 as a Novel Diagnostic Marker for Solid Pseudopapillary Neoplasm of the Pancreas.

The diagnosis of solid pseudopapillary neoplasm of the pancreas (SPN) can be challenging due to potential confusion with other pancreatic neoplasms, particularly pancreatic neuroendocrine tumors (NETs), using current pathological diagnostic markers. We conducted a comprehensive analysis of bulk RNA sequencing data from SPNs, NETs, and normal pancreas, followed by experimental validation. This analysis revealed an increased accumulation of peroxisomes in SPNs. Moreover, we observed significant upregulation of the peroxisome marker ABCD1 in both primary and metastatic SPN samples compared with normal pancreas and NETs. To further investigate the potential utility of ABCD1 as a diagnostic marker for SPN via immunohistochemistry staining, we conducted verification in a large-scale patient cohort with pancreatic tumors, including 127 SPN (111 primary, 16 metastatic samples), 108 NET (98 nonfunctional pancreatic neuroendocrine tumor, NF-NET, and 10 functional pancreatic neuroendocrine tumor, F-NET), 9 acinar cell carcinoma (ACC), 3 pancreatoblastoma (PB), 54 pancreatic ductal adenocarcinoma (PDAC), 20 pancreatic serous cystadenoma (SCA), 19 pancreatic mucinous cystadenoma (MCA), 12 pancreatic ductal intraepithelial neoplasia (PanIN) and 5 intraductal papillary mucinous neoplasm (IPMN) samples. Our results indicate that ABCD1 holds promise as an easily applicable diagnostic marker with exceptional efficacy (AUC=0.999, sensitivity=99.10%, specificity=100%) for differentiating SPN from NET and other pancreatic neoplasms through immunohistochemical staining.

Sequencing Treatments in Patients with Advanced Well-Differentiated Pancreatic Neuroendocrine Tumor (pNET): Results from a Large Multicenter Italian Cohort.

Background: The optimal treatment sequencing for advanced, well-differentiated pancreatic neuroendocrine tumors (pNETs) is unknown. We performed a multicenter, retrospective study to evaluate the best treatment sequence in terms of progression-free survival to first-line (PFS1) and to second-line (PFS2), and overall survival among patients with advanced, well-differentiated pNETs. Methods: This multicenter study retrospectively analyzed the prospectively collected data of patients with sporadic well-differentiated pNETs who received at least two consecutive therapeutic lines, with evidence of radiological disease progression before change of treatment lines. Results: Among 201 patients, 40 (19.9%) had a grade 1 and 149 (74.1%) a grade 2 pNET. Primary tumor resection was performed in 98 patients (48.8%). First-line therapy was performed in 128 patients with somatostatin analogs (SSA), 35 received SSA + radioligand therapy (RLT), 21 temozolomide-based chemotherapy, and 17 SSA + targeted therapy. PFS was significantly longer in patients with grade 1 pNETs compared to those with grade 2, in patients who received primary tumor surgery, and in patients treated with RLT compared to other treatments. At multivariate analysis, the use of upfront RLT was independently associated with improved PFS compared to SSA. Second-line therapy was performed in 94 patients with SSA + targeted therapy, 35 received chemotherapy, 45 SSA + RLT, and 27 nonconventional-dose SSA or SSA switch. PFS was significantly longer in patients treated with RLT compared to other treatments. At multivariate analysis, the type of second-line therapy was independently associated with the risk for progression. OS was significantly longer in patients who received primary tumor surgery, with Ki67 < 10%, without extrahepatic disease, and in patients who received SSA-RLT sequence compared to other sequences. Conclusions: In this large, multicenter study, RLT was associated with better PFS compared to other treatments, and the SSA-RLT sequence was associated with the best survival outcomes in patients with pNETs with Ki67 < 10%. Primary tumor surgery was also associated with improved survival.

ASO Author Reflections: Can We Evaluate Surgical Quality for Pancreatic Neuroendocrine Tumors?

ASO Author Reflections: Can We Evaluate Surgical Quality for Pancreatic Neuroendocrine Tumors?

Deciphering pancreatic neuroendocrine tumors: Unveiling through circulating small extracellular vesicles

The survival rate over a five-year period for rare pancreatic neuroendocrine tumors (PanNET) is notably lower compared to other neuroendocrine tumors due to late-stage detection, which is a consequence of the absence of suitable diagnostic markers; therefore, there exists a critical need for an early-stage biomarker-specific to PanNETs. This study introduces a novel approach, investigating the impact of small extracellular vesicles (sEV) in PanNET growth and metastasis. As proof of concept, this study shows a correlation between sEV concentration in controls and PanNET. Notably, higher sEV concentrations were observed in PanNETs than in controls (p < 0.0001) with a sensitivity of 100%. Further, apparent differences were observed in the sEV concentrations between controls and grades 1 PanNET (p = 0.005). The expression of sEV markers was confirmed using CD63, TSG101, CD9, Flotillin-1, and GAD65 antibodies. Additionally, the expression of cancer marker BIRC2/cIAP1 (p = 0.002) and autophagy marker Beclin-1 (p = 0.02) were observed in plasma-derived sEVs and PanNET tissue. This study represents the first to indicate the increased secretion of sEV in PanNET patients' blood plasma, proposing potential function of sEV as a new biomarker for early-stage PanNET detection.

Treatment strategies for borderline resectable pancreatic neuroendocrine tumors: a narrative review.

Well-differentiated pancreatic neuroendocrine tumors (pNETs) are a group of rare, heterogeneous tumors that originate in the endocrine tissue of the pancreas and account for 1-2% of all pancreatic neoplasms. The majority of pNETs are non-functional and typically follow a more indolent course. Especially at early stages, the primary management of pNETs is surgical resection which is associated with relatively low rates of recurrence and excellent long-term prognosis. On the other hand, some patients will present with locally advanced primary tumors or low volume metastatic disease in which complete surgical resection may be more difficult to achieve and recurrence rates are significant. Unlike treatment of borderline resectable (BR) pancreatic adenocarcinoma, in which neoadjuvant treatment strategies are becoming standardized, borderline resectability is not a currently established terminology for pNETs and the optimal multidisciplinary treatment approach is poorly understood. We performed a literature search on PubMed, Google Scholar, and ClinicalTrials.gov using keywords, including 'pancreatic neuroendocrine tumor' and 'borderline resectable'. All studies and review articles in English with full text were considered. Each publication was independently reviewed. We introduce the concept of BR-pNETs, focusing on important criteria that should be included in their definition by balancing the feasibility of resection and the clinical utility of surgery. We suggest that extended resection, involving vascular reconstruction, adjacent organ resection, and/or liver metastasis, should be considered at experienced, high volume centers. Furthermore, we outline multidisciplinary treatment strategies, including systemic and locoregional treatment options, for optimizing outcomes for this growing patient population. Formalizing the definition of resectability in pNETs through multidisciplinary collaborative research will be important for standardizing the indications for multimodality treatment and aggressive surgical approaches for patients.