Hálfdánarson, Þorvarður R.

The prognosis of high-grade gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is highly variable and reported median overall survival remains low. There is no established standard of care for patients with higher grade 2 (G2) (Ki-67 ≥ 10% and ≤ 20%) and grade 3 (G3) (Ki-67 ≥ 20% and ≤ 55%) GEP-NETs and most of the current treatment regimens, particularly for G3 NETs, are extrapolated from lower-grade GEP-NET treatments or based on data from small retrospective studies. Robust evidence to support treatment recommendations for high-grade NETs, especially in the first-line (1L) setting, is limited and the optimal treatment sequence has not been clearly defined. This review summarizes the latest literature on sequencing of therapies, identifies patient selection considerations for utilizing peptide receptor radionuclide therapy (PRRT), and offers data-driven expert opinions and clinical practice recommendations in high-grade GEP-NETs. As authors, we recommend that all patients with well-differentiated, higher G2 and G3 NETs are evaluated with [68Ga]Ga-DOTA-peptide positron emission tomography (PET) for baseline somatostatin receptor expression and if positive, a 1L treatment option of PRRT should be considered, especially in clinically stable patients. Somatostatin analog therapy may benefit patients with low-volume, indolent disease, and chemotherapy is usually a better fit for patients in visceral crisis, in need of urgent treatment, or with no access to [68Ga]Ga-DOTA-peptide PET. In complex cases, a robust discussion at a multidisciplinary NET tumor board can be beneficial.

AbstractNeuroendocrine neoplasms (NENs) with peritoneal metastases (PM) represent a complex clinical challenge because of low incidence and heterogeneous phenotypes. This commentary describes the results of a national consensus aimed at addressing clinical management of patients with NENs and PM. An update of the 2018 Chicago consensus guidelines was conducted with a modified Delphi technique, which encompassed two rounds of voting. The levels of agreement for various pathway blocks were assessed, and key systemic therapy concepts were summarized by content experts. Supporting evidence was evaluated via a rapid literature review. Overall, the level of evidence for the management of PM in this disease was universally low. In total, 107 participants responded in the first round, with 88 of 107 (82%) participating in the second round. Strong consensus (>90%) was achieved in five of seven (71%) and seven of seven (100%) blocks in rounds 1 and 2, respectively. A multidisciplinary approach including psychosocial and wellness assessments received a strong positive recommendation. Management of NENs with PM was organized according to disease grade and symptom profiles. In grade 1 and 2 well‐differentiated NENs, cytoreductive surgery received strong support (>95%) after the management of functional syndromes (if present). For grade 3 well‐differentiated NENs, systemic therapy is the primary recommendation, with surgical resection considered in select cases. Given the limited evidence, the consensus‐driven clinical pathway offers vital clinical guidance for the management of NENs with PM. The need for high‐quality evidence remains critical to the field.

Abstract Peptide receptor radionuclide therapy (PRRT) with lutetium-177-Dotatate (177Lu-DOTATATE) has transformed neuroendocrine tumor (NET) treatment, improving progression-free survival, symptom control, and quality of life. However, long-term hematologic toxicities, including therapy-related myeloid neoplasms (tMN), are increasingly recognized. These rare but severe complications, such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), appear multifactorial, influenced by prior cytotoxic therapies, radiation exposure, clonal hematopoiesis, and germline predispositions. This review synthesizes data on PRRT-related hematologic toxicities, including findings from pivotal studies and real-world evidence. We explore risk factors, underlying mechanisms, and the potential role of biomarkers, such as clonal hematopoiesis and germline mutations, in predicting toxicity. Emerging approaches, including alpha particle radioligand therapy and advanced dosimetry, are explored as strategies to optimize patient selection and minimize adverse outcomes. To maximize the benefits of PRRT while safeguarding patient safety, future efforts should focus on integrating predictive biomarkers, refining treatment sequencing, and developing personalized risk-stratified approaches to therapy.

Abstract Malignant insulinomas are rare pancreatic neuroendocrine tumors characterized by excessive insulin secretion and a high propensity for metastasis, leading to challenging management. This study retrospectively analyzed 57 patients treated for malignant insulinoma at Mayo Clinic sites between 1992 and 2024, focusing on the efficacy of systemic therapies in improving hypoglycemic control and survival outcomes. The most commonly used therapies included somatostatin analogs (SSA), everolimus, capecitabine-temozolomide (CAPTEM), and peptide receptor radionuclide therapy (PRRT). PRRT demonstrated the highest efficacy in controlling hypoglycemia (93%), followed by CAPTEM (68%) and everolimus (62%). SSA, chemotherapy, and streptozocin were less effective, with hypoglycemic improvement seen in 37.5, 33.3, and 28.6% of patients, respectively. Overall survival (OS) was longest with SSA at 84.67 months, followed by CAPTEM at 81.67 months and everolimus at 74.07 months. PRRT demonstrated a median OS of 49.73 months. In contrast, chemotherapy and streptozocin-based therapies had significantly shorter OS times of 15.23 and 8.35 months, respectively. These findings highlight significant variability in systemic therapy efficacy for malignant insulinoma, with PRRT emerging as a promising treatment for refractory hypoglycemia and long survival. Cox regression analysis identified primary tumor resection and a history of benign insulinoma as associated with longer OS. Optimal sequencing of therapies remains unclear, and individualized treatment plans based on hypoglycemic burden and tumor characteristics are critical for improving survival and quality of life in these patients.

3005 Background: [ 212 Pb]VMT-α-NET, a next generation 212 Pb-based, SSTR2-targeted alpha-particle radiopharmaceutical therapy (RPT), was designed to achieve superior biodistribution via optimized tumor uptake and retention and rapid renal clearance. Results reported here are from the Phase 1/2a first-in-human study [NCT05636618]. Methods: Safety, pharmacokinetics, dosimetry and efficacy using RECIST v1.1 were investigated in the treatment of participants with [ 212 Pb]VMT-α-NET who had SSTR2-expressing, well-differentiated adult NETs of any grade. Participants received ≥1 prior therapy. No prior peptide receptor radionuclide therapy was allowed. The trial has multiple dose cohorts including 92.5 MBq (2.5 mCi, cohort 1) and 185 MBq (5 mCi, cohort 2) of administered activity based on a Bayesian modified toxicity probability interval (mTPI-2) design. Up to 8 participants per cohort were treated with 4 doses of [ 212 Pb]VMT-α-NET for DLT observation. Cohort 2 enrollment was expanded to further define the safety and efficacy profile at this dose level. Results: Nine (9) gastroenteropancreatic NET participants were enrolled into cohorts 1 and 2 for DLT observation. The ninth of these participants was enrolled more than 1 year prior to presentation of these data. Among these participants at the time of abstract submission, no DLTs were observed, and there were no grade 4, 5 or serious adverse events (SAEs). Specifically, no renal insufficiency or dysphagia were observed. Hematologic AEs were low grade and few in number. No treatment discontinuations due to AE occurred. Three (3) of the 7 cohort 2 participants enrolled for DLT observation achieved investigator-assessed partial responses (PRs). Two PRs were unconfirmed at the time of abstract submission. Durable progression-free survival (PFS) was consistently observed. More than 15 additional participants were enrolled in the cohort 2 expansion. Preliminary data for these patients will be reported at the congress. Conclusions: [ 212 Pb]VMT-α-NET is a well-tolerated, next generation RPT showing signs of clinical activity at early dose-levels in this phase 1/2a study. Based on these clinical data, further dose-escalation and development of this promising therapy are warranted. Clinical trial information: NCT05636618 .

4020 Background: In previously treated patients (pts) with advanced extra-pancreatic NET (epNET) or pancreatic NET (pNET), cabozantinib (cabo) demonstrated improved progression-free survival compared to placebo (pbo) in the CABINET trial (NCT03375320). Here we present HRQOL data from CABINET. Methods: Pts with previously treated unresectable, locally advanced or metastatic epNET or pNET were randomized (2:1) in separate cohorts to receive cabo 60 mg daily vs pbo. HRQOL was an exploratory endpoint measured using the EORTC QLQ-C30, QLQ-GI.NET21, Patient Global Impression of Change (PGIC), and PRO-CTCAE questionnaires. Optional participation was by paper surveys at baseline and every 12 weeks (wks) until disease progression or new anticancer therapy. Mean changes from baseline were compared between treatment arms at wk12 using general linear mixed models. Minimally important within-arm improvements and between-arm differences were defined as 8 points on the C30 Global Health Status (GHS)/QOL Scale. PGIC was dichotomized as improved vs unchanged/worsened and compared using Chi-squared tests. Rates of pt-reported adverse events (AEs) by PRO-CTCAE were baseline-adjusted and compared using Fisher’s exact tests. Results: 172 pts (113 cabo, 59 pbo) with epNET and 81 pts (53 cabo, 28 pbo) with pNET consented for survey participation. Pts completed 524 (82%) of 640 expected surveys across baseline, wk12, and wk24. For epNET, C30 GHS/QOL was significantly improved at wk12 in pts receiving cabo (mean change 9.5, standard error (SE) 2.2, p < 0.001) but not pbo (mean change 0.2, SE 3.1, p = 0.95) resulting in significantly different mean changes from baseline between arms (p = 0.02). For pNET, C30 QHS/QOL was significantly improved at wk12 in pts receiving cabo (mean change 8.0, SE 3.0, p = 0.008) but not pbo (mean change 6.8, SE 4.4, p = 0.12); mean changes from baseline did not statistically differ between arms (p = 0.82). No significant differences in mean changes from baseline at wk12 in C30 Physical, Role, Emotional, Cognitive and Social Function were observed between arms in the epNET or pNET cohorts. In both cohorts at wk12, pts on cabo reported improved overall status as measured by PGIC more often than those on pbo (epNET: 38% vs 19%, p = 0.04; pNET: 57% vs 18%, p = 0.006). Rates of pt-reported AEs were statistically significantly higher in cabo for diarrhea (68% vs 53%), hand-foot syndrome (57% vs 26%), mouth or throat sores (47% vs 27%), and dysgeusia (67% vs 37%) [all p < 0.05]. GI.NET21 data will be presented. Conclusions: Although cabo is associated with pt-reported AEs consistent with its known safety profile, global HRQOL was maintained. A higher proportion of patients receiving cabo reported improved overall status. Results support cabo as a treatment option for pts with previously treated advanced NET that preserves patient HRQOL. Clinical trial information: NCT03375320 .

ASCO Guidelines provide recommendations with comprehensive review and analyses of the relevant literature for each recommendation, following the guideline development process as outlined in the ASCO Guidelines Methodology Manual . ASCO Guidelines follow the ASCO Conflict of Interest Policy for Clinical Practice Guidelines . Clinical Practice Guidelines and other guidance (“Guidance”) provided by ASCO is not a comprehensive or definitive guide to treatment options. It is intended for voluntary use by clinicians and should be used in conjunction with independent professional judgment. Guidance may not be applicable to all patients, interventions, diseases or stages of diseases. Guidance is based on review and analysis of relevant literature and is not intended as a statement of the standard of care. ASCO does not endorse third-party drugs, devices, services, or therapies and assumes no responsibility for any harm arising from or related to the use of this information. See complete disclaimer in Appendix 1 and 2 (online only) for more. PURPOSE To develop a clinical practice guideline and recommendations for symptom management of patients with well-differentiated grade 1 to grade 3 metastatic gastroenteropancreatic neuroendocrine tumors. METHODS ASCO convened an Expert Panel to develop a clinical practice guideline by reviewing the literature for relevant guidelines, systematic reviews, randomized controlled trials (RCTs), and observational studies to develop recommendations for clinical practice. RESULTS The literature review identified eight guidelines, 19 systematic reviews, and three RCTs that informed the development of guideline recommendations. RECOMMENDATIONS Recommendations are included for carcinoid syndrome, carcinoid heart disease and carcinoid crisis, and functional pancreatic neuroendocrine tumor syndromes. Recommendations are provided for surgical management, liver-directed therapy, and systemic therapy options, as well as palliative care. Limited guidance is provided for sequencing of interventions. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

Objectives: Pancreatic neuroendocrine tumors (pNETs) are uncommon, comprising 3%–7% of pancreatic tumors. With increasing incidence due to advanced imaging techniques, there is a need for detailed characterization of these tumors. This study aims to describe the clinical features, diagnostic evaluations, and pathology characteristics of pNETs in a large cohort from a single tertiary center, and to compare these findings with other larger cohort studies. Methods: We conducted a retrospective analysis of 866 patients with pNETs who underwent surgical resection at Mayo Clinic, Rochester, from March 2000 to December 2019. Data on demographics, clinical presentation, laboratory tests, imaging, and pathology were extracted and analyzed. Descriptive statistics were used to summarize the data. Results: The cohort had a median age of 57 years. Nonfunctional tumors were much more prevalent (77.5%), with functional tumors primarily being insulinomas (75.9%). Common presenting symptoms included gastrointestinal (45.3%) and nongastrointestinal symptoms (30.7%). Chromogranin A levels were elevated in 57.5% of patients. Imaging revealed enhancing lesions in most cases, with computed tomography scans performed in 90.9% of patients. Endoscopic ultrasound (EUS) identified tumors in 98.1% of cases, with EUS-FNA showing a sensitivity of 82%. Ki-67 index, used in 58.1% of cases, indicated grade 2 tumors as the most common (55.9%). Metastasis was observed in 39.4% of patients at the time of diagnosis, predominantly in the liver. Conclusion: This study provides a comprehensive description of pNET characteristics in a large surgical cohort. Findings highlight the predominance of nonfunctional tumors and the importance of imaging and EUS in diagnosis. The data can aid in inter-institutional comparisons and enhance understanding of pNETs, contributing to improved patient management and future research.

Abstract Pancreatic neuroendocrine tumors (PanNETs) have an age-adjusted incidence of 1.5 per 100,000 people, with a notable rise in the incidence of small (≤2 cm) non-functional PanNETs (NF-PanNETs) in recent decades. While surgery is traditionally the preferred treatment for localized NF-PanNETs, active surveillance is now an accepted management strategy for tumors smaller than 2 cm due to their relatively benign behavior. However, this approach has not yet been fully integrated into routine clinical practice. There is considerable histopathological heterogeneity observed in NF-PanNETs, which results in significant variability in clinical presentation, behavior and treatment outcomes. Hence, tumor size alone does not provide sufficient certainty regarding a benign clinical course for decision-making. Although studies advocate for incorporating WHO grade into clinical prognostic assessments, this marker also has limitations. Several established tissue-based markers, such as ATRX and DAXX alterations, alternative lengthening of telomeres, and copy number variations, can be used for PanNET subtyping and correlate with metastatic risk. Combining these markers with traditional histopathological parameters may yield a more comprehensive and accurate prognostic assessment. This review discusses the advantages and limitations of current prognostication methods for small NF-PanNETs and highlights recently established prognostic markers, along with the requirements for their implementation into routine clinical practice. It also proposes practical solutions to address the challenges associated with the immediate integration of these biomarkers into routine care.

Abstract Given the heterogeneous clinical behavior of pancreatic neuroendocrine tumors (pNETs), improved prognostic markers are needed to guide management and post‐resection surveillance. Patients who underwent resection of large (≥3 cm) sporadic well‐differentiated pNETs from 2000 to 2019 were identified. The Ki‐67 proliferation index was determined using immunohistochemistry, and alternative lengthening of telomeres (ALT) status was assessed using fluorescence in situ hybridization. Recurrence‐free and overall survival were estimated using Kaplan–Meier analysis. Multivariable Cox regression analysis evaluated factors associated with recurrence‐free survival. A total of 106 patients were identified. ALT was positive in 57 (54%) and negative in 49 (46%). Ki‐67 was ≥3% in 74 (70%) and <3% in 32 (30%). Tumors with Ki‐67 ≥3% were more likely to be ALT positive (61% vs. 38%, p = .046). Stratifying by ALT status and Ki‐67 proliferation index, median recurrence‐free survival was 4.6 years for patients with ALT‐positive/Ki‐67 ≥3% tumors, 3.1 years for patients with ALT‐positive/Ki‐67 <3% tumors, 12.4 years for patients with ALT‐negative/Ki‐67 ≥3% tumors, and 20.2 years for patients with ALT‐negative/Ki‐67 <3% tumors ( p < .001). Initial recurrence was distant in 82% and locoregional in 18%. Across all groups, overall survival was similar ( p = .19). In multivariable analysis, advanced age, ALT positivity, perineural invasion, and lymph node metastases were associated with increased recurrence risk (all p < .05). ALT and Ki‐67 provide complementary information on post‐resection recurrence risk, which can guide subsequent surveillance and management strategies. These data support the incorporation of ALT testing into routine clinical practice.