Citations

Abstract Everolimus 10 mg daily is the standard dose for advanced neuroendocrine tumors (NETs), but adverse events frequently necessitate dose reduction. As a result, oncologists often adopt a dose‐escalation strategy starting at 5 mg and increasing the dose as tolerated. In this multicenter study, we evaluated the effect of reduced dose (RD) and standard dose (SD) everolimus on survival, progression, and toxicity in patients with advanced NETs. We conducted a multicenter retrospective cohort study of patients with advanced NETs treated with everolimus at Mayo Clinic and University Hospitals (Cleveland, OH). Patients were grouped by starting dose (5 mg vs. 10 mg). Primary endpoints were overall survival (OS), real‐world progression‐free survival (rwPFS), and adverse events. Multivariable Cox models, inverse probability of treatment weighting (IPTW), and time‐varying dose sensitivity analysis were used to account for confounding and dose crossover. Among 170 patients (48 started on 5 mg; 122 on 10 mg), the 5 mg cohort was older, had worse ECOG PS, and was more heavily pretreated. Median OS was 43.7 months (5 mg) versus 81.5 months (10 mg; log‐rank p = .02). However, after multivariable adjustment ( N = 124 G1–G2 patients; 51 events), the association was no longer statistically significant (adjusted HR, 0.59; 95% CI, 0.31–1.12; p = .11). Median rwPFS was 7.0 versus 12.4 months (log‐rank p = .05); the adjusted rwPFS difference was not statistically significant (HR, 0.95; 95% CI, 0.56–1.61; p = .84). Nearly half (46.7%) of 10 mg starters required dose reduction. Any‐grade toxicity was more common with 10 mg (89% vs. 75%; p = .05). The apparent survival advantage of standard‐dose everolimus was substantially attenuated after adjustment. These findings do not establish dose equivalence and should be interpreted in the context of limited statistical power. Given its more favorable observed tolerability profile, RD everolimus warrants prospective evaluation as a starting strategy for patients at increased risk of treatment‐related toxicity who may not tolerate SD.

Abstract The 6th Edition of the World Health Organization Classification of Digestive System Tumours has introduced two new categories of gastric neuroendocrine tumors, reflecting recent data on subtypes that do not conform to the three established subtypes: type 1 (associated with autoimmune gastritis), type 2 (associated with Zollinger-Ellison Syndrome) and type 3 (sporadic). The new type 4 category is exceptionally rare and is caused by endogenous dysfunction of parietal cell proton pumps, potentially secondary to mutation of ATP4A. Type 5 gastric NETs are caused by chronic pharmacologic inhibition of the parietal cell proton pump, typically due to proton pump inhibitor use, and are increasingly common. Given the relatively low malignant potential of the new subtypes compared to sporadic (type 3) gastric NETs, it is important that clinicians and pathologists recognize these entities, limiting radical surgical resections when unnecessary.

Abstract Background Optimal treatment following first-line immunotherapy for advanced hepatocellular carcinoma (HCC) remains uncertain. This study evaluated futibatinib, a pan-FGFR inhibitor, combined with pembrolizumab in previously treated patients with FGF19-expressing HCC. Methods Eligible patients were ≥18 years old with advanced HCC, prior systemic therapy, Child-Pugh A-B7 liver function, ECOG 0–2, and FGF19 overexpression. Patients received futibatinib 20 mg orally daily plus pembrolizumab 200 mg intravenously every 3 weeks. The primary endpoint was progression-free survival at 6 months (PFS6). Secondary endpoints included overall survival (OS), objective response rate (ORR), quality of life, and safety. Results Between August 2021 and March 2024, 14 patients enrolled and 13 were evaluable. Median age was 72 years (range, 60–87), 53.8% were male, 92.3% had Child-Pugh A liver function, and all had received prior immunotherapy. Median progression-free survival was 15 weeks (95% CI, 9.0–NE), with a PFS6 rate of 23.1% (95% CI, 8.6–62.3%). ORR was 0% (95% CI, 0–24.7%), while stable disease was observed in 53.9% of patients. Median OS was 55.7 weeks (95% CI, 47.3–NE). Grade ≥3 adverse events occurred in 69.2% of patients, and grade ≥4 adverse events in 15.4%. One grade 5 event (acute-on-chronic kidney injury) was deemed unrelated to treatment. Common adverse events included hyperphosphatemia, fatigue, diarrhea, elevated transaminases, dry eye, nail changes, rash, and oral mucositis. Conclusions Futibatinib plus pembrolizumab demonstrated an acceptable safety profile but did not meet efficacy thresholds supporting further study in FGF19-expressing HCC. Effective post-immunotherapy treatment strategies remain an unmet need.

Abstract Incretin‐based therapies, including glucagon‐like peptide‐1 receptor agonists (GLP‐1RA) and dual incretin agonists, are increasingly used for the management of diabetes, obesity, and cardiometabolic disease. Although their systemic benefits are well established, uncertainty remains regarding their safety in patients with neuroendocrine neoplasms (NENs), a biologically heterogeneous group of tumors with diverse molecular profiles. Preclinical studies suggest that GLP‐1 receptor activation may promote tumor growth in select receptor‐expressing models, although receptor expression varies widely across NEN subtypes and is often absent in common tumors such as ileal neuroendocrine tumors. Population‐level and retrospective clinical data have not demonstrated a consistent increase in oncologic risk but are limited by methodological constraints. In this expert consensus statement, the authors synthesize current evidence and provide a practical framework for the use of incretin mimetics in patients with NENs. The authors emphasize individualized risk assessment, shared decision‐making, and multi‐disciplinary collaboration, balancing potential but unquantified oncologic risks against substantial cardiometabolic benefits. Until prospective data are available, careful patient selection, dose optimization, and close clinical and radiologic surveillance remain essential to guide safe and effective use of these agents in this population.

Abstract Introduction: Next generation of Theranostics studies are looking at novel combinations with radiation sensitizers to enhance PRRT’s efficacy. Here, we present safety and efficacy data from a multi-center phase 1 study of a [¹⁷⁷Lu]lutetium-dotatate -triapine combination in patients with GEP-NETs. Methods: The study consisted of two phases (dose escalation and expansion) administering the recommended phase 2 doses (RP2D) for the two agents. All patients received 200 mCi of [¹⁷⁷Lu]lutetium-dotatate on day 1 of four 8-week cycles, in combination with oral triapine administered at assigned dose levels (100 mg, 150 mg or 200mg) from days 1 to 14 of each cycle. Results: A total of 31 (A: 15 ; B: 16 ) patients received treatment. Nine patients experienced dose-limiting toxicities; Grade 3 anemia (n=1), Grade 5 cardiac arrest (n=1), and Grade 4 neutropenia (n=7). Based on the overall safety and pharmacokinetics data, a [¹⁷⁷Lu]lutetium-dotatate (200 mCi) plus triapine (150 mg) dose was selected as the RP2D for the expansion phase. Grade ≥3 treatment related adverse events were observed in 77% patients: anemia (23%), nausea and vomiting (3% ), lymphopenia ( 58%), neutropenia ( 35%) and leukopenia ( 39%). The majority of cytopenias were transient and resolved within two weeks. Among the 28 evaluable patients, the objective response rate (ORR) was 21.4% and the median progression-free survival (mPFS) has not been reached (median follow-up period: 23.7 months). Conclusions: The combination of [¹⁷⁷Lu]lutetium-dotatate (200 mCi) and oral triapine (150 mg D1-14) was well tolerated and demonstrated preliminary activity in patients with well-differentiated GEP-NETs. (NCT04234568).

PURPOSE Deficient mismatch repair/microsatellite instability (dMMR, MSI-H) in biliary tract cancers (BTCs) is observed in 1%-5% of tumors. MSI-H across solid tumors has demonstrated durable response to immune checkpoint inhibitors (ICIs) regardless of the anatomic location. Here, we describe clinical outcomes and surgical conversion of MSI-H BTC treated with ICIs. Patients and Methods We conducted a multicenter, retrospective analysis of BTC patients with dMMR/MSI-H between 2017 and 2024 at Mayo Clinic, University of Michigan, and University Hospitals Seidman Cancer Center. Outcomes of interest were surgical resection rate, rate of pathologic response, 2-year overall survival (OS; time from initiation of treatment to death/last follow-up), and time to treatment discontinuation (TTD; time from initiation of treatment to cessation because of any cause). Analyses were descriptive. RESULTS Thirty patients with MSI-H BTC were identified: 19 with cholangiocarcinoma, three with gallbladder cancer, and 8 with BTC undefined. The median age at diagnosis was 61.5 years (range, 26-86). Twenty-six (86.7%) patients had advanced stage at diagnosis. Twenty-seven patients (90%) received first-line systemic therapy, and 13 (48.1%) continued onto second line. Six patients (23.1%) were restaged to resectable from advanced disease after ICI therapy and underwent resection; all remained recurrence-free at last follow-up. Of these six patients, 3 (50%) achieved a pathologic complete response. Among those receiving first-line therapy, the median TTD was 9.9 months (95% CI, 5.7 to 14.5 months) and the 2-year OS was 73% (95% CI, 56% to 94%). CONCLUSION ICI therapy in patients with MSI-H BTC demonstrated durable response and downstaged some BTC to a resectable stage. dMMR/MSI-H should be performed up-front to guide treatment decisions.

Abstract Carcinoid heart disease (CHD) is associated with advanced neuroendocrine tumor liver metastases (NETLM) and may preclude surgical cytoreduction. We assessed perioperative and long‐term outcomes of hepatectomy in patients with CHD. We retrospectively analyzed 311 patients undergoing cytoreductive hepatectomy for intestinal NETLM: non‐functional ( n = 163), carcinoid syndrome (CS) without CHD ( n = 110), and CHD ( n = 38), including patients undergoing pre‐hepatectomy valve replacement. CHD patients more frequently had >10 liver metastases (78%) and larger lesions (median 9.5 cm) and required major hepatectomy more often (58%). Major morbidity was higher in CHD (up to 47%), yet 90‐day mortality remained low (≤4%). Median overall survival after hepatectomy was comparable across groups (12.5 vs. 9.1 vs. 11.4 years; p = .19), including matched analyses. With optimal cardiac management, cytoreductive hepatectomy in CHD is feasible and provides long‐term survival comparable to patients without CHD.

Neuroendocrine neoplasms (NENs) represent a heterogeneous group of malignancies ranging from relatively indolent well-differentiated neuroendocrine tumors (NETs) to more aggressive poorly differentiated neuroendocrine carcinomas (NECs). The advent of somatostatin receptor (SSTR)–targeting therapies, particularly radioligand therapy (RLT), has transformed the therapeutic landscape of NETs. Ongoing efforts are aimed at maximizing the therapeutic benefit of RLT and include retreatment and combination strategies as well as novel α-emitter–based radiopharmaceuticals. The increasing use of molecular profiling has led to the identification of recurrent canonical alterations in pancreatic NETs, including in MEN1 , ATRX / DAXX , PI3K/Akt/mTOR, and angiogenic signaling pathways, facilitating the development of effective targeted therapies. However, despite the addition of newer targeted therapies to the therapeutic armamentarium, resistance remains inevitable and highlights the need for improved predictive markers to inform therapy sequencing and novel biomarker-selected therapies. In addition, the development of novel therapeutic strategies including SSTR antagonists, nonpeptide drug conjugates, and novel radiopharmaceutical constructs highlights the potential of biomarker-informed therapies in this space. By contrast, treatment options for NECs remain limited, with modest therapeutic benefit of platinum-based chemotherapy. The identification of delta-like ligand 3 (DLL3) as a therapeutic target in high-grade NENs has led to the development of novel targeted therapies such as T-cell engagers, which have demonstrated promising activity in early phase clinical trials. In addition, other DLL3-targeting agents such as antibody-drug conjugates, trispecific engagers, and cellular therapies remain under investigation. Collectively, these advances underscore the potential of biomarker-informed treatment approaches to personalize treatment decisions and improve long-term outcomes across the NEN spectrum.

Background: Colorectal neuroendocrine carcinomas (NECs), including small cell (SCNEC) and large cell (LCNEC) subtypes, are rare but aggressive malignancies with limited population-level data. Moreover, prior studies have limited stratification by histologic subtype and anatomic location, despite evidence of disease heterogeneity in colorectal malignancies. This study aimed to characterize the clinical characteristics, treatment patterns, and outcomes of colorectal NEC by histologic subtype and tumor location, and to compare them with neuroendocrine tumors (NETs) and adenocarcinomas (ACs). Methods: A retrospective cohort review was conducted utilizing the SEER database from 2000 to 2022 to identify patients with colorectal SCNEC, LCNEC, NET, and AC. Demographic, clinical, therapeutic and survival data were analyzed and compared using Kaplan–Meier methods, log-rank tests, and Cox proportional hazards regression. Results: A total of 790 SCNEC, 498 LCNEC, 31,200 NET, and 638,898 AC cases were identified. SCNEC and LCNEC were associated with advanced stage at diagnosis (66% and 55% stage IV, respectively) and inferior survival outcomes compared to NET and AC (median OS (mOS) of 7 and 8 months for SCNEC and LCNEC, respectively, p = 0.0002). Stratified by location, colonic SCNEC had the poorest survival (mOS 5 months), worse than rectal SCNEC (mOS 9 months); this pattern was not observed in LCNEC. Surgical resection was associated with improved OS in both NEC subtypes (HR range 0.25–0.56, all p < 0.012). Radiation therapy was associated with improved survival in NEC overall (SCNEC HR 0.58; LCNEC HR 0.71, both p < 0.05), with the observed benefit appearing greatest in rectal NEC. Demographic factors were associated with survival in NET and AC but had no significant impact in NEC. Conclusions: Colorectal SCNEC and LCNEC are highly aggressive malignancies with poor outcomes, with SCNEC demonstrating modestly inferior outcomes compared to LCNEC. This study demonstrates that both histologic subtype and anatomic site of disease are important determinants of prognosis and treatment response. This supports the concept that colorectal NEC represents a biologically heterogeneous disease, with colonic SCNEC showing the worst outcomes and rectal NEC associated with a potential enhanced response to radiation. These findings support the need for further prospective and molecular studies to better define treatment approaches and targeted therapies for these rare malignancies.

Purpose: Neuroendocrine neoplasms (NENs) are increasingly recognized to have a hereditary predilection, yet the prevalence and clinical relevance of pathogenic germline variants (PGVs) in unselected patients with NEN remain poorly defined. This prospective, multicenter study aimed to evaluate the prevalence and clinical utility of PGVs through universal multigene panel testing in a diverse cohort of patients with NENs. Patients and Methods: Between 2018 and 2024, we enrolled unselected patients with NENs from 3 Mayo Clinic Cancer Centers. Germline genetic testing was performed using a next-generation sequencing panel of up to 84 cancer predisposition genes. Patients were not selected based on age, disease stage, ethnicity, or family history. Variants were classified as PGVs, variants of uncertain significance (VUS), or negative. Clinical and demographic data were analyzed descriptively. Results: Among 88 patients, PGVs were identified in 15.9% (n=14), most frequently in high- or moderate-penetrance genes including MEN1 , CHEK2 , MITF , and MUTYH . PGVs were most commonly found in pancreatic NENs [n=12/55 (21.8%)], followed by small bowel NENs [n=2/20 (10%)], with no PGVs detected in lung NENs. Mismatch repair (MMR) gene alterations were identified in 5.7% of patients, including 1 MLH1 PGV and 4 MSH2/MSH6 VUS, 2 of which demonstrated MMR deficiency by protein testing. VUS were reported in 34.1% of patients. Notably, 35.7% of PGV-positive patients did not meet current NCCN or ACMG testing criteria, and 53.9% had PGVs in genes outside of cancer-specific guideline recommendations. Conclusions: Universal germline testing in unselected patients with NEN identified clinically relevant PGVs in over 15% of cases. These findings support broader genetic testing approaches to guide treatment, enhance familial risk assessment, and inform cascade testing—regardless of traditional clinical selection criteria.