PRRT in high-grade digestive neuroendocrine neoplasms (NET G3 and NEC).

Peptide receptor radionuclide therapy (PRRT) has been primarily studied in low and intermediate-grade digestive neuroendocrine tumors (NET G1-G2). The documentation of a similar benefit for high-grade digestive neuroendocrine neoplasms (NEN) has been limited. This review evaluates the use of PRRT for high-grade digestive NEN (well-differentiated NET G3 and poorly differentiated neuroendocrine carcinomas [NEC]). We identified one phase III trial and seven retrospective studies reporting specifically on PRRT outcome of >10 digestive high-grade NEN patients. The retrospective single-arm studies indicate a benefit for PRRT in NET G3. The randomized phase III NETTER-2 trial demonstrates major PFS superiority of PRRT versus somatostatin analog therapy as the first-line treatment for the NET G3 subgroup. PRRT can now be considered a potential first-line treatment for somatostatin receptor-positive NET G3 patients, but whether it should be the first-line standard of care for all NET G3 patients is still not clarified. For NEC, scarce data are available, and pathologic distinction between NEC and NET G3 can be difficult when Ki-67 is below 55%. PRRT could be considered as a treatment for refractory NEC in very selected cases when there is a high uptake on somatostatin receptor imaging, Ki-67 is below 55%, and there is no rapid tumor progression.

Phase 3 Trial of Cabozantinib to Treat Advanced Neuroendocrine Tumors.

BACKGROUND: Treatment options for patients with advanced neuroendocrine tumors are limited. The efficacy of cabozantinib in the treatment of previously treated, progressive extrapancreatic or pancreatic neuroendocrine tumors is unclear. METHODS: We enrolled two independent cohorts of patients - those with extrapancreatic neuroendocrine tumors and those with pancreatic neuroendocrine tumors - who had received peptide receptor radionuclide therapy or targeted therapy or both. Patients were randomly assigned in a 2:1 ratio to receive cabozantinib at a dose of 60 mg daily or placebo. The primary end point was progression-free survival as assessed by blinded independent central review. Key secondary end points included objective response, overall survival, and safety. RESULTS: In the cohort of 203 patients with extrapancreatic neuroendocrine tumors, the median progression-free survival with cabozantinib was 8.4 months, as compared with 3.9 months with placebo (stratified hazard ratio for progression or death, 0.38; 95% confidence interval [CI], 0.25 to 0.59; P<0.001). In the cohort of 95 patients with pancreatic neuroendocrine tumors, the median progression-free survival with cabozantinib was 13.8 months, as compared with 4.4 months with placebo (stratified hazard ratio, 0.23; 95% CI, 0.12 to 0.42; P<0.001). The incidence of confirmed objective response with cabozantinib was 5% and 19% among patients with extrapancreatic and pancreatic neuroendocrine tumors, respectively, as compared with 0% with placebo. Grade 3 or higher adverse events were noted in 62 to 65% of the patients treated with cabozantinib, as compared with 23 to 27% of the patients who received placebo. Common treatment-related adverse events of grade 3 or higher included hypertension, fatigue, diarrhea, and thromboembolic events. CONCLUSIONS: Cabozantinib, as compared with placebo, significantly improved progression-free survival in patients with previously treated, progressive advanced extrapancreatic or pancreatic neuroendocrine tumors. Adverse events were consistent with the known safety profile of cabozantinib. (Funded by the National Cancer Institute and others; CABINET ClinicalTrials.gov number, NCT03375320.).

Response to hepatic arterial infusion chemotherapy combined with camrelizumab and targeted therapy in advanced primary hepatic neuroendocrine carcinoma: a case report and literature review.

Background: Primary hepatic neuroendocrine carcinoma (PHNEC), which often lacks distinctive radiological features or specific clinical symptoms, is extremely rare. In this report, we describe a rare case of PHNEC that was successfully treated with hepatic arterial infusion chemotherapy (HAIC) combined with camrelizumab and targeted therapy. Case Description: This report describes the treatment of a 53-year-old male with PHNEC in China. The patient was admitted for persistent upper right quadrant abdominal pain. Dynamic contrast-enhanced abdominal computed tomography (CT) and magnetic resonance imaging (MRI) both detected multiple masses, enlarged portal lymph nodes, and retroperitoneal lymph nodes. Histological and immunohistochemistry of the largest mass biopsy specimen from the right liver lobe confirmed the neuroendocrine tumor of the liver. The patient underwent HAIC with a modified fluorouracil and oxaliplatin (mFOLFOX) regimen. Meanwhile, the patient received camrelizumab (200 mg, intravenously, q3w) apatinib (250 mg, oral, daily) within 7 days after the start of HAIC. CT and MRI showed a marked decrease in the size of the largest mass of the liver and the portal lymph nodes, indicating a partial response of the tumor. Conclusions: PHNEC is a very rare tumor, and the treatment for its advanced type is controversial and remains to be standardized. HAIC combined with camrelizumab and targeted therapy may be an effective and safe therapeutic option for patients with PHNEC.

Safety and Efficacy of Peptide Receptor Radionuclide Therapy (PRRT) Following Bland Embolization for Metastatic Neuroendocrine Tumors.

Rationale: Evaluating the long-term safety and efficacy of peptide receptor radionuclide therapy (PRRT) in patients with metastatic neuroendocrine tumors (mNETs) who have undergone prior bland hepatic transarterial embolization (TAE). Methods: Retrospective review of mNET patients who received PRRT with 177Lu-DOTATATE between 4/2018 and 02/2022 with and without prior TAE. The most recent clinical, imaging, and laboratory findings, including hepatic Common Terminology Criteria for Adverse Events v5.0, were compared to pre-PRRT. Results: 171 patients (95 M, 76 F, median age = 66) with mNET of different primary sites (9 foregut, 100 midgut, 9 hindgut, 44 pancreas, 9 unknown) received at least 1 cycle of PRRT with at least 6 months of follow-up, 110 of whom were embolization-naïve and 61 who had prior TAE. The median follow up was 22 months (range: 6-43). Patients with prior TAE had higher liver tumor burden on average than patients without prior TAE; however, the difference was not statistically significant (p = 0.06). There was no significant difference in the rates of G3 or G4 hepatotoxicity (p = 0.548 and p = 0.999, respectively) in patients who underwent prior TAE and those who were TAE-naïve. The hepatic progression-free survival was 22.9 months in TAE-naïve patients and 25.7, 20.2, and 12.8 months in patients with 1, 2, and 3 prior TAE treatments, respectively. Conclusion: Peptide receptor radionuclide therapy following transarterial bland embolization for mNET is safe and effective.

Efficacy and Toxicity Analysis of mFOLFIRINOX in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms.

BACKGROUND: High-grade neuroendocrine neoplasms (NENs) comprise both well-differentiated grade 3 neuroendocrine tumors (G3 NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) nearly always include poorly differentiated NEC as the neuroendocrine component. The efficacy and safety of frontline mFOLFIRINOX chemotherapy has never been investigated in patients with high-grade NENs. PATIENTS AND METHODS: We conducted a multi-institutional retrospective analysis of patients with advanced high-grade NEN of the gastroenteropancreatic tract or of unknown origin seen between February 2016 and April 2023 who received treatment with frontline mFOLFIRINOX. RESULTS: A total of 35 patients were included (G3 NETs: n=2; NECs: n=25; MiNENs: n=8; stage III: n=5; stage IV: n=30). The objective response rate was 77% (complete response: 3%; partial response: 74%). Median progression-free survival was 12 months (95% CI, 9.2-16.2 months) and median overall survival was 20.6 months (95% CI, 17.2-30.6 months). No significant differences in efficacy were seen according to primary site, histopathology, and Ki-67 proliferative index. All 5 patients with stage III disease who received mFOLFIRINOX obtained an objective response and underwent radical surgery or definitive radiotherapy with curative intent, with a recurrence rate of 40%. Grade 3 or 4 adverse events were observed in 43% of patients (mainly neutropenia and diarrhea). Females were at significantly increased risk of developing severe toxicities. CONCLUSIONS: mFOLFIRINOX shows antitumor activity against high-grade NENs. Well-designed, prospective clinical trials are needed to assess the efficacy of mFOLFIRINOX in both the neoadjuvant and metastatic settings.

Biomarker Analysis from a Phase I/Ib Study of Regorafenib and Nivolumab in Mismatch Repair-Proficient Advanced Refractory Colorectal Cancer.

Previously, we reported the modest but durable anticancer activity of regorafenib/nivolumab in mismatch repair-proficient (pMMR) refractory colorectal cancer in our I/Ib study. Our finding suggests the necessity of biomarkers for better selection of patients. Baseline clinical and pathological characteristics, blood and tumor samples from the patients in the trial were collected and evaluated to discover potential biomarkers. The obtained samples were assessed for immunohistochemistry, ELISA and RNA sequencing. Their correlations with clinical outcome were analyzed. A high albumin level was significantly associated with improved progression-free survival (PFS), overall survival (OS) and disease control. Non-liver metastatic disease showed prolonged PFS and OS. Low regulatory T-cell (Treg) infiltration correlated with prolonged PFS. Low MIP-1ß was associated with durable response and improved OS significantly. Upregulation of 23 genes, including CAPN9, NAPSA and ROS1, was observed in the durable disease control group, and upregulation of 10 genes, including MRPS18A, MAIP1 and CMTR2, was associated with a statistically significant improvement of PFS. This study suggests that pretreatment albumin, MIP-1ß, non-liver metastatic disease and Treg infiltration may be potential predictive biomarkers of regorafenib/nivolumab in pMMR colorectal cancer. Further studies are needed to confirm these findings.

Cutaneous Neuroendocrine Metastases of Visceral Origin Responsive to Surgical Resection and Targeted Radionuclide Therapy.

Neuroendocrine neoplasms (NENs) encompass a diverse range of biologically and behaviorally distinct epithelial malignancies that derive from neuroendocrine cells. These neoplasms are able to secrete a variety of bioactive amines or peptide hormones. The majority of NENs are well-differentiated and are defined as neuroendocrine tumors (NETs). While NETs are known to frequently metastasize to lymph nodes, liver, and lungs, spread to the skin is extremely rare and is often a late finding. Because cutaneous metastasis from a visceral site represents distant tumor dissemination, prompt histologic diagnosis is critical in terms of selecting further treatment options and ultimately impacts subsequent prognosis. This report presents a man with painful cutaneous NET metastases initially on the face then scalp. He had a prior history of longstanding and progressive stage IV visceral disease. Multimodal therapy with initial surgical resection of the larger facial lesion and radionuclide infusion therapy was undertaken. Excision fully removed the temple lesion and resolved pain. Peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE, a radiolabeled somatostatin analog that targets somatostatin receptors on NETs, was given along with maintenance lanreotide therapy, which resolved the scalp lesion, prevented recurrence of prior lesions and development of new cutaneous metastases, and controlled his visceral disease. PRRT has not been previously described in the management of cutaneous NET metastases. Due to the rare nature of cutaneous NET metastases, there is no consensus regarding optimal management. As such, we propose novel multimodal therapy involving excision and targeted radionuclide therapy as a possible effective option.

Sequencing of Somatostatin-Receptor-Based Therapies in Neuroendocrine Tumor Patients.

Most well-differentiated neuroendocrine tumors (NETs) express high levels of somatostatin receptors, particularly subtypes 2 and 5. Somatostatin analogs (SSAs) bind to somatostatin receptors and are used for palliation of hormonal syndromes and control of tumor growth. The long-acting SSAs octreotide long-acting release and lanreotide are commonly used in the first-line metastatic setting because of their tolerable side effect profile. Radiolabeled SSAs are used both for imaging and for treatment of NETs. 177Lu-DOTATATE is a ß-emitting radiolabeled SSA that has been proven to significantly improve progression-free survival among patients with progressive midgut NETs and is approved for treatment of metastatic gastroenteropancreatic NETs. A key question in management of patients with gastroenteropancreatic and lung NETs is the sequencing of 177Lu-DOTATATE in relation to other systemic treatments (such as everolimus) or liver-directed therapies. This question is particularly complicated given the heterogeneity of NETs and the near absence of randomized trials comparing active treatment options. This state-of-the-art review examines the evidence supporting use of somatostatin-receptor-targeted treatments within the larger landscape of NET therapy and offers insights regarding optimal patient selection, assessment of benefit versus risk, and treatment sequencing.

RNA Expression-based Analysis to Predict Response in Patients with Metastatic Mismatch Repair Proficient Colorectal Cancer Treated with Regorafenib and Nivolumab.

Introduction We previously conducted a phase I/Ib study (NCT03712943) with regorafenib and nivolumab in patients with refractory metastatic mismatch repair proficient (pMMR) colorectal cancer (CRC). This study aimed to investigate the role of Xerna™ TME Panel in predicting the treatment response. Methods 22 archival pretreatment tumor samples were subjected to the Xerna™ TME Panel, a machine learning-based RNA-sequencing biomarker assay. The Xerna TME subtypes were evaluated for correlation with overall survival (OS), progression free survival (PFS), disease control rate (DCR), and other biomarkers including KRAS, PD-L1, CD8 expression, and Treg cells in tumor microenvironment. Results Based on Xerna™ TME Panel, four patients with immune active (IA) subtype and six patients with immune suppressed (IS) subtype were classified as biomarker-positive, and five with angiogenic (A) subtype and seven with immune desert (ID) subtype were biomarker-negative. While not reaching statistical significance, Xerna TME biomarker-positive patients seemed to have longer median PFS (7.9 vs. 4.1 months, P=0.254), median OS (15.75 vs. 11.9 months, P=0.378), and higher DCR (70% vs. 58%, P=0.675). The IA subtype in our cohort had higher levels of CD4+ FOXP3+ Treg cells, whereas the A subtype showed lower levels of Treg cells. Conclusion Xerna™ TME Panel analysis in patients with refractory metastatic pMMR CRC who were treated with regorafenib plus nivolumab might be of value for predictive clinical benefit. Further studies are needed to evaluate the predictive role of Xerna™ TME Panel analysis in patients with refractory metastatic pMMR CRC.

Targeted radionuclide therapy in endocrine-related cancers: advances in the last decade.

Targeted radionuclide therapy plays an increasingly important role in managing endocrine-related tumors and significantly advances the therapeutic landscape for patients with these diseases. With increasing FDA-approved therapies and advances in the field, come an increased knowledge of the potential for long-term toxicities associated with these therapies and the field must develop new strategies to increase potency and efficacy while individualizing the selection of patients to those most likely to respond to treatment. Novel agents and modalities of therapy are also being explored. This review will discuss the current landscape and describe the avenues for growth in the field currently being explored.

Somatostatin Receptor Expression in Lung Neuroendocrine Tumors: An Analysis of DOTATATE PET Scans.

Somatostatin receptor (SSTR) expression in metastatic lung neuroendocrine tumors (NETs) has not been well characterized using PET imaging. Understanding the degree and uniformity of SSTR expression is important to establish the role of SSTR-targeted treatments in lung NETs. Methods: A retrospective institutional review of patients with metastatic lung NETs who underwent DOTATATE PET imaging from March 2017 to February 2023 was performed. Results: In total, 48 patients with metastatic lung NETs who underwent 68Ga- or 64Cu-DOTATATE PET imaging were identified. Four had completely negative SSTR expression, and 10 had very weak expression (less than in a normal liver). Among the remaining 34 patients, 21 had uniformly positive DOTATATE PET scans, and 13 had heterogeneous expression. Only 44% had uniformly positive receptor expression, identifying them as candidates for peptide receptor radionuclide therapy. Conclusion: Most metastatic lung NETs lack uniform SSTR expression and are thus suboptimal candidates for SSTR-targeted therapy. SSTR imaging in lung NETs should be evaluated carefully for uniformity of expression.

A phase II study of bevacizumab and temsirolimus in advanced extra-pancreatic neuroendocrine tumors.

We assessed the efficacy and safety of combining bevacizumab with temsirolimus in patients with advanced extra-pancreatic neuroendocrine tumors. This NCI-sponsored multicenter, open-label, phase II study (NCT01010126) enrolled patients with advanced, recurrent, or metastatic extra-pancreatic neuroendocrine tumors. All patients were treated with temsirolimus and bevacizumab until disease progression or unacceptable toxicity. Temsirolimus 25 mg was administered i.v. on days 1, 8, 15, and 22 and bevacizumab 10 mg/kg i.v. on days 1 and 15 of a 4-week cycle. Discontinuation of temsirolimus or bevacizumab did not require discontinuation of the other agent. The primary endpoints were objective response rate and 6-month progression-free survival rate. Fifty-nine patients were enrolled in this study, and 54 were evaluated for efficacy and adverse events. While median progression-free survival was 7.1 months, the median duration of treatment with temsirolimus was 3.9 months and that with bevacizumab was 3.5 months. The objective response rate of combination therapy was 2%, and 6-month progression-free survival was 48%. The most frequently reported grade 3-4 adverse events included fatigue (13%), hypertension (13%), and bleeding (13%). Close to 54% of the patients discontinued treatment due to adverse events, refusal of further treatment, or treatment delays. Three deaths occurred in the study, of which two were due to treatment-related bowel perforations. Given the minimal efficacy and increased toxicity seen with the combination of bevacizumab and temsirolimus, we do not recommend the use of this regimen in patients with advanced extra-pancreatic neuroendocrine tumors.

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

PURPOSE: To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). METHODS: ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice. RESULTS: Eight randomized controlled trials met the inclusion criteria for the systematic review. RECOMMENDATIONS: Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)-positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

ACTH-secreting pancreatic neuroendocrine neoplasms: A case-series.

Ectopic Cushing's syndrome (CS) occurs rarely in patients with pancreatic neuroendocrine neoplasms. Early recognition of symptoms is critical given the high morbidity and mortality associated with CS. A database of pancreatic neuroendocrine neoplasms (NENs) seen at the Moffitt Cancer Center between 1/2008 and 4/2022 was reviewed and cases of ectopic CS were identified. Information was extracted on tumor characteristics, clinical signs and symptoms, therapies, and outcomes. Thirteen cases were identified, ranging in age from 16 to 65 years at the initial time of diagnosis (median 42). Twelve of 13 patients had metastatic tumors at presentation. All were well-differentiated at diagnosis although two were described as transformed to poorly differentiated on rebiopsy. A total of 4 patients also experienced Zollinger-Ellison syndrome. Three patients underwent bilateral adrenalectomy to manage uncontrolled CS. Median overall survival of was 56 months from the time of initial cancer diagnosis but only 18 months from diagnosis of CS. Our study showed that ectopic CS is a highly morbid condition when occurring in pancreatic NENs and is associated with aggressive disease. Bilateral adrenalectomy can be considered for syndrome control. To our knowledge, this is the largest institutional case-series of ACTH-secreting metastatic pancreatic NEN.

HORMONET: a phase II trial of tamoxifen for estrogen/progesterone receptor-positive neuroendocrine tumors.

Background: Nearly 30% of neuroendocrine tumors (NETs) have evidence of immunohistochemical (IHC) expression of estrogen (ER) and/or progesterone (PR) receptors. Therefore, targeting ER/PR may offer an effective NET-directed treatment to select patients. Methods: We conducted a multicenter Simon two-stage single-arm phase II trial of tamoxifen in patients with metastatic, progressive NETs. Eligible patients had positive IHC expression of ER and/or PR ⩾ 1%. Prior therapy with somatostatin analogs was required for progressing/functioning cases. Main exclusion criterion was aggressive disease requiring cytotoxic therapy. The primary end point was disease control rate (DCR) at week 24 by Response Evaluation Criteria in Solid Tumors version 1.1. We planned to enroll 23 patients in the first stage, to reach a DCR at week 24 of 70% (versus 50%); if ⩾12 patients reached the primary end point, a total of 37 would be included. Results: From February 2019 to February 2022, 23 out of 59 patients were eligible and enrolled: 15 (65%) were females; the most common sites were pancreas (11; 48%) and small bowel (6; 26%). In all, 13 patients (56.5%) had G2 NETs. At a median follow-up of 27 months, 13 patients (56.5%) had stable disease at week 24 and median progression-free survival (PFS) was 7.9 months [interquartile range (IQR): 3.7-12.1]. The best response was stable disease in 13 patients, with most patients experiencing minor tumor growth. Median PFS times were not significantly different according to ER/PR < or ⩾30% (p = 0.49) or ER versus PR expression (p = 0.19). One patient experienced grade 2 constipation. Conclusion: Tamoxifen for ER-/PR-positive NETs patients is safe but offers modest antitumor effects. Trial registry name: Study of Tamoxifen in Well Differentiated Neuroendocrine Tumors and Hormone Receptor Positive Expression (HORMONET). URL: https://clinicaltrials.gov/ct2/show/NCT03870399?term=03870399&draw=2&rank=1. Registration number: NCT03870399.

Neuroendocrine Tumor Metastases to the Breast: A Case Report and Review of the Literature.

Breast metastases from neuroendocrine neoplasms (NENs) are considered infrequent. We report a case of a patient with ileocecal neuroendocrine tumor (NET) metastases to both breasts, for whom the initial clinical presentation was chronic diarrhea. Breast metastasis was initially suspected by a 68-Gallium DOTANOC positron emission tomography (PET)/CT and was confirmed by histopathology. We also performed a literature review in which we identified 116 cases of NENs metastatic to the breast reported so far. Most cases occurred in older women, were caused by NETs, and had the gastrointestinal tract as the primary site.