Somatostatin Analogue Research Articles

Perioperative short-acting somatostatin analogue use in patients undergoing neuroendocrine tumour excision - do we need a change in guidelines?

Perioperative short-acting somatostatin analogue use in patients undergoing neuroendocrine tumour excision - do we need a change in guidelines?

Pancreatic Neuroendocrine Neoplasms: Classification and Novel Role of Endoscopic Ultrasound in Diagnosis and Treatment Personalization.

The incidence and prevalence of pancreatic neuroendocrine neoplasms are steadily increasing. These tumors are highly heterogeneous, with treatment options ranging from observation to surgery, and various medical therapies. The choice of treatment is influenced by factors such as tumor stage, grade (proliferative activity), and the presence of hormone-related syndromes. Endoscopic ultrasound (EUS) is becoming increasingly valuable for assessing pancreatic neuroendocrine neoplasms, offering detailed morphological, vascular, and functional information through techniques such as contrast enhancement and elastography. It also allows biopsies that are useful for both histopathological and molecular analyses. These tumors are highly heterogeneous, with treatment options ranging from observation to various medical therapies and surgery. Recent data suggest that small, non-functioning PanNENs with low proliferation rates may be safely monitored, whereas more aggressive or functioning tumors typically require surgery. EUS-guided ablation is a promising alternative for patients with functional pancreatic neuroendocrine neoplasms who are unsuitable for surgery, although randomized trials are needed. In non-resectable pancreatic neuroendocrine neoplasms, treatment options include somatostatin analogs, targeted therapies (e.g., everolimus, sunitinib), chemotherapy, and radioligand therapy. This review discusses key factors in planning personalized treatment strategies for pancreatic neuroendocrine neoplasms.

Comparison of the dosimetry and cell survival effect of 177Lu and 161Tb somatostatin analog radiopharmaceuticals in cancer cell clusters and micrometastases.

177Lu-based radiopharmaceuticals (RPs) are the most used for targeted radionuclide therapy (TRT) due to their good response rates. However, the worldwide availability of 177Lu is limited. 161Tb represents a potential alternative for TRT, as it emits photons for SPECT imaging, β--particles for therapy, and also releases a significant yield of internal conversion (IE) and Auger electrons (AE). This research aimed to evaluate cell dosimetry with the MIRDcell code considering a realistic localization of three 161Tb- and 177Lu-somatostatin (SST) analogs in different subcellular regions as reported in the literature, various cell cluster sizes (25-1000µm of radius) and percentage of labeled cells. Experimental values of the α- and β-survival coefficients determined by external beam photon irradiation were used to estimate the survival fraction (SF) of AR42J pancreatic cell clusters and micrometastases. The different localization of RPs labeled with the same radionuclide within the cells, resulted in only slight variations in the dose absorbed by the nuclei (ADN) of the labeled cells with no differences observed in either the unlabeled cells or the SF. ADN of labeled cells (MDLC) produced by 161Tb-RPs were from 2.8-3.7 times higher than those delivered by 177Lu-RPs in cell clusters with a radius lower than 0.1mm and 10% of labeled cells, due to the higher amount of energy emitted by 161Tb-disintegration in form of IE and AE. However, the 161Tb-RPs/177Lu-RPs MDLC ratio decreased below 1.6 in larger cell clusters (0.5-1mm) with > 40% labeled cells, due to the significantly higher 177Lu-RPs cross-irradiation contribution. Using a fixed number of disintegrations, SFs of 161Tb-RPs in clusters with > 40% labeled cells were lower than those of 177Lu-RPs, but when the same amount of emitted energy was used no significant differences in SF were observed between 177Lu- and 161Tb-RPs, except for the smallest cluster sizes. Despite the emissions of IE and AE from 161Tb-RPs, their localization within different subcellular regions exerted a negligible influence on the ADN. The same cell damage produced by 177Lu-RPs could be achieved using smaller quantities of 161Tb-RPs, thus making 161Tb a suitable alternative for TRT.

Predictive value of 68[Ga]Ga-DOTA-TATE PET/CT volumetric parameters in assessing treatment response to long-acting somatostatin analogues in patients with well-differentiated neuroendocrine tumours.

Over the past decade, numerous treatment options have emerged for patients with locally advanced and metastatic neuroendocrine tumours (NETs). Nevertheless, the optimal timing of treatment interventions remains uncertain, given the highly variable disease course observed in these patients, even when patients have the same tumour stage and grade. The aim of the study was to evaluate the predictive role of standardized uptake values (SUVs) and volumetric parameters obtained from pretreatment [68Ga]Ga-DOTA-TATE for response to SSA therapy in patients with NET. In this retrospective study, we included 42 patients (21 women, 21 men; age range: 46-84years) with histologically confirmed, metastatic, NET (G1 13, G2 28 cases); median Ki-67 index 5%, range 1-16) who received long acting SSA as a first line treatment and underwent [68Ga]Ga-DOTA-TATE PET/CT before SSA treatment. For all [68Ga]Ga-DOTA-TATE avid lesion SUVmax, SUVmean, somatostatin receptor expression tumour volume (STV), total lesion somatostatin receptor expression (TLD, STV multiplied by SUV mean) and Tmean/Smean (SUVmean of tumours/metastases divided by SUVmean of normal spleen) were measured. Finally, the sum of STV (total STV, TSTV) and TLD (total TLD, TTLD) was calculated for each patient and used in the analysis. During the study period, 14 patients had stable disease (33.3%) and 28 patients experienced progression (66.7%), among whom 12 patients died. The median progression-free survival (PFS) and overall survival (OS) were 26.5 and 46.5months, respectively. In the univariate and multivariate analysis, in the whole population study, Tmean/Smean ratio (HR 1.88, 95% CI 1.06-3.35, p = 0.03), Ki-67 index (HR 1.14, CI 1.03-1.26, p = 0.01) and pre-treatment chromogranin A serum concentration (HR 1.01, CI 1.0-1.03, p = 0.01) were significantly associated with PFS. Among patients with small intestinal NETs, TSTV (< 125.85 cm3 vs. ≥ 125.85 cm3, p = 0.023) and TTLD (< 4168.95 vs. ≥ 4168.95, p = 0.026) were significantly associated with PFS in the univariate analyses. No significant correlation was found between measured volumetric parameters and OS. Volumetric parameters of pretreatment 68[Ga]Ga-DOTA-TATE PET/CT may be useful in prediction of the response to SSA (used in monotherapy as a first-line therapy) in patients with NET.

Dumping syndrome: Update on pathophysiology, diagnosis, and management.

Dumping syndrome is a complex of gastrointestinal symptoms originally studied in peptic ulcer surgery patients. At present, it is most prevalent in patients who underwent bariatric, upper gastrointestinal cancer or anti-reflux surgery. The symptom pattern comprises early and late dumping symptoms. Several management options have been reported including nutritional, pharmacological and surgical approaches. In this study, we aimed to review the current evidence on dumping syndrome definition, diagnosis and treatment, including preliminary data from newer pharmacological studies. Current pathophysiological concepts and analyses of provocative tests has led to a clear definition of dumping syndrome, including both early and late dumping symptoms. The term postbariatric hypoglycemia represents a limited focus on late dumping only. The diagnosis relies on recognition of symptoms and signs in a patient with appropriate surgical history; and can be confirmed by provocative testing or registration of spontaneous hypoglycemia. The initial treatment focuses on dietary intervention, to which meal viscosity enhancers and/or the glycosidase inhibitor acarbose can be added. The most effective therapy is the use of short- or long-acting somatostatin analogues, which is however expensive and entails side effect issues. In case of refractory hypoglycemia, diazoxide or SGLT2 inhibitors can be considered, based on limited evidence. In refractory patients, continuous enteral feeding or (rarely) surgical reinterventions have been advocated, although not supported by solid evidence. Therapies under current evaluation include the broad-spectrum somatostatin analogue pasireotide, GLP-1 receptor antagonists, GLP-1 receptor agonists and administration of stable forms of glucagon are currently under study. Dumping syndrome is a well-defined but probably under-diagnosed complication of upper gastrointestinal, especially bariatric, and surgeries. Diagnosis is confirmed by a provocative test and incremental therapies starting with diet, adding meal viscosity enhancers or glycosidase inhibitors and adding somatostatin analogues in refractory cases. A number of emerging therapies targeting intestinal propulsion, peptide hormone effects and hypoglycemic events are under evaluation.

Neuroendocrine tumours and pregnancy: Real-world data from an European Neuroendocrine Tumour Centre of Excellence.

Neuroendocrine neoplasms (NENs) arise from the diffuse endocrine system and have been considered to be rare. However, the incidence and prevalence of these tumours have increased in recent years, and they are being seen in younger patients including women in the reproductive age group. Due to the paucity of data, diagnostic and therapeutic strategies in managing such tumours during pregnancy can be challenging to both treating physicians and patients. This article describes the experience and outcomes of managing pregnant women with NEN at a European Neuroendocrine Tumour Society (ENETS) Centre of Excellence. In this retrospective analysis, we evaluated a total of 22 pregnancies in 18 pregnant women with concurrent diagnoses of NENs who were managed at Royal Free Hospital ENETS Centre of Excellence throughout their pregnancy. These were identified from our tumour registry of 3500 NEN patients between 2015 and 2023. Cross-sectional imaging (computed tomography (CT)/magnetic resonance imaging (MRI)), pre- and post-pregnancy, for each patient was reviewed by an experienced radiologist. Tumour growth rate (TGR) was calculated using the formula: TGR = 100 × [exp (TG) - 1]; TG. [3 × log (D2/D1)]/time (months), where D1 is the tumour size at date 1; D2 is the tumour size at date 2; and time (months) = (Date 2 - Date 1 + 1)/30.44. Tumour growth rate pre-conception (TGRpc) and tumour growth rate post-partum (TGRpp) were calculated for each patient. In a sub-group of patients, positivity for oestrogen and progesterone receptors were analysed on the tumour tissue to evaluate whether the presence of these receptors affected tumour progression during the pregnancy. We also reviewed the pregnancy outcome in patients treated with somatostatin analogues during pregnancy. We analysed the data of a total 22 pregnancy encounters in 18 women: 15 pregnancies (68%) preceded the diagnosis of the NEN, whereas the diagnosis of NEN was made during pregnancy or in the post-partum period in 5 (23%) and 2 (9%) pregnancies respectively. Eight patients (44%) had a diagnosis of a pancreatic NEN, whereas 5 (28%) were diagnosed with mid-gut NENs, and a further 5 at other sites. The majority of the patients (n = 12, 67%) had evidence of metastatic disease at the time of diagnosis. Most pregnancies had a successful outcome (n = 19, 86%), whereas 3 patients (14%) had miscarriages in the 1st trimester. Five patients in total of 6 pregnancies were treated with somatostatin analogues as monotherapy during the pregnancy, and all of them had stable disease after pregnancy. All of them delivered healthy babies without any side effects or complications due to therapy. The average TGRpc was -0.8% (n = 5) and the average TGRpp was +0.96% (n = 6); 2 patients who did not have suitable targets for calculation of TGRpc developed new lesions suggesting disease progression. Moreover, 2 of the 4 patients who have had both pre-conception and post-pregnancy scans showed an increase in TGRpp compared to TGRpc. The management of NENs during pregnancy should be multidisciplinary with an individualised approach to each patient. Somatostatin analogues appear to be safe during pregnancy, though further robust studies are needed. Pregnancy per se may accelerate tumour progression, and patients should be counselled regarding this possibility.

Cephalgic syndrome in patients with acromegaly

The aim of this review is to summarize the data available in the literature on the causes of headache in patients with acromegaly, as well as on the effect of various methods of acromegaly treatment on headache. Publications were searched in the PubMed database using the keywords «Headache in patients with acromegaly», «Headache in patients with pituitary adenomas», «Tension-type headache», «Migraine». Headache in patients with pituitary adenomas secreting somatotropic hormone (STH) is not uncommon: according to various authors, cephalgic syndrome occurs in 30-70% of patients with acromegaly and can worsen their quality of life, along with other factors, up to disability. By the nature of development, headache with acromegaly is classified into primary (migraine, tension headache, trigeminal autonomic cephalgia, for example, SUNCT syndrome and cluster headaches), and can also be caused by various causes directly related to the tumor. All this requires differential diagnosis. The factors causing headaches in somatotropinomas have not yet been well studied and require further research. These include the mass effect of the tumor, hormonal hypersecretion, pathology of the temporomandibular joint, sodium and fluid retention in the body, psychological factors, etc. The authors evaluated the effect on headache of various methods of acromegaly treatment: transnasal transsphenoidal adenomectomy, radiation therapy and drug therapy with somatostatin analogues, dopamine agonists and growth hormone receptor antagonist. However, even when normal levels of STH and insulin-like growth factor 1 (IGF-1) are reached, cephalgic syndrome may persist, therefore patients should be warned about this in advance and referred to a cephalgologist to select adequate headache therapy.

Ablative Dose Y90 Radiation Segmentectomy for Treatment of Neuroendocrine Liver Metastases

PurposeTo assess the safety and efficacy of Y90 radiation segmentectomy (RS) for neuroendocrine tumor liver metastases (NELMs). Materials and MethodsThis single-institution retrospective study included 18 patients with 23 liver tumors not amenable to resection or ablation, who underwent RS between 2009 and 2021. Tumor grades by Ki-67/mitotic indices were Grade I (n=9/23, 39%), Grade II (n=10/23, 45%) and Grade III (n=4/23, 17%). Eleven patients (61%) were previously treated with somatostatin analogs, five (28%) with chemotherapy, and two (11%) with peptide receptor radionuclide therapy. Safety was assessed with pre/post liver chemistries, blood counts and clinical adverse events (AEs) using National Cancer Institute Common Terminology Criteria for AEs v5.0. Tumor response was assessed per Response Evaluation Criteria in Solid Tumors 1.1 and modified RECIST criteria. Kaplan-Meier analysis was used to estimate median overall survival (OS), progression-free survival (PFS), and time to progression (TTP) from the date of Y90. ResultsMedian follow-up was 31.9 months. Grade 1 fatigue was observed in 13/18 patients (72%), with 1/18 patient (6%) experiencing grade 3 fatigue. Three patients (17%) exhibited grade 3 lymphopenia. No other grade 3 or any grade 4 AE was observed. Tumor objective response was achieved in 83% of patients by RECIST size criteria and 100% by mRECIST enhancement criteria. Median OS was 69.4 months (95% CI, 23.1-99.4) and median PFS was 12.2 months (95% CI, 4.6-28.8). Median overall TTP was 13.0 months (95% CI, 4.6-45.1), with median treated tumor TTP not reached. ConclusionY90 RS demonstrates high rates of antitumor response with a favorable toxicity profile and durable OS in the treatment of NELMs.

Metastatic insulinoma—outcomes in the current era

Abstract Background Multimodal interventions in neuroendocrine tumors appear to have a beneficial impact on survival. Metastatic insulinoma is associated with hypoglycemia and, historically, a shortened life expectancy. Methods The authors retrospectively analyzed the clinical outcomes of patients with metastatic insulinomas treated at a tertiary care center between 2006 and 2023. Results Clinical data on 14 patients with metastatic insulinoma (metastases to the liver, skeleton, and lung) were reviewed in this descriptive study. The patients underwent various treatments including surgery; liver directed therapies (embolization, selective internal radiotherapy), somatostatin analogs; targeted agents (everolimus); systemic chemotherapy (capecitabine/temozolomide; carboplatin/etoposide); external beam radiation; and peptide receptor radiotherapy. Seven subjects died during follow-up. The time of the 7 deaths ranged from 2.5 to 10.4 years (median time to death was 8.2 years). This compares to previous reports of median survival of about 2 years. Seven subjects are alive 1.2-12.3 years after diagnosis. Hypoglycemia was well-controlled and did not cause the deaths. Conclusions Multimodal interventions in metastatic insulinoma can be effective in managing hypoglycemia. The patients on multimodal treatments also lived a long time when considering previous published reports of median survival of just 2 years. Our findings challenge previous assumptions regarding clinical outcomes in this patient population.

The small-for-size syndrome in living donor liver transplantation: current management.

Small-for-size syndrome poses a significant challenge in living donor liver transplantation, with potentially severe consequences including liver failure and death. This review explores the management strategies for SFSS, starting from the pathophysiology of the disease. SFSS arises from insufficient liver mass in the graft and hyperdynamic circulation in cirrhotic recipients, leading to portal hyperperfusion and subsequent liver injury. Risk factors include graft size, quality, recipient factors, and hemodynamic changes during transplantation.Hemodynamic monitoring is crucial during living donor liver transplantation to optimize portal vein and hepatic artery flow. Prevention strategies focus on donor-recipient matching and intraoperative graft inflow modulation. Optimizing venous outflow and avoiding portal hyperperfusion is essential. Management of established small-for-size syndrome involves supportive care, pharmacologic interventions, and radiological and surgical options. Pharmacotherapy includes somatostatin analogues, beta-blockers, and vasopressin analogues to reduce portal flow and pressure. Surgical interventions aim to modulate portal flow and mitigate complications. Retransplantation may be necessary in severe cases, guided by persistent graft dysfunction despite liver flow modulations. In conclusion, preventing and managing small-for-size syndrome in living donor liver transplantation requires comprehensive assessment and tailored interventions. Advancements in graft/recipient matching, hemodynamic monitoring, pharmacologic and surgical techniques aiming to inflow modulation have improved outcomes, enabling successful transplantation even with ultra-small grafts.

The impact of peptide receptor radionucleotide therapy with Lutetium-177 DOTATATE on cardiac metastases in neuroendocrine tumors

Abstract Background Cardiac metastasis from neuroendocrine tumors (NET) is rare and has been thought to potentially result in life threatening sequalae. Peptide receptor radionucleotide therapy (PRRT), such as Lutetium-177 (Lu-177) DOTATATE, has been validated as effective treatment for patients with NET who have progressed on somatostatin analogue (SSA) therapy and more recently suggested for use in SAA-naïve higher risk grade 2 and grade 3 NETs. However, Lu-177 DOTATATE therapy has been found to have potentially serious adverse effects both locally and systemically. Overall, the clinical significance of cardiac metastasis of NET, as well as the safety and efficacy of Lu-177 DOTATATE in this cohort, has not been thoroughly evaluated. Purpose This study assessed the outcomes and clinical consequences of cardiac metastatic involvement in patients with NET. Furthermore, this study investigated the safety of Lu-177 DOTATATE therapy in patients with cardiac metastases from NET. Methods All patients who underwent 68Ga-DOTATATE positron emission tomography for evaluation of NET across three tertiary centers between 2016 and 2022 were retrospectively evaluated. Patients with evidence of cardiac metastasis were further evaluated. Baseline characteristics, treatment modality, and clinical outcomes including mortality, arrhythmia or conduction disease, carcinoid heart disease, and heart failure admissions were recorded. Patients with cardiac metastases were grouped and compared based on therapeutic modality (conservative therapy with surveillance or SSA, Lu-177 DOTATATE therapy, or surgical resection of metastases). Results From 3253 patients with NET, 51 patients were identified to have cardiac metastases (mean age 66.7 ± 12.2 years, 54% male). Three patients underwent surgical resection of cardiac metastases, and in two of whom this was concomitant while undergoing valve surgery for carcinoid heart disease. Patients with cardiac metastasis had significantly higher mortality than patients without cardiac metastasis (HR 2.12, 95%CI 1.00 – 4.52, p = 0.049, Figure 1A). Median follow-up from diagnosis of cardiac metastasis was 3.64 years [IQR 1.59 – 5.64]. There was no significant difference in clinical outcomes between patients that received Lu-177 DOTATATE therapy (n = 27) and conservative therapy (n = 21). Specifically, there was no significant difference in mortality risk at five years post the diagnosis of cardiac metastasis between these groups (p = 0.47, Figure 1B). Conclusion Patients with cardiac metastasis from NETs have worse clinical outcomes than NET patients without cardiac metastatic involvement. Lu-177 DOTATATE therapy appears to be safe in patients with cardiac metastasis from NET.Figure 1AFigure 1B

PET imaging of pheochromocytoma and paraganglioma - 18F-FDOPA vs. somatostatin analogues.

Functional imaging with positron emission tomography (PET) scans is an essential part of the diagnostic workup for pheochromocytoma and paraganglioma (PPGL). The purpose of this review is a) to provide a brief overview of functional imaging for PPGL, b) summarize selected present and older guideline and review recommendations, and c) conduct a literature review on the diagnostic performance of the most used PET tracers for PPGL. We conducted a systematic literature search in PubMed from January 2004 to August 2024 with the search string: ("Pheochromocytoma" OR "Paraganglioma") AND ("Positron-Emission Tomography" OR "Radionuclide Imaging" OR ("PET" AND ("FDG" OR "DOTATOC" OR "DOTANOC" OR "DOTATATE" OR "DOPA" OR "FDOPA"))). Studies involving PET scans of at least 20 individuals with PPGL, or at least five individuals in a rare, well-defined subgroup of PPGL (e.g. sympathetic or head-neck paragangliomas, and specific pathogenic variants) were included. Seventy studies were identified of which 21 were head-to-head comparisons of at least two different PET tracers (18F-fluorodihydroxyphenylalanine, 18F-FDOPA; 68Ga-DOTA-conjugated somatostatin analogues, 68Ga-SSA; and 18F-fluorodeoxyglucose, 18F-FDG). 18F-FDOPA had higher sensitivity for pheochromocytoma compared to 68Ga-SSA and equal sensitivity for metastatic pheochromocytoma. 18F-FDOPA and 68Ga-SSA had similar sensitivity for primary non-SDHx sympathetic and head-neck paraganglioma. However, 68Ga-SSA had higher sensitivity for metastatic sympathetic and head-neck paraganglioma and for SDHx-related paraganglioma. 18F-FDOPA and 68Ga-SSA PET are both sensitive for localizing PPGL. However, 18F-FDOPA is the most sensitive for detecting pheochromocytoma, while 68Ga-SSA is superior to 18F-FDOPA for metastatic sympathetic and head-neck paraganglioma and SDHx-related paraganglioma.

Current Status of Immunotherapy in Management of Small Bowel Neuroendocrine Tumors.

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

Chinese multidisciplinary expert consensus on the rational use of surufatinib in clinical practice（2024 edition）

Neuroendocrine neoplasms are a group of heterogeneous tumors originating from the neuroendocrine system, which can occur in any part of the body. Pulmonary and gastroenteropancreatic neuroendocrine tumors are the most common. In recent years, the global incidence of neuroendocrine tumors has increased more significantly than other types of tumors, especially in the past 40 years. The drug treatment of neuroendocrine tumors includes somatostatin analogues, anti-angiogenesis targeting drugs, nuclide therapy and chemotherapy. Surufatinib is an oral tyrosine kinase receptor inhibitors that targets for vascular endothelial growth factor receptor (VEGFR1-3), fibroblast growth factor receptor 1 (FGFR1), and colony-stimulating factor-1 receptor (CSF-1R), has received approval in 2020 and 2021 for the treatment of locally advanced or metastatic, progressive nonfunctional, well-differentiated (G1, G2) neuroendocrine tumors (NETs) of both pancreatic and extrapancreatic origin that are unresectable. Ongoing exploratory studies are investigating its potential application in other tumor types. Common adverse reactions observed during surufatinib treatment include hypertension, proteinuria, bleeding events, and hepatic lab test abnormal and diarrhea. Chinese multidisciplinary expert consensus on the rational use of surufatinib in clinical practice (2024 edition) aims to provide standardized guidance for its rational use and enhance patient compliance to maximize therapeutic benefits.

Tumor-induced phosphopenic osteomalacia: modern approaches to diagnostics and treatment

Phosphopenic osteomalacia (PPOM) is a rare variant of paraneoplastic syndrome caused by tumor synthesis of fibroblast growth factor 23 (FGF23). FGF23 secretion leads to a decrease in phosphate reabsorption and calcitriol levels, which leads to the development of severe hypophosphataemia and hypocalcaemia. FGF23 synthesis is predominantly associated with benign mesenchymal tumors, but has also been described in malignant neoplasms. The main clinical manifestations of PPOM are generalized myalgias and myopathy, ostealgia, pathological fractures, etc. The diagnosis of the disease requires a step-by-step investigation using somatostatin receptor-based imaging techniques, as these have the highest sensitivity for the detection of neoplasms causing osteomalacia. Surgical intervention is clearly the treatment of choice. Promising non-surgical methods include treatment with burosumab and somatostatin analogues.

Adverse Events of Radioligand Therapy in Patients with Progressive Neuroendocrine Neoplasms: The Biggest Eastern European Prospective Study.

Neuroendocrine neoplasms (NENs) are neoplastic tumors developing in every part of the body, mainly in the gastrointestinal tract and pancreas. Their treatment involves the surgical removal of the tumor and its metastasis, long-acting somatostatin analogs, chemotherapy, targeted therapy, and radioligand therapy (RLT). A total of 127 patients with progressive neuroendocrine neoplasms underwent RLT-4 courses, administered every 10 weeks-with the use of 7.4 GBq [177Lu]Lu-DOTA-TATE or tandem therapy with 1.85 GBq [177Lu]Lu-DOTA-TATE and 1.85 GBq [90Y]Y-DOTA-TATE. Assessment of short- and long-term complications, as well as the calculation of progression-free survival (PFS) and overall survival (OS) were performed. RLT caused a statistically but not clinically significant decrease in blood morphology parameters during both short- and long-term observations. Glomerular filtration rate (GFR) significantly decreased only in a long-term observation after RLT; however, it was clinically acceptable. Computed predictions of progression-free survival (PFS) and overall survival (OS) indicated that five years post-RLT, there is a 74% chance of patients surviving, with only a 58.5% likelihood of disease progression. Computed predictions of PFS and OS confirmed treatment efficiency and good patient survival. RLT should be considered a safe and reliable line of treatment for patients with progressive NENs as it causes only a low number of low-grade adverse events.

The current status of somatostatin analogs in the treatment of neuroendocrine tumors and future perspectives.

Somatostatin analogs (SSAs) were developed as antisecretory agents to palliate hormonal symptoms in patients with functioning neuroendocrine tumors (NETs). Their antiproliferative activity has been established in the phase 3 PROMID and CLARINET trials. SSAs currently represent the standard first-line therapy for the majority of well-differentiated G1/G2 gastroenteropancreatic NETs as well as for pulmonary NETs. An update on the clinical applications of established SSAs for the treatment of NETs is provided. Perspectives on emerging nonpeptide SSAs such as paltusotine and innovative formulations of octreotide (CAM2029) are included. SSAs represent the cornerstone of treatment for both functioning and nonfunctioning NETs. While standard-dose SSAs have a defined place in the therapeutic algorithm of well-differentiated NETs, uncertainties remain on how to best integrate above-label doses of SSAs in the treatment sequence, particularly when tumor control is the goal. Octreotide and lanreotide appear to be clinically interchangeable, and no signs of superiority of one agent over the other has been observed so far. Whether SSAs may be exploited in the maintenance setting following more aggressive treatments, whether continuing SSAs beyond-progression after first-line therapy could be an effective treatment strategy, and whether new-generation SSAs such as pasireotide could overcome resistance to established SSAs are key areas of investigation.

Advancing Treatment Options for Merkel Cell Carcinoma: A Review of Tumor-Targeted Therapies.

Although rare, Merkel cell carcinoma (MCC) is a highly aggressive and increasingly prevalent neuroendocrine cancer of the skin. While current interventions, including surgical resection, radiation, and immunotherapy have been employed in treating many patients, those who remain unresponsive to treatment are met with sparse alternatives and a grim prognosis. For this reason, it is of interest to expand the repertoire of available therapies for MCC patients who remain resistant to current primary interventions. Recently, our improved mechanistic understanding of aberrant cell signaling observed in both MCPyV-positive and -negative MCC has facilitated exploration into several small molecules and inhibitors, among them receptor tyrosine kinase inhibitors (TKIs) and somatostatin analogs (SSAs), both of which have positively improved response rates and reduced tumor volumes upon application to treatment of MCC. The introduction of such targeted therapies into treatment protocols holds promise for more personalized care tailored towards patients of diverse subtypes, thereby improving outcomes and mitigating tumor burden, especially for treatment-resistant individuals. In this review, we characterize recent findings surrounding targeted treatments that have been applied to MCC and provide an overview of emerging perspectives on translatable options that can be further developed to offer additional therapeutic avenues for patients with the disease.

Somatostatin receptor 2A expression in von Hippel-Lindau-related hemangioblastomas.

Central nervous system hemangioblastomas are the most prevalent manifestation of von Hippel-Lindau (VHL) disease and remain the main cause of mortality. Surgical resection is the primary treatment strategy, but is not always possible, and should be used as restrictively as possible. There is an unmet need for less invasive treatment strategies, such as targeted therapy. Expression of somatostatin receptor 2A (SSTR2A) in VHL-related hemangioblastomas has been described earlier, but the extent of expression in a larger population has yet to be determined. The authors hypothesize that a substantial subset of VHL-related hemangioblastomas show SSTR2A expression, which may serve as a potential new treatment target. Patients who were surgically treated for a VHL-related hemangioblastoma from 1990 until 2021 at the UMC Utrecht were included. Clinical data was derived from a clinical database. Tissue samples were histopathologically examined with use of hematoxylin and eosin staining, and immunohistochemical analysis of SSTR2A expression was performed. Forty-three tissue samples were obtained from 26 patients. Nine showed strong positivity for SSTR2A expression, whereas 13 showed moderate and 15 sparse expression. Three samples showed no expression of SSTR2A. The distribution showed right-skewedness favoring a strong expression. SSTR2A expression colocalized with endothelial markers and not with stromal cells. Additionally, within-patient variability for SSTR2A expression was described in 14 patients. SSTR2A is expressed in varying degrees in the majority of VHL-related hemangioblastomas. Future treatment with somatostatin analogues or even peptide receptor radionuclide treatment may be considered for SSTR2A-positive cases.

Gastroenteropancreatic Neuroendocrine Tumor with Peritoneal Metastasis: A Review of Current Management.

Peritoneal metastasis in gastroenteropancreatic neuroendocrine tumors poses a significant clinical challenge, with limited data guiding management strategies. We review the existing literature on surgical and systemic treatment modalities for peritoneal metastasis from gastroenteropancreatic neuroendocrine tumors. Surgical interventions, including cytoreductive surgery, have shown promise in improving symptom control and overall survival-particularly in cases in which 70% cytoreduction can be achieved. Hyperthermic intraperitoneal chemotherapy remains controversial due to a paucity of high-level evidence and a lack of consensus for routine use. The use of systemic therapy in the setting of peritoneal metastasis from gastroenteropancreatic neuroendocrine tumors is extrapolated from high-quality evidence for its use in the setting of the solid organ metastasis of this disease. The use of somatostatin analogs for symptom control and some antiproliferative effects is supported by large clinical trials. Additional strong evidence exists for the use of interferon-alpha, everolimus, and sunitinib, particularly in pancreatic neuroendocrine tumors. Cytotoxic chemotherapy and peptide receptor radionuclide therapy may be used in select cases, though as an emerging treatment modality, the optimal sequence of peptide receptor radionuclide therapy within the existing algorithms is unknown. Significant gaps in understanding and standardized management exist, particularly for those patients presenting with peritoneal metastasis, and targeted research to optimize outcomes in this population is needed.