[Interpretation on the update of 2022 WHO classification of neuroendocrine tumors].

The 5th edition of the WHO Endocrine and Neuroendocrine Oncology Blue Book, released in 2022, contained some changes in the classification of neuroendocrine tumors. A brief summary of the main changes has been provided in this section. Mainly summarized as changes in naming, differentiation and classification of neuroendocrine tumors, and tumor grading systems related to anatomical locations, morphological characteristics of neuroendocrine tumors in different locations, auxiliary diagnostic and prognostic/therapeutic markers, differential diagnosis and diagnostic difficulties of neuroendocrine tumors.

Evaluation of a blood miRNA/mRNA signature to follow-up Lu-PRRT therapy for G1/G2 intestinal neuroendocrine tumors.

Background: 177Lu-oxodotreotide peptide receptor therapy (LuPRRT) is an efficient treatment for midgut neuroendocrine tumors (NETs) of variable radiological response. Several clinical, biological, and imaging parameters may be used to establish a relative disease prognosis but none is able to predict early efficacy or toxicities. We investigated expression levels for mRNA and miRNA involved in radiosensitivity and tumor progression searching for correlations related to patient outcome during LuPRRT therapy. Methods: Thirty-five patients received LuPRRT for G1/G2 midgut NETs between May 2019 and September 2021. Peripheral blood samples were collected prior to irradiation, before and 48 h after the second and the fourth LuPRRT, and at 6-month follow-up. Multiple regression analyses and Pearson correlations were performed to identify the miRNA/mRNA signature that will best predict response to LuPRRT. Results: Focusing on four mRNAs and three miRNAs, we identified a miRNA/mRNA signature enabling the early identification of responders to LuPRRT with significant reduced miRNA/mRNA expression after the first LuPRRT administration for patients with progressive disease at 1 year (p < 0.001). The relevance of this signature was reinforced by studying its evolution up to 6 months post-LuPRRT. Moreover, nadir absolute lymphocyte count within the first 2 months after the first LuPRRT administration was significantly related to low miRNA/mRNA expression level (p < 0.05) for patients with progressive disease. Conclusion: We present a pilot study exploring a miRNA/mRNA signature that correlates with early hematologic toxicity and therapeutic response 12 months following LuPRRT. This signature will be tested prospectively in a larger series of patients.

Endoscopic ultrasonography-based intratumoral and peritumoral machine learning radiomics analyses for distinguishing insulinomas from non-functional pancreatic neuroendocrine tumors.

Objectives: To develop and validate radiomics models utilizing endoscopic ultrasonography (EUS) images to distinguish insulinomas from non-functional pancreatic neuroendocrine tumors (NF-PNETs). Methods: A total of 106 patients, comprising 61 with insulinomas and 45 with NF-PNETs, were included in this study. The patients were randomly assigned to either the training or test cohort. Radiomics features were extracted from both the intratumoral and peritumoral regions, respectively. Six machine learning algorithms were utilized to train intratumoral prediction models, using only the nonzero coefficient features. The researchers identified the most effective intratumoral radiomics model and subsequently employed it to develop peritumoral and combined radiomics models. Finally, a predictive nomogram for insulinomas was constructed and assessed. Results: A total of 107 radiomics features were extracted based on EUS, and only features with nonzero coefficients were retained. Among the six intratumoral radiomics models, the light gradient boosting machine (LightGBM) model demonstrated superior performance. Furthermore, a peritumoral radiomics model was established and evaluated. The combined model, integrating both the intratumoral and peritumoral radiomics features, exhibited a comparable performance in the training cohort (AUC=0.876) and achieved the highest accuracy in predicting outcomes in the test cohorts (AUC=0.835). The Delong test, calibration curves, and decision curve analysis (DCA) were employed to validate these findings. Insulinomas exhibited a significantly smaller diameter compared to NF-PNETs. Finally, the nomogram, incorporating diameter and radiomics signature, was constructed and assessed, which owned superior performance in both the training (AUC=0.929) and test (AUC=0.913) cohorts. Conclusion: A novel and impactful radiomics model and nomogram were developed and validated for the accurate differentiation of NF-PNETs and insulinomas utilizing EUS images.

Clonal Hematopoiesis in Patients With Neuroendocrine Tumor Treated With Lutetium-177 and the Risk of Thrombocytopenia: A Prospective Study.

PURPOSE: Thrombocytopenia is a relatively common dose-limiting toxicity during peptide receptor radionuclide therapy (PRRT) in patients with NET. Although uncommon, some patients develop persistent cytopenia and eventually therapy-related myeloid neoplasm (t-MN), which has a dismal prognosis. As the indications for PRRT are expanding, it is important to investigate factors that may predict cytopenias during/after PRRT. We prospectively evaluated the prevalence of clonal hematopoiesis (CH) and cytopenia in patients with NET undergoing PRRT. MATERIALS AND METHODS: Patients with metastatic NET with plan to receive four cycles of lutetium-177 were enrolled. CH was evaluated before PRRT using a panel of 220 genes with a targeted depth of ≥1,000×. Patients were followed during PRRT and every 3 months thereafter. RESULTS: Of 37 patients enrolled, the median age was 68 years and 51.4% were male. Previous treatment exposures included alkylating agents in 30%, platinum agents in 8%, and external radiation in 13%. CH was detected in 35.1% using a variant allele frequency (VAF) cutoff of ≥2% and 45.9% with a VAF of ≥1%. The most common mutations were in age-related genes (DNMT3A, TET2). CH was not associated with anemia or neutropenia; however, it was associated with lower platelet count at baseline and more time spent in a thrombocytopenic state during/after PRRT. Five patients had bone marrow biopsies (BMBs) because of sustained hematologic dysfunction post-PRRT, and of those, diagnoses included clonal cytopenia of undetermined significance (CCUS) in three and idiopathic cytopenia of undetermined significance (ICUS) in two. CONCLUSION: CH is present in 35.1% of patients with NET and is associated with thrombocytopenia risk during PRRT. Future studies with long-term follow-up will delineate whether CH might be a predictor for higher risk of t-MN after PRRT.

Metabolic Tumor Volume on 18-Fluorodeoxyglucose Positron Emission Tomography as a Prognostic Marker of Survival in Patients With Locally Advanced or Metastatic Neuroendocrine Neoplasms Treated With 177Lutetium-DOTA-Octreotate Peptide Receptor Radionuclide Therapy.

OBJECTIVE: We investigated metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on pre-treatment FDG-PET as prognostic markers for survival in patients with metastatic neuroendocrine neoplasms (NENs) receiving peptide receptor radionuclide therapy (PRRT). METHODS: A retrospective review of patients with metastatic NENs receiving PRRT was undertaken. Pre-treatment FDG-PET images were analyzed and variables collected included MTV and TLG (dichotomized by median into high vs low). Main Outcomes were overall survival (OS) and progression-free survival (PFS) by MTV and TLG (high vs low). RESULTS: One hundred five patients were included. Median age was 64 years (50% male). Main primary NEN sites were small bowel (43.8%) and pancreas (40.0%). Median MTV was 3.8 mL and median TLG was 19.9. Dichotomization formed identical cohorts regardless of whether MTV or TLG were used. Median OS was 72 months; OS did not differ based on MTV/TLG high versus low (47.4 months vs not reached; hazard ratio, 0.43; 95% confidence interval [CI], 0.18-1.04; P = 0.0594). Median PFS was 30.4 months; PFS differed based on MTV/TLG high versus low (21.6 months vs 45.7 months; hazard ratio, 0.35; 95% CI, 0.19-0.64; P = 0.007). CONCLUSIONS: Low MTV/TLG on pre-treatment FDG-PET was associated with longer PFS in metastatic NEN patients receiving PRRT.

[Key updates and interpretation of the ninth version of AJCC staging system for neuroendocrine tumors of the stomach].

The cancer staging system of the American Joint Committee on Cancer (AJCC) is the most widely used clinical basis for tumor staging. In October 2023, AJCC released the staging system (ninth version) for the neuroendocrine tumors of stomach (NET), which has been implemented in January 2024. The ninth version of NET staging system mainly updated the histopathologic classification, diagnosis and staging methods, clinical and pathological staging, prognosis grade, tumor and non-tumor prognostic features. The update and implementation of the staging system provide a more detailed reference for the accurate diagnosis, staging and precise treatment of gastric neuroendocrine tumors. Moreover, it is convenient for clinicians to carry out clinical practice. The purpose of our article is to provide a high-level overview of the major changes in AJCC staging system (version 9) for gastric NET based on the latest evidence-based medical research.

Suspected silent pituitary somatotroph neuroendocrine tumor associated with acromegaly-like bone disorders: a case report.

BACKGROUND: Growth hormone (GH) positive pituitary neuroendocrine tumors do not always cause acromegaly. Approximately one-third of GH-positive pituitary tumors are classified as non-functioning pituitary tumors in clinical practice. They typically have GH and serum insulin-like growth factor 1 (IGF-1) levels in the reference range and no acromegaly-like symptoms. However, normal hormone levels might not exclude the underlying hypersecretion of GH. This is a rare and paradoxical case of pituitary tumor causing acromegaly-associated symptoms despite normal GH and IGF-1 levels. CASE PRESENTATION: We report a case of a 35-year-old woman with suspicious acromegaly-associated presentations, including facial changes, headache, oligomenorrhea, and new-onset diabetes mellitus and dyslipidemia. Imaging found a 19 × 12 × 8 mm pituitary tumor, but her serum IGF-1 was within the reference, and nadir GH was 0.7ng/ml after glucose load at diagnosis. A thickened skull base, increased uptake in cranial bones in bone scan, and elevated bone turnover markers indicated abnormal bone metabolism. We considered the pituitary tumor, possibly a rare subtype in subtle or clinically silent GH pituitary tumor, likely contributed to her discomforts. After the transsphenoidal surgery, the IGF-1 and nadir GH decreased immediately. A GH and prolactin-positive pituitary neuroendocrine tumor was confirmed in the histopathologic study. No tumor remnant was observed three months after the operation, and her discomforts, glucose, and bone metabolism were partially relieved. CONCLUSIONS: GH-positive pituitary neuroendocrine tumors with hormonal tests that do not meet the diagnostic criteria for acromegaly may also cause GH hypersecretion presentations. Patients with pituitary tumors and suspicious acromegaly symptoms may require more proactive treatment than non-functioning tumors of similar size and invasiveness.

Correlation between Neurotransmitters (Dopamine, Epinephrine, Norepinephrine, Serotonin), Prognostic Nutritional Index, Glasgow Prognostic Score, Systemic Inflammatory Response Markers, and TNM Staging in a Cohort of Colorectal Neuroendocrine Tumor Patients.

Neuroendocrine tumors are uncommon in the gastrointestinal system but can develop in the majority of the body's epithelial organs. Our goal was to examine the presence and clinical application of serum dopamine (DA), serotonin (ST), norepinephrine (NE), and epinephrine (EPI), in addition to determining the significance of the Prognostic Nutritional Index (PNI), Glasgow Prognostic Score (GPS), and systemic inflammatory response (SIR) markers as a prognostic factor for patients with colorectal neuroendocrine tumors (CR-NETs), in various tumor-node-metastasis (TNM) stages. We also wanted to identify the possible connection between them. This study included 25 consecutive patients who were diagnosed with CR-NETs and a control group consisting of 60 patients with newly diagnosed colorectal cancer (CRC). We used the Enzyme-Linked Immunosorbent Assay (ELISA) technique. This study revealed that CR-NET patients showed significantly higher serum levels of DA compared to CRC patients. We showed that serum DA was present in the early stages of CR-NETs, with increasing levels as we advanced through the TNM stages. Moreover, we found a close relationship between the levels of DA and the inflammation and nutritional status of the CR-NET patients in this study. CR-NET patients from the PNI < 47.00 subgroup had a higher level of DA than those from the PNI ≥ 47.00 subgroup. Pearson's correlation analysis revealed correlations between DA, PNI, and the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR). Both hematological indices were negatively correlated with albumin (ALB). Our investigation's findings relating to the PNI, GPS, SIR, and DA indicate that these tools can be markers of nutritional and systemic inflammatory status, are simple to use, and are repeatable. Further research on this topic could provide valuable insights into which biomarkers to incorporate into clinical practice for the management of CR-NET patients.

Cylindrical TGR as early radiological predictor of RLT progression in GEPNETs: a proof of concept.

This study aims to assess the predictive capability of cylindrical Tumor Growth Rate (cTGR) in the prediction of early progression of well-differentiated gastro-entero-pancreatic tumours after Radio Ligand Therapy (RLT), compared to the conventional TGR. Fifty-eight patients were included and three CT scans per patient were collected at baseline, during RLT, and follow-up. RLT response, evaluated at follow-up according to RECIST 1.1, was calculated as a percentage variation of lesion diameters over time (continuous values) and as four different RECIST classes. TGR between baseline and interim CT was computed using both conventional (approximating lesion volume to a sphere) and cylindrical (called cTGR, approximating lesion volume to an elliptical cylinder) formulations. Receiver Operating Characteristic (ROC) curves were employed for Progressive Disease class prediction, revealing that cTGR outperformed conventional TGR (area under the ROC equal to 1.00 and 0.92, respectively). Multivariate analysis confirmed the superiority of cTGR in predicting continuous RLT response, with a higher coefficient for cTGR (1.56) compared to the conventional one (1.45). This study serves as a proof of concept, paving the way for future clinical trials to incorporate cTGR as a valuable tool for assessing RLT response.

Super Mario sign at somatostatin receptor PET/CT.

68Ga-DOTA NOC PET-CT imaging has been shown to have high accuracy for the evaluation of neuroendocrine tumours. We present the case of a 59-year-old male with well differentiated gastric neuroendocrine tumour (grade II) treated with surgery. 68Ga-DOTA NOC PET/CT was performed to rule out metastasis. 68Ga-DOTA NOC showed physiological uptake in the bilateral adrenal and horseshoe kidney appearing as the famous character Super Mario. There is no evidence of any abnormal somatostatin avid lesion.

[Pituitary Crooke cell neuroendocrine tumor of adrenocorticotropic hormone differentiation-specific transcription factor lineage: a clinicopathological analysis of six cases].

Objective: To investigate the clinicopathological features of Crooke cell tumor of adrenocorticotropic hormone differentiation specific transcription factor (TPIT, also known as transcription factor 19, TBX19) lineage neuroendocrine tumors. Methods: Six cases of Crooke cell tumor diagnosed at the First Affiliated Hospital of University of Science and Technology of China, Hefei, China from October 2019 to October 2023 were collected. The clinical and pathological features of these cases were analyzed. Results: Among the six cases, one was male and five were female, with ages ranging from 26 to 75 years, and an average age of 44 years. All tumors occurred within the sella turcica. Clinical presentations included visual impairment in two cases, menstrual disorders in one case, Cushing's syndrome in one case, headache in one case, and one asymptomatic case discovered during a physical examination. Preoperative serum analyses revealed elevated levels of cortisol and adrenocorticotropic hormones in two cases, elevated cortisol in two cases, elevated adrenocorticotropic hormone in one case, and one case with a mild increase in prolactin due to the pituitary stalk effect. Magnetic resonance imaging revealed uneven enhancement of masses with maximum diameters ranging from 1.7 to 3.2 cm, all identified as macroadenomas. Microscopically, tumor cells exhibited irregular polygonal shapes, solid sheets, or pseudo-papillary arrangements around blood vessels. The cell nuclei were eccentric or centrally located, varying in size, with abundant cytoplasm. Some tumor cells showed perinuclear halo. Immunohistochemistry demonstrated diffuse strong positivity for TPIT in five cases, focal weak positivity for TPIT in one case, diffuse strong positivity for adrenocorticotropic hormone in all cases, and faint staining around the nuclei in a few cells. CK8/18 showed a strong positive ring pattern in more than 50% of tumor cells, focal weak positive expression of p53, and the Ki-67 positive index ranged 1%-5%. Periodic acid-Schiff staining revealed positive cytoplasm and negative perinuclear areas. Conclusions: Crooke cell tumor is a rare type of pituitary neuroendocrine tumors. Its pathological characteristics include a distinctive perinuclear clear zone and immunohistochemical markers, such as CK8/18 exhibiting a ring or halo pattern. This entity represents a high-risk subtype among pituitary neuroendocrine tumors, displaying a high risk of invasion and a propensity for recurrence. Accurate diagnosis is crucial for the postoperative follow-up and multimodal treatment planning.

Understanding the molecular regulators of neuroendocrine prostate cancer.

Worldwide, prostate cancer (PCa) remains a leading cause of death in men. Histologically, the majority of PCa cases are classified as adenocarcinomas, which are mainly composed of androgen receptor-positive luminal cells. PCa is initially driven by the androgen receptor axis, where androgen-mediated activation of the receptor is one of the primary culprits for disease progression. Therefore, in advanced stage PCa, patients are generally treated with androgen deprivation therapies alone or in combination with androgen receptor pathway inhibitors. However, after an initial decrease, the cancer recurs for majority patients. At this stage, cancer is known as castration-resistant prostate cancer (CRPC). Majority of CRPC tumors still depend on androgen receptor axis for its progression to metastasis. However, in around 20-30% of cases, CRPC progresses via an androgen receptor-independent pathway and is often presented as neuroendocrine cancer (NE). This NE phenotype is highly aggressive with poor overall survival as compared to CRPC adenocarcinoma. NE cancers are resistant to standard taxane chemotherapies, which are often used to treat metastatic disease. Pathologically and morphologically, NE cancers are highly diverse and often co-exist with adenocarcinoma. Due to the lack of proper biomarkers, it is often difficult to make an early diagnosis of this lethal disease. Moreover, increased tumor heterogeneity and admixtures of adeno and NE subtypes in the same tumor make early detection of NE tumors very difficult. With the advancement of our knowledge and sequencing technology, we are now able to better understand the molecular mediators of this transformation pathway. This current study will give an update on how various molecular regulators are involved in these lineage transformation processes and what challenges we are still facing to detect and treat this cancer.

INSM1 expression in neuroendocrine tumors in a tertiary care hospital.

AIM: Neuroendocrine tumors are heterogenous group of neoplasms that includes benign and malignant tumors that originate from neuroendocrine or nonneuroendocrine organs. Insulinoma-associated protein 1 (INSM1) is a zinc finger transcription factor originally isolated from subtraction library of human insulinoma. The main aim was to study the INSM1 expression in a spectrum of neuroendocrine tumors and a limited spectrum of nonneuroendocrine tumors. MATERIALS AND METHODS: A total of 100 cases of which 57 neuroendocrine neoplasms and 43 nonneuroendocrine neoplasms were included in the study. Immunohistochemistry (IHC) was done and expression patterns of INSM1 were analyzed. Pituitary adenoma, medullary carcinoma of thyroid, pheochromocytoma lung, gastrointestinal, and pancreatic neuroendocrine tumors were the neuroendocrine tumors that were included in the study. Papillary carcinoma of thyroid, gastrointestinal adenocarcinoma, lung adenocarcinoma, and squamous cell carcinoma were the nonneuroendocrine tumors that were included in the study. Depending upon the tissue availability, comparison of INSM1 with synaptophysin and chromogranin was also done in few neuroendocrine tumors. RESULTS: All the 57 neuroendocrine tumors showed positive expression for INSM1 and all the nonneuroendocrine tumors were negative for INSM1. This study is statistically significant. CONCLUSION: Our study suggests that INSM1 is a diagnostic marker for neuroendocrine tumors with high degree of sensitivity and specificity. The study is significant and suggests that INSM1- IHC shows nuclear positivity in a spectrum of neuroendocrine tumors. Being a nuclear marker, interpretation is easy and more reliable than the cytoplasmic markers. INSM1 has a stronger positivity than synaptophysin and chromogranin in the present study especially for small cell carcinoma lung. Hence, INSM1 may be included in the routine panel for neuroendocrine tumors along with synaptophysin and chromogranin.

Neoadjuvant Capecitabine Plus Temozolomide in Atypical Lung NETs.

Neoadjuvant and adjuvant treatment in lung neuroendocrine tumors (NETs) is a field that has not been explored in-depth, with little information on the impact on disease-free survival. This case study highlights the effectiveness of neoadjuvant treatment with capecitabine plus temozolomide (CAPTEM) in a woman with well-differentiated atypical carcinoid. The patient was asymptomatic at diagnosis and was referred to the outpatient NET clinic at Sotiria Hospital in Athens, following an incidental finding on a chest x-ray. 18F-fluorodeoxyglucose (FDG) PET/CT and 68Ga-Dotatoc PET/CT revealed another mass in the pancreas, with avidity in both imaging studies. The patient underwent treatment for 6 months with CAPTEM with a response in the lung NET and mediastinal lymph nodes. However, the mass in the pancreas slightly increased and was removed with a central pancreatectomy. The patient continued treatment with CAPTEM for 6 more months. There was further response according to RECIST 1.1 criteria (partial response in the mediastinal lymph nodes and a 21% regression in the primary tumor size). Pathology report after lobectomy with lymph node dissection showed a pathologic complete response in the mediastinal lymph nodes. Twenty-four months after surgery, the patient remains disease-free and has a good quality of life. Although large clinical trials are needed, this case study underlines the value of preoperative chemotherapy in atypical carcinoids.

Gastroenteropancreatic neuroendocrine tumors in children and adolescents.

BACKGROUND: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare in children and adolescents. Standard management of these tumors has not been well established due to their rarity in this age group. We aimed to report the clinical and pathological characteristics of patients with this rare disease followed and treated between the years 1993-2022. MATERIALS AND METHODS: The medical records of patients with GEP-NETs were reviewed. RESULTS: Fourteen patients (11 girls, 3 boys) were diagnosed with GEP-NET. The median age was 13 (9-18) years. Tumor localization was the appendix in 12, stomach in one and pancreas in one patient. Mesoappendix invasion was detected in four patients two of whom underwent right hemicolectomy (RHC) and lymph node dissection (LND). Of those, one patient had lymph node involvement. The other two had not further operations. Somatostatin was used in one with pancreatic metastatic disease and the other with gastric disease after surgery. No additional treatment was given in other patients. All patients are under follow-up without evidence of disease at a median follow-up of 85 months (7-226 months). CONCLUSION: GEP-NETs should be considered in the differential diagnosis of acute appendicitis and in cases with persistent abdominal pain. In children, there is invariably a favorable prognosis, and additional surgical interventions other than simple appendectomies generally do not provide benefits. Mesoappendix invasion may not necessitate RHC and LND.

Enhancing precision: A predictive model for 177Lu-DOTATATE treatment response in neuroendocrine tumors using quantitative 68Ga-DOTATATE PET and clinicopathological biomarkers.

Purpose: This study aims to elucidate the role of quantitative SSTR-PET metrics and clinicopathological biomarkers in the progression-free survival (PFS) and overall survival (OS) of neuroendocrine tumors (NETs) treated with peptide receptor radionuclide therapy (PRRT). Methods: A retrospective analysis including 91 NET patients (M47/F44; age 66 years, range 34-90 years) who completed four cycles of standard 177Lu-DOTATATE was conducted. SSTR-avid tumors were segmented from pretherapy SSTR-PET images using a semiautomatic workflow with the tumors labeled based on the anatomical regions. Multiple image-based features including total and organ-specific tumor volume and SSTR density along with clinicopathological biomarkers including Ki-67, chromogranin A (CgA) and alkaline phosphatase (ALP) were analyzed with respect to the PRRT response. Results: The median OS was 39.4 months (95% CI: 33.1-NA months), while the median PFS was 23.9 months (95% CI: 19.3-32.4 months). Total SSTR-avid tumor volume (HR = 3.6; P = 0.07) and bone tumor volume (HR = 1.5; P = 0.003) were associated with shorter OS. Also, total tumor volume (HR = 4.3; P = 0.01), liver tumor volume (HR = 1.8; P = 0.05) and bone tumor volume (HR = 1.4; P = 0.01) were associated with shorter PFS. Furthermore, the presence of large lesion volume with low SSTR uptake was correlated with worse OS (HR = 1.4; P = 0.03) and PFS (HR = 1.5; P = 0.003). Among the biomarkers, elevated baseline CgA and ALP showed a negative association with both OS (CgA: HR = 4.9; P = 0.003, ALP: HR = 52.6; P = 0.004) and PFS (CgA: HR = 4.2; P = 0.002, ALP: HR = 9.4; P = 0.06). Similarly, number of prior systemic treatments was associated with shorter OS (HR = 1.4; P = 0.003) and PFS (HR = 1.2; P = 0.05). Additionally, tumors originating from the midgut primary site demonstrated longer PFS, compared to the pancreas (HR = 1.6; P = 0.16), and those categorized as unknown primary (HR = 3.0; P = 0.002). Conclusion: Image-based features such as SSTR-avid tumor volume, bone tumor involvement, and the presence of large tumors with low SSTR expression demonstrated significant predictive value for PFS, suggesting potential clinical utility in NETs management. Moreover, elevated CgA and ALP, along with an increased number of prior systemic treatments, emerged as significant factors associated with worse PRRT outcomes.

[Appendix ... it's not just appendicitis: neuroendocrine tumors.] / L'appendice... non è solo appendicite: i tumori neuroendocrini.

Well-differentiated neuroendocrine tumors of the appendix (NETs) are rare in pediatric and adolescent age groups. However, they are the most common gastrointestinal epithelial tumor in this age group and the most common malignancy of the appendix in the general population. The classification of these tumors considers factors such as the proliferation index, size of the neoplasm, and the presence of perineural and/or lymphovascular invasion, which can contribute to distant metastases. Preoperative diagnosis is challenging, except in cases where patients exhibit symptoms of carcinoid syndrome or signs of metastatic disease, which are uncommon in pediatric and adolescent patients. For tumors smaller than 1 cm, appendectomy is usually curative, while larger tumors or those at risk of spreading may require right hemicolectomy with lymphadenectomy. We present a case of an adolescent with NET and provide a literature review on the diagnostic and therapeutic approaches that should be considered for this relatively rare condition.Key words. Adolescent age, appendix, neuroendocrine tumors, pediatric age.

[Systemic treatment of patients with metastatic neuroendocrine Neoplasia]. / Systemtherapie von neuroendokrinen Neoplasien.

Due to the complexity and heterogeneity of metastatic NEN an interdisciplinary expert team should be involved in an individualized treatment strategy. SSA is the mainstay of antisecretory treatment in most functioning tumors. In antiproliferative intention SSA are first line treatment in receptor positive low proliferative NET. In intestinal metastatic disease PRRT is best established second line treatment. Further options are Everolimus (labeled) and tyrosine kinase inhibitors (off-label). Everolimus is the only approved drug for antiproliferative treatment in patients with metastatic lung NET, whereas in pancreatic NET more therapeutic options are available (SSA, chemotherapy, PRRT, Sunitinib, Everolimus) without a standard of best sequence. In patients with metastatic NEC standard first line treatment (platinum + etoposide) has not changed for decades and new treatment options for this fatal disease are urgently needed. Benefit of immunotherapy is limited to a small subset of patients - new combinations are under investigation. This review summarizes the standard of care, criteria of treatment selection and new developments for systemic therapy in patients with metastatic NEN.