Neuroendocrine Tumors of the Gastrointestinal Tract and Pancreas.Surg Pathol Clin. 2019;12:1021-1044. [PMID: 31672292 DOI: 10.1016/j.path.2019.08.007]

Prognostic value of neutrophil-lymphocyte ratio in gastroenteropancreatic neuroendocrine neoplasm: a systematic review and meta-analysis

Purpose

A high neutrophil-to-lymphocyte ratio (NLR) might be connected with an unfavorable tumor prognosis. We sought to conduct a meta-analysis of published studies exploring the prognostic value of NLR in patients with gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN).

Methods

We have referred to the PRISMA 2020 for the Abstracts checklist and have registered our review at the International Prospective Register of Systematic Reviews (registration number CRD42020187679). The PubMed, Embase, and Web of Science databases were screened using words like 'neutrophil to lymphocyte ratio', 'neuroendocrine tumors', and others up to July 2024. In our study, we evaluated the significance of NLR on overall survival (OS), recurrence-free survival (RFS), and progression-free survival (PFS) of patients with GEP-NEN. Subgroup analysis were conducted to identify the origins of heterogeneity and examine the impact of factor grouping.

Results

We gathered 18 cohorts with 2,995 cases. All included studies were high quality, with Newcastle Ottawa Scale (NOS) scores ranging from 6 to 8. The pooled analysis revealed that a higher NLR related to worse OS (hazard ratio (HR): 4.59, 95% confidence interval (CI) [3.35-6.29], p < 0.00001) and poor RFS (HR: 4.05, 95% CI [2.78-5.90], p < 0.00001) in patients with GEP-NEN. Subgroup analysis of race, tumor sites, and therapy showed good predictive significance, however, NLR is not effective in predicting the overall survival time of non-operative patients.

Conclusion

This meta-analysis showed that a high NLR predicted poor OS, RFS, and PFS in patients with GEP-NEN and can be used as a promising predictor.

Clinical and biological heterogeneity of Grade 2 digestive neuroendocrine neoplasms: prognostic significance of the 10% Ki-67 index cutoff and implications for treatment strategies. A longitudinal study

BACKGROUND

Digestive neuroendocrine neoplasms (NENs) encompass a heterogeneous group of tumors with varying prognoses and clinical behaviors. Grade 2 (G2) tumors, defined by a Ki-67 index between 3% and 20%, are particularly challenging to manage due to their intermediate and variable biological behavior. Evidence suggests a distinct prognosis between G2 digestive NENs with a Ki-67 index < 10% and those with a Ki-67 index ≥ 10%.

AIM

To investigate the clinical and biological heterogeneity between Grade 1 (G1) and G2 digestive NENs, and within G2 tumors, with a focus on the prognostic significance of a 10% Ki-67 index cutoff.

METHODS

This study involved a combined retrospective and prospective analysis of patients with low-grade G1 and G2 digestive NENs managed at IRCCS San Gerardo Hospital in Monza, Italy, between January 2000 and May 2024. Data on patient demographics, tumor characteristics, treatment modalities, and survival outcomes were collected and potential differences were analyzed between G1, G2 with Ki-67 index < 10% and G2 with Ki-67 index ≥ 10%.

RESULTS

Out of a total of 113 enrolled patients, 69 (61%) had G1 tumors, and 44 (39%) had G2 tumors. Median tumor size at diagnosis was 19 mm (IQR: 12-25 mm), with primary lesions mainly localized in the pancreas (57% among G1 and 45% among G2). Most G1 tumors were diagnosed at stage I (29 patients, 42%), while the majority of G2 tumors were metastatic at diagnosis (24 patients, 54.5%). Patients with G1 tumors exhibited a slightly higher 5-year OS rate compared to G2 tumors (98.1% vs. 92.8% respectively, though not statistically significant), and a significantly longer median PFS (141 vs. 22 months, p = 0.0003). Within the G2 group, 31 patients (70%) had a Ki-67 index < 10%, while 13 (30%) had a Ki-67 index ≥ 10%, with comparable baseline characteristics. A Ki-67 index < 10% was associated with a significantly better median PFS (38 vs. 8 months for tumors with Ki-67 index ≥ 10% G2 tumors, p = 0.002). PFS after first-line medical therapy was significantly longer in patients with a Ki-67 index < 10%, compared to those with ≥ 10% (undefined vs. 16 months, p = 0.0085), as well as median post-surgical PFS (84 vs. 10.5 months, p < 0.0001). Multivariate analysis identified higher tumor grade, advanced stage at diagnosis, and absence of PRRT as independent predictors of worse outcomes.

CONCLUSIONS

The findings highlight the significant clinical heterogeneity within G2 digestive NENs. A Ki-67 index cutoff of 10% within G2 tumors may serve as a critical prognostic marker, with patients with a Ki-67 index < 10% exhibiting significantly better outcomes in terms of PFS. These results suggest that the Ki-67 index could play an essential role in guiding treatment strategies, emphasizing the need for personalized approaches in managing G2 digestive NENs.

NET guidelines for white patients may not fit Asian patients

INTRODUCTION

Pancreatic neuroendocrine tumors (pNETs) are slow growing, malignant tumors that show different survival outcomes by race. Current size-based guidelines were largely developed in White patients. Our aim was to investigate tumor size and incidence of lymph node metastasis (LNM) between White and Asian pNET patients to evaluate generalizability of established guidelines.

METHODS

Using the National Cancer Database (NCDB), we conducted a multi-institutional analysis of patients with low grade, resected, nonfunctional, sporadic, non-metastatic pNETs. Chi-squared tests were implemented to determine correlation between PTS and LMN incidence as well as race and LMN incidence. A logistic regression model was utilized to determine correlation between LMN, tumor size, and race. Overall survival was assessed using the Kaplan-Meier method.

RESULTS

A total of 4977 pNET patients (205 Asian and 4772 White) were included in our analysis. Asian patients presented with smaller tumors (3.0 ​cm vs 3.9 ​cm, p ​= ​0.029) but when grouped by size, there was no difference in the distribution (p ​= ​0.77). White patients demonstrated a higher incidence of lymph node metastasis at presentation compared to Asian patients (27 ​% vs 19 ​%, p ​= ​0.013), a higher likelihood of an R0 resection (95.3 ​% vs. 89.3 ​%, p ​< ​0.0001). Within both populations, tumor size (<2 ​cm, 2-3 ​cm, and ≥3 ​cm) positively correlated with incidence of LNM (11.5 ​%, 24.6 ​%, and 39.1 ​%). No difference of LNM was seen between racial cohorts at PTS <3 ​cm, however, Asian patients were less likely to exhibit LNM at PTS ≥3 ​cm (28.2 ​% and 39.5 ​%, p ​= ​0.04). Overall survival was not significantly different between racial groups (p ​= ​0.92).

CONCLUSION

Size based surgical resection guidelines for pancreatic neuroendocrine tumors based on a predominantly White patient population may not be generalizable to the Asian population. Within this population, we found the risk of lymph node metastasis did not increase at similar rates with increasing primary tumor size.

Epidemiology, treatment and outcomes of gastroenteropancreatic neuroendocrine neoplasms

To investigate incidence, treatment patterns and outcomes of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) in the United States. The 2019 National Cancer Database was searched for adult GEP-NEN patients. Main outcomes included overall and site-specific incidence, treatment patterns, and overall survival (OS). Overall survival was evaluated using averaged Cox regression. 86,324 GEP-NEN patients were included (6.33% of all GEP malignancies). From 2004 to 2016, annual GEP-NEN cases increased (n = 4,010 to n = 9,379), largely driven by low-stage, low-grade disease. Most patients received surgery, either alone (72.9%) or in combination with systemic therapy (4.9%). Longest overall survival (OS) was evident in patients with low stage and low grade GEP-NEN of the small intestine and rectum (p < 0.001). Patients undergoing surgical resection demonstrated longest OS. The addition of systemic therapy was most effective in high stage G3 NEN. Having higher income (≥$63,333) and private insurance or Medicare, but not Medicaid, was associated with improved survival. GEP-NEN incidence increases, likely due to improved detection and diagnosis. Treatment patterns have evolved to follow the latest international guidelines and site-specific improvement in survival is noted. In addition to disease specific factors, insurance access and socioeconomic factors emerged as potential targets for improving outcomes.

Modern Management of Gastric Neuroendocrine Neoplasms

OPINION STATEMENT

Gastric neuroendocrine neoplasms (G-NENs) are a heterogeneous group of tumors that broadly fall into two groups. The first group, driven by oversecretion of gastrin, are generally multifocal, small, and behave indolently with a low (but non-zero) risk of progression and metastatic spread. They are conventionally categorized into type 1, with endogenous gastric-based overproduction of gastrin, and type 2 G-NEN, with overproduction of gastrin from an extra-gastric gastrin-secreting tumor. The second group, termed type 3 G-NEN, occur spontaneously and are potentially more aggressive, having a clinical course analogous to other neuroendocrine tumors of the gastrointestinal tract. Type 1 G-NEN can be managed with endoscopic surveillance and resection of visible lesions with great success, reserving surgery for the rare high-risk lesion, whereas surgical resection of the causative gastrin-secreting tumor in type 2 G-NEN is usually curative. Type 3 G-NEN is usually managed with formal surgical resection but there is growing evidence that limited surgery or even endoscopic resection in appropriately selected patients with low risk is both safe and effective. A novel subtype of G-NEN, associated with long-term proton pump inhibitor usage, is increasing in incidence. The pathophysiology seems to parallel type 1 G-NEN. In the setting of metastatic disease, which can occur in any subtype but is most common by far in type 3 G-NEN, the lack of trial data unique to G-NEN results in extrapolation of strategies and agents for treatment of non-gastric neuroendocrine disease. The rapid pace of development in this area is likely to benefit the metastatic G-NEN patient as well. As treatment is predicate on type of G-NEN, establishing the etiology of the lesion is crucial but growing knowledge of G-NEN pathophysiology and close collaboration between pathologists, gastroenterologists, radiologists, surgeons, and oncologists have enabled a growing trend towards de-escalation and less-invasive treatment paradigms.

Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience

INTRODUCTION

Well-differentiated neuroendocrine tumors of the appendix (A-WDNET) are the most common neoplasms of the appendix but are rare and incidental. INSM1 is a novel transcription factor marker with high sensitivity and specificity for neuroendocrine differentiation. It may display architecturally diverse tumor growth patterns including solid, nest, insular trabecular, and acinar.

AIMS

The aim of this study was to determine the staining expression of INSM1 in A-WDNETs and detail the morphological tumor growth patterns.

MATERIALS AND METHODS

INSM1 immunohistochemistry was performed on 35 A-WDNET patients. Tumors were histologically classified according to their growth patterns.

RESULTS

Thirty-five patients, 60% of whom were male, had a mean age of 30 years at diagnosis and a mean tumor size of 0.9 cm. Eight percent of the tumors invaded the mucosa/submucosa, 34.3% showed invasion into the muscularis propria, 57.1% showed invasion into the subserosa or mesoappendix, LN metastasis was observed in two patients, lymph-vascular invasion in two patients, and perineural invasion in five patients. Ninety-four percent of the tumors were grade 1, the mitotic rate was >2% in two cases, and Ki-67 PI was >3% in two cases. INSM1 was positive in all cases (100%), 1+ 8.6%, 2+ 5.7%, 3+ 17.1%, 4+ 68.6%, weak staining in 11.4%, moderate staining in 22.9%, and strong staining in 67.7%. Type A histological growth pattern was observed in 54.3%, type B in 31.4%, and type C in 14.3% architecturally.

CONCLUSIONS

INSM1 was positive in all A-WDNET morphological patterns and was 100% sensitive. INSM1 IHC can be used as an alternative to traditional neuroendocrine markers or in combination with the diagnosis of neuroendocrine tumors.

Small Cell Carcinoma of the Rectum Associated With a Tubulovillous Adenoma: An Atypical Case Presentation

Small cell carcinoma of the rectum (SCCR) is a rare and aggressive neuroendocrine tumor. Its association with a tubulovillous adenoma is an exceptional occurrence, presenting significant implications for diagnosis and treatment. This case report details a 62-year-old male, undergoing treatment for hepatocellular carcinoma, presented with symptoms of diarrhea. A colonoscopy initially suggested a benign tubulovillous adenoma, but the presence of discordant clinical findings led to further evaluation. The final diagnosis, established post-surgery, was SCCR originating from a tubulovillous adenoma. This case highlights the diagnostic challenges when unusual presentations arise from atypical pathological findings, especially in patients with concurrent malignancies. The management followed standard care protocols, including robotic transanal surgery, despite the patient's ongoing HCC treatment. This case adds to the limited existing literature on SCCR, particularly its rare association with a tubulovillous adenoma. It emphasizes the importance of a multi-disciplinary approach in diagnosing and managing rare entities in colorectal cancer while demonstrating the feasibility of standard care in patients with complex comorbidities.

Radiation Exposure from GEP NET Surveillance

BACKGROUND

Neuroendocrine tumors (NET) are neoplasms that secrete peptides and neuroamines. For gastroenteropancreatic (GEP) NET, surgical resection represents the only curative option. Ten-year imaging surveillance programs are recommended due to long time-to-recurrence following resection. We performed retrospective chart review evaluating radiation exposure and practice patterns from surveillance of completely resected GEP NET.

METHODS

We performed a retrospective cohort study of cases with well-differentiated GEP NET from January 2005 to July 2020. Location of primary, modality of imaging, and duration of follow-up were collected. Dosimetry data was collected to calculate effective dose.

RESULTS

62 cases were included with 422 surveillance scans performed. Cross-sectional imaging was used in 82% and functional imaging was used in 18% of scans. Mean number of scans per year was 1.25 (0.42-3). Mean total effective dose was 56.05 mSv (SD 45.56; 0 to 198 mSv) while mean total effective dose per year was 10.62 mSv (SD 9.35; 0 to 45 mSv). Over the recommended ten years of surveillance the estimated total effective dose was 106 mSv.

CONCLUSIONS

Surveillance of completely resected GEP NET results in cumulative radiation doses in the range associated with secondary malignancy development. Strategies to minimize radiation exposure in surveillance should be considered in future guideline development.

GASTRIC NEUROENDOCRINE TUMOR: WHEN SURGICAL TREATMENT IS INDICATED?

BACKGROUND

Gastric neuroendocrine tumors are a heterogeneous group of neoplasms that produce bioactive substances. Their treatment varies according to staging and classification, using endoscopic techniques, open surgery, chemotherapy, radiotherapy, and drugs analogous to somatostatin.

AIMS

To identify and review cases of gastric neuroendocrine neoplasia submitted to surgical treatment.

METHODS

Review of surgically treated patients from 1983 to 2018.

RESULTS

Fifteen patients were included, predominantly female (73.33%), with a mean age of 55.93 years. The most common symptom was epigastric pain (93.3%), and the mean time of symptom onset was 10.07 months. The preoperative upper digestive endoscopy (UDE) indicated a predominance of cases with 0 to 1 lesion (60%), sizing ≥1.5 cm (40%), located in the gastric antrum (53.33%), with ulceration (60%), and Borrmann III (33.33%) classification. The assessment of the surgical specimen indicated a predominance of invasive neuroendocrine tumors (60%), with angiolymphatic invasion in most cases (80%). Immunohistochemistry for chromogranin A was positive in 60% of cases and for synaptophysin in 66.7%, with a predominant Ki-67 index between 0 and 2%. Metastasis was observed in 20% of patients. The surgical procedure most performed was subtotal gastrectomy with Roux-en-Y reconstruction (53.3%). Tumor recurrence occurred in 20% of cases and a new treatment was required in 26.67%.

CONCLUSIONS

Gastric neuroendocrine tumors have a low incidence in the general population, and surgical treatment is indicated for advanced lesions. The study of its management gains importance in view of the specificities of each case and the need for adequate conduct to prevent recurrences and complications.

Prognostic Implications of PET-Derived Tumor Volume and Uptake in Patients with Neuroendocrine Tumors

Historically, molecular imaging of somatostatin receptor (SSTR) expression in patients with neuroendocrine tumors (NET) was performed using SSTR scintigraphy (SRS). Sustained advances in medical imaging have led to its gradual replacement with SSTR positron-emission tomography (SSTR-PET). The higher sensitivity in comparison to SRS on the one hand and conventional cross-sectional imaging, on the other hand, enables more accurate staging and allows for image quantification. In addition, in recent years, a growing body of evidence has assessed the prognostic implications of SSTR-PET-derived prognostic biomarkers for NET patients, with the aim of risk stratification, outcome prognostication, and prediction of response to peptide receptor radionuclide therapy. In this narrative review, we give an overview of studies examining the prognostic value of advanced SSTR-PET-derived (semi-)quantitative metrics like tumor volume, uptake, and composite metrics. Complementing this analysis, a discussion of the current trends, clinical implications, and future directions is provided.

Gastric neuroendocrine neoplasms: a primer for radiologists

Gastric neuroendocrine neoplasms are uncommon tumors with variable differentiation and malignant potential. Three main subtypes are recognized: type 1, related to autoimmune atrophic gastritis; type 2, associated with Zollinger-Ellison and MEN1 syndrome; and type 3, sporadic. Although endoscopy alone is often sufficient for diagnosis and management of small, indolent, multifocal type 1 tumors, imaging is essential for evaluation of larger, high-grade, and type 2 and 3 neoplasms. Hypervascular intraluminal gastric masses are typically seen on CT/MRI, with associated perigastric lymphadenopathy and liver metastases in advanced cases. Somatostatin receptor nuclear imaging (such as Ga-68-DOTATATE PET/CT) may also be used for staging and assessing candidacy for peptide receptor radionuclide therapy. Radiotracer uptake is more likely in well-differentiated, lower-grade tumors, and less likely in poorly differentiated tumors, for which F-18-FDG-PET/CT may have additional value. Understanding disease pathophysiology and evolving histologic classifications is particularly useful for radiologists, as these influence tumor behavior, preferred imaging, therapy options, and patient prognosis.

Time to give up traditional methods for the management of gastrointestinal neuroendocrine tumours

Neuroendocrine tumors (NETs) are a rare and heterogeneous disease group and constitute 0.5% of all malignancies. The annual incidence of NETs is increasing worldwide. The reason for the increase in the incidence of NETs is the detection of benign lesions, incidental detection due to the highest use of endoscopic and imaging procedures, and higher recognition rates of pathologists. There have been exciting developments regarding NET biology in recent years. Among these, first of all, somatostatin receptors and downstream pathways in neuroendocrine cells have been found to be important regulatory mechanisms for protein synthesis, hormone secretion, and proliferation. Subsequently, activation of the mammalian target of rapamycin pathway was found to be an important mechanism in angiogenesis and tumor survival and cell metabolism. Finally, the importance of proangiogenic factors (platelet-derived growth factor, vascular endothelial growth factor, fibroblastic growth factor, angiopoietin, and semaphorins) in the progression of NET has been determined. Using the combination of biomarkers and imaging methods allows early evaluation of the appropriateness of treatment and response to treatment.

Added Value of Tomoelastography for Characterization of Pancreatic Neuroendocrine Tumor Aggressiveness Based on Stiffness

Simple Summary

The prediction of pancreatic neuroendocrine tumor (PNET) aggressiveness is important for treatment planning. The aim of this study was to evaluate the diagnostic performance of magnetic resonance elastography (MRE) with tomoelastography postprocessing (tomoelastography) in differentiating PNET from healthy pancreatic tissue and to correlate PNET stiffness with aggressiveness using asphericity derived from positron emission tomography (PET) as reference. In this prospective study we showed in a group of 13 patients with PNET that tomoelastography detected PNET by increased stiffness (p < 0.01) with a high diagnostic performance (AUC = 0.96). PNET was positively correlated with PET derived asphericity (r = 0.81). Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness.

Abstract

Purpose: To evaluate the diagnostic performance of tomoelastography in differentiating pancreatic neuroendocrine tumors (PNETs) from healthy pancreatic tissue and to assess the prediction of tumor aggressiveness by correlating PNET stiffness with PET derived asphericity. Methods: 13 patients with PNET were prospectively compared to 13 age-/sex-matched heathy volunteers (CTR). Multifrequency MR elastography was combined with tomoelastography-postprocessing to provide high-resolution maps of shear wave speed (SWS in m/s). SWS of pancreatic neuroendocrine tumor (PNET-T) were compared with nontumorous pancreatic tissue in patients with PNET (PNET-NT) and heathy pancreatic tissue (CTR). The diagnostic performance of tomoelastography was evaluated by ROC-AUC analysis. PNET-SWS correlations were calculated with Pearson’s r. Results: SWS was higher in PNET-T (2.02 ± 0.61 m/s) compared to PNET-NT (1.31 ± 0.18 m/s, p < 0.01) and CTR (1.26 ± 0.09 m/s, p < 0.01). An SWS-cutoff of 1.46 m/s distinguished PNET-T from PNET-NT (AUC = 0.89; sensitivity = 0.85; specificity = 0.92) and a cutoff of 1.49 m/s differentiated pancreatic tissue of CTR from PNET-T (AUC = 0.96; sensitivity = 0.92; specificity = 1.00). The SWS of PNET-T was positively correlated with PET derived asphericity (r = 0.81; p = 0.01). Conclusions: Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness.

Tumor neuroendocrino en recto simulando una neoplasia benigna: reporte de caso y revisión de la literatura

Los tumores neuroendocrinos se definen como un grupo heterogéneo de neoplasias de origen epitelial, provenientes de células enterocromafines diseminadas por todo el organismo, y representan alrededor del 1 al 4 % de todas las neoplasias. Su mayor distribución se encuentra en el tracto gastrointestinal, donde se localiza el 75 % de los tumores neuroendocrinos, siendo los ubicados en el recto, el 27 % de todos los que afectan el tracto gastrointestinal. A propósito de esta revisión de tema, presentamos el caso de un paciente de 71 años de edad, que consultó por sangrado rectal rojo rutilante, sin otra sintomatología asociada, y se le diagnosticó un tumor neuroendocrino grado 1, que se comportaba como una lesión benigna del recto.

Endoscopic Treatment of Gastric and Duodenal Neuroendocrine Tumors: Present and Future

Gastric and duodenal neuroendocrine tumors (NETs) are not common; however, there is an increase in the incidence due to increased use of endoscopy. Endoscopic treatment has been applied to treat small NET G1 in the stomach and duodenum. For the endoscopic treatment of NETs, it is necessary to evaluate tumor size, depth of invasion, and lymphatic and distant metastasis. This article will review the current knowledge concerning the endoscopic treatment of gastric and duodenal neuroendocrine tumors.

Radiology of the neuroendocrine neoplasms of the gastrointestinal tract: a comprehensive review

Neuroendocrine neoplasms (NENs) are a group of neoplasms arising from the diffuse endocrine system (DES). The gastrointestinal tract (GIT) is the most common site of NEN. The WHO classification divides NEN into three broad categories viz. well-differentiated NENs, poorly differentiated NENs, and mixed neuroendocrine-non-neuroendocrine neoplasms. All GIT NEN have the potential to synthesize and secrete various bioactive substances which may lead to various clinical syndromes. The NEN may occur anywhere in the GIT and exhibit varying clinical presentation, prognosis, and metastatic potential. Further, some tumors show association with familial syndromes like multiple endocrine neoplasia type 1 and neurofibromatosis type 1. Ultrasonography, computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT are the imaging modalities useful in the diagnosis, localization, and staging of GIT NEN. Management depends on the site, size, grade, and stage of the tumor with interventional radiology playing a significant role in some cases. This imaging review describes the role of a radiologist in the management of GIT NEN.

MRI-based radiomics approach for differentiation of hypovascular non-functional pancreatic neuroendocrine tumors and solid pseudopapillary neoplasms of the pancreas

BACKGROUND

This study aims to investigate the value of radiomics parameters derived from contrast enhanced (CE) MRI in differentiation of hypovascular non-functional pancreatic neuroendocrine tumors (hypo-NF-pNETs) and solid pseudopapillary neoplasms of the pancreas (SPNs).

METHODS

Fifty-seven SPN patients and twenty-two hypo-NF-pNET patients were enrolled. Radiomics features were extracted from T1WI, arterial, portal and delayed phase of MR images. The enrolled patients were divided into training cohort and validation cohort with the 7:3 ratio. We built four radiomics signatures for the four phases respectively and ROC analysis were used to select the best phase to discriminate SPNs from hypo-NF-pNETs. The chosen radiomics signature and clinical independent risk factors were integrated to construct a clinic-radiomics nomogram.

RESULTS

SPNs occurred in younger age groups than hypo-NF-pNETs (P < 0.0001) and showed a clear preponderance in females (P = 0.0185). Age was a significant independent factor for the differentiation of SPNs and hypo-NF-pNETs revealed by logistic regression analysis. With AUC values above 0.900 in both training and validation cohort (0.978 [95% CI, 0.942-1.000] in the training set, 0.907 [95% CI, 0.765-1.000] in the validation set), the radiomics signature of the arterial phase was picked to build a clinic-radiomics nomogram. The nomogram, composed by age and radiomics signature of the arterial phase, showed sufficient performance for discriminating SPNs and hypo-NF-pNETs with AUC values of 0.965 (95% CI, 0.923-1.000) and 0.920 (95% CI, 0.796-1.000) in the training and validation cohorts, respectively. Delong Test did not demonstrate statistical significance between the AUC of the clinic-radiomics nomogram and radiomics signature of arterial phase.

CONCLUSION

CE-MRI-based radiomics approach demonstrated great potential in the differentiation of hypo-NF-pNETs and SPNs.

Soluble Urokinase Plasminogen Activator Receptor (suPAR) Concentrations Are Elevated in Patients with Neuroendocrine Malignancies

Neuroendocrine neoplasia (NEN) comprises heterogeneous tumors that are challenging to diagnose and, especially in cases of poorly differentiated (G3) NEN, are associated with very limited survival. Novel biomarkers allowing an early diagnosis as well as an optimal selection of suitable treatment options are urgently needed to improve the outcome of these patients. Recently, alterations of soluble urokinase-type plasminogen activator receptor (suPAR) serum levels were described in various types of cancers. However, the role of circulating suPAR as a biomarker in patients with NEN is unknown. In this study, we measured suPAR serum levels in a large and well-characterized cohort of 187 patients with NEN (neuroendocrine carcinomas (NEC) n = 30; neuroendocrine tumors (NET), n = 157) as well as 44 healthy controls. suPAR concentrations were significantly elevated in patients compared to controls. However, suPAR concentrations were independent of tumor-related factors such as the proliferation activity according to Ki-67, tumor grading, TNM (TNM classification of malignant tumors) stage, somatostatin receptor expression or clinical features such as functional or nonfunctional disease and the presence of tumor relapse. Interestingly, suPAR concentrations in NET patients were similar when compared to those measured in NEC patients. In contrast to previous results from other malignancies, in our analysis suPAR levels were not a significant predictor of overall survival. In conclusion, our data suggests that suPAR serum concentrations are elevated in NEN patients but do not allow prediction of outcome.