NET G1 Research Articles

Spectrum of neuroendocrine neoplasms of GIT – a histomorphological study in a tertiary care centre

Background. Neuroendocrine neoplasms are diverse in terms of sites of origin, functional status, and degrees of aggressiveness. Since neuroendocrine cells are ubiquitous in the human body, these neoplasms can arise in different organs, with gastrointestinal tract being most frequently involved. The past few years have seen a surge in the diagnosis of these neoplasms, which were earlier considered to be rare. Their nomenclature, classification, and diagnostic criteria are revamped frequently, as new knowledge emerges. Aim. To study the histopathological spectrum of neuroendocrine neoplasms of gastrointestinal tract and assess the immunohistochemical expression of neuroendocrine markers in them. Material and methods. Ours is a descriptive study of the distribution and pathologic characteristics of gastrointestinal neuroendocrine neoplasms in a tertiary care hospital in Kerala, over a three year period. Neoplasms were categorised based on 2019 updated WHO classification. Results. Among the 59 cases, we observed a male predominance. (Male to female ratio - 1.8:1). Most patients were in 6th and 7th decades of life. Duodenum was most frequently involved followed by rectum and appendix. NET G2 and G1 constituted the predominant histologic grades (47% and 24% respectively). NEC and MiNEN were infrequent. All cases were positive for synaptophysin, with variable positivity for chromogranin. Ki67 helped establish the histologic grade. We also came across a rare case of neuroendocrine tumor with coexisting mucinous neoplasm in appendix. Conclusions. With evolving knowledge and advanced imaging modalities, the incidence of these neoplasms is increasing with time. Histopathology is the mainstay of diagnosis and plays a decisive role in influencing management protocols and prognosis.

NET G3 vs NEC: p53 and Rb1 Immunolabeling in High-grade Gastrointestinal Neuroendocrine Neoplasms - Is It Enough for the Differential Diagnosis?

High-grade gastrointestinal neuroendocrine neoplasms (GI-NENs) are divided into well-differentiated G3 neuroendocrine tumors (NETs G3) and neuroendocrine carcinomas (NECs), having identical cut-offs of proliferation, but different biomolecular origins. This translates in distinct treatment choices. Our aim was to establish if p53/Rb1 immunohistochemical status in GI-NENs with Ki67 index >20% can predict the histopathological diagnosis. p53/Rb1 immunolabelling was performed on 42 cases of high-grade GI-NENs, diagnosed as NET G3, NEC and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) with NEC component. Immunolabeled slides were digitally scanned, with automatic quantification of p53 and Rb1, blind to the diagnosis. The p53 positive percentage was stratified; two cut-offs were selected, naming the intervals as N (null, <1%), T (tumor, 1%-20%) and C (carcinoma, >20%). The Rb1 expression loss in >90% of neoplastic cells was considered mutational. NETs G3 mainly showed the T status (14/16, 87.5%), followed by N (1/16, 6.25%) and C (1/16, 6.25%); NECs and NEC components in MiNENs predominantly expressed the C status (19/26, 73.08%), followed by N (5/26, 19.23%) and T (2/26, 7.69%) (p<0.001, χ 2 =27.017). NET G3s showed positive expression for Rb1; 73.08% of NECs expressed negative Rb1 (p<0.001, χ 2 =21.351). NECs and NEC components in MiNENs showed Rb1 mutational status in 13 C cases (13/19, 68.42%), 4 N cases (4/5, 80%) and in both the T cases (p=0.002, χ 2 =11.187). Our results highlight the correlations between the p53/Rb1 immunostainings and the histopathological diagnosis of high-grade GI-NENs. NECs and NEC components in MiNENs showed a p53 mutational status (0% or 21-100%) and predominantly negative Rb1 expression. NETs G3 showed a p53 wild-type status (1-20%) and retained Rb1 expression. These findings suggest that the differential diagnosis of high-grade GI-NENs may benefit from p53/Rb1 immunohistochemical tests in everyday practice.

Oxaliplatin based chemotherapy for advanced well-differentiated neuroendocrine tumors: A systematic review and meta-analysis.

e16240 Background: Currently, chemotherapy is predominantly considered in advanced well-differentiated neuroendocrine tumors (NENs) with high ki67 proliferation index and tumor burden. So far, no standard regimen is available and alkylating agents alone, such as temozolomide or in combination with 5-fluorouracil or capecitabine are widely used. Besides, oxaliplatin based chemotherapy has shown promising antitumor activity without being influenced by the MGMT status. In the current SRMA, we aim to address the efficacy of oxaliplatin based chemotherapy in advanced well differentiated NENs. Methods: We conducted a systematic database search using PubMed/MEDLINE and EMBASE. Eligible studies included randomized and single-arm trials, prospective observational and retrospective studies documenting the clinical efficacy of oxaliplatin based chemotherapy for advanced well-differentiated NENs. The pooled overall response rate (ORR), median progression-free survival (PFS), and median overall survival (OS) were calculated and weighted using generic inverse variance in a random-effects model, as well as subgroup analysis for pts with pancreatic NETs (pNETs) and extra-pancreatic NETs (epNETs), G1-2 and G3 NETs. Results: 14 of 24 identified publications were included with a combined total of 865 patients in 3 phase II trial and 11 retrospective studies. 495 pts received FOLFOX, 155 pts XELOX, 130 pts GEMOX and 138 pts plus bevacizumab. 48.4% (419/865) patients were pNETs, and G3 NETs accounted for 21.7% (188/865). The pooled ORR was 27.9% (237/865, 95% CI: 23.2-32.5). pNETs showed much higher ORRs (37.7%,114/303, 95% CI: 31.1-44.3) than epNETs (14.9%, 40/251, 95% CI: 10.5-19.2), χ2 = 32.17, p &lt; 0.001. ORRs in G1-2 NETs was 23.1% (66/273, 95% CI: 18.2-28.1), while in G3 NETs was 45.7% (42/85, 95% CI: 29.7-61.6), χ2 = 19.60, p &lt; 0.001. FOLFOX plus bevacizumab showed a higher ORR (38.3%, 38/98, 95% CI: 28.8-47.9) than the oxaliplatin based regimens without bevacizumab (26.9%, 166/594, 95% CI: 23.4-30.4), χ2 = 4.745, p = 0.029. The median PFS in pNETs was 8.1 months (n = 247, 95% CI: 6.3-9.9), similar to 8.4 months in epNETs (n = 211, 95% CI 5.7-11.2). The median PFS in G1-G2 and G3 NET was 13.4 months (95% CI 9.1-17.6) and 7.1 months (95% CI 4.1-9.6) respectively. Besides, FOLFOX plus bevacizumab also showed a trend of a longer PFS (12.4months, 95% CI 9.5-15.2) than those without bevacizumab (7.6months, 95% CI 6.8-8.3). The pooled median overall survival was 28.8months (95% CI 26.7-30.9). Conclusions: Among the advanced well-differentiated neuroendocrine tumors, oxaliplatin based chemotherapy alone or plus bevacizumab could be a good alternative regimen, especially in pts with pNETs and G3 NETs.

Sigmoid colon schwannoma difficult to distinguish from peritoneal dissemination 13 years after pancreatic neuroendocrine tumor surgery

BackgroundSchwannoma, which clinicians sometimes struggle to diagnose, is a tumor arising from Schwann cells of peripheral nerves, often in the soft tissues and rarely in the gastrointestinal tract. Pancreatic neuroendocrine tumor (PNET) is rare among pancreatic tumors, and recurrence can occur long after resection. Here, we were presented with a case where a sigmoid colon schwannoma was difficult to distinguish from a postoperative recurrence of PNET and was diagnosed after laparoscopic resection.Case presentationA 51-year-old man was diagnosed with PNET (NET G2) after a distal pancreatectomy (DP) 13 years ago. The patient underwent hepatectomy due to liver metastasis 12 years after initial radical surgery. The follow-up magnetic resonance imaging (MRI) after hepatectomy showed pelvic nodules, and laparoscopic surgery was performed for both diagnosis and treatment because peritoneal dissemination of PNET could not be ruled out. Since the tumor was in the sigmoid colon, a partial colon resection was performed. The histopathological diagnosis was a schwannoma, and the patient was discharged on the seventh postoperative day.ConclusionsWe experienced a case of sigmoid colon schwannoma that was difficult to differentiate from peritoneal dissemination of PNET and was later diagnosed after laparoscopic resection. In addition, this case involved a long-term postoperative recurrence of PNET that was amenable to radical resection, further establishing the importance of long-term imaging follow-up.

Long-term organoid culture of a small intestinal neuroendocrine tumor.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare and highly heterogeneous neoplasms whose incidence has markedly increased over the last decades. A grading system based on the tumor cells' proliferation index predicts high-risk for G3 NETs. However, low-to-intermediate grade (G1/G2) NETs have an unpredictable clinical course that varies from indolent to highly malignant. Cultures of human cancer cells enable to perform functional perturbation analyses that are instrumental to enhance our understanding of cancer biology. To date, no tractable and reliable long-term culture of G1/G2 NET has been reported to permit disease modeling and pharmacological screens. Here, we report of the first long-term culture of a G2 metastatic small intestinal NET that preserves the main genetic drivers of the tumor and retains expression patterns of the endocrine cell lineage. Replicating the tissue, this long-term culture showed a low proliferation index, and yet it could be propagated continuously without dramatic changes in the karyotype. The model was readily available for pharmacological screens using targeted agents and as expected, showed low tumorigenic capacity in vivo. Overall, this is the first long-term culture of NETs to faithfully recapitulate many aspects of the original neuroendocrine tumor.

Baseline tumor growth rate highlights the heterogeneity of well differentiated gastroenteropancreatic neuroendocrine tumors and predicts for increases in Ki67 index over time.

Refined risk stratification for gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has the potential to improve comparisons of study populations across clinical trials and facilitate drug development. Tumor growth rate (TGR) is a radiological metric with demonstrated prognostic value in well differentiated grade 1 and 2 (G1-2) GEP-NETs, but little is known about TGR in G3 NETs. In this retrospective study of 48 patients with advanced G1-3 GEP-NET, we calculated baseline TGR (TGR0 ) from radiological images of metastases acquired prior to first-line therapy and evaluated its association with disease characteristics and outcomes. The median pretreatment Ki67 proliferation index for G1-3 tumors combined was 5% (range = 0.1%-52%) and median TGR0 was 4.8%/month (m) (range = 0%-45.9%/m). TGR0 correlated with pretreatment Ki67 across G1-3 pooled and within G3 GEP-NET. Patients with higher TGR0 (>11.7%/m) tumors, which were primarily G3 pancreatic NETs, exhibited decreased time to first therapy (median, 2.2 vs. 5.3 months; p = .03) and shorter overall survival (median, 4.1 years vs. not reached; p = .003). Independent of therapies given, higher TGR0 GEP-NETs experienced a greater incidence of Ki67 increase (100 vs. 50%; p = .02) and greater magnitude of Ki67 change (median, 14.0 vs. 0.1%; p = .04) upon serial biopsy. Importantly, TGR0 , but not grade, predicted for future Ki67 increase in this series. Given the heterogeneity of well differentiated GEP-NETs, future clinical trials may benefit from stratification for TGR0 , particularly in G1-2 tumors, in which TGR0 does not correlate with Ki67. TGR0 has the potential to noninvasively identify patients with previously undiagnosed grade progression and those in whom more or less frequent monitoring may be appropriate. Additional research is needed to determine the prognostic and predictive value of TGR0 in larger and more homogeneously treated cohorts, and to ascertain if post-treatment TGR has value in previously treated patients starting a new line of therapy.

Partial Response Upon Peptide Receptor Radionuclide Therapy in a Highly Proliferative Pancreatic Neuroendocrine Tumor.

We report on a patient diagnosed with an aggressive pancreatic neuroendocrine tumor (NET G3; Ki67 = 60%), who underwent pancreatic resection with partial removal of liver lesions. The patient refused chemotherapy. Dual-tracer imaging with 18 F-FDG and somatostatin receptor (SSTR)-targeted PET/CT was conducted. Radiotracer accumulation on both imaging modalities in bilobar hepatic lesions was observed. "Cold" somatostatin analogues with four cycles of peptide receptor radionuclide therapy (PRRT) were initiated, leading to partial response. Even in highly proliferative but differentiated G3 NET (Ki67>55%), SSTR expression in sites of disease should be evaluated, which may then allow PRRT, even as first-line systemic treatment.

Well-differentiated gastro-entero-pancreatic neuroendocrine tumors with positive FDG-PET/CT: a retrospective chart review.

Rarely, well-differentiated gastro-entero-pancreatic neuroendocrine tumors (GEP NETs) can have positive uptake on 18F-fluorodeoxyglucose-PET/computerized tomography ( 18 F-FDG-PET/CT), with or without a positive 68 Ga-PET/CT. We aim to evaluate the diagnostic role of 18 F-FDG-PET/CT in patients with well-differentiated GEP NETs. We retrospectively reviewed a chart of patients diagnosed with GEP NETs between 2014 and 2021, at the American University of Beirut Medical Center, who have low (G1; Ki-67 ≤2) or intermediate (G2; and Ki-67 >2-≤20) well-differentiated tumors with positive findings on FDG-PET/CT. The primary endpoint is progression-free survival (PFS) compared to historical control, and the secondary outcome is to describe their clinical outcome. In total 8 out of 36 patients with G1 or G2 GEP NET met the inclusion criteria for this study. The median age was 60 years (range 51-75 years) and 75% were male. One patient (12.5%) had a G1 tumor whereas 7 (87.5%) had G2, and seven patients were stage IV. The primary tumor was intestinal in 62.5% of the patients and pancreatic in 37.5%. Seven patients had both 18 F-FDG-PET/CT and 68 Ga-PET/CT positive and one patient had a positive 18 F-FDG-PET/CT and negative 68 Ga-PET/CT. Median and mean PFS in patients positive for both 68 Ga-PET/CT and 18 F-FDG-PET/CT were 49.71 months and 37.5 months (95% CI, 20.7-54.3), respectively. PFS in these patients is lower than that reported in the literature for G1/G2 NETs with positive 68 Ga-PET/CT and negative FDG-PET/CT (37.5 vs. 71 months; P = 0.0217). A new prognostic score that includes 18 F-FDG-PET/CT in G1/G2 GEP NETs could identify more aggressive tumors.

Establishment and validation of a nomogram for predicting prognosis of gastric neuroendocrine neoplasms based on data from 490 cases in a single center

To develop and validate a nomogram for predicting outcomes of patients with gastric neuroendocrine neoplasms (G-NENs). We retrospectively collected the clinical data from 490 patients with the diagnosis of G-NEN at our medical center from 2000 to 2021. Log-rank test was used to analyze the overall survival (OS) of the patients. The independent risk factors affecting the prognosis of G-NEN were identified by Cox regression analysis to construct the prognostic nomogram, whose performance was evaluated using the C-index, receiver-operating characteristic (ROC) curve, area under the ROC curve (AUC), calibration curve, DCA, and AUDC. Among the 490 G-NEN patients (mean age of 58.6±10.92 years, including 346 male and 144 female patients), 130 (26.5%) had NET G1, 54 (11.0%) had NET G2, 206 (42.0%) had NEC, and 100 (20.5%) had MiNEN. None of the patients had NET G3. The numbers of patients in stage Ⅰ-Ⅳ were 222 (45.3%), 75 (15.3%), 130 (26.5%), and 63 (12.9%), respectively. Univariate and multivariate analyses identified age, pathological grade, tumor location, depth of invasion, lymph node metastasis, distant metastasis, and F-NLR as independent risk factors affecting the survival of the patients (P < 0.05). The C-index of the prognostic nomogram was 0.829 (95% CI: 0.800-0.858), and its AUC for predicting 1-, 3- and 5-year OS were 0.883, 0.895 and 0.944, respectively. The calibration curve confirmed a good consistency between the model prediction results and the actual observations. For predicting 1-year, 3-year and 5-year OS, the TNM staging system and the nomogram had AUC of 0.033 vs 0.0218, 0.191 vs 0.148, and 0.248 vs 0.197, respectively, suggesting higher net benefit and better clinical utility of the nomogram. The prognostic nomogram established in this study has good predictive performance and clinical value to facilitate prognostic evaluation of individual patients with G-NEN.

Molecular genetic sequencing of neuroendocrine tumors of the gastrointestinal tract.

651 Background: The objective of this work was to evaluate the molecular and genetic features of the NET gastrointestinal tract. Genomic sequencing of 30 tumor samples of the latest generation was carried out and the data obtained were evaluated. Methods: In total, 30 tumor blocks of patients with gastrointestinal NET were tested by the new generation sequencing (NGS) method. The following genes were analyzed: ATM, ATR, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CDK12, CHEK1, CHEK2, EPCAM, FANCL, MLH1, MSH2, NBN, NF1, PALB2, PMS2, RAD51B, RAD51C, RAD51D, RAD54L, STK11, TP53, POLE, KRAS, NRAS, BRAF, EGFR, ERBB2, PIK3CA, MET ex14, BAT25, BAT26, NR21, NR24, MONO27, KIT, PDGFRA, Pi3Ca. Preparation of libraries for sequencing was carried out using NimblGen SepCapEZ Choice. Sequencing was performed on the Illumina MiSeq device. Results: In the study cohort of patients whose tumor blocks were sent for examination by the NGS method, there were more women – 19 (63.3%) than men – 11 (36.7%). When analyzing the age of patients, it should be noted that among all age groups, elderly patients predominated (60-74 years according to the WHO classification, 2016) – 12 (40%). In the majority of patients – 10 (33.3%) – the primary tumor focus was localized in the pancreas, in 6 (20%) patients it was primarily affected stomach, 7 (23.3%) – small intestine. Other parts of the gastrointestinal tract were affected much less frequently: the colon – in 1 (3.3%) patients. According to the division according to the degree of differentiation of gastrointestinal NET10 tumors had a degree of differentiation G1 (33.3%), 16 -G3 (54.3%), 4– G3 (13.3%). In the tumor sample of a patient with gastric NET G1 (Ki 67 = 2%), POLE mutations were found: c.2276G &gt; A, p.R759H and CHEK2: c.470T &gt; C, p.I157T. Also, mutations MLH1: c.199G &gt; A, p.G67R BRCA1: c.1881 were found in the tumor sample of another patient with gastric NET G2 (Ki 67 = 7%). Conclusions: To improve the survival rates of patients, it is worth paying special attention to the molecular genetic study of the NET gastrointestinal tract. It is molecular genetic profiling that can become the basis for building more individualized algorithms for treating patients. The results of this study allow us to count on the fact that when conducting a study on a larger cohort of patients with gastrointestinal NET, it is possible to obtain results that will expand our knowledge of this nosology and allow us to supplement the already available information about prognosis factors and predictors of response to treatment.

Correlation of four-phase CT findings of rectal neuroendocrine neoplasms with different World Health Organization grades.

To investigate the four-phase computed tomography (CT) features of rectal neuroendocrine neoplasms (R-NENs) as they relate to different World Health Organization pathological grades. A total of 42 patients who underwent pre-operative four-phase CT for evaluation of neoplasms confirmed as different pathological grades of R-NENs by surgery were included. The CT features were retrospectively analyzed by two radiologists in consensus including the tumor location, shape, long diameter, necrosis, boundary, transmural invasion, CT attenuation values of noncontrast and different enhancement phases, intra mesenteric metastasis, lateral lymph node metastasis, and distant metastasis. The differences among R-NENs of different pathological grades were analyzed using T-test, analysis of variance, and non-parametric rank sum test. Among 42 cases (23 males, 19 females, aged 57 ± 10.48years) of R-NENs, neuroendocrine tumors G1, G2, and G3 (NET G1, NET G2, NET G3) and neuroendocrine carcinoma (NEC) were 13, 13, 3 and 13 cases, respectively. There were statistically significant differences in tumor long diameter, shape, necrosis, boundary, transmural invasion, CT values in delayed phase, intra mesenteric metastasis, lateral lymph node metastasis, and liver metastasis of different pathological grades (P < 0.001, P = 0.014, P = 0.004, P < 0.001, P < 0.001, P = 0.038, P = 0.006, P = 0.022, and P = 0.020, respectively). Features on four-phase CT can correlate with WHO pathological grades of R-NENs; this may be helpful for preoperative diagnosis and prognosis evaluation.

A relook at gastroenteropancreatic neuroendocrine tumours as per 2019 WHO classification-A tertiary centre experience.

Neuroendocrine neoplasm of GIT (gastrointestinal tract) and pancreas is heterogenous with variable clinical features and disease outcomes. Despite multiple attempts of risk stratification by grading and staging, some have unpredictable clinical courses. Well-differentiated grade 3 neuroendocrine tumour (G3NET) is a recent subcategory introduced in the 2019 WHO classification based on morphology, molecular profile and prognosis distinguishing it from neuroendocrine carcinoma(NEC). This study aimed at describing the spectrum of NENs encountered in a tertiary centre with focus on reclassifying previously reported G3 tumours into G3 NET and NEC and comparing the survival between them. This is an 8-year retrospective study of all gastro-entero-pancreatic neuroendocrine neoplasms reclassified according to the 2019 WHO classification based on morphology and Ki-67 index with analysis of the survival rates between the categories. Minimum follow-up period was 20months. Eighty-six patients with NENs of gastro-entero-pancreas were included, with median age group of 40-60years (age range 9 to 79years) and male:female ratio of 1.7:1. The tumour grade correlated with the TNM staging and most of the syndromic NETs were low grade. Eleven percent of the tumours were reclassified as well-differentiated G3NETs. The survival of G3 NETs was higher than NEC. Grading of NEN is vital for therapeutic decisions and for prognostication. Currently, morphology is the key to recognise the well-differentiated G3 NETs, but can be subject to interobserver variability. Molecular surrogates may play a role in accurately identifying these entities, the validity of which is warranted.

ODP554 insulinoma with a delayed diagnosis of 25 years

Abstract Introduction Most insulinomas are rare pancreatic neuroendocrine tumours that are typically sporadic, solitary, with the great majority less than 2cm in diameter at presentation 1; fewer than 5% of insulinomas are larger than 3cm, and in such cases are not infrequently malignant. The median duration of symptoms before diagnosis is variable, but is usually brief, often just 12–18months, although longer durations are occasionally reported. We report the case of a benign insulinoma whose diagnosis was delayed for 25 years, and who eventually presented with a relatively large but benign tumour &amp;gt;4cm in diameter. Case presentation The patient was a50year-old male who presented to our service with a history of hypoglycaemia episodes dating back 25 years. The first, whilst living in Pakistan, he became unwell on his wedding day and was found to have an unspecified but very low blood glucose, confirmed at his local hospital. Since that time, he reported that he had "learned to live with the symptoms" by eating frequent small carbohydrate-rich meals, although missing a meal led to typical hypoglycaemic symptoms. He continued this regimen on moving to the UK, but over a recent period of three months he reported a substantial deterioration in his symptoms(confusion, disorientation, slurred speech, generalised weakness, tachycardia and palpitations), and indeed collapsed on two occasions. He had a fasting glucose of 2.9 mmol/L with grossly elevated and inappropriate insulin and C-peptide level, with a normal cortisol response to Cosyntropin. MRI demonstrated asingle4.1cm lesion in the body of the pancreas, however 68 Gallium-DOTATATE-PET scanning showed no uptake at any site. Accordingly, he was started on diazoxide 50mg tds and referred to the surgical team for distal pancreatectomy: histopathology revealed a 4.4 cm well-differentiated pancreatic neuroendocrine neoplasm of intermediate grade (NET G2, 2017 WHO Pancreatic-NET classification) which immunostained positive for insulin. Post-operatively, his hypoglycaemic episodes have ceased and he remains under active surveillance. Conclusion The great majority of insulinomas are small benign tumours, with a short history, with large tumours often indicating malignancy. Our case demonstrates that untreated and without specific therapy, such tumours may continue to grow and attain a large size without this indicating malignant potential. 68 Gallium-DOTATATE-PET is negative in more than 50% of benign insulinomas. We believe that this represents the longest survival, 25 years, of a patient with a benign insulinoma in the absence of treatment. Presentation: No date and time listed

Multiple rectal neuroendocrine tumors: An analysis of 15 cases and literature review.

Multiple neuroendocrine tumors (M-NETs) are rare in the rectum and there is no consensus on their characteristics and treatments. Here, we report 15 cases of rectal M-NETs and review the previous literature. We discuss the clinical characteristics, endoscopic features and pathological features of rectal M-NETs, aiming to analyze the treatments and follow-up strategies in combination with these characteristics. We retrospectively reviewed and analyzed the data of 15 patients with rectal M-NETs who were diagnosed and treated at Beijing Friendship Hospital, Capital Medical University. Their clinical data, endoscopic findings, pathological features and treatments were analyzed. Follow-up evaluations and literature review were performed. In all, 14 male (93.3%) and 1 female (6.7%) were recruited. The average age at diagnosis was 55.7 years. The clinical manifestations include asymptomatic in 9 patients (60.0%), defecation habits changes in 2 patients (13.3%), anal distension in 2 patients (13.3%), and abdominal distension in 2 patient (13.3%). The largest tumor diameter ≤10mm was found in 13 patients (86.7%) and >10mm in 2 patients (13.3%). All of the lesions originated from the mucous or submucosa layer. WHO grades were all NET G1. The number of tumors diagnosed by pathology in 13 patients was consistent with that observed by endoscopy, while more lesions were observed by pathology than endoscopy in two patients. Lymph node metastasis occurred in 1 patient (6.7%), and vascular or lymphatic invasion occurred in 9 patients (60.0%). Among the 13 patients with the largest tumor diameter being ≤10mm, lymphovascular invasion occurred in 8 patients (61.5%). And among the 2 patients with the largest tumor diameter of >10mm, lymphovascular invasion occurred in 1 patient (50.0%). 14 patients underwent endoscopic resection and 1 underwent surgical excision. Postoperative follow-up was achieved in 13 patients and no recurrence or metastasis was found. The true number of rectal M-NETs may be more than seen under endoscopy. Rectal M-NETs is associated with a high risk of metastasis; therefore, treatment and surveillance strategies should be more radical than single lesion.

Long-term results of minimally invasive transanal surgery for rectal tumors in 249 consecutive patients

PurposeTo delineate the long-term results of minimally invasive transanal surgery (MITAS) for selected rectal tumors.MethodsWe analyzed data, retrospectively, on consecutive patients who underwent MITAS between 1995 and 2015, to establish the feasibility, excision quality, and perioperative and oncological outcomes of this procedure.ResultsMITAS was performed on 243 patients. The final histology included 142 cancers, 47 adenomas, and 52 neuroendocrine tumors (NET G1). A positive margin of 1.6% and 100% en bloc resection were achieved. The mean operative time was 27.4 min. Postoperative morbidity occurred in 7% of patients, with 0% mortality. The median follow-up was 100 months (up to ≥ 5 years or until death in 91.8% of patients). Recurrence developed in 2.9% of the patients. The 10-year overall survival rate was 100% for patients with NET G1 and 80.3% for those with cancer. The 5-year DFS was 100% for patients with Tis cancer, 90.6% for those with T1 cancer, and 87.5% for those with T2 or deeper cancers. MITAS for rectal tumors ≥ 3 cm resulted in perioperative and oncologic outcomes equivalent to those for tumors < 3 cm.ConclusionMITAS is feasible for the local excision (LE) of selected rectal tumors, including tumors ≥ 3 cm. It reduces operative time and secures excision quality and long-term oncological outcomes.

On the Linearity of External Forcing Response in Solar Geoengineering Experiments

AbstractAs an idealized proxy for solar geoengineering, the GeoMIP G1 experiment forces Earth System Models with prescribed reductions in solar radiation to balance increases in atmospheric CO2. One key source of uncertainty is the magnitude of solar constant reduction required to offset a CO2 quadrupling. Here, we employ single‐forcing simulations with Community Earth System Model to decompose the distinct radiative adjustments associated with solar and CO2 forcing in the G1 experiment. We find that radiative adjustments to both single forcings have a net positive effect on top of atmosphere energy balance such that they both increase the net G1 forcing. Stratospheric temperature and shortwave cloud adjustments are the main sources of positive adjustment in both Solar and CO2 simulations. We also show that net radiative adjustment in G1 cannot be represented linearly with CO2 and solar forcing adjustments, which is primarily traced to reductions in boundary layer clouds.

Well-Differentiated Grade 3 Neuroendocrine Tumors: Characteristics, Treatments, and Outcomes From a Population-Based Study.

We evaluated a population-based cohort of metastatic well-differentiated grade 3 gastroenteropancreatic neuroendocrine tumors (G3 NETs) to describe their characteristics, prognosis, and treatment outcomes. The British Columbia provincial database was queried for G3 NETs diagnosed 2004 to 2021, and charts were reviewed to describe clinical features and outcomes. Forty-one patients were identified, most were diagnosed with pancreatic (58.5%) or midgut (26.8%) primary tumor and Ki-67 was less than 55% in 68.3%. The primary was resected in 19 (46.3%) with median disease-free survival of 25.2 months. Once metastatic, patients received a median of one line of systemic therapy. Median overall survival with metastatic disease was 33.8 months. Median progression-free survival was longest in patients treated with capecitabine-temozolomide (20.6 months) or somatostatin analogs (7.9 months), while etoposide-platinum provided little benefit (2.4 months). Limited data of efficacy for targeted therapies and radionuclide therapy was available. Seven patients (17.1%) were also treated with local therapies, which were associated with improved overall survival (median not reached, hazard ratio, 0.23; P = 0.012). Capecitabine-temozolomide and somatostatin analogs were associated with clinically meaningful benefit, and use of local therapies provided benefits in selected patients. Multidisciplinary discussion is essential to optimize individual outcomes in this heterogeneous population.

Immuntherapie bei neuroendokrinen Tumoren

BackgroundNeuroendocrine tumors (NET) of the digestive system and lung carcinoids are rare neoplasms. In advanced unresectable disease, various systemic therapies are used. Primary tumor site, pathological classification including grading, tumor slope and tumor burden, as well as expression of somatostatin receptors and functional activity have an impact on treatment choices. Established treatment options include somatostatin analogs (octreotide, lanreotide), peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTA-TATE, molecular targeted therapies (everolimus, sunitinib), and systemic chemotherapy with streptozotocin- or temozolomide-based regimes in well-differentiated NET, or platinum/etoposide in poorly differentiated neuroendocrine carcinoma. There is a high unmet need for novel therapies.AimReview of the current status of immunotherapy in neuroendocrine neoplasms of the digestive system and of lung carcinoids.ResultsImmunotherapy with checkpoint inhibitors is a well-established therapy for example in non-small cell lung cancer (NSCLC), melanoma, hepatocellular carcinoma, and Merkel cell carcinoma, and in combination therapy in small cell lung cancer (SCLC). Studies are limited so far and demonstrate absent or low response rates in well-differentiated NET G1/G2. Other subgroups of patients have shown benefit particularly with dual checkpoint inhibitor therapy with 17–44% objective response rates (ORR). These include primarily neuroendocrine carcinomas of gastroenteropancreatic origin, but also atypical lung carcinoids and possibly also more proliferative NET G3, although data for NET G3 are limited.

Enhancer of Zeste Homolog 2 (EZH2) Is a Marker of High-Grade Neuroendocrine Neoplasia in Gastroenteropancreatic and Pulmonary Tract and Predicts Poor Prognosis.

Simple SummaryNeuroendocrine neoplasms most frequently arise in the gastroenteropancreatic and pulmonary tract and show an increasing incidence and prevalence. The prognosis and treatment depend on tumor proliferation and clinical behavior. Highly proliferating grade 3 neoplasms especially, show a wildly divergent therapy response and prognosis. In particular, it is crucial to securely separate the more indolent G3 tumors from the more aggressive carcinomas. Currently, this distinction is based on a combination of clinical, morphologic, immunohistochemical, and molecular biomarkers. However, none of these markers allow for a reliable distinction, and additional markers are needed. EZH2 has attracted increasing interest in different tumor entities. We aimed to analyze the expression of EZH2 in different neuroendocrine neoplasms and to correlate the expression with clinical parameters and survival. We demonstrate that EZH2 is nearly exclusively expressed in highly proliferative neoplasms and is a robust biomarker for identifying aggressive G3 tumors with poor prognosis.Tumor grading is a robust prognostic predictor in patients with neuroendocrine neoplasms (NEN) and guides therapy, especially in tumors with high proliferation. NEN can be separated into well-differentiated and poorly differentiated types. The more aggressive NEN have been further separated into neuroendocrine tumors (NET G3) with a better prognosis and neuroendocrine carcinomas (NEC) with a worse prognosis. Despite this distinction’s tremendous clinical and therapeutic relevance, optimal diagnostic biomarkers are still lacking. In this study, we analyzed the protein expression and prognostic impact of Enhancer of Zeste Homolog 2 (EZH2) by immunohistochemistry in 219 tissue samples of gastroenteropancreatic (GEP-NEN) and pulmonary NEN (P-NEN). EZH2 was almost exclusively expressed in NEN with a proliferation rate above 20% (G3), while all low-grade tumors were nearly negative. Among high-grade NEN, 65% showed high and 35% low expression of EZH2. In this group, the high expression of EZH2 was significantly associated with poor overall survival and NEC histology. Interestingly, EZH2 seems to act independently of Polycomb Repressive Complex 2 (PRC2) in NEN. In conclusion, we propose EZH2 as a robust biomarker for distinguishing between NET G3 and NEC among gastroenteropancreatic and pulmonary NEN.

Treatment Approaches and Outcome of Patients with Neuroendocrine Neoplasia Grade 3 in German Real-World Clinical Practice.

Simple SummaryGrade 3 neuroendocrine neoplasms (NEN G3) are a rare and heterogeneous subtype of NEN and include poorly differentiated neuroendocrine carcinomas and well-differentiated neuroendocrine tumors G3 (NET G3). Standard chemotherapy with platinum plus etoposide may not be appropriate for all subgroups, but more tailored approaches suffer from the lack of data. In our study, we provide real-world data from a large center-based cohort of the German NET Registry and hope to stimulate efforts to conduct clinical trials for well-defined entities.Background: Neuroendocrine neoplasia grade 3 (NEN G3) represents a rare and heterogeneous cancer type with a poor prognosis. The aim of our study was to analyze real-world data from the German NET Registry with a focus on therapeutic and prognostic aspects. Methods: NEN G3 patients were identified within the German NET Registry. Demographic data and data on treatments and outcomes were retrieved. Univariate analyses were performed using the Kaplan–Meier-method. Multivariate analysis was performed using a Cox proportional hazard model. Results: Of 445 included patients, 318 (71.5%) were diagnosed at stage IV. Well-differentiated morphology (NET G3) was described in 31.7%, 60% of cases were classified as neuroendocrine carcinoma (NEC), and the median Ki67 value was 50%. First-line treatment comprised chemotherapy in 43.8%, with differences in the choice of regimen with regard to NET or NEC, and surgery in 41.6% of patients. Median overall survival for the entire cohort was 31 months. Stage, performance status and Ki67 were significant prognostic factors in multivariate analysis. Conclusions: The survival data of our national registry compare favorably to population-based data, probably mainly because of a relatively low median Ki67 of 50%. Nevertheless, the best first- and second-line approaches for specific subgroups remain unclear, and an international effort to fill these gaps is needed.