Immunohistochemical expression of ephrin receptors in neuroendocrine neoplasms: a case-series of gastroenteropancreatic neuroendocrine neoplasms and a systematic review of the literature.

PURPOSE: Erythropoietin-producing hepatocellular (EPH) receptors are the largest known family of tyrosine kinases receptors (TKR) in humans, implicated in cell proliferation, adhesion, migration, tumor angiogenesis, invasion and metastasis. The aim of the present study is to assess the expression of EPHs in neuroendocrine neoplasms (NENs). METHODS: Immunohistochemical staining of specimens of 30 patients with gastroenteropancreatic and lung NENs was performed for EPH-A1, EPH-A2, EPH-A4, EPH-A5 protein expression, in addition to ki-67 multiplication index and programmed death-ligand 1. Additionally, we performed a systematic review of the available literature in three different databases reporting on the expression of EPH in all neuroendocrine neoplasms. RESULTS: Positive expression was seen in 16/19 (84%) specimens for EPH-A1, 15/23 (65%) for EPH-A2, 21/24 (88%) for EPH-A4, 24/26 (92%) for EPH-A5. EPH-A1 was expressed in 9/9 pancreatic, 3/4 small intestine, but not in one lung NEN, EPH-A2 in 5/10 pancreatic, 3/4 small intestine and lung, and in one of each of gastric, appendix, colorectal, and cervical NENs, respectively. EPH-A4 showed positive expression in 9/11 pancreatic, 4/4 small intestine, 3/3 lung specimens and EPH-A5 in 10/11, 4/4 and 4/4, respectively. Data retrieved from the systematic review of the literature in combination with the data from the present study are suggestive of a frequent EPH expression in pituitary, thyroid, lung and gastroenteropancreatic NENs, yet, with varying expressions of the single receptor subtypes. CONCLUSION: EPHs may have a role in NEN tumorigenesis, prognosis as well as a role in the evolving molecular-targeted therapies.

Longitudinal Changes in Ki-67 Indices in Small-Intestinal Neuroendocrine Tumours and Their Impact on Survival.

INTRODUCTION: The purpose of this study was to evaluate longitudinal changes in Ki-67 indices of SI-NETs and assess the impact of these in overall survival (OS). METHODS: We screened 551 patients with SI-NETs diagnosed from 1993, through 2021, identified using the SI-NET databases from five European referral centres. Only patients with well-differentiated tumours and available baseline tumour samples and follow-up re-biopsies were included. For tumour grading, apart from 2017 WHO classification system, we applied a recently proposed SI-NET site-specific modified histopathological grading system with Ki-67 cut-offs of 5 and 10%. Uni- and multivariable regression analyses were used to determine whether there was a difference between OS in SI-NET patients stratified by increment of Ki-67 indices over time and/or progression to a higher grade. RESULTS: We included 45 patients. Median Ki-67 index at SI-NET diagnosis was 2% (range: 0.5-15%). Thirty-three patients had Ki-67 indices <5% (70.2%), 6 had Ki-67: 5-10% (12.8%), and 8 had Ki-67 ≥10% (17%). Mean time to re-biopsy was 48.8 months (SD: ±162.5). At re-biopsy, the median change in Ki-67 index (absolute value; follow-up minus time of diagnosis) was 1% (range: -10 to +38%). An increase in Ki-67 occurred in 20 patients (42.6%); in 14 patients, the change in Ki-67 resulted in progression to higher tumour grade following the modified grading system. Patients with an increment in Ki-67 ≥1% had a median OS of 32.9 months versus 80.5 months in patients without (HR = 5.6, 95% CI: 1.42-22.02; p = 0.014). When applying the novel modified histopathological grading system for SI-NETs, patients with grade progression had a median OS of 32.9 months versus 53.7 months in those without (HR = 4.61, 95% CI: 1.22-13.54; p = 0.022). At multivariable analysis, grade progression was confirmed as an independent predictor for death (HR = 7.2, 95% CI: 1.58-32.82; p = 0.011). CONCLUSIONS: Metachronous increment in Ki-67 indices and related grade progression over time following a site-specific modified histopathological grading system with Ki-67 cut-offs of 5 and 10% is observed in approximately 1/3 of SI-NETs subjected to re-biopsy and it is associated with worse survival outcomes.

Molecular developments in parasellar tumors and potential therapeutic implications.

The parasellar region is the anatomical area around the sella turcica that represents a crucial crossroad for important adjacent structures. Several distinct tumors can primarily originate from this area, the most common being meningiomas, gliomas, embryonal cell tumors, germ cell tumors and craniopharyngiomas. In addition, a number of systemic and inflammatory disorders can also affect the parasellar region most commonly involving the pituitary. These lesions have different pathology characteristics and malignant potential according to the new WHO CNS5 2021 classification. Signs and symptoms may be non-specific and are mostly related to a mass effect on the surrounding anatomical structures and/or impairment of endocrine function whereas the vast majority lack a secretory component. The mutational signature analysis based on advances in molecular techniques, has recently enabled the identification of specific gene mutations or signalling pathway aberrations. These developments may serve as a powerful mean to delineate the pathophysiology of these lesions and serve as a diagnostic, prognostic and therapeutic tool, particularly for high-risk populations. Treatment options include surgery alone or in combination with radiotherapy, chemotherapy and disease-specific medical therapy in order to prevent recurrence or further tumor growth along with replacement of coexistent pituitary hormonal deficiencies. In this comprehensive review, we present current state-of-the-art developments in the histopathology and molecular biology of these lesions that may be utilized by a dedicated multidisciplinary team of relevant specialties for the diagnosis, monitoring and treatment of the parasellar lesions that often represent a diagnostic and therapeutic challenge.

Transformation of a Benign Adrenocortical Adenoma to a Metastatic Adrenocortical Carcinoma Is Rare But It Happens.

The transformation of an adrenocortical adenoma (ACA) to an adrenocortical carcinoma (ACC) is extremely rare. Current guidelines suggest against further imaging studies and follow-up in patients with nonfunctional adrenal incidentalomas (NFAIs) with benign imaging characteristics. Herein, we present a 64-year-old male patient diagnosed initially with a NFAI of 3 cm in size with imaging characteristics consistent with an ACA. However, 13 years after initial diagnosis, this apparent ACA developed into a high-grade cortisol and androgen-secreting ACC with synchronous metastases. The literature review revealed a further 9 case reports of adrenal incidentalomas initially characterized as ACA that subsequently developed into ACC within a period ranging from 1 to 10 years. The pathogenesis of transformation of an initially denoted ACA to ACC is not fully delineated, although the existing literature focuses on the preexisting or changing genetic background of these lesions, highlighting the need to develop robust prognostic markers to identify patients at risk and individualize the follow-up of these unique cases.

Hereditary Syndromes Associated with Pancreatic and Lung Neuroendocrine Tumors.

Pancreatic neuroendocrine tumors (PanNETs) and lung NETs (LNETs) represent a rare but clinically significant subgroup of neoplasms. While the majority is sporadic, approximately 17% of PanNETs and a subset of LNETs develop in the context of monogenic familial tumor syndromes, especially multiple endocrine neoplasia type 1 (MEN1) syndrome. Other inherited syndromes associated with PanNETs include MEN4, von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC). These syndromes are highly penetrant and their clinical manifestations may vary even among members of the same family. They are attributed to genetic mutations involving key molecular pathways regulating cell growth, differentiation, and angiogenesis. Pancreatic NETs in hereditary syndromes are often multiple, develop at a younger age compared to sporadic tumors, and are associated with endocrine and nonendocrine tumors derived from multiple organs. Lung NETs are not as common as PanNETs and are mostly encountered in MEN1 syndrome and include typical and atypical lung carcinoids. Early detection of PanNETs and LNETs related to inherited syndromes is crucial, and specific follow-up protocols need to be employed to optimize diagnosis and management. Genetic screening is recommended in childhood, and diagnostic screening starts often in adolescence, even in asymptomatic mutation carriers. Optimal management and therapeutic decisions should be made in the context of a multidisciplinary team in specialized centers, whereas specific biomarkers aiming to identify patients denoted to follow a more aggressive course need to be developed.

EndoBridge 2023: highlights and pearls.

EndoBridge 2023 took place on October 20-22, 2023, in Antalya, Turkey. Accredited by the European Council, the 3-day scientific program of the 11th Annual Meeting of EndoBridge included state-of-the-art lectures and interactive small group discussion sessions incorporating interesting and challenging clinical cases led by globally recognized leaders in the field and was well attended by a highly diverse audience. Following its established format over the years, the program provided a comprehensive update across all aspects of endocrinology and metabolism, including topics in pituitary, thyroid, bone, and adrenal disorders, neuroendocrine tumors, diabetes mellitus, obesity, nutrition, and lipid disorders. As usual, the meeting was held in English with simultaneous translation into Russian, Arabic, and Turkish. The abstracts of clinical cases presented by the delegates during oral and poster sessions have been published in JCEM Case Reports. Herein, we provide a paper on highlights and pearls of the meeting sessions covering a wide range of subjects, from thyroid nodule stratification to secondary osteoporosis and from glycemic challenges in post-bariatric surgery to male hypogonadism. This report emphasizes the latest developments in the field, along with clinical approaches to common endocrine issues. The 12th annual meeting of EndoBridge will be held on October 17-20, 2024 in Antalya, Turkey.

Modified Histopathological Grading Optimizes Prediction of Survival Outcomes in Small Intestinal Neuroendocrine Tumours.

CONTEXT: One of the major prognostic indices in neuroendocrine tumours (NETs) is Ki67 proliferation index. OBJECTIVE: To identify optimal grading Ki-67 cut-offs to delineate differences in prognosis of patients with small intestinal NETs (SI-NETs). DESIGN, SETTING, PARTICIPANTS: Multicentre retrospective cohort analysis of 551 SI-NET patients diagnosed from 1993 through 2021 at five European referral centres with a mean(±SD) follow-up time of 51.5(±52.9) months. MAIN OUTCOME MEASURES: Overall- and event-free survival (OS and EFS) rates. RESULTS: Median age at baseline was 62.3(range:17-90) years; 252(45.7%) patients were female. All SI-NETs were well-differentiated with 326 being grade 1(G1; 59.2%), 169G2(30.7%), and only 8G3(1.5), while 48 tumours were of unspecified grade (8.7%). The median Ki67 was 2%(range:1-70%). Two-hundred forty-seven patients (44.8%) had distant metastases at baseline (stage IV), 217 locoregional disease (41.1%; stage III), whereas 29(7.1%) and 25(4.5%) presented at stages II and I, respectively. The median OS was 214.7(95%CI:152.7-276.6) months and the median EFS was 79.8(95%CI:68.2-91.5) months, respectively. In multivariable Cox-regression OS analysis, the proposed modified histopathological Ki67 grading system (K67:5-10% group: HR=2.2, 95%CI:1.15-4.31; p=0.018 and K67≥10% group: HR=5.11, 95%CI:2.87-9.09; p<0.001), age (HR=1.07, 95%CI:1.04-1.09; p<0.001), Charlson Comorbidity Index (HR=1.08, 95%CI:1-1.16; p=0.028) and TNM stage (HR=1.79, 95%CI:1.05-3.06; p=0.034) were independent predictors for death. Pertinent EFS analysis, confirmed the proposed modified histopathological Ki67 grading system (K67≥10% group: HR=4.01, 95%CI:2.6-6.37; p<0.001) and age (HR=1.04, 95%CI:1.02-1.05; p<0.001) as independent predictors for recurrence, progression and/or death. CONCLUSIONS: Ki-67 proliferation index was a strong and independent predictor of OS and EFS. A modified histopathological grading system applying Ki-67 cut-offs of 5 and 10% could be superior to predict differences in SI-NET patient survival outcomes.

Immunotherapy for endocrine tumours: a clinician's perspective.

Immunotherapy has revolutionised the treatment of oncological patients, but its application in various endocrine tumours is rather limited and is mainly used when conventional therapies have failed. Immune checkpoint inhibitors (ICIs) have been employed in progressive adrenocortical carcinoma, primarily utilizing the anti-PD-L1 agent pembrolizumab, obtaining overall response rates ranging between 14% and 23%. In contrast, the response rate in phaeochromocytoma/paraganglioma was substantially less at 9%, considering the small number of patients treated. Similarly, the response rate in advanced differentiated thyroid carcinomas treated with pembrolizumab was also low at 9%, although the combination of ICIs with tyrosine kinase inhibitors showed higher efficacy. Low response rates to ICIs have also been observed in progressive medullary thyroid cancer, except in tumours with a high mutation burden (TMB). Pembrolizumab or spartalizumab can be utilized in patients with high TMB anaplastic thyroid cancer, obtaining better response rates, particularly in patients with high PD-L1 expression. Immunotherapy has also been used in a few cases of parathyroid carcinoma, showing limited antitumour effect. Pituitary carcinomas may exhibit a more favourable response to ICIs compared to aggressive pituitary tumours, particularly corticotroph tumours. Patients with advanced neuroendocrine tumours achieve an overall response rate of 15%, which varies according to the primary tumour site of origin, degree of differentiation, and therapeutic regimen utilised. Future research is needed to evaluate the potential role of immunohistochemical biomarkers, such as programmed death 1/programmed death ligand 1 and TMB, as predictors for the response to immunotherapy. Furthermore, randomised prospective studies could provide more robust data on the efficacy and side effects of ICIs.

High Filamin a Expression in Adrenocortical Carcinomas Is Associated with a Favourable Tumour Behaviour: A European Multicentric Study.

The insulin-like growth factor 2 (IGF2) promotes cell growth by overactivating the IGF system in an autocrine loop in adrenocortical carcinomas (ACCs). The cytoskeleton protein filamin A (FLNA) acts as a repressor of IGF2 mitogenic signalling in ACC cells. The aims of this study were to test FLNA expression by immunohistochemistry in 119 ACCs and 26 adrenocortical adenomas (ACAs) and to evaluate its relationship with clinicopathological features and outcome in ACCs. We found that 71.4% of ACCs did not express FLNA, whereas FLNA absence was a rare event in ACAs (15.4%, p < 0.001 vs. ACCs). In addition, the expression of FLNA was associated with a less aggressive tumour behaviour in ACCs. Indeed, the subgroup of ACCs with high FLNA showed a lower ENSAT stage, Weiss score, and S-GRAS score compared to ACCs with low FLNA expression (p < 0.05). Moreover, patients with high FLNA had a longer overall survival than those with low FLNA (p < 0.05). In conclusion, our data suggest that FLNA may represent a "protective" factor in ACCs, and the integration of FLNA immunohistochemical expression in ACC tissues along with other clinical and molecular markers could be helpful to improve diagnostic accuracy and prognosis prediction in ACCs.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for appendiceal neuroendocrine tumours (aNET).

The aim of the present guidance paper is to update the previous ENETS guidelines on well differentiated appendiceal neuroendocrine tumours (NET), providing practical guidance for the diagnosis and management of appendiceal NET (aNET); poorly differentiated neoplasms are dealt with in a separate guidance paper. This paper is structured on a question-answer format in order to also address controversial issues and areas where uncertainty regarding the management and follow-up of aNET exists. All recommendations are offered on the basis of the best available evidence, along with the authors' experiences in managing these neoplasms. Each recommendation for treatment will provide a level of evidence and grade of recommendation as per the GRADE system (adapted in Infectious Disease Society of United States Public Health Service grading system).

Satisfaction with injection experience of patients with neuroendocrine tumors enrolled on lanreotide autogel patient support programs: Results from the international HomeLAN survey.

Lanreotide autogel/depot (LAN) is a somatostatin analog used in first-line treatment for neuroendocrine tumors (NETs). The aim of HomeLAN was to evaluate the satisfaction with injection experience among patients with NETs receiving at-home LAN injection via patient support programs (PSPs). This was an international, non-interventional, cross-sectional, online survey in adults with NETs enrolled in PSPs, receiving LAN injections at home, administered by a healthcare professional (HCP) or administered independently (self or caregiver administering injection). The primary endpoint was satisfaction with the most recent LAN injection. Secondary endpoints included the level of anxiety prior to injection, impact on daily life, and the extents to which participants felt in control of their life and agreed that home administration met their medical needs. In total, 111 participants from Belgium, Greece, the Netherlands, and Spain completed the survey (50.5% male; mean age, 63.6 years; most common primary tumor site was intestine [47.7%]). For 99 participants, their most recent injection was administered by an HCP. Overall, 95.5% of all participants were satisfied with their most recent injection experience (95% confidence interval: 89.89%-98.06%); 67% reported experiencing no anxiety prior to injection, 91.0% reported that home injection had a "great deal" or "quite a bit" of positive impact on their daily life, and 85.6% strongly agreed that the PSP met their medical needs. In the HCP injection subgroup, 71.7% reported that this mode of administration helped them to feel in control of their lives. In this patient survey, satisfaction levels were high among patients with NETs receiving LAN injections at home via a LAN PSP. Most patients did not experience anxiety prior to their most recent injection and acknowledged that thanks to their treatment they had a good quality of life despite their disease. Most strongly agreed that the PSP met their medical needs, which highlights the valuable service that LAN PSPs provide for patients with NETs.

Established and novel circulating neuroendocrine tumor biomarkers for diagnostic, predictive and prognostic use.

The management of neuroendocrine tumors (NETs) represents a clinical challenge due to heterogeneity of their clinical behaviour, molecular biology and response to treatment. Over the years, several circulating biomarkers have been developed for the early diagnosis and follow-up of NETs. The specific secretory products of tumors associated with a secretory syndrome (functioning tumors) may be used as diagnostic and/or prognostic biomarkers while the most common non-specific circulating biomarkers, that may be increased in both functioning and non-functioning tumors, are chromogranin A and the neuron specific enolase. However, the diagnostic accuracy as well as the prognostic and predictive value of these biomarkers are limited and novel techniques of multianalyte analysis of regulators of tumor biology have been developed. The NETest has been most extensively studied and proved to be useful in NET diagnosis, early detection of post-operative recurrence and prediction of response to treatment but further investigation establishing higher level of evidence is required for implementation in clinical practice.

Emerging therapies for advanced insulinomas and glucagonomas.

Pancreatic neuroendocrine neoplasms (panNENs) are rare relatively malignancies that, despite their frequently slow-growing pattern, have the ability to metastasize. Metastatic and/or advanced insulinomas and glucagonomas are functioning panNENs emerging from the pancreas displaying unique peculiarities, depending on their hormonal syndromes and increased malignant potential. Advanced insulinomas management follows usually the panNENs therapeutic algorithm, but some distinctions are well advised together with aiming to control hypoglycemias that occasionally can be severe and refractory to treatment. When first-generation somatostatin analogues (SSAs) fail to control hypoglycemia syndrome, second-generation SSAs and everolimus have to be considered for exploiting their hyperglycemic effect. There is evidence that everolimus is still effective after rechallenge retaining its hypoglycemic effect independently of its antitumor effect that seems to be mediated by different molecular pathways. Peptide receptor radionuclide therapy (PRRT) constitutes a promising therapeutic option for both its antisecretory and antitumoral action. Similarly, advanced and/or metastatic glucagonomas management also follows the panNENs therapeutic algorithm, but the clinical syndrome has to be addressed by aminoacid infusion and by first-generation SSAs to improve the patient performance status. PRRT seems to be an effective treatment when surgery and SSAs fail. The application of these therapeutic modalities has been shown to be efficacious in controlling the manifestations of the secretory syndrome and prolonging the overall survival of patients suffering from these malignancies.

What is the role of CHCHD2 in adrenal tumourigenesis?

PURPOSE: CHCHD2 is an antiapoptotic mitochondrial protein acting through the BCL2/BAX pathway in various cancers. However, data on the regulatory role of CHCHD2 in adrenal tumourigenesis are scarce. METHODS: We studied the expression of CHCHD2, BCL2, and BAX in human adrenocortical tissues and SW13 cells. mRNA and protein levels were analyzed through qPCR and immunoblotting, respectively, in 16 benign adrenocortical neoplasms (BANs), along with their adjacent normal adrenal tissues (controls), and 10 adrenocortical carcinomas (ACCs). BCL2/BAX mRNA expression was also analyzed in SW13 cells after CHCHD2 silencing. MTS, flow cytometry and scratch assays were performed to assess cell viability, apoptosis, and invasion, respectively. RESULTS: BCL2 and CHCHCD2 mRNA and protein expression was increased in BANs compared to normal adrenal tissues whereas BAX was decreased. BAX and CHCHD2 mRNA and protein levels were significantly downregulated and upregulated, respectively, in ACCs compared with either BANs or controls. Expression of the studied genes was not different among cortisol-secreting and nonfunctional ACAs. No significant association was found between genes' expression and other established prognostic markers of ACCs patients. In vitro analysis showed that CHCHD2 silencing resulted in reduced cell viability and invasion as well as increased SW13 cells apoptosis. CONCLUSIONS: CHCHD2 expression seems to be implicated in adrenal tumourigenesis and its absence resulted to increased apoptosis in vitro. However, the exact mechanism of action and particularly its association with the BAX/BCL2 pathway needs to be further studied and evaluate whether it could be a protentional therapeutic target.

Pancreatic metastases in patients with neuroendocrine neoplasms: A multi-centre cohort study.

Pancreatic metastases (PMs) from neuroendocrine neoplasms (NENs) are rare but the increased sensitivity of new diagnostic tools such as 68 Ga-DOTATATE PET/CT has resulted in their increased recognition at initial diagnosis or follow-up. A retrospective analysis of the data of patients from six tertiary referral centres was performed in order to identify the characteristics and the prognostic significance of PMs in patients with NENs. We used a control group of 69 age-, sex- and primary tumour - matched NEN patients from the same cohort with stage IV disease but no PMs. Overall survival (OS) was assessed using the Kaplan-Meier method log-rank analysis was used to assess the impact of various clinical and histopathological variables in OS. We identified 25 patients (11 females) with PMs with a median age at diagnosis of 60 years. The small intestine was the most common primary (80%) with a prevalence of 4.2% PMs (21/506). Fourteen patients presented with synchronous PMs whereas 11 developed metachronous PMs after a median time of 28 months (range: 7-168 months). Grading was available in 24 patients; 16 patients had G1 tumours, four G2, two atypical lung carcinoid, one typical and one atypical thymic carcinoid. Most patients had other concomitant metastases (12 hepatic, 4 lung and 6 bone) while five patients exhibited peritoneal carcinomatosis. Median OS in the PMs group was not reached compared with 212 months in the control group (95% CI: 26-398). The univariate analysis identified no prognostic factors statistically significantly associated with the OS. In conclusion, PMs are encountered with a low prevalence among NEN patients mostly developing in patients with advanced metastatic disease. The presence of PMs does not seem to be associated with a negative prognostic impact in OS.

Efficacy of denosumab monotherapy among adults with Langerhans cell histiocytosis: A prospective clinical trial.

This phase IIb clinical trial evaluated the efficacy of a bimonthly treatment schedule (Q8W) with 4 subcutaneous doses of denosumab 120 mg among adults with Langerhans cell histiocytosis needing first-line systemic therapy for either multifocal single-system disease or multisystem disease without risk organ involvement. Two months after the last treatment administration, seven patients showed disease regression, one stable disease, one non-active disease, and one disease progression. One year after treatment, progression was evident in two patients, while the remaining exhibited either a regression (three patients) or non-active disease (five patients). No permanent sequalae developed during the study and no adverse events were adjudicated in treatment. In conclusion, four doses of denosumab 120 mg Q8W subcutaneously are an effective treatment option in Langerhans cell histiocytosis patients without risk organ involvement exhibiting a response rate of 80%. Further studies are needed to confirm its role as a disease modifying agent.

The Role of Somatostatin Analogues in the Control of Diarrhea and Flushing as Markers of Carcinoid Syndrome: A Systematic Review and Meta-Analysis.

BACKGROUND: Somatostatin analogues (SSAs) are the cornerstone of treatment for carcinoid syndrome (CS)-related symptoms. The aim of this systematic review and meta-analysis is to evaluate the percentage of patients achieving partial (PR) or complete response (CR) with the use of long-acting SSAs in patients with CS. METHODS: A systematic electronic literature search was conducted in PubMed, Cochrane, and Scopus to identify eligible studies. Any clinical trials reporting data on the efficacy of SSAs to alleviate symptoms in adult patients were considered as potentially eligible. RESULTS: A total of 17 studies reported extractable outcomes (PR/CR) for quantitative synthesis. The pooled percentage of patients with PR/CR for diarrhea was estimated to be 0.67 (95% confidence interval (CI): 0.52-0.79, I2 = 83%). Subgroup analyses of specific drugs provided no evidence of a differential response. With regards to flushing, the pooled percentage of patients with PR/CR was estimated to be 0.68 (95% CI: 0.52-0.81, I2 = 86%). Similarly, no evidence of a significant differential response in flushing control was documented. CONCLUSIONS: We estimate there is a 67-68% overall reduction in symptoms of CS associated with SSA treatment. However, significant heterogeneity was detected, possibly revealing differences in the disease course, in management and in outcome definition.

Resistance of neuroendocrine tumours to somatostatin analogs.

INTRODUCTION: A common feature shared by most neuroendocrine tumors (NETs) is the expression on their surface of somatostatin receptors (SSTRs) that are essential for their pathophysiological regulation, diagnosis, and management. The first-generation synthetic somatostatin analogs (SSAs), octreotide and lanreotide, constitute the cornerstone of treatment for growth hormone secreting pituitary adenomas and functioning, progressive functioning, and non-functioning gastro-entero-pancreatic (GEP-NETs). SSAs exert their mechanism of action through binding to the SSTRs; however, their therapeutic response is frequently attenuated or diminished by the development of resistance. The phenomenon of resistance is complex implicating the presence of additional epigenetic and genetic mechanisms. AREAS COVERED: We aim to analyze the molecular, genetic, and epigenetic mechanisms of resistance to SSA treatment. We also summarize recent clinical data related to the development of resistance on conventional and non-conventional modes of administration of the first-generation SSAs and the second-generation SSA pasireotide. We explore mechanisms used to counteract the resistance to SSAs using higher doses or more frequent mode of administration of SSAs and/or combination treatments. EXPERT OPINION: There is considerable heterogeneity in the development of resistance to SSAs that is tumor-specific necessitating the delineation of the underlying pathophysiological processes to further expand their therapeutic applications.

Hemicolectomy versus appendectomy for patients with appendiceal neuroendocrine tumours 1-2 cm in size: a retrospective, Europe-wide, pooled cohort study.

BACKGROUND: Awareness of the potential global overtreatment of patients with appendiceal neuroendocrine tumours (NETs) of 1-2 cm in size by performing oncological resections is increasing, but the rarity of this tumour has impeded clear recommendations to date. We aimed to assess the malignant potential of appendiceal NETs of 1-2 cm in size in patients with or without right-sided hemicolectomy. METHODS: In this retrospective cohort study, we pooled data from 40 hospitals in 15 European countries for patients of any age and Eastern Cooperative Oncology Group performance status with a histopathologically confirmed appendiceal NET of 1-2 cm in size who had a complete resection of the primary tumour between Jan 1, 2000, and Dec 31, 2010. Patients either had an appendectomy only or an appendectomy with oncological right-sided hemicolectomy or ileocecal resection. Predefined primary outcomes were the frequency of distant metastases and tumour-related mortality. Secondary outcomes included the frequency of regional lymph node metastases, the association between regional lymph node metastases and histopathological risk factors, and overall survival with or without right-sided hemicolectomy. Cox proportional hazards regression was used to estimate the relative all-cause mortality hazard associated with right-sided hemicolectomy compared with appendectomy alone. This study is registered with ClinicalTrials.gov, NCT03852693. FINDINGS: 282 patients with suspected appendiceal tumours were identified, of whom 278 with an appendiceal NET of 1-2 cm in size were included. 163 (59%) had an appendectomy and 115 (41%) had a right-sided hemicolectomy, 110 (40%) were men, 168 (60%) were women, and mean age at initial surgery was 36·0 years (SD 18·2). Median follow-up was 13·0 years (IQR 11·0-15·6). After centralised histopathological review, appendiceal NETs were classified as a possible or probable primary tumour in two (1%) of 278 patients with distant peritoneal metastases and in two (1%) 278 patients with distant metastases in the liver. All metastases were diagnosed synchronously with no tumour-related deaths during follow-up. Regional lymph node metastases were found in 22 (20%) of 112 patients with right-sided hemicolectomy with available data. On the basis of histopathological risk factors, we estimated that 12·8% (95% CI 6·5 -21·1) of patients undergoing appendectomy probably had residual regional lymph node metastases. Overall survival was similar between patients with appendectomy and right-sided hemicolectomy (adjusted hazard ratio 0·88 [95% CI 0·36-2·17]; p=0·71). INTERPRETATION: This study provides evidence that right-sided hemicolectomy is not indicated after complete resection of an appendiceal NET of 1-2 cm in size by appendectomy, that regional lymph node metastases of appendiceal NETs are clinically irrelevant, and that an additional postoperative exclusion of metastases and histopathological evaluation of risk factors is not supported by the presented results. These findings should inform consensus best practice guidelines for this patient cohort. FUNDING: Swiss Cancer Research foundation.

Prognostic Biomarkers in Pituitary Tumours: A Systematic Review.

Pituitary tumours (PTs) are the second most common intracranial tumour. Although the majority show benign behaviour, they may exert aggressive behaviour and can be resistant to treatment. The aim of this review is to report the recently identified biomarkers that might have possible prognostic value. Studies evaluating potentially prognostic biomarkers or a therapeutic target in invasive/recurrent PTs compared with either non-invasive or non-recurrent PTs or normal pituitaries are included in this review. In the 28 included studies, more than 911 PTs were evaluated. A systematic search identified the expression of a number of biomarkers that may be positively correlated with disease recurrence or invasion in PT, grouped according to role: (1) insensitivity to anti-growth signals: minichromosome maintenance protein 7; (2) evasion of the immune system: cyclooxygenase 2, arginase 1, programmed cell death protein 1 (PD-1)/programmed death ligand 2, cluster of differentiation (CD) 80/CD86; (3) sustained angiogenesis: endothelial cell-specific molecule, fibroblast growth factor receptor, matrix metalloproteinase 9, pituitary tumour transforming gene; (4) self-sufficiency in growth signals: epidermal growth factor receptor; and (5) tissue invasion: matrix metalloproteinase 9, fascin protein. Biomarkers with a negative correlation with disease recurrence or invasion include: (1) insensitivity to anti-growth signals: transforming growth factor ß1, Smad proteins; (2) sustained angiogenesis: tissue inhibitor of metalloproteinase 1; (3) tissue invasion: Wnt inhibitory factor 1; and (4) miscellaneous: co-expression of glial fibrillary acidic protein and cytokeratin, and oestrogen receptors α36 and α66. PD-1/programmed cell death ligand 1 showed no clear association with invasion or recurrence, while cyclin A, cytotoxic T lymphocyte-associated protein 4, S100 protein, ephrin receptor, galectin-3 , neural cell adhesion molecule, protein tyrosine phosphatase 4A3 and steroidogenic factor 1 had no association with invasion or recurrence of PT. With the aim to develop a more personalized approach to the treatment of PT, and because of the limited number of molecular targets currently studied in the context of recurrent PT and invasion, a better understanding of the most relevant of these biomarkers by well-d esigned interventional studies will lead to a better understanding of the molecular profile of PT. This should also meet the increased need of treatable molecular targets.