Ianus Bifrons: The Two Faces of Metformin.

The ancient Roman god Ianus was a mysterious divinity with two opposite faces, one looking at the past and the other looking to the future. Likewise, metformin is an "old" drug, with one side looking at the metabolic role and the other looking at the anti-proliferative mechanism; therefore, it represents a typical and ideal bridge between diabetes and cancer. Metformin (1,1-dimethylbiguanidine hydrochloride) is a drug that has long been in use for the treatment of type 2 diabetes mellitus, but recently evidence is growing about its potential use in other metabolic conditions and in proliferative-associated diseases. The aim of this paper is to retrace, from a historical perspective, the knowledge of this molecule, shedding light on the subcellular mechanisms of action involved in metabolism as well as cellular and tissue growth. The intra-tumoral pharmacodynamic effects of metformin and its possible role in the management of different neoplasms are evaluated and debated. The etymology of the name Ianus is probably from the Latin term ianua, which means door. How many new doors will this old drug be able to open?

Impact of Vitamin D Deficiency on Tumor Aggressiveness in Neuroendocrine Neoplasms.

Background: The role of vitamin D (25(OH)D) in the pathogenesis and outcome of several conditions, including autoimmune diseases, diabetes and cancers is largely described in the literature. The aims of this study were to evaluate the prevalence of 25(OH)D deficit in a cohort of patients with neuroendocrine neoplasms (NENs) in comparison to a matched healthy control group and to analyze the possible role of 25(OH)D as a prognostic factor for NENs in terms of biological aggressiveness, tumor progression and survival. Methods: From 2009 to 2023, 172 patients with NENs (99 females; median age, 63 years) were included in the study. Serum 25(OH)D levels were defined as deficient if ≤20 ng/mL. The possible associations between 25(OH)D levels and disease grading, staging, ki67%, overall survival (OS), and progression-free survival (PFS) were considered. Results: NEN patients had significantly lower 25(OH)D levels compared to controls (p < 0.001) regardless of the primary origin. Patients with 25(OH)D < 20 ng/mL had a significantly higher ki67 index (p = 0.02) compared to the ones with 25(OH)D levels above 20 ng/mL. Patients with disease progression were found to have a significantly lower 25(OH)D at baseline (p = 0.02), whereas PFS and OS were not significantly influenced by 25(OH)D. Conclusions: Vitamin D deficiency is highly prevalent among NENs and is associated with higher ki67 and disease progression. Our study highlights the importance of monitoring 25(OH)D levels in patients with NENs, as its deficiency appeared to be linked to the worst biological tumor aggressiveness.

Calcium-stimulated calcitonin test for the diagnosis of medullary thyroid cancer: results of a multicenter study and comparison between different assays.

BACKGROUND: A basal serum calcitonin (Ct) increase >100 pg/mL in patients with a thyroid nodule is consistent with the diagnosis of medullary thyroid cancer (MTC). In cases where the CT test have a slight to moderate increase, the calcium gluconate stimulation test is helpful to increase diagnostic accuracy. However, reliable cut-offs for calcium-stimulated Ct are still lacking. The aim of this study was to evaluate the sex-specific calcium-stimulated Ct cutoffs for the diagnosis of MTC in a multicenter series. A comparison between different Ct assays has been also performed. METHODS: 90 subjects undergone calcium-stimulated Ct for a suspected MTC in 5 Endocrine Units between 2010-2021 were retrospectively analyzed. Serum Ct concentrations were assessed by immunoradiometric (IRMA) or chemiluminescence (CLIA) assays. RESULTS: MTC was diagnosed in 37 (41.1%) and excluded in 53 (58.9%) patients. The best calcium-stimulated Ct cut-off to identify MTC was 611 pg/mL in males (AUC =0.90, 95% CI (0.76;1) and 445 pg/mL in females (AUC=0.79, 95% CI (0.66;0.91). Logistic regression analysis showed that both basal (OR 1.01, P=0.003) and peak Ct after stimulation (OR 1.07, P=0.007) were significantly associated with MTC, together with sex (OR=0.06, P<0.001). The "Ct assay" variable was also considered in the logistic regression model, but it was not significantly associated with MTC (OR=0.93, P=0.919). CONCLUSIONS: This study indicates that calcium test could be helpful to identify patients with early-stage MTC and those without MTC. A Ct value of 611 pg/mL in males and 445 pg/mL in females are proposed as the optimal Ct cut-offs at the stimulation test.

An unusual cause of adrenal insufficiency with elevation of 17-hydroxyprogesterone: case report.

BACKGROUND: We present an intriguing case of primary adrenal lymphoma, with associated primary adrenal insufficiency (PAI), in a patient presenting a transitory partial 21-hydroxylase deficiency during the active phase of the adrenal disease. CASE PRESENTATION: An 85-years old woman was referred because of worsening asthenia, lumbar pain, generalized myalgia and arthralgia. During investigations a computed tomography (CT) scan evidenced two large bilateral adrenal masses, highly suspicious for primary adrenal tumor. The hormonal assessment revealed very low levels of morning plasma cortisol and 24-h urinary cortisol, elevated ACTH levels with low plasma concentration of aldosterone, pointing to the diagnosis of PAI. After diagnosis of PAI our patient started glucocorticoid and mineralcorticoid replacement therapy with clinical benefit. In order to further characterize the adrenal lesions, adrenal biopsy, was performed. The histology revealed a high grade non-Hodgkin lymphoma with an immunophenotype consistent with intermediate aspects between diffuse large B-cell and Burkitt lymphoma, with a high proliferation index (KI-67 > 90%). The patient received chemotherapy with epirubicin, vincristine, cyclophosphamide, and rituximab, associated with methylprednisolone that resulted in a complete clinical and radiological remission within one year. After 2 years from the diagnosis and a total of 6 cycles of rituximab, the patient was in good clinical condition and was taking only the replacement therapy for PAI. The patient initially presented also a slight increase of 17-hydroxyprogesterone (17-OHP) for age that normalize after resolution of lymphoproliferative disease. CONCLUSIONS: In the presence of bilateral adrenal disease and/or in the presence of signs and symptoms of PAI clinicians must exclude the presence of PAL. The evidence of elevated ACTH-stimulated 17-OHP levels also in patients with other adrenal masses, together with the detection of elevated basal 17-OHP levels in our patient make it more plausible, in our view, an effect of the lesion on the "healthy" adrenal tissue residue than a direct secretory activity by the adrenal tumor.

The diagnostic and prognostic role of combined [18F]FDG and [68Ga]-DOTA-peptides PET/CT in primary pulmonary carcinoids: a multicentric experience.

OBJECTIVES: In the present retrospective multicentric study, we combined [68Ga]-DOTA-peptides and [18F]FDG-PET/CT findings aiming to investigate their capability to differentiate typical (TC) and atypical pulmonary carcinoids (AC) and their prognostic role. METHODS: From three centers, 61 patients were retrospectively included. Based on a dual tracer combination we classified PET scans as score 1, [18F]FDG- and [68Ga]-DOTA-peptides negative; score 2, [68Ga]-DOTA-peptides positive and [18F]FDG-negative; score 3, [68Ga]-DOTA-peptides negative and [18F]FDG-positive; score 4, both tracers positive. Moreover, for each patient, the ratios of SUVmax on [68Ga]-DOTA-PET to that on [18F]FDG-PET were calculated (SUVr). RESULTS: Thirty-five patients had a final diagnosis of TC. Twenty-two TC (57%) had positive [68Ga]-DOTA-peptides PET; instead, 21/26 (81%) AC had positive [18F]FDG-PET/CT. On dual-tracer analysis, scores 1, 2, 3 and 4 were 13%, 20%, 43% and 24% for all populations; 17%, 26%, 20% and 37% for TC; 8%, 11%, 73% and 8% for AC. Median SUVr was significantly higher in TC than AC (6.4 vs. 0.4, p = 0.011). The best value of SUVr to predict the final diagnosis was 1.05 (AUC 0.889). Relapse or progression of disease happened in 17 patients (11 affected by AC) and death in 10 cases (7 AC). AC diagnosis, positive [18F]FDG-PET, negative DOTA-PET and dual tracer score were significantly correlated with PFS (p = 0.013, p = 0.033, p = 0.029 and p = 0.019), while only AC diagnosis with OS (p = 0.022). CONCLUSION: PET/CT findings had also a prognostic role in predicting PFS. Dual-tracer PET behavior may be used to predict the nature of pulmonary carcinoids and select the most appropriate management. KEY POINTS: • Combination of [18F]FDG and [68Ga]-DOTA-peptides PET/CT results may help to differentiate between atypical and typical lung carcinoids. • The SUVmax ratio between [18F]FDG and [68Ga]-DOTA-peptides PET may help to differentiate between atypical and typical lung carcinoids. • Histotype and PET/CT features have a prognostic impact on PFS.

Prognostic Effect of Lymph Node Metastases and Mesenteric Deposits in Neuroendocrine Tumors of the Small Bowel.

Well-differentiated, low-grade neuroendocrine tumors (NETs) are the most frequent tumor types of the small bowel. Despite their generally indolent growth patterns and grade, these tumors tend to metastasize; indeed, at presentation, approximately 50% show nodal metastases and 30% of patients have distant metastases, even though they potentially show long survival. Little is available in the literature concerning the optimal nodal yield in small-bowel resections, and the clinical significance of nodal metastases and lymph node ratio (LNR) at this site is still debated. The aim of this review, through a systematic literature search, is to explore and analyze data regarding nodal status, adequacy of lymphadenectomy, and LNR on the prognosis of small bowel NETs using defined end points (progression-free survival, recurrence-free survival, and overall survival). Some surgical series have demonstrated that extended regional mesenteric lymphadenectomy, together with primary tumor resection, is associated with improved patient survival, and LNR is proving a prognostically important parameter. The new feature of mesenteric tumor deposits (MTDs; neoplastic deposits found in the mesenteric perivisceral adipose tissue that are not LN associated) seems to be a better prognostic predictor in small-bowel NETs compared to nodal metastases, and this feature is explored and critiqued in this review. In particular, increasing number of tumor deposits is correlated with increased risk of disease-specific death, and MTDs seem to correlate with peritoneal carcinomatosis.

2-[18F]FDG PET in the Management of Radioiodine Refractory Differentiated Thyroid Cancer in the Era of Thyrosin-Kinases Inhibitors: A Real-Life Retrospective Study.

Purpose To evaluate the role of 2-[18F]FDGPET/CT in the follow-up of radioiodine refractory thyroid cancer (RR-TC). Methods Forty-six 2-[18F]FDGPET/CT scans from 14 RR-TC patients were considered. Thyroid function tests: thyroglobulin (Tg), levothyroxine (LT4), and tyrosine-kinases inhibitors (TKIs) assumptions were recorded. Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated from each scan and correlated with clinical parameters and the overall survival (OS). Results Baseline TLG and MTV predicted OS (p = 0.027 and p = 0.035), and negative correlation with OS was also confirmed when the same parameters were measured in follow-up scans (p = 0.015 and p = 0.021). Tg also correlated with the OS; (p = 0.014; p = 0.019 and p = 0.009). However, TLG and MTV were not significantly correlated with Tg levels. MTV and TLG variation in time were reduced during TKI therapy (p = 0.045 and p = 0.013). Conclusions 2-[18F]FDGPET/CT confirmed its prognostic role at the first assessment and during the follow-up of RR-TC patients. 2-[18F]FDGPET/CT parameters seem at least partially independent from Tg. TKI therapy resulted in a measurable effect on the variation of 2-[18F]FDGPET/CT parameters over time.

Insights into Mechanisms of Tumorigenesis in Neuroendocrine Neoplasms.

Genomic studies have identified some of the most relevant genetic players in Neuroendocrine Neoplasm (NEN) tumorigenesis. However, we are still far from being able to draw a model that encompasses their heterogeneity, elucidates the different biological effects consequent to the identified molecular events, or incorporates extensive knowledge of molecular biomarkers and therapeutic targets. Here, we reviewed recent insights in NEN tumorigenesis from selected basic research studies on animal models, highlighting novel players in the intergenic cooperation and peculiar mechanisms including splicing dysregulation, chromatin stability, or cell dedifferentiation. Furthermore, models of tumorigenesis based on composite interactions other than a linear progression of events are proposed, exemplified by the involvement in NEN tumorigenesis of genes regulating complex functions, such as MEN1 or DAXX. Although limited by interspecies differences, animal models have proved helpful for the more in-depth study of every facet of tumorigenesis, showing that the identification of driver mutations is only one of the many necessary steps and that other mechanisms are worth investigating.

Prognostic features of gastro-entero-pancreatic neuroendocrine neoplasms in primary and metastatic sites: Grade, mesenteric tumour deposits and emerging novelties.

Updates in classification of gastro-entero-pancreatic neuroendocrine neoplasms better reflect the biological characteristics of these tumours. In the present study, we analysed the characteristics of neuroendocrine tumours that could aid in a more precise stratification of risk groups. In addition, we have highlighted the importance of grade (re)assessment based on investigation of secondary tumour lesions. Two hundred and sixty-four cases of neuroendocrine tumours of gastro-entero-pancreatic origin from three centres were included in the study. Tumour morphology, mitotic count and Ki67 labelling index were evaluated in specimens of primary tumours, lymph node metastases and distant metastases. These variables were correlated with overall survival (OS) and relapse-free survival (RFS). Tumour stage, number of affected lymph nodes, presence of tumour deposits and synchronous/metachronous metastases were tested as possible prognostic features. Mitotic count, Ki-67 labelling index, primary tumour site, tumour stage, presence of tumour deposits and two or more affected lymph nodes were significant predictors of OS and RFS. At the same time, mitotic count and Ki-67 labelling index can be addressed as continuous variables determining prognosis. We observed a very high correlation between the measures of proliferative activity in primary and secondary tumour foci. The presence of isolated tumour deposits was identified as an important determinant of both RFS and OS for pancreatic (hazard ratio [HR] = 7.61, 95% confidence interval [CI] = 3.96-14.6, P < 0.0001 for RFS; HR = 3.28, 95% CI = 1.56-6.87, P = 0.0017 for OS) and ileal/jejunal neuroendocrine tumours (HR = 1.98, 95% CI = 1.25-3.13, P = 0.0036 for RFS and HR 2.59, 95% CI = 1.27-5.26, P = 0.009 for OS). The present study identifies the presence of mesenterial tumour deposits as an important prognostic factor for gastro-entero-pancreatic neuroendocrine tumours, provides evidence that proliferative parameters need to be treated as continuous variables and further supports the importance of grade determination in all available tumour foci.

Pathology Reporting in Neuroendocrine Neoplasms of the Digestive System: Everything You Always Wanted to Know but Were Too Afraid to Ask.

During the 5th NIKE (Neuroendocrine tumors Innovation in Knowledge and Education) meeting, held in Naples, Italy, in May 2019, discussions centered on the understanding of pathology reports of gastroenetropancreactic neuroendocrine neoplasms. In particular, the main problem concerned the difficulty that clinicians experience in extrapolating relevant information from neuroendocrine tumor pathology reports. During the meeting, participants were asked to identify and rate issues which they have encountered, for which the input of an expert pathologist would have been appreciated. This article is a collection of the most rated questions and relative answers, focusing on three main topics: 1) morphology and classification; 2) Ki67 and grading; 3) immunohistochemistry. Patient management should be based on multidisciplinary decisions, taking into account clinical and pathology-related features with clear comprehension between all health care professionals. Indeed, pathologists require clinical details and laboratory findings when relevant, while clinicians require concise and standardized reports. In keeping with this last statement, the minimum requirements in pathology datasets are provided in this paper and should be a baseline for all neuroendocrine tumor professionals.

"Present and future of immunotherapy in Neuroendocrine Tumors".

Immunotherapy, so promising in many neoplasms, still does not have a precise role in the treatment of neuroendocrine neoplasms (NENs). In this article, we provide an overview on the current knowledge about immunotherapy with immune checkpoint inhibitors (ICIs) applied to NENs, evaluating future perspectives in this setting of tumors.Evidence so far available for ICIs in gastroenteropancreatic (GEP)-NENs is definitively not as robust as for other tumors such as Small Cell Lung Cancer or Merkel Cell Carcinoma. In fact, with regard to the well-differentiated forms of NENs (NETs), the results obtained nowadays have been disappointing. However, the near future, might reserve interesting results for ICIs in GEP-NEN from a total of nine different ICI drugs, used throughout 19 randomised controlled trials. Such numbers highlight the growing attention gathering around NENs and ICIs, in response to the need of stronger evidences supporting such therapy.For the future, the most important aspect will be to study strategies that can make NETs more susceptible to response to ICI and, thus, enhance the effectiveness of these treatments. Therefore, the combination of conventional therapy, target therapy and immunotherapy deserve attention and warrant to be explored. A sequential chemotherapy, possibly inducing an increase in tumor mutational burden and tested before immunotherapy, could be a hypothesis deserving more consideration. A radiation treatment that increases tumor-infiltrating lymphocytes, could be another approach to explore before ICIs in NENs. Equally essential will be the identification of biomarkers useful for selecting patients potentially responsive to this type of treatment.

Efficacy of a Novel Second-Generation Somatostatin-Dopamine Chimera (TBR-065) in Human Medullary Thyroid Cancer: A Preclinical Study.

INTRODUCTION: Somatostatin and dopamine (DA) receptors have a pivotal role in controlling hormone secretion and cell proliferation in different neuroendocrine neoplasms, including medullary thyroid cancer (MTC). In the present preclinical study, we evaluated the anti-tumor activity of TBR-065 (formerly BIM-23B065), a second-generation somatostatin-DA chimera, in 2 human MTC cell lines. METHODS: The effects of lanreotide (LAN) and TBR-065 on cell growth and proliferation, calcitonin (CT) secretion, cell cycle, apoptosis, cell migration, and tumor-induced angiogenesis have been evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, DNA flow cytometry with propidium iodide (PI), Annexin V-FITC/PI staining, electrochemiluminescence immuno assay, wound-healing assay, and zebrafish platform, respectively. RESULTS: TBR-065 exerted a more prominent anti-tumor activity than LAN in both MTC cell lines, as shown by inhibition of cell proliferation (maximal inhibition in TT: -50.3 and -37.6%, respectively; in MZ-CRC-1: -58.8 and -27%, respectively) and migration (in TT: -42.7 and -22.9%, respectively; in MZ-CRC-1: -75.5 and -58.2%, respectively). Only the new chimera decreased significantly the fraction of cells in S phase (TT: -33.8%; MZ-CRC-1: -18.8%) and increased cells in G2/M phase (TT: +13%; MZ-CRC-1: +30.5%). In addition, TBR-065 exerted a more prominent pro-apoptotic effect than LAN in TT cells. A concomitant decrease in CT secretion was observed after 2 days of incubation with both drugs, with a more relevant effect of TBR-065. However, neither LAN nor TBR-065 showed any effect on tumor-induced angiogenesis, as evaluated using a zebrafish/tumor xenograft model. DISCUSSION/CONCLUSION: In MTC cell lines, a second-generation somatostatin-DA analog, TBR-065, exerts a more relevant anti-tumor activity than LAN, through modulation of cell cycle, induction of apoptosis, and reduction in migration. Further studies are required to establish whether TBR-065 has comparable potent inhibitory effects on tumor growth in vivo.

From microbiota toward gastro-enteropancreatic neuroendocrine neoplasms: Are we on the highway to hell?

Gut microbiota is represented by different microorganisms that colonize the intestinal tract, mostly the large intestine, such as bacteria, fungi, archaea and viruses. The gut microbial balance has a key role in several functions. It modulates the host's metabolism, maintains the gut barrier integrity, participates in the xenobiotics and drug metabolism, and acts as protection against gastro-intestinal pathogens through the host's immune system modulation. The impaired gut microbiota, called dysbiosis, may be the result of an imbalance in this equilibrium and is linked with different diseases, including cancer. While most of the studies have focused on the association between microbiota and gastrointestinal adenocarcinomas, very little is known about gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs). In this review, we provide an overview concerning the complex interplay between gut microbiota and GEP NENs, focusing on the potential role in tumorigenesis and progression in these tumors.

Epidemiology of pancreatic neuroendocrine neoplasms: a gender perspective.

PURPOSE: Pancreatic neuroendocrine neoplasms (PNENs) are a group of clinically rare and heterogeneous tumors of the pancreas. Currently there are no studies investigating the gender difference in PNEN susceptibility. Thus, the purpose of this study was aimed at examining how gender shapes risk factors, clinicopathological features, and comorbidities in PNENs. METHODS: The study design consisted of an Italian multicenter, retrospective study. The study included all consecutive patients with PNENs followed at the participating centers. Two hundred and twenty-nine patients (105 males,124 females, age 54 ± 0.98 years) with PNENs were enrolled at the participating centers. The clinicopathological features (age, gender, BMI, histology, tumor size, tumor grade, distant metastasis, hormonal function, and diagnostic circumstances), comorbidities (cardiovascular diseases (CVD), pancreatitis, type 2 diabetes (T2DM), and potential risk factors (smoking and drinking) were included in the analysis. RESULTS: Females were slightly prevalent (54.15%). PNENs were diagnosed at younger age in females compared to males (p = 0.04). The prevalence of CVD was significantly higher in males than in females (p = 0.006). In the female group, the presence of T2DM was significantly associated with higher tumor grade (p = 0.04) and metastatic disease (p = 0.02). The proportion of smokers and alcohol drinkers was significantly higher in the male group (p < 0.001). No significant gender differences were detected regarding the other parameters included in the analysis. CONCLUSIONS: This study has identified gender differences of PNENs in terms of age at diagnosis, associated comorbidities, and potential risk factors. A gender-tailored approach could become a potential strategy to better understand the natural history of PNENs and improve the effectiveness of PNENs clinical management.

Biliary Stone Disease in Patients with Neuroendocrine Tumors Treated with Somatostatin Analogs: A Multicenter Study.

BACKGROUND: Somatostatin analogs (SSAs) are the mainstay of neuroendocrine tumor (NET) treatment. Biliary stone disease is reported as a common side effect of SSAs, with a frequency ranging from 10% to 63%. Studies on SSA-treated patients for acromegaly report an increased incidence of biliary stone disease compared with the general population, whereas data on patients with NETs are few. Guidelines are based on weak evidence, thus resulting in conflicting recommendations. The aim of the study is to evaluate biliary stone disease incidence, complications, and risk factors in a large population of SSA-treated patients with NETs. MATERIALS AND METHODS: A retrospective analysis of a prospectively collected database was performed. Patients with a diagnosis of NET in seven dedicated centers from 1995 to 2017 were included at the time of SSA start. RESULTS: A total of 754 SSA-treated patients were evaluated. Patients with history of cholecystectomy or with known biliary stone disease were excluded; 478 patients were included. Among them, 118 patients (24.7%) received prophylactic ursodeoxycholic acid (UDCA). During the study period, 129 patients (27.0%) developed biliary stone disease; of them, 36 (27.9%) developed biliary complications. On multivariate analysis, primary gastrointestinal (GI)-NET (hazard ratio [HR] 1.76) and related surgery (HR 1.58) were independent risk factors for biliary stone disease. CONCLUSION: We report a high incidence of biliary stone disease particularly in GI-NET or GI surgery. UDCA prophylaxis does not seem to have a protective role. Our data suggest that all patients with primary GI-NET or undergoing abdominal surgery should be considered for prophylactic cholecystectomy; no conclusion could be drawn on the indication of prophylactic cholecystectomy in patients with primary pancreatic or thoracic NET for whom abdominal surgery is not planned. IMPLICATIONS FOR PRACTICE: The results of this study confirm an increased rate of gallstones development and related complications in patients with neuroendocrine tumors (NETs) treated with somatostatin analogs (SSAs). NETs of the gastrointestinal (GI) tract and related surgery are independent risk factors for biliary stone disease development. Therefore, all patients with primary GI-NET or undergoing abdominal surgery should be considered for prophylactic cholecystectomy. Data on other subgroups are not exhaustive, and management also evaluating additional clinical features (life expectancy, surgical and anesthesiological risks) should be considered. Prophylactic treatment with ursodeoxycholic acid does not seem to be a protective factor for SSA-related biliary stone disease.

Nonconventional Doses of Somatostatin Analogs in Patients With Progressing Well-Differentiated Neuroendocrine Tumor.

PURPOSE: To evaluate the antiproliferative activity and safety of nonconventional high doses of somatostatin analogs (HD-SSA) in patients with well-differentiated gastroenteropancreatic (GEP) neuroendocrine tumors (NET) with radiological disease progression according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria on a previous treatment. METHODS: A retrospective analysis of prospectively maintained databases from 13 Italian NET-dedicated centers was performed. Main inclusion criteria were: well-differentiated G1 or G2 GEP-NET, progressive disease on a previous treatment, and subsequent treatment with HD-SSA (either by increased administered dose [dose intensity] or shortened interval between administrations [dose density]). Main endpoints were progression-free survival (PFS) and safety. RESULTS: Of 198 patients, 140 matched inclusion criteria and were included in the analysis. Overall, median PFS was 31 months. Use of HD-SSA as second-line treatment was associated with reduced risk for progression or death compared with third- or further-line treatment (HR: 2.12; P = 0.004). There was no difference in PFS between HD-SSA by increased dose density (N = 133; 95%) or intensity (N = 7; 5%). Partial response according to RECIST criteria was observed in 12 patients (8.6%), and stable disease was achieved in 106 (75.7%) patients. Adverse events occurred in 21 patients (15.0%), 2 of whom had grade 3 biliary stone disease. No patients discontinued HD-SSA treatment due to adverse events. CONCLUSIONS: HD-SSA is an active and safe treatment option in patients with progressive well-differentiated GEP-NET. The high rate of objective responses observed deserves prospective validation in ad hoc clinical trials.

Morphological Factors Related to Nodal Metastases in Neuroendocrine Tumors of the Appendix: A Multicentric Retrospective Study.

OBJECTIVE: The aim of this study was to evaluate clinical and morphological features related to nodal involvement in appendiceal neuroendocrine tumors (NETs), to identify patients who should be referred for oncological radicalization with hemicolectomy. BACKGROUND: Appendiceal NETs are usually diagnosed accidentally after appendectomy; the indications for right hemicolectomy are currently based on several parameters (ie, tumor size, grading, proliferative index, localization, mesoappendiceal invasion, lymphovascular infiltration). Available guidelines are based on scarce evidence inferred by small, retrospective, single-institution studies, resulting in discordant recommendations. METHODS: A retrospective analysis of a prospectively collected database was performed. Patients who underwent surgical resection of appendiceal NETs at 11 tertiary Italian centers, from January 1990 to December 2015, were included. Clinical and morphological data were analyzed to identify factors related to nodal involvement. RESULTS: Four-hundred fifty-seven patients were evaluated, and 435 were finally included and analyzed. Of them, 21 had nodal involvement. Grading G2 [odds ratio (OR) 6.04], lymphovascular infiltration (OR 10.17), size (OR 18.50), and mesoappendiceal invasion (OR 3.63) were related to nodal disease. Receiver operating characteristic curve identified >15.5 mm as the best size cutoff value (area under the curve 0.747). On multivariate analysis, grading G2 (OR 6.98), lymphovascular infiltration (OR 8.63), and size >15.5 mm (OR 35.28) were independently related to nodal involvement. CONCLUSIONS: Tumor size >15.5 mm, grading G2, and presence of lymphovascular infiltration are factors independently related to nodal metastases in appendiceal NETs. Presence of ≥1 of these features should be considered an indication for oncological radicalization. Although these results represent the largest study currently available, prospective validation is needed.

Biological and Biochemical Basis of the Differential Efficacy of First and Second Generation Somatostatin Receptor Ligands in Neuroendocrine Neoplasms.

Endogenous somatostatin shows anti-secretory effects in both physiological and pathological settings, as well as inhibitory activity on cell growth. Since somatostatin is not suitable for clinical practice, researchers developed synthetic somatostatin receptor ligands (SRLs) to overcome this limitation. Currently, SRLs represent pivotal tools in the treatment algorithm of neuroendocrine tumors (NETs). Octreotide and lanreotide are the first-generation SRLs developed and show a preferential binding affinity to somatostatin receptor (SST) subtype 2, while pasireotide, which is a second-generation SRL, has high affinity for multiple SSTs (SST5 > SST2 > SST3 > SST1). A number of studies demonstrated that first-generation and second-generation SRLs show distinct functional properties, besides the mere receptor affinity. Therefore, the aim of the present review is to critically review the current evidence on the biological effects of SRLs in pituitary adenomas and neuroendocrine tumors, by mainly focusing on the differences between first-generation and second-generation ligands.