Treatment Of Neuroendocrine Tumors Research Articles

Association of guideline adherence in diagnosis and treatment of pancreatic neuroendocrine tumors with survival.

e16241 Background: Clinical guidelines and their adherence are important instruments to ensure quality in diagnosis and treatment, especially when treating rare diseases like pancreatic neuroendocrine tumors (PanNET). However, data on guideline adherence and its impact on outcome in PanNET is limited. Methods: Cases of PanNET according to 2017 WHO definition at our university hospital between 2010 and 2019 were retrospectively identified. Adherence to ENETS guideline 2007/2012 and the German S2k guideline was evaluated among four categories (diagnostics: chromogranin A (CgA) testing, somatostatin receptor imaging, discussion in an interdisciplinary tumor board; pathology: reporting of grading, Ki67 and synaptophysin expression; surgical treatment; systemic treatment including aftercare). Guideline adherence within these categories was valued with one point per fulfilled criterion and a final score between 0-8 points was calculated. Data was analyzed using Student’s t-test, Chi-square test and Spearman’s correlation coefficient test. Results were considered significant at α = 0.05. Results: Overall, 115 patients (47% female) with a diagnosis of PanNET were identified. Mean age was 61 (±13.5) years. Mean overall survival (OS) was 45 months, mean recurrence free survival (RFS) was 47 months. During the study period 21 patients (18%) had died, 6 patients (5%) were lost-to-follow-up and 11 patients (10%) had a recurrent disease after initially curative resection. 24 patients (21%) presented with metastatic disease upon diagnosis. Guideline adherence concerning pathology reports (97%) as well as systemic (91%) and surgical treatment (75%) was high, while complete adherence in diagnostic modalities was low (5%). However, the latter was mainly driven by lack of CgA testing (31%), and somatostatin receptor imaging (11%) not being performed on initial diagnosis, but in most cases during follow-up. Subsequently, complete guideline adherence (8/8) across all categories was rare (3%). However, a higher overall score was associated with survival (p = 0.032, V = 0.321). Long term survivors had a higher mean overall adherence score (5.6 vs. 6.1; p = 0.05). In addition, the composite score of surgical and systemic therapy was significantly correlated with RFS (ρ = 0.254, p = 0.016). Conclusions: The quality in diagnosis and treatment of PanNET in our cohort was high. These are the first data to demonstrate a positive impact of guideline adherence on survival and RFS in PanNET.

Real world use of lanreotide in neuroendocrine tumors.

Treatment for metastatic neuroendocrine tumors (NETs) is often with somatostatin analogues (SSA) such as lanreotide in the first-line setting. Real world use of lanreotide in Canada is not well studied. We performed a retrospective chart review of 69 patients to study real world use of lanreotide at our centre. Lanreotide was the first-line of systemic treatment in 60 patients. Watch-and-wait was a common strategy and was seen in 31 patients. SSA switch strategy was seldom applied. Majority of patients on lanreotide had low-grade NETs. Standard starting dose of lanreotide 120 mg every 28 days was used in 66 patients. Dose escalation to 120 mg every 21 days occurred in 7 patients. The primary intention for treatment was tumor control in 32 patients, and both tumor and symptom control in 34 patients. Median time on treatment was 21.6 months. Overall, our findings were in keeping with current guidelines. It will be interesting to assess how clinical practice evolves in the future and to determine the role of dose escalation for disease control.

Consensus report of the 2021 National Cancer Institute neuroendocrine tumor clinical trials planning meeting.

Important progress has been made over the last decade in the classification, imaging, and treatment of neuroendocrine neoplasm (NENs), with several new agents approved for use. Although the treatment options available for patients with well-differentiated neuroendocrine tumors (NETs) have greatly expanded, the rapidly changing landscape has presented several unanswered questions about how best to optimize, sequence, and individualize therapy. Perhaps the most important development over the last decade has been the approval of 177Lu-DOTATATE for treatment of gastroenteropancreatic-NETs, raising questions around optimal sequencing of peptide receptor radionuclide therapy (PRRT) relative to other therapeutic options, the role of re-treatment with PRRT, and whether PRRT can be further optimized through use of dosimetry among other approaches. The NET Task Force of the National Cancer Institute GI Steering Committee convened a clinical trial planning meeting in 2021 with multidisciplinary experts from academia, the federal government, industry, and patient advocates to develop NET clinical trials in the era of PRRT. Key clinical trial recommendations for development included 1) PRRT re-treatment, 2) PRRT and immunotherapy combinations, 3) PRRT and DNA damage repair inhibitor combinations, 4) treatment for liver-dominant disease, 5) treatment for PRRT-resistant disease, and 6) dosimetry-modified PRRT.

Epidemiology of neuroendocrine tumors (NETs) and socio-clinical profile of patients according to data from the National Cancer Registry and the Federal Patient Registry of the MOLNEO Medical Society for Treatment of Neuroendocrine Tumor

It is well known that the incidence of NETs significantly exceeds the increase in the incidence of all other malignant tumors.

161Tb-DOTATOC Production Using a Fully Automated Disposable Cassette System: A First Step Toward the Introduction of 161Tb into the Clinic.

161Tb is an interesting radionuclide for application in the treatment of neuroendocrine neoplasms' small metastases and single cancer cells because of its conversion and Auger-electron emission. Tb has coordination chemistry similar to that of Lu; therefore, like 177Lu, it can stably radiolabel DOTATOC, one of the leading peptides used for the treatment of neuroendocrine neoplasms. However, 161Tb is a recently developed radionuclide that has not yet been specified for clinical use. Therefore, the aim of the current work was to characterize and specify 161Tb and to develop a protocol for the synthesis and quality control of 161Tb-DOTATOC with a fully automated process conforming to good-manufacturing-practice guidelines, in view of its clinical use. Methods: 161Tb, produced by neutron irradiation of 160Gd in high-flux reactors followed by radiochemical separation from its target material, was characterized regarding its radionuclidic purity, chemical purity, endotoxin level, and radiochemical purity (RCP) in analogy to what is described in the European Pharmacopoeia for no-carrier-added 177Lu. In addition, 161Tb was introduced into a fully automated cassette-module synthesis to produce 161Tb-DOTATOC, as used for 177Lu-DOTATOC. The quality and stability of the produced radiopharmaceutical in terms of identity, RCP, and ethanol and endotoxin content were assessed by means of high-performance liquid chromatography, gas chromatography, and an endotoxin test, respectively. Results: 161Tb produced under the described conditions showed, as the no-carrier-added 177Lu, a pH of 1-2, radionuclidic purity and RCP of more than 99.9%, and an endotoxin level below the permitted range (175 IU/mL), indicating its appropriate quality for clinical use. In addition, an efficient and robust procedure for the automated production and quality control of 161Tb-DOTATOC with clinically applicable specifications and activity levels, that is, 1.0-7.4 GBq in 20 mL, was developed. The radiopharmaceutical's quality control was also developed using chromatographic methods, which confirmed the product's stability (RCP ≥ 95%) over 24 h. Conclusion: The current study demonstrated that 161Tb has appropriate features for clinical use. The developed synthesis protocol guarantees high yields and safe preparation of injectable 161Tb-DOTATOC. The investigated approach could be translated to other DOTA-derivatized peptides; thus, 161Tb could be successfully applied in clinical practice for radionuclide therapy.

Epigenetic regulation of SST2 expression in small intestinal neuroendocrine tumors.

Somatostatin receptor type 2 (SST2) expression is critical for the diagnosis and treatment of neuroendocrine tumors and is associated with improved patient survival. Recent data suggest that epigenetic changes such as DNA methylation and histone modifications play an important role in regulating SST2 expression and tumorigenesis of NETs. However, there are limited data on the association between epigenetic marks and SST2 expression in small intestinal neuroendocrine tumors (SI-NETs). Tissue samples from 16 patients diagnosed with SI-NETs and undergoing surgical resection of the primary tumor at Erasmus MC Rotterdam were analysed for SST2 expression levels and epigenetic marks surrounding the SST2 promoter region, i.e. DNA methylation and histone modifications H3K27me3 and H3K9ac. As a control, 13 normal SI-tissue samples were included. The SI-NET samples had high SST2 protein and mRNA expression levels; a median (IQR) of 80% (70-95) SST2-positive cells and 8.2 times elevated SST2 mRNA expression level compared to normal SI-tissue (p=0.0042). In comparison to normal SI-tissue, DNA methylation levels and H3K27me3 levels were significantly lower at five out of the eight targeted CpG positions and at two out of the three examined locations within the SST2 gene promoter region of the SI-NET samples, respectively. No differences in the level of activating histone mark H3K9ac were observed between matched samples. While no correlation was found between histone modification marks and SST2 expression, SST2 mRNA expression levels correlated negatively with DNA methylation within the SST2 promoter region in both normal SI-tissue and SI-NETs (p=0.006 and p=0.04, respectively). SI-NETs have lower SST2 promoter methylation levels and lower H3K27me3 methylation levels compared to normal SI-tissue. Moreover, in contrast to the absence of a correlation with SST2 protein expression levels, significant negative correlations were found between SST2 mRNA expression level and the mean level of DNA methylation within the SST2 promoter region in both normal SI-tissue and SI-NET tissue. These results indicate that DNA methylation might be involved in regulating SST2 expression. However, the role of histone modifications in SI-NETs remains elusive.

Endoscopic Ultrasound-Guided Local Ablative Therapies for the Treatment of Pancreatic Neuroendocrine Tumors and Cystic Lesions: A Review of the Current Literature.

Since its emergence as a diagnostic modality in the 1980s, endoscopic ultrasound (EUS) has provided the clinician profound access to gastrointestinal organs to aid in the direct visualization, sampling, and subsequent identification of pancreatic pathology. In recent years, advancements in EUS as an interventional technique have promoted the use of local ablative therapies as a minimally invasive alternative to the surgical management of pancreatic neuroendocrine tumors (pNETs) and pancreatic cystic neoplasms (PCNs), especially for those deemed to be poor operative candidates. EUS-guided local therapies have demonstrated promising efficacy in addressing a spectrum of pancreatic neoplasms, while also balancing local adverse effects on healthy parenchyma. This article serves as a review of the current literature detailing the mechanisms, outcomes, complications, and limitations of EUS-guided local ablative therapies such as chemical ablation and radiofrequency ablation (RFA) for the treatment of pNETs and PCNs, as well as a discussion of future applications of EUS-guided techniques to address a broader scope of pancreatic pathology.

Efficacy and safety of temozolomide in the treatment of aggressive pituitary neuroendocrine tumours in Spain

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

An international, simulated-use study assessing nurses' preferences between two lanreotide syringes (Somatuline Autogel vs Pharmathen) for treatment of neuroendocrine tumours (NETs) and/or acromegaly: PRESTO 3

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

In silico Study on the Binding Interactions of SSTA and 18F-SSTA Towards Somatostatin Receptor Subtype 2.

Somatostatin analogs (SSTAs) are versatile drugs that target a group of proteins known as somatostatin receptors. SSTAs are used for the treatment and PET-molecular imaging of Neuro Endocrine Tumors (NET), for they are labeled with the radionuclide 18F, a positron emitter radionuclide. The aim of this work was to theoretically study the binding interactions of SSTA labeled with 18F (half-life of 109.7 min) and somatostatin receptor subtype 2. As the labeling of SSTA with 18F required the use of a prosthetic group, a hydrophilicity enhancer, and a linker, the influence of these traits on the interactions of 18F-SSTA with the SSTR-2 binding site was studied. The binding modes of 18F-labeled analogues with SSTR-2 were studied by using protein homology modelling, non-equilibrium molecular dynamics, and molecular docking calculations, by means of three docking software: MVD, MOE, and VINA. The results showed the main role of Asp122, Asn276, Phe272 and Phe294 from the SSTR-2 binding site, which form interactions with residues Lys, Trp, Tyr, and Thr from 18F-labeled somatostatin analogues. The interaction between Lys (from 18F-SSTA) and Asp122 (from SSTR-2) was identified as the most energetic and considered the one that drives the binding between 18F-SSTA and SSTR-2 (the anchor interaction). Despite the presence of prosthetic groups, linkers, and hydrophilicity enhancers, all the studied 18F-SSTA formed the anchor interaction. The trend in the results agreed with the experimental reports, identifying the main role of Asp122 in the binding of somatostatin-14 to SSTR-2.

Safety and Therapeutic Optimization of Lutetium-177 Based Radiopharmaceuticals.

Peptide receptor radionuclide therapy (PRRT) using Lutetium-177 (177Lu) based radiopharmaceuticals has emerged as a therapeutic area in the field of nuclear medicine and oncology, allowing for personalized medicine. Since the first market authorization in 2018 of [¹⁷⁷Lu]Lu-DOTATATE (Lutathera®) targeting somatostatin receptor type 2 in the treatment of gastroenteropancreatic neuroendocrine tumors, intensive research has led to transfer innovative 177Lu containing pharmaceuticals to the clinic. Recently, a second market authorization in the field was obtained for [¹⁷⁷Lu]Lu-PSMA-617 (Pluvicto®) in the treatment of prostate cancer. The efficacy of 177Lu radiopharmaceuticals are now quite well-reported and data on the safety and management of patients are needed. This review will focus on several clinically tested and reported tailored approaches to enhance the risk-benefit trade-off of radioligand therapy. The aim is to help clinicians and nuclear medicine staff set up safe and optimized procedures using the approved 177Lu based radiopharmaceuticals.

Treatment of localized well-differentiated rectal neuroendocrine tumors: A focused review

Abstract The frequency of rectal neuroendocrine tumors increases with the increase in the number of colonoscopies performed for colorectal cancer screening. The treatment of localized rectal well-differentiated neuroendocrine tumors involves local excision, including endoscopic treatment or rectal resection with lymphadenectomy. Although it is important to determine the risk of lymph node metastasis, there are points of disagreement among the guidelines regarding surgical indications. In this review, we discuss the current status of the treatment of well-differentiated rectal neuroendocrine tumors. The PubMed database was searched for relevant studies. In Japan, the criteria for curative endoscopic resection are very strict: less than 10 mm, G1, no invasion of the muscularis propria, no suspicion of lymph node metastasis, and no lymphovascular invasion. Meanwhile, in Western guidelines, local excision (endoscopic treatment is preferable) is recommended as the initial treatment for tumors measuring ≥10 mm and <20 mm in diameter, and radical surgery is recommended for tumors ≥20 mm in diameter. There are still many points where evidence is lacking, and future research is warranted.

Endoscopic mucosal resection with double band ligation versus endoscopic submucosal dissection for small rectal neuroendocrine tumors.

Endoscopic resection remains an effective method for the treatment of small rectal neuroendocrine tumors (NETs) (≤ 10 mm). Moreover, endoscopic mucosal resection (EMR) with double band ligation (EMR-dB), a simplified modification of EMR with band ligation, is an alternative strategy to remove small rectal NETs. To evaluate the feasibility and safety of EMR-dB for the treatment of small rectal NETs (≤ 10 mm). A total of 50 patients with small rectal NETs, without regional lymph node enlargement or distant metastasis confirmed by endoscopic ultrasound, computerized tomography scan, or magnetic resonance imaging, were enrolled in the study from March 2021 to June 2022. These patients were randomly assigned into the EMR-dB (n = 25) group or endoscopic submucosal dissection (ESD) group (n = 25). The characteristics of the patients and tumors, procedure time, devices cost, complete resection rate, complications, and recurrence outcomes were analyzed. There were 25 patients (13 males, 12 females; age range 28-68 years old) in the EMR-dB group, and the ESD group contained 25 patients (15 males, 10 females; age range 25-70 years old). Both groups had similar lesion sizes (EMR-dB 4.53 ± 1.02 mm, ESD 5.140 ± 1.74 mm; P = 0.141) and resected lesion sizes(1.32 ± 0.52 cm vs 1.58 ± 0.84 cm; P = 0.269). Furthermore, the histological complete resection and en bloc resection rates were achieved in all patients (100% for each). In addition, there was no significant difference in the complication rate between the two groups. However, the procedure time was significantly shorter and the devices cost was significantly lower in the EMR-dB group. Besides, there was no recurrence in both groups during the follow-up period. The procedure time of EMR-dB was shorter compared with ESD, and both approaches showed a similar curative effect. Taken together, EMR-dB was a feasible and safe option for the treatment of small rectal NETs.

Casting a Wider NET: Pancreatic Exocrine Insufficiency Induced by Somatostatin Analogues among Patients with Neuroendocrine Tumours?

Somatostatin-analogues (SSAs) are a first-line treatment of unresectable neuroendocrine tumours (NETs). However, SSAs inhibit pancreatic secretions, which could lead to pancreatic exocrine insufficiency (PEI). PEI is known to be detrimental to patient quality of life and nutritional status. This study aimed to evaluate the effect of SSAs on pancreatic exocrine function in patients with NETs, using the 13C-mixed triglyceride breath test (13C-MTGT). Exocrine function was assessed using the 13C-MTGT at baseline and after a third SSA injection (two months). A quotient of 13CO2/12CO2 was measured by mass spectrometry, and the cumulative percent dose recovered at 6 h (cPDR) is reported. The secondary endpoints investigated were change in weight, HbA1C, and vitamin D levels. Ten patients completed the study. Exocrine function reduced in all patients (n = 10) following SSA therapy (median reduction from baseline: -23.4% (range: -42.1-0.5%, p = 0.005)). vitamin D levels decreased in all but one patient (median decrease from baseline: -26.5%, (-44.7-10%; p = 0.038)), and median HbA1C levels increased by 8.0% (0-59.3%; p = 0.008). Change in weight was not significant (median decrease from baseline: -0.21% (-4.5-3.5%, p = 1.000)). SSA therapy has a consistent impact on exocrine function from early in the treatment course, but the long-term clinical effects of this remain to be defined. Further studies are required to determine the clinical relevance of this observation and optimise the management of PEI in this cohort.

Endoscopic Ultrasound-guided Radiofrequency Ablation Versus Surgical Resection for Treatment of Pancreatic Insulinoma

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is emerging as a safe and effective treatment for pancreatic neuroendocrine tumors. We aimed to compare EUS-RFA and surgical resection for the treatment of pancreatic insulinoma (PI). Patients with sporadic PI who underwent EUS-RFA at 23 centers or surgical resection at 8 high-volume pancreatic surgery institutions between 2014 and 2022 were retrospectively identified and outcomes compared using a propensity-matching analysis. Primary outcome was safety. Secondary outcomes were clinical efficacy, hospital stay, and recurrence rate after EUS-RFA. Using propensity score matching, 89 patients were allocated in each group (1:1), and were evenly distributed in terms of age, sex, Charlson comorbidity index, American Society of Anesthesiologists score, body mass index, distance between lesion and main pancreatic duct, lesion site, size, and grade. Adverse event (AE) rate was 18.0% and 61.8% after EUS-RFA and surgery, respectively (P < .001). No severe AEs were observed in the EUS-RFA group compared with 15.7% after surgery (P< .0001). Clinical efficacy was 100% after surgery and 95.5% after EUS-RFA (P= .160). However, the mean duration of follow-up time was shorter in the EUS-RFA group (median, 23 months; interquartile range, 14-31 months vs 37 months; interquartile range, 17.5-67 months in the surgical group; P < .0001). Hospital stay was significantly longer in the surgical group (11.1 ± 9.7 vs 3.0 ± 2.5 days in the EUS-RFA group; P < .0001). Fifteen lesions (16.9%) recurred after EUS-RFA and underwent a successful repeat EUS-RFA (11 patients) or surgical resection (4 patients). EUS-RFA is safer than surgery and highly effective for the treatment of PI. If confirmed in a randomized study, EUS-RFA treatment can become first-line therapy for sporadic PI.

The effect of endoscopic transsphenoidal somatotroph tumors resection on pituitary hormones: systematic review and meta-analysis

PurposeCurrently, endoscopic transsphenoidal surgery is the main treatment for pituitary neuroendocrine tumors (PitNETs). Excision of the tumor may have positive or negative effects on pituitary endocrine function, and the pituitary function of somatotroph tumors is a point of particular concern after the operation. This study aimed to conduct a meta-analysis on the effect of endoscopic transsphenoidal somatotroph tumor resection on pituitary function.MethodsA systematic literature search was conducted for articles that included the evaluation of pituitary target gland before and after endoscopic transsphenoidal pituitary tumor resection and were published between 1992 and 2022 in PubMed, Cochrane, and Ovid MEDLINE.ResultsSixty-eight studies that included biochemical remission rates in 4524 somatotroph tumors were concluded. According to the 2000 consensus, the biochemical remission rate after transsphenoidal endoscopic surgery was 66.4% (95% CI, 0.622–0.703; P = 0.000), the biochemical remission rate was 56.2% according to the 2010 consensus (95% CI, 0.503–0.620; P = 0.041), and with the rate of biochemical remission ranging from 30.0 to 91.7% with investigator’s definition. After endoscopic resection, adrenal axis dysfunction was slightly higher than that before surgery, but the difference was not statistically significant. Hypothyroidism was 0.712 times higher risk than that before surgery (OR = 0.712; 95% CI, 0.527–0.961; P = 0.027). Hypogonadism was 0.541 times higher risk than that before surgery (OR = 0.541; 95% CI, 0.393–0.746; P = 0.000). Hyperprolactinemia was 0.131 times higher risk than that before surgery (OR = 0.131; 95% CI, 0.022–0.783; P = 0.026). The incidence of pituitary insufficiency was 1.344 times the risk before surgery after endoscopic resection of somatotroph tumors, but the difference was not statistically significant.ConclusionsIn patients with somatotroph tumors after undergoing endoscopic surgery, the risk of dysfunction and pituitary insufficiency tend to increase, while preoperative thyroid insufficiency, gonadal insufficiency, and hyperprolactinemia will be partially relieved.

Spleen-Preserving Retrograde Distal Pancreatectomy for Malignant Insulinoma

Introduction: Distal pancreatectomy is performed primarily for malignant and premalignant diseases of the pancreas. Neuroendocrine tumors within the body and tail of the pancreas can be resected or enucleated depending upon the size and relationship of the tumor with the pancreatic duct.1,2 This video presents the technical details of a spleen-preserving laparoscopic distal pancreatectomy using a retrograde dissection (Kimura technique) for malignant pancreatic neuroendocrine tumor treatment. Operative Technique: A 47-year-old woman with medical history of hypertension and hypothyroidism comes to endocrinology presenting 3 months history of lumbar pain and 6 months history of neuroglycopenic symptoms. The work-up demonstrated hyperinsulinemic hypoglycemia produced by a 2.7 cm insulin-producing tumor of the body of the pancreas. A 1 cm cyst of the tail of the pancreas, a 5 mm sellar mass, and an adenoma of one parathyroid gland with elevated parathyroid hormone and calcium are seen as well, indicatory of a multiple endocrine neoplasia type 1.3–5 A five-trocar laparoscopic distal pancreatectomy was performed with one surgeon between the legs and two more surgeons on each side of the patient. The liver was retracted for better visibility and started with the section of splenocolic ligament to release the splenic angle of the colon and move it to the midline. Short gastric vessels of the gastrosplenic ligament are sectioned to address the posterior face of the stomach, through the lesser sac. The stomach was retracted cephalad, allowing for a better exposure of the pancreas. The insulinoma became visible on the anteroinferior margin and was well delimited with intraoperative manipulation. Pancreas is accessed through the retroperitoneum. Splenic vessels are dissected. The splenic artery and vein are identified and referred to be able to dissect along the upper edge of the pancreas, in a retrograde approach to preserve vascular structures. Ligaclips are placed on the branches of the splenic vessels. Transection is performed at the level of the junction of the head and neck of the pancreas, leaving enough space between the mass using a linear stapler capable of 60 mm long cuts and with 3.5 mm open staple height. The integrity of the piece is verified and is extracted with a laparoscopic specimen retrieval bag. In the case of this patient with previous surgery, an existing Pfannenstiel-type scar is used to avoid extension of the laparoscopic scars. Blake-type drain is placed in situ. Results: The postoperative course was uneventful. No postoperative diabetes was observed and no treatment for hypoglycemia was necessary. Early oral feeding postoperatively was well tolerated. The patient was discharged home 3 days after surgery with a placed drain. Histology analysis confirmed the full resection of the intrapancreatic neuroendocrine tumor. No competing financial interests exist. Runtime of video: 9 mins 24 secs

Liver transplantation in gastroenteropancreatic neuroendocrine tumors.

Neuroendocrine tumors are part of a heterogeneous group of tumors located in organs such as the gastrointestinal tract (GIT), lungs, thymus, thyroid, and adrenal glands. The most prevalent sites are the small intestine, cecal appendix, and pancreas. More than 50% of these tumors are associated with metastases at the time of diagnosis. Neuroendocrine tumors are classified according to the degree of cell differentiation and the histopathological proliferation index of the lesion. Neuroendocrine tumors can be well differentiated or poorly differentiated. G3 tumors are characterized by Ki-67 expression greater than 20% and can be either well differentiated (G3 NET) or poorly differentiated (G3 NEC). Neuroendocrine carcinoma (NEC G3) is subdivided into small-cell and large-cell types. When neuroendocrine tumors present clinical and compressive symptoms, carcinoid syndrome is evident. Carcinoid syndrome occurs when the tumor produces neuroendocrine mediators that cannot be metabolized by the liver due to either the size of the tumor or their secretion by the liver itself. Several therapeutic strategies have been described for the treatment of metastatic neuroendocrine tumors, including curative or palliative surgical approaches, peptide receptor radionuclide therapy, percutaneous therapy, systemic chemotherapy, and radiotherapy. Liver surgery is the only approach that can offer a cure for metastatic patients. Liver metastases must be completely resected, and in this context, orthotopic liver transplantation has gained prominence for yielding very promising outcomes in selected cases. The aim of this study is to review the literature on OLT as a form of treatment with curative intent for patients with gastroenteropancreatic neuroendocrine tumors with liver metastasis.

Real-world outcomes in patients with gastroenteropancreatic neuroendocrine tumors receiving somatostatin analogue: Data from a public hospital in Brazil.

650 Background: Neuroendocrine tumors are rare malignant neoplasms derived from endocrine cells and known for their heterogeneous behavior and histopathological characteristics; however, largely associated with a favorable clinical outcome. Somatostatin analogues (SSA) were initially used to control the symptoms of secretory neuroendocrine tumors, and later, they were considered effective as a first-line systemic treatment in unresectable or metastatic neuroendocrine tumors of the gastroenteropancreatic tract (NET-GEP). Randomized clinical trials are performed in controlled environments, with strict inclusion and exclusion criteria, and therefore, real-world studies can add to efficacy and safety data in the general population. Methods: To evaluate, in the real world scenario of a tertiary hospital of the public health system, the efficacy and toxicities of first-line treatment with somatostatin analogue in patients diagnosed with unresectable or metastatic NET-GEP, to find real-world progression free survival (rwPFS) and real-world overall survival (rwOS), in addition to the toxicity profile in our population and possible subgroups that benefit from first-line treatment, through the analysis of variables. Results: 29 patients met the study inclusion criteria, which were diagnosed in the period from 2009 to 2017. The median wrSLP and wrSG were 4.4 (95% CI 3.2 – 5.6) and 8.2 years (CI 95% 6.2 – 10.2), respectively. In an adjusted analysis of rwSLP, the HR for patients with hindgut tumors compared to midgut tumors was 4.41 with p 0.05, indicating that these patients had a 4x increased risk for disease progression (p 0 .05). In the adjusted analysis of wrSG, a trend towards a more favorable evolution was observed in the group of patients with well-differentiated tumors, with p 0.05. Assessment of toxicities revealed grade 2 and grade 3 adverse events in 34.48% of patients. Abdominal pain was the most incident toxicity, occurring in 17.24%, followed by headache (13.79%) and diarrhea (10.34%). Conclusions: Treatment with SSA was effective in our sample, with rwPFS and rwOS data above those found in randomized clinical trials. The toxicities were easily manageable and caused no documented harm to patients.

Development of a Novel Anti-SSTR Bispecific T-Cell Engager (BiTE)-like Molecule for the Treatment of Neuroendocrine Tumors

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)