Advances and Current Concepts in the Medical Management of Gastroenteropancreatic Neuroendocrine Neoplasms.
ABSTRACT: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare and heterogeneous group of tumors presenting as localised or metastatic disease and in a subset with distinct clinical syndromes. Treatment is aimed at controlling the functional syndrome, eradicating the tumor, and/or preventing further tumor growth. Surgery is the treatment of choice in removing the primary tumor and/or reducing tumor burden but cannot be applied to all patients. Somatostatin analogs (SS-analogs) obtain control of functional syndromes in the majority of GEP-neuroendocrine tumors (NETs); phase III trials have shown that SS-analogs can be used as first-line antiproliferative treatment in patients with slow-growing GEP-NETs. The role of the recently approved serotonin inhibitor, telotristat ethyl, and gastrin receptor antagonist, netazepide, is evolving. Streptozotocin-based chemotherapy has been used for inoperable or progressing pancreatic NENs but the orally administered combination of capecitabine/temozolomide is becoming more popular due to its better tolerability and potential effect in other GEP-NENs. Phase III trials have shown efficacy of molecular targeted therapies in GEP-NETs and of radionuclide treatment in patients with midgut carcinoid tumors expressing somatostatin receptors. Most patients will develop disease progression necessitating further therapeutic options. A combination of currently available treatments along with the molecular signature of each tumor will guide future treatment.
Project description:Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a large and very diverse group of neoplasms. Clinical presentation of NETs depends on the site of the primary tumor and whether the tumor is functioning (i.e., secreting peptides or neuroamines that produce symptoms). The diagnosis of GEP-NET is further complicated by symptomatic differences that occur depending on the type of secreted peptide or neuroamine. Due to their heterogeneity and unique characteristics, early diagnosis of GEP-NETs is difficult, which increases the likelihood of metastatic disease and reduces the scope of therapeutic possibilities. Thus, a multidisciplinary approach for the treatment of GEP-NETs is necessary. This review is the result of presentations that were delivered during an expert meeting on the treatment of GEP-NETs supported by Ipsen. We summarize the current knowledge on the epidemiology, incidence, diagnosis, and treatment of GEP-NETs. We examined the role of the somatostatin analog (SSA) lanreotide and the impact of the data from the recently published, randomized, double-blind, placebo-controlled CLARINET study (Controlled study of Lanreotide Antiproliferative Response In Neuroendocrine Tumors) on disease management. We also review the recent treatment options and recommendations for GEP-NETs.
Project description:BACKGROUND:Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a complex family of tumors of widely variable clinical behavior. The World Health Organization (WHO) 2010 classification provided a valuable tool to stratify neuroendocrine neoplasms (NENs) in three prognostic subgroups based on the proliferation index. However, substantial heterogeneity remains within these subgroups, and simplicity sometimes entails an ambiguous and imprecise prognostic stratification. The purpose of our study was to evaluate the prognostic impact of histological differentiation within the WHO 2010 grade (G) 1/G2/G3 categories, and explore additional Ki-67 cutoff values in GEP-NENs. SUBJECTS, MATERIALS, AND METHODS:A total of 2,813 patients from the Spanish National Tumor Registry (RGETNE) were analyzed. Cases were classified by histological differentiation as NETs (neuroendocrine tumors [well differentiated]) or NECs (neuroendocrine carcinomas [poorly differentiated]), and by Ki-67 index as G1 (Ki-67 <2%), G2 (Ki-67 3%-20%), or G3 (Ki-67 >20%). Patients were stratified into five cohorts: NET-G1, NET-G2, NET-G3, NEC-G2, and NEC-G3. RESULTS:Five-year survival was 72%. Age, gender, tumor site, grade, differentiation, and stage were all independent prognostic factors for survival. Further subdivision of the WHO 2010 grading improved prognostic stratification, both within G2 (5-year survival: 81% [Ki-67 3%-5%], 72% [Ki-67 6%-10%], 52% [Ki-67 11%-20%]) and G3 NENs (5-year survival: 35% [Ki-67 21%-50%], 22% [Ki-67 51%-100%]). Five-year survival was significantly greater for NET-G2 versus NEC-G2 (75.5% vs. 58.2%) and NET-G3 versus NEC-G3 (43.7% vs. 25.4%). CONCLUSION:Substantial clinical heterogeneity is observed within G2 and G3 GEP-NENs. The WHO 2010 classification can be improved by including the additive effect of histological differentiation and the proliferation index. IMPLICATIONS FOR PRACTICE:Gastroenteropancreatic neuroendocrine neoplasms are tumors of widely variable clinical behavior, roughly stratified by the World Health Organization (WHO) 2010 classification into three subgroups based on proliferation index. Real-world data from 2,813 patients of the Spanish Registry RGETNE demonstrated substantial clinical heterogeneity within grade (G) 2 and G3 neuroendocrine neoplasms. Tumor morphology and further subdivision of grading substantially improves prognostic stratification of these patients and may help individualize therapy. This combined, additive effect shall be considered in future classifications of neuroendocrine tumors and incorporated for stratification purposes in clinical trials.
Project description:Gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) represents a various family of rare tumours. Surgery is the first choice in GEP-NENs patients with localized disease whilst in the metastatic setting many other treatment options are available. Somatostatin analogues are indicated for symptoms control in functioning tumours. Furthermore they may be effective to inhibit tumour progression. GEP-NENs pathogenesis has been extensively studied in the last years therefore several driver mutations pathway genes have been identified as crucial factors in their tumourigenesis. GEP-NENs can over-express vascular endothelial growth factor (VEGF), basic-fibroblastic growth factor, transforming growth factor (TGF-? and -?), platelet derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1) and their receptors PDGF receptor, IGF-1 receptor, epidermal growth factor receptor, VEGF receptor, and c-kit (stem cell factor receptor) that can be considered as potential targets. The availability of new targeted agents, such as everolimus and sunitinib that are effective in advanced and metastatic pancreatic neuroendocrine tumours, has provided new treatment opportunities. Many trials combing new drugs are ongoing.
Project description:Method Data of patients who were surgically treated and clinicopathologically diagnosed as (MH)-NENs secondary to (GEP)-NENs at West China Hospital of Sichuan University from January 2006 to December 2018 were retrospectively collected and analyzed by the grading classification for (GEP)-NENs. Results We identified 150 patients with (MH)-NENs secondary to (GEP)-NENs, including 10 patients with G1 NETs, 26 with G2 NETs, 33 with G3 NETs, and 81 with G3 NECs. There were significant differences between patients with G1/G2/G3 NETs and those with G3 NECs, such as age at diagnosis (P=0.041), synchronous liver lesion (P=0.032), incidental diagnosis (P=0.014), tumor largest diameter (P=0.047), vascular invasion (P=0.017), and extrahepatic metastatic disease (P=0.029). The estimated 3-year overall survival for patients with G1 NETs, G2 NETs, G3 NETs, and G3 NECs was 100%, 79.4%, 49.5%, and 20.7%, respectively (P < 0.001). The survival of G1 NETs or G2 NETs was significantly better than that of G3 NETs (P=0.013, P=0.037, respectively) and G3 NECs (P=0.001, P < 0.001; respectively). Patients with G3 NECs present notably worse survival than those with G3 NETs (P=0.012), while survival comparison between G1 NETs and G2 NETs was not statistically different (P=0.131). The grading classification for (GEP)-NENs was an effective independent predictor of survival for (MH)-NENs secondary to (GEP)-NENs (hazard ratio: 4.234; 95% confidence intervals: 1.984–6.763; P=0.003). Conclusion Our demonstration revealed that the grading classification for (GEP)-NENs could well stratify (MH)-NENs secondary to (GEP)-NENs into prognostic groups and supported its wide use in clinical practice.
Project description:Neuroendocrine tumors (NETs) originate from the neuroendocrine cell system in the bronchial and gastrointestinal tract and can produce hormones leading to distinct clinical syndromes. Systemic treatment of patients with unresectable NETs aims to control symptoms related to hormonal overproduction and tumor growth. In the last decades prognosis has improved as a result of increased detection of early stage disease and the introduction of somatostatin analogs (SSAs) as well as several new therapeutic options. SSAs are the first-line medical treatment of NETs and can control hormonal production and tumor growth. The development of next-generation multireceptor targeted and radiolabelled somatostatin analogs, as well as target-directed therapies (as second-line treatment options) further improve progression-free survival in NET patients. To date, however, a significant prolongation of overall survival with systemic treatment in NET has not been convincingly demonstrated. Several new medical options and treatment combinations will become available in the upcoming years, and although preliminary results of preclinical and clinical trials are encouraging, large, preferrably randomized clinical studies are required to provide definitive evidence of their effect on survival and symptom control.
Project description:In 2016, the third version of guidelines for the diagnosis and treatment of neuroendocrine tumors (NETs) has been published by the European Neuroendocrine Tumor Society (ENETS). These guidelines reflect the progress in treatment of NETs, and by comparing the newest guidelines with the first guidelines of 2001, this progress can be clearly recognized. Diagnostic accuracy has been increased by the introduction of PET-CT with Ga-labelled somatostatin analogs, and multiple new treatments and treatment schedules have been developed, like peptide receptor radiotherapy with radiolabeled somatostatin analogs, or targeted therapies. Evidence and indications for these therapies are discussed in the ENETS guidelines. In this review, we aim to show the progress in NET diagnosis and treatment on the basis of the advances in the guidelines, but also to discuss the unsolved questions and unmet needs which still remain.
Project description:A meta-analysis has systematically investigated the antineoplastic efficacy and safety of somatostatin analogs (SSAs) in advanced gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). Randomized controlled trials (RCTs) reporting the hazard ratio (HR) for disease progression (DP) were evaluated. Response rate and risk ratio (RR) for adverse events were also analyzed. A total of 289 patients (143 receiving SSAs vs. 146 placebo) were evaluated from two RCTs. A significant benefit from SSAs in terms of disease control was observed (HR 0.41, 95% CI: 0.29 to 0.58, P < 0.01; I20%), response rate being 58.0% vs. 32.2%, respectively.The occurrence of adverse events significantly differed from the placebo arm only in terms of biliary stones (RR 3.79, 95% CI: 1.28 to 11.17, P = 0.02; I20%). In conclusion, SSAs showed an antiproliferative effect in advanced GEP-NETs, with a good safety profile.
Project description:Neuroendocrine tumors (NETs) are associated with variable prognosis, with grade 1 and 2 NETs having more favorable outcomes than grade 3. Patients with gastroenteropancreatic (GEP)-NET need individualized interdisciplinary evaluations and treatment. New treatment options have become available with significant improvements in progression-free survival. Peptide receptor radionuclide therapy (PRRT) using (90)Y or (177)Lu-labeled somatostatin analogues (SSTa) has also shown promise in the treatment of advanced progressive NETs. (68)Ga-1,4,7,10-tetraazacyclodecane-1,4,7,10-tetraacetic acid (DOTA)-SSTa can be used as companion imaging agents to assist in radionuclide therapy selection. (68)Ga-DOTA-SSTa PET/computed tomography might also provide information for prognosis, tumor response assessment to PRRT, and internal dosimetry.
Project description:Somatostatin analogs for the diagnosis and therapy of neuroendocrine tumors (NETs) have been used in clinical applications for more than two decades. Five somatostatin receptor subtypes have been identified and molecular mechanisms of somatostatin receptor signaling and regulation have been elucidated. These advances increased understanding of the biological role of each somatostatin receptor subtype, their distribution in NETs, as well as agonist-specific regulation of receptor signaling, internalization, and phosphorylation, particularly for the sst2 receptor subtype, which is the primary target of current somatostatin analog therapy for NETs. Various hypotheses exist to explain differences in patient responsiveness to somatostatin analog inhibition of tumor secretion and growth as well as differences in the development of tumor resistance to therapy. In addition, we now have a better understanding of the action of both first generation (octreotide, lanreotide, Octreoscan) and second generation (pasireotide) FDA-approved somatostatin analogs, including the biased agonistic character of some agonists. The increased understanding of somatostatin receptor pharmacology provides new opportunities to design more sophisticated assays to aid the future development of somatostatin analogs with increased efficacy.
Project description:Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumoral syndrome, featured by a combination of neoplasms of various endocrine and nonendocrine tissues. Approximately 33% of MEN1-related deaths are due to the malignant behaviour of well-differentiated neuroendocrine tumors (NETs), for which a preventive surgical treatment is not feasible. Somatostatin analogues (SSA) have been employed in the treatment of NETs in the stage of advanced or metastatic disease, in order to control the growth and secretion of tumor lesions. A longitudinal, open label study named "LARO-MEN1" was undertaken in order to assess whether early medical treatment with long-acting SSA could act as a preventive approach in small MEN1-related gastroenteropancreatic (GEP) NETs. Thirty consecutive patients affected by MEN1 were screened and 8 patients with small (<2 cm) NETs and abnormal laboratory values of at least one of the GEP hormones were administered octreotide acetate slow-release formulation (LAR) (10 mg i.m. every 28 days). Octreotide LAR was effective in decreasing GEP hormones and overall safe in the majority of patients up to six years of treatment, maintaining the disease stable also in terms of tumor size. The positive outcomes of this study in MEN1 patients reinforce the results obtained in advanced NETs on the use of SSA, opening to the opportunity for preventive use of octreotide LAR, aimed to delay or even avoid surgery in these patients.