Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine?

Gastroenteropancreatic neuroendocrine neoplasia (GEPNEN) comprises clinically as well as prognostically diverse tumour entities often diagnosed at late stage. Current classification provides a uniform terminology and a Ki67-based grading system, thereby facilitating management. Advances in the study of genomic and epigenetic landscapes have amplified knowledge of tumour biology and enhanced identification of prognostic and potentially predictive treatment subgroups. Translation of this genomic and mechanistic biology into advanced GEPNEN management is limited. 'Targeted' treatments such as somatostatin analogues, peptide receptor radiotherapy, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are treatment options but predictive tools are lacking. The inability to identify clonal heterogeneity and define critical oncoregulatory pathways prior to therapy, restrict therapeutic efficacy as does the inability to monitor disease status in real time. Chemotherapy in the poor prognosis NEN G3 group, though associated with acceptable response rates, only leads to short-term tumour control and their molecular biology requires delineation to provide new and more specific treatment options.The future requires an exploration of the NEN tumour genome, its microenvironment and an identification of critical oncologic checkpoints for precise drug targeting. In the advance to personalised medical treatment of patients with GEPNEN, clinical trials need to be based on mechanistic and multidimensional characterisation of each tumour in order to identify the therapeutic agent effective for the individual tumour.This review surveys advances in NEN research and delineates the current status of translation with a view to laying the basis for a genome-based personalised medicine management of advanced GEPNEN.

Peritoneal Carcinomatosis in Gastro-Entero-Pancreatic Neuroendocrine Neoplasms: Clinical Impact and Effectiveness of the Available Therapeutic Options.

BACKGROUND: Peritoneal carcinomatosis (PC) can affect the quality of life of patients with gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs). Peritoneal disease control by medical therapies in these patients has been poorly investigated Objectives: To describe, in a consecutive series of GEP-NENs, the clinical impact of PC and to report the effectiveness of available treatments in PC control. METHODS: A retrospective, monocenter analysis was performed of 135 GEP-NENs (1993-2016) with at least a 12-month follow-up. Peritoneal disease progression was defined as detection of a significant increase in size or appearance of new implants by imaging. RESULTS: A total of 62.9% of cases had diffuse PC (involving at least 2 abdominal quadrants). According to WHO 2017 classification, cases were 42.3% neuroendocrine tumors NET-G1, 45.5% NET-G2, 6.5% NET-G3, 4.9% neuroendocrine carcinomas NEC-G3, and 0.8% mixed neuroendocrine-nonneuroendocrine neoplasms. Bowel obstruction occurred in 30 (22.2%) patients mainly depending on size of peritoneal implants (HR: 1.10; 95% CI: 1.02-1.20; p = 0.01). Patients with diffuse PC treated with peptide receptor radionuclide therapy (PRRT) showed peritoneal progression in 37.5% of cases, and bowel obstruction or ascites in 28.1%. Better peritoneal disease control was observed in cases receiving somatostatin analogs at first-line therapy, probably due to a less aggressive disease behavior for these patients. CONCLUSIONS: Bowel obstruction is not uncommon in GEP-NENs with PC. PRRT should be adopted with caution in GEP-NENs with diffuse PC, but larger series are needed to confirm these data.

Stage IV Gastro-Entero-Pancreatic Neuroendocrine Neoplasms: A Risk Score to Predict Clinical Outcome.

BACKGROUND: Several risk factors predict clinical outcome in gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs); however, the impact of their combination has not been investigated so far. PATIENTS AND METHODS: A retrospective analysis of stage IV GEP-NENs was performed. Multivariate analysis for progression of disease (PD) was performed by Cox proportional hazards method to obtain a risk score. Area under the curve obtained by receiver operating characteristic analysis was used to assess the score performance. Progression-free survival analysis was performed by Kaplan-Meier method. RESULTS: Two hundred eighty-three stage IV GEP-NENs were evaluated, including 93 grade 1 neuroendocrine tumors (32.9%), 153 grade 2 neuroendocrine tumors (54%), and 37 grade 3 neuroendocrine carcinomas (13.1%). Independent risk factors for PD were Ki67, proportion of metastatic liver involvement, and presence of extra-abdominal metastases. The risk score was calculated as follows: (0.025 × Ki67) + [(0 if no liver metastases or liver involvement <25%) OR (0.405 if liver involvement 25%-50%) OR (0.462 if liver involvement >50%)] + [(0 if no extra-abdominal metastases) OR (0.528 if extra-abdominal metastases present)]. The risk score accuracy to predict PD was superior compared with the G grading system (area under the curve: 0.705 and 0.622, respectively). Three subgroups of patients with low, intermediate, and high risk of PD according to risk score were identified, median progression-free survival being 26 months, 19 months, and 12 months, respectively. CONCLUSION: In stage IV GEP-NENs, a risk score able to predict PD was obtained by combining Ki67, proportion of metastatic liver involvement, and presence of extra-abdominal metastases. The score may help to discriminate patients with different progression risk level to plan tailored therapeutic approaches and follow-up programs. The Oncologist 2017;22:409-415Implications for Practice: Clinical outcome of patients with advanced gastro-entero-pancreatic neuroendocrine neoplasms is affected by several risk factors, including the proliferative index Ki67, extension of liver metastases, and the presence of distant extra-abdominal lesions. A risk score that combines these variables may help physicians dealing with these diseases to plan the optimal therapeutic approach and follow-up program.