Chemotherapy in NETs: When and how

Therapeutic management of patients with advanced thymic malignancies: A review for clinicians

Thymic epithelial tumors (TETs) are a heterogeneous group of rare tumors that arise from thymic epithelial cells in the anterior mediastinum. They can be divided into three different histological subtypes: thymomas, thymic carcinomas (TC), and neuroendocrine carcinomas (TNET). TCs and TNETs are rarer but more aggressive entities with frequent distant metastasis. Thymomas occur in 90 % of cases in a localized/locally advanced stage, on the other hand about 70 % of TCs are locally advanced at the time of diagnosis. Surgery plays a primary role in the management of patients in whom complete resection is feasible. The benefit of post-operative radiotherapy (PORT) is still controversial, since it could be related to stage, histotype, and preoperative chemotherapy. If the tumor is unresectable at diagnosis, radiotherapy or concurrent chemoradiotherapy is the most commonly used approach. Cisplatin and anthracycline-based regimens are standard of care in patients with unresectable or metastatic thymomas, but, at the same time, regimens with carboplatin and paclitaxel are the most widely used especially in patients with contraindications to cisplatin/anthracyclines, due to better tolerance. Recently, the anti-VEGFR antibody Ramucirumab has shown promising activity in combination with carboplatin plus paclitaxel in previously untreated advanced TCs. Several clinical trials with chemotherapy combination, target therapy and immunotherapy are still ongoing to define the best therapeutic strategy in this disease, also for the second line treatment, for which in daily practice there is currently no standard of care for patients who went into progression to the first line.

Diagnostic Approaches to Neuroendocrine Neoplasms of Unknown Primary Site

ABSTRACT

Neuroendocrine tumors (NETs) are relatively uncommon heterogeneous neoplasms arising from endocrine and neuronal origin cells showing highly variable clinical behavior. By the time these tumors are discovered, up to 14% of patients with histologically proven NETs have metastasis, with the liver as the most frequently affected organ. Sometimes, no known primary site can be identified via routine imaging. Neuroendocrine tumors of unknown origin carry a poorer prognosis (compared with metastatic NETs with a known primary site) because of a lack of tailored surgical intervention and appropriate medical therapy (eg, chemotherapy or targeted therapy). A multimethod approach is frequently used in the trial to accurately determine the primary site for NETs of unknown primary sites and may include clinical, laboratory, radiological, histopathological, and surgical data. New molecular techniques using the genomic approach to identify the molecular signature have shown promising results. Various imaging modalities include ultrasound, computed tomography (CT), dual-energy CT, magnetic resonance imaging, and functional and hybrid imaging (positron emission tomography/CT, positron emission tomography/magnetic resonance imaging); somatostatin receptor imaging with new tracers is frequently used in an attempt for localization of the primary site.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (64Cu-DOTATATE or 68Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.

Treatment personalization in gastrointestinal neuroendocrine tumors

The clinical scenario of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) is continuously changing due to significant improvements in the definition of their molecular landscapes and the introduction of innovative therapeutic approaches. Many efforts are currently employed in the integration of the genetics/epigenetics and clinical information. This is leading to an improvement of tumor classification, prognostic stratification and ameliorating the management of patients based on a personalized approach.

Temozolomide Alone or Combined with Capecitabine for the Treatment of Metastatic Neuroendocrine Neoplasia: A "Real-World" Data Analysis

BACKGROUND

Neuroendocrine neoplasias (NENs) are a rare group of tumors with different prognosis and response to therapy. Their heterogeneity is dependent on the site of origin, morphology, and Ki67. Temozolomide (TEM) appears to be active in metastatic NENs (mNENs) but there is limited evidence about its efficacy in gastrointestinal NENs. We analyzed "real-world" data on the use of TEM alone or in association with capecitabine (CAPTEM) in patients with mNENs.

PATIENTS AND METHODS

One hundred consecutive patients with advanced NENs treated with TEM or CAPTEM between 2009 and 2019 were included. A pretreatment tumor growth rate (TGR0) was calculated. Overall survival (OS), progression-free survival (PFS), tolerance, objective response rate (ORR), and disease control rate (DCR) were analyzed. A propensity score analysis and inverse probability of treatment weights for Cox regression models were used.

RESULTS

TEM-based therapy was administered to 95 patients (26.3% CAPTEM and 83.7% TEM) with a median age of 59 years (range 26-85) years. ECOG performance status was 0-2. Carcinoid syndrome was reported in 12 (12.6%) patients. Twenty (21.1%) patients with grade (G) 3 neuroendocrine carcinoma (NEC) and 9 (9.4%) with G3 neuroendocrine tumors (NETs) were included in the analysis. Median PFS of the entire group was 10.4 months (95% confidence interval [CI]: 6.0-11.5). In multivariate analysis, a higher risk of progression was observed for NEC G3 patients (hazard ratio [HR] 2.70, 95% CI: 1.25-5.84) and for a TGR ≥19.55 (HR: 2.53, 95% CI: 1.45-4.40). Median OS was 23.4 months (95% CI: 17.0-29.0) and was similar in both treatment groups (23.9 vs. 20.5 months for TEM and CAPTEM, respectively, p = 0.585). In multivariate analysis, TGR ≥19.55 was associated with a higher risk of death (HR: 2.18, 95% CI: 1.16-4.11) than TGR <19.55, as was NEC G3 (HR: 2.42, 95% CI: 1.04-5.59) with respect to NETs. No differences in terms of mPFS or mOS were seen in relation to the primary site of disease. In the 86 patients evaluable for response, ORR was 44.1% and the DCR was 70.9%. Mild adverse events (grade I-II) included anemia, neutropenia, and headache. Rare cases of G 3 neutropenia and thrombocytopenia were recorded.

CONCLUSIONS

TEM-based regimens are associated with a high DCR and a relatively tolerable toxicity profile in NENs of pancreatic, intestinal, and lung origin. Further investigation of these specific NETs is warranted in prospective clinical trials.

Medical Treatment of Gastrointestinal Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are rare tumours that arise mainly in the gastrointestinal or pulmonary system. Most NENs are well-differentiated and may obtain prolonged survival besides the presence of metastatic disease; however, a subset (poorly differentiated NENs) may display a truly aggressive behaviour exhibiting a poor prognosis. The recently developed classification systems along with advances in functional imaging have helped stratify patients to the administration of appropriate therapeutic options. Surgery is the mainstay of treatment of NENs, but in recent decades there has been a considerable evolution of medical treatments that are used for locally advanced or metastatic disease not amenable to surgical resection. Long acting somatostatin analogues are the main therapeutic modality for patients with functioning and well-differentiated low grade NENs exhibiting symptomatic control and mainly stabilisation of tumour growth. Other systemic treatments include chemotherapy, molecular targeted agents, interferon-α, peptide receptor radionuclide therapy (PRRT), and immunotherapy. In addition, new agents such as telotristat may be used for the control of symptoms of carcinoid syndrome. The choice and/or sequence of therapeutic agents should be individualized according to tumour origin and differentiation, disease burden, presence of clinical symptoms and patients' performance status in the context of a multidisciplinary approach. Recent advances in the molecular pathogenesis of NENs set the field for a more personalised treatment approach.

Endocrinological Toxicity Secondary to Treatment of Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs)

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are increasingly recognized, characterized by prolonged survival even with metastatic disease. Their medical treatment is complex involving various specialties, necessitating awareness of treatment-related adverse effects (AEs). As GEP-NENs express somatostatin receptors (SSTRs), long-acting somatostatin analogs (SSAs) that are used for secretory syndrome and tumor control may lead to altered glucose metabolism. Everolimus and sunitinib are molecular targeted agents that affect glucose and lipid metabolism and may induce hypothyroidism or hypocalcemia, respectively. Chemotherapeutic drugs can affect the reproductive system and water homeostasis, whereas immunotherapeutic agents can cause hypophysitis and thyroiditis or other immune-mediated disorders. Treatment with radiopeptides may temporarily lead to radiation-induced hormone disturbances. As drugs targeting GEP-NENs are increasingly introduced, recognition and management of endocrine-related AEs may improve compliance and the quality of life of these patients.

Neuroendocrine Neoplasms of the Small Bowel and Pancreas

The traditionally promulgated perspectives of neuroendocrine neoplasms (NEN) as rare, indolent tumours are blunt and have been outdated for the last 2 decades. Clear increments in their incidence over the past decades render them increasingly clinically relevant, and at initial diagnosis many present with nodal and/or distant metastases (notably hepatic). The molecular pathogenesis of these tumours is increasingly yet incompletely understood. Those arising from the small bowel (SB) or pancreas typically occur sporadically; the latter may occur within the context of hereditary tumour predisposition syndromes. NENs can also be associated with endocrinopathy of hormonal hypersecretion. Tangible advances in the development of novel biomarkers, functional imaging modalities and therapy are especially applicable to this sub-set of tumours. The management of SB and pancreatic neuroendocrine tumours (NET) may be challenging, and often comprises a multidisciplinary approach wherein surgical, medical, interventional radiological and radiotherapeutic modalities are implemented. This review provides a comprehensive overview of the epidemiology, pathophysiology, diagnosis and treatment of SB and pancreatic NETs. Moreover, we provide an outlook of the future in these tumour types which will include the development of precision oncology frameworks for individualised therapy, multi-analyte predictive biomarkers, artificial intelligence-derived clinical decision support tools and elucidation of the role of the microbiome in NEN development and clinical behaviour.

Outcomes of Lymph Node Dissection for Non-metastatic Pancreatic Neuroendocrine Tumors: A Propensity Score-Weighted Analysis of the National Cancer Database

BACKGROUND

Although the National Comprehensive Cancer Network (NCCN) guidelines recommend use of lymph node dissection (LND) in patients with pancreatic neuroendocrine tumors (pNETs) > 2 cm, there is limited evidence to support the association between use of LND and overall survival (OS).

METHODS

Patients with resected pNETs were identified in the National Cancer Database (2004-2014). The inverse probability of treatment weighting (IPTW) method was used to reduce the selection bias. IPTW-adjusted Kaplan-Meier curves and Cox proportional hazards models were used to compare OS of patients in different treatment groups.

RESULTS

A total of 2664 patients diagnosed met the study entry criteria. Of these, 2132 patients (80.6%) received LND, with a median of nine nodes removed. Positive nodes were identified in 28.0% of patients who underwent LND. IPTW-adjusted Kaplan-Meier analysis showed that median OS was similar between the LND and LND-omitted groups (152.8 vs. 147.3 months; p = 0.61). In IPTW-adjusted Cox proportional hazards regression analysis, LND was not associated with an OS benefit (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.94-1.42; p = 0.18). The results were consistent across subgroups stratified by clinical T and N stages. Among patients with lymph node metastasis, the number of removed nodes (NRN) above the median was not associated with an improved OS (HR 0.82, 95% CI 0.60-1.13; p = 0.22).

CONCLUSIONS

LND had no additional therapeutic benefit among patients undergoing resection for pNETs. The present findings should be considered when managing patients with resectable pNETs.

The Pancreas as a Site of Metastasis or Second Primary in Patients with Small Bowel Neuroendocrine Tumors

BACKGROUND

The small bowel and pancreas are the most common primary sites of neuroendocrine tumors (NETs) giving rise to metastatic disease. Some patients with small bowel NETs (SBNETs) present with synchronous or metachronous pancreatic NETs (PNETs), and it is unclear whether these are separate primaries or metastases from one site to the other.

METHODS

A surgical NET database including patients undergoing operations for SBNETs or PNETs was reviewed. Patients with synchronous or metachronous tumors in both the small bowel and pancreas were identified, and available tissues from primary tumors and metastases were examined using a 4-gene quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) panel developed for evaluating NETs of unknown primary.

RESULTS

Of 338 patients undergoing exploration, 11 had NETs in both the small bowel and pancreas. Tissues from 11 small bowel tumors, 9 pancreatic tumors, and 10 metastases were analyzed. qPCR and IHC data revealed that three patients had separate SBNET and PNET primaries, and five patients had SBNETs that metastasized to the pancreas. Pancreatic tissue was unavailable in two patients, and qPCR and IHC gave discrepant results in one patient.

CONCLUSIONS

NETs in both the small bowel and pancreas were found in 3% of our patients. In nearly two-thirds of evaluable patients, the pancreatic tumor was a metastasis from the SBNET primary, while in the remaining one-third of patients it represented a separate primary. Determining the origin of these tumors can help guide the choice of systemic therapy and surgical management.

Current concepts in the diagnosis and management of neuroendocrine neoplasms of unknown primary origin

Neuroendocrine neoplasms (NENs) of unknown primary origin (UPO-NENs) are advanced neoplasms constituting 11-22% of all NENs that by definition their primary tissue of origin has not been identified with standard diagnostic work-up. Delineating the primary site of origin of UPO-NENs has important implications for selecting the appropriate treatment and overall prognosis. The small bowel, followed by the lung and pancreas are the most prevalent primary sites of origin of UPO-NENs that are uncovered during an extensive and prolonged diagnostic work-up; however, a number of UPO-NENs may still remain occult even after prolonged follow-up. A number of diagnostic algorithms that incorporate histopathological, molecular, imaging (either morphological or functional imaging), and serum biomarkers can help to identify the primary tumor origin. It is expected that advances in these fields will help reduce significantly the number of UPO-NENs.

Current best practice in the management of neuroendocrine tumors

Neuroendocrine neoplasms are rare tumors that display marked heterogeneity with varying natural history, biological behavior, response to therapy and prognosis. Their management is complex, particularly as a number of them may be associated with a secretory syndrome and involve a variety of options. A number of factors such as proliferation rate, degree of differentiation, functionality and extent of the disease are mostly utilized to tailor treatment accordingly, ideally in the context of a multidisciplinary team. In addition, a number of relevant scientific societies have published therapeutic guidelines in an attempt to direct and promote evidence-based treatment. Surgery remains the treatment of choice with an intention to cure while it may also be recommended in some cases of metastatic disease and difficult to control secretory syndromes. Long-acting somatostatin analogs constitute the main treatment for the majority of functioning tumors, whereas specific evolving agents such as telotristat may be used for the control of carcinoid syndrome and related sequelae. In patients with advanced disease not amenable to surgical resection, treatment options include locoregional therapies, long-acting somatostatin analogs, molecular targeted agents, radionuclides, chemotherapy and recently immunotherapy, alone or in combination. However, the ideal time of treatment initiation, sequence of administration of different therapies and identification of robust prognostic markers to select the most appropriate treatment for each individual patient still need to be defined.

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

Recently, there have been a number of advances in imaging pancreatic neuroendocrine tumors (panNETs), as well as other neuroendocrine tumors (NETs), which have had a profound effect on the management and treatment of these patients, but in some cases are also associated with controversies. Areas covered: These advances are the result of numerous studies attempting to better define the roles of both cross-sectional imaging, endoscopic ultrasound, with or without fine-needle aspiration, and molecular imaging in both sporadic and inherited panNET syndromes; the increased attempt to develop imaging parameters that correlate with tumor classification or have prognostic value; the rapidly increasing use of molecular imaging in these tumors and the attempt to develop imaging parameters that correlate with treatment/outcome results. Each of these areas and the associated controversies are reviewed. Expert commentary: There have been numerous advances in all aspects of the imaging of panNETs, as well as other NETs, in the last few years. The advances are leading to expanded roles of imaging in the management of these patients and the results being seen in panNETs/GI-NETs with these newer techniques are already being used in more common tumors.

Peptide Receptor Radionuclide Therapy in Grade 3 Neuroendocrine Neoplasms: Safety and Survival Analysis in 69 Patients

To date, limited data are available concerning peptide receptor radionuclide therapy (PRRT) of grade 3 (G3) neuroendocrine neoplasms (NENs) with a Ki-67 proliferation index of greater than 20%. The purpose of this study was to analyze the long-term outcome, efficacy, and safety of PRRT in patients with somatostatin receptor (SSTR)-expressing G3 NENs. Methods: A total of 69 patients (41 men; age, 28-81 y) received PRRT with ¹⁷⁷Lu- or ⁹⁰Y-labeled somatostatin analogs (DOTATATE or DOTATOC). Twenty-two patients had radiosensitizing chemotherapy. Kaplan-Meier analysis was performed to calculate progression-free survival (PFS) and overall survival (OS), defined from the start of PRRT, including a subgroup analysis for patients with a Ki-67 index of less than or equal to 55% and a Ki-67 index of greater than 55%. Treatment response was evaluated according to RECIST 1.1 as well as molecular imaging criteria (European Organization for Research and Treatment of Cancer). Short- and long-term toxicity was documented (Common Terminology Criteria for Adverse Events, v 5.0) using a structured database (comprising >250 items per patient) and retrospectively analyzed. Results: Forty-six patients had pancreatic NENs, 11 had unknown primary cancer, 6 had midgut NENs, 3 had gastric NENs, and 3 had rectal NENs. The median follow-up was 94.3 mo. The median PFS was 9.6 mo, and the median OS was 19.9 mo. For G3 NENs with a Ki-67 index of less than or equal to 55% (n = 53), the median PFS was 11 mo and the median OS was 22 mo. Patients with a Ki-67 index of greater than 55% (n = 11) had a median PFS of 4 mo and a median OS of 7 mo. For patients with positive SSTR imaging but no ¹⁸F-FDG uptake, the median PFS was 24 mo and the median OS was 42 mo. A significant difference was found for both PFS and OS, with median PFS of 16 mo and 5 mo and median OS of 27 mo and 9 mo for an SUV_max of greater than 15.0 and an SUV_max of less than or equal to 15.0, respectively, on SSTR PET. In the group with ¹⁸F-FDG uptake scored as 3 or 4, the median PFS was 7.1 mo and the median OS was 17.2 mo. In the group with ¹⁸F-FDG uptake scored as 0-2, the median PFS was 24.3 mo and the median OS was 41.6 mo. PRRT was well tolerated by all patients; no grade 3 or grade 4 hematotoxicity occurred, and no clinically significant decline in renal function was observed. There was no hepatotoxicity. Conclusion: PRRT was tolerated well, without significant adverse effects, and was efficacious in G3 NENs; the clinical outcome was promising, especially in patients with a Ki-67 index of less than or equal to 55% and even in patients for whom chemotherapy had failed. Baseline ¹⁸F-FDG along with SSTR molecular imaging was useful for stratifying G3 NEN patients with high uptake on SSTR PET/CT and no or minor ¹⁸F-FDG avidity-a mismatch pattern that was associated with a better long-term prognosis.

Black swans - neuroendocrine tumors of rare locations

Neuroendocrine neoplasms (NEN) are rare and heterogeneous. Therefore, they often remain unrecognized for many years, causing significant disease burden. We here report on four unusual NEN presentations including a metastatic NEN of the kidney, hypoglycemia caused by an insulin-like growth factor-2-oma (previously called non-islet-cell tumor hypoglycemia), multifocal pheochromocytoma in von Hippel Lindau syndrome, and ileal NEN metastatic to the heart. One could say that each one of these tumors were "black swans" and learning about them will increase further awareness of the spectrum of NEN.

Nutrition and neuroendocrine tumors: An update of the literature

Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms with worldwide increasing incidence, high prevalence and survival. Both the tumor itself and the systemic therapy may have an impact on patients' nutrition. Malnutrition negatively impacts on outcome in NETs patients. Moreover, it has been demonstrated that body mass index was a risk factor for NET development and that metabolic syndrome was associated with worse prognosis in these patients. Of note, food could also interact with the metabolism of oral target therapy and antineoplastic agents used for the treatment of progressive NETs. Therefore, the nutritional assessment, based on body composition, and lifestyle modifications should be an integral component of management of the NET patients. The nutrition care plans are an integral part of the multidisciplinary management team for patients with NETs. Nutritionists with expertise in NETs can provide dietary approaches to improve the quality of life and nutritional status during various therapeutic modalities used in patients with NETs. The aim of this review is to critically discuss the importance of nutrition and body composition in patients with NETs.

Management of neuroendocrine tumors of unknown primary

Neuroendocrine neoplams (NENs) are mostly relatively indolent malignancies but a significant number have metastatic disease at diagnosis mainly to the liver. Although in the majority of such cases the primary origin of the tumor can be identified, in approximately 11-22% no primary tumor is found and such cases are designated as NENs of unknown primary origin (UPO). This has significant therapeutic implications with respect to potentially resectable hepatic disease and/or application of appropriate medical therapy, either chemotherapeutic agents or targeted treatment, as the response to various treatments varies according to the origin of the primary tumor. This lack of tumor specific orientated treatment may also account for the relatively poorer prognosis of NENs of UPO compared to metastatic NENs with a known primary site. In the majority of cases the primary tumors are located in the small bowel and the lung, but a number may still elude detection. Occasionally the presence of a functional syndrome may direct to the specific tissue of origin but in the majority of cases a number of biochemical, imaging, histopathological and molecular modalities are utilized to help identify the primary origin of the tumor and direct treatment accordingly. Several diagnostic algorithms have recently been developed to help localize an occult primary tumor; however, in a number of cases no lesion is identified even after prolonged follow-up. It is expected that the delineation of the molecular signature of the different NENs may help identify such cases and provide appropriate treatment.