Multimodality Management of "Borderline Resectable" Pancreatic Neuroendocrine Tumors: Report of a Single-Institution Experience.

BACKGROUND: Pancreatic neuroendocrine tumors (PanNETs) constitute approximately 3% of pancreatic neoplasms. Like patients with pancreatic ductal adenocarcinoma (PDAC), some of these patients present with "borderline resectable disease." For these patients, an optimal treatment approach is lacking. We report our institution's experience with borderline resectable PanNETs using multimodality treatment. METHODS: We identified patients with borderline resectable PanNETs who had received neoadjuvant therapy at our institution between 2000 and 2013. The definition of borderline resectability was based on National Comprehensive Cancer Network criteria for PDAC. Neoadjuvant regimen, radiographic response, pathologic response, surgical margins, nodal retrieval, number of positive nodes, and recurrence were documented. Statistics were descriptive. RESULTS: Of 112 patients who underwent surgical resection for PanNETs during the study period, 23 received neoadjuvant therapy, 6 of whom met all inclusion criteria and had borderline resectable disease. These 6 patients received at least 1 cycle of temozolomide and capecitabine, with 3 also receiving radiation. All had radiographic evidence of treatment response. Four (67%) had negative-margin resections. Four patients had histologic evidence of a moderate response. Follow-up (3.0-4.3 years) indicated that all patients were alive, with 5/6 free of disease (1 patient with metastatic disease still on treatment without progression). CONCLUSIONS: A multimodality treatment strategy (neoadjuvant temozolomide and capecitabine ± radiation) can be successfully applied to patients with PanNETs who meet NCCN borderline resectable criteria for PDAC. To our knowledge, this is the first report of the use of a multimodality protocol in the treatment of patients with borderline resectable PanNETs.

Impact of Previous Somatostatin Analogue Use on the Activity of Everolimus in Patients with Advanced Neuroendocrine Tumors: Analysis from the Phase III RADIANT-2 Trial.

BACKGROUND/AIMS: The phase III placebo-controlled RADIANT-2 trial investigated the efficacy of everolimus plus octreotide long-acting repeatable (LAR) in patients with advanced neuroendocrine tumors (NET) associated with carcinoid syndrome. Here we report a secondary analysis based on the previous somatostatin analogue (SSA) exposure status of patients enrolled in RADIANT-2. METHODS: Patients were randomly assigned to receive oral everolimus 10 mg/day plus octreotide LAR 30 mg intramuscularly (i.m.) or to receive matching placebo plus octreotide LAR 30 mg i.m. every 28 days. SSA treatment before study enrollment was permitted. Patient characteristics and progression-free survival (PFS) were analyzed by treatment arm and previous SSA exposure status. RESULTS: Of the 429 patients enrolled in RADIANT-2, 339 were previously exposed to SSA (95% received octreotide); 173 of 339 patients were in the everolimus plus octreotide LAR arm. All patients had a protocol-specified history of secretory symptoms, but analysis by type showed that more patients who previously received SSA therapy had a history of flushing symptoms (77%), diarrhea (86%), or both (63%) compared with SSA-naive patients (62, 62, and 24%, respectively). Patients who received everolimus plus octreotide LAR had longer median PFS regardless of previous SSA exposure (with: PFS 14.3 months, 95% confidence interval, CI, 12.0-20.1; without: 25.2 months, 95% CI, 12.0-not reached) compared with patients who received placebo plus octreotide LAR (with: 11.1 months, 95% CI, 8.4-14.6; without: 13.6 months, 95% CI, 8.2-22.7). CONCLUSION: Everolimus in combination with octreotide improves PFS in patients with advanced NET associated with carcinoid syndrome, regardless of previous SSA exposure.

GEPNETs update: Radionuclide therapy in neuroendocrine tumors.

Peptide receptor radionuclide therapy (PRRT) is a promising new treatment modality for inoperable or metastasized gastroenteropancreatic neuroendocrine tumors (GEPNETs) patients. Most studies report objective response rates in 15-35% of patients. Also, outcome in terms of progression free survival (PFS) and overall survival compares very favorably with that for somatostatin analogs, chemotherapy, or new, 'targeted' therapies. They also compare favorably to PFS data for liver-directed therapies. Two decades after the introduction of PRRT, there is a growing need for randomized controlled trials comparing PRRT to 'standard' treatment, that is treatment with agents that have proven benefit when tested in randomized trials. Combining PRRT with liver-directed therapies or with targeted therapies could improve treatment results. The question to be answered, however, is whether a combination of therapies performed within a limited time-span from one another results in a better PFS than a strategy in which other therapies are reserved until after (renewed) tumor progression. Randomized clinical trials comparing PRRT with other treatment modalities should be undertaken to determine the best treatment options and treatment sequelae for patients with GEPNETs.

Telotristat etiprate, a novel serotonin synthesis inhibitor, in patients with carcinoid syndrome and diarrhea not adequately controlled by octreotide.

Serotonin produced by neuroendocrine tumors is believed to be a principal cause of the diarrhea in carcinoid syndrome. We assessed the safety and efficacy of telotristat etiprate, an oral serotonin synthesis inhibitor, in patients with diarrhea associated with carcinoid syndrome. In this prospective, randomized study, patients with evidence of carcinoid tumor and ≥4 bowel movements (BMs)/day despite stable-dose octreotide LAR depot therapy were enrolled in sequential, escalating, cohorts of four patients per cohort. In each cohort, one patient was randomly assigned to placebo and three patients to telotristat etiprate, at 150, 250, 350, or 500 mg three times a day (tid). In a subsequent cohort, one patient was assigned to placebo and six patients to telotristat etiprate 500 mg tid. Patients were assessed for safety, BM frequency (daily diary), 24 h urinary 5-hydroxyindoleacetic acid (u5-HIAA), and adequate relief of carcinoid gastrointestinal symptoms (using a weekly questionnaire). Twenty-three patients were treated: 18 received telotristat etiprate and five received placebo. Adverse events were generally mild. Among evaluable telotristat etiprate-treated patients, 5/18 (28%) experienced a ≥30% reduction in BM frequency for ≥2 weeks, 9/16 (56%) experienced biochemical response (≥50% reduction or normalization in 24-h u5-HIAA) at week 2 or 4, and 10/18 (56%) reported adequate relief during at least 1 of the first 4 weeks of treatment. Similar activity was not observed in placebo-treated patients. Telotristat etiprate was well tolerated. Our observations suggest that telotristat etiprate has activity in controlling diarrhea associated with carcinoid syndrome. Further studies confirming these findings are warranted.

Predictors of lymph node metastases and impact on survival in resected pancreatic neuroendocrine tumors: a single-center experience.

BACKGROUND: Staging for pancreatic neuroendocrine tumors (PNET) considers tumor size and lymph node (LN) status; however, correlation with survival remains unclear. METHODS: A single-institution database of patients with resected PNET was analyzed. RESULTS: Of the 150 patients, incidentally discovered PNET was the most common presentation (42%). One hundred thirteen patients (75%) had LN data, 32 (28%) with positive LN (LN+). Procedure and tumor size did not predict LN+. Perineural invasion (P = .016) and lymphovascular (P < .001) invasion, however, were more common in LN+. Multivariate analysis showed poor/moderate differentiation predicted LN+. Median follow-up was 52 months and median overall survival was 225 months. Fifty-two patients (35%) developed recurrence and median disease-free survival (DFS) was 74 months. Only poor/moderate differentiation affected DFS. CONCLUSIONS: PNET has an unclear prognosis based on variables factored into stage. In this study, tumor size did not predict LN+; furthermore, LN+ did not impact overall survival or DFS. Tumor differentiation appears to be more important in determining prognosis.

Peptide receptor radionuclide therapy with 177Lu-DOTATATE for patients with somatostatin receptor-expressing neuroendocrine tumors: the first US phase 2 experience.

OBJECTIVE: Peptide receptor radionuclide therapy with radiolabeled somatostatin analogs is a novel method of treatment in patients with metastatic neuroendocrine tumors (NETs). For the first time in the United States, we present preliminary results of the treatment with Lutetium (177)(Lu) DOTATATE in patients with progressive NETs. METHODS: Thirty-seven patients with grade 1 and grade 2 disseminated and progressive gastroenteropancreatic NET were enrolled in a nonrandomized, phase 2 clinical trial. Repeated cycles of 200 mCi (7.4 GBq; ±10%) were administered up to the cumulative dose of 800 mCi (29.6 GBq; ±10%). RESULTS: Among 32 evaluable patients, partial response and minimal response to treatment were seen in 28% and 3%, respectively, and stable disease was seen in 41% of patients. A total of 28% had progressive disease. A response to treatment was significantly associated with lower burden of disease in the liver. No significant acute or delayed hematologic or kidney toxicity was observed. An impressive improvement of performance status and quality of life were seen after Lu-DOTATATE therapy. CONCLUSIONS: Treatment with multiple cycles of (177)Lu-DOTATATE peptide receptor radionuclide therapy is well tolerated. This treatment results in control of the disease in most patients, whereas systemic toxicities are limited and reversible. Quality of life is also improved.

Above-Label Doses of Octreotide-LAR in Patients With Metastatic Small Intestinal Carcinoid Tumors.

BACKGROUND: Octreotide LAR is indicated for treatment of malignant carcinoid syndrome and has been studied at doses of 10 to 30 mg intramuscularly every 4 weeks. In clinical practice, higher doses are often prescribed for patients who experience refractory carcinoid syndrome (flushing and/or diarrhea) or tumor growth while on the maximum label-recommended dose. METHODS: We performed a retrospective, longitudinal review of octreotide LAR administration at a tertiary institution to determine the frequency of above-label dosing and outcomes. RESULTS: Three hundred thirty-eight patients were considered evaluable, among whom 100 (30%) underwent at least 1 increase in dose or frequency of octreotide-LAR above the standard label dose. The most common maximum doses were 40 mg every 4 weeks (n = 37 patients), 60 mg every 4 weeks (n = 34), and 30 mg every 3 weeks (n = 18). The indications for dose increase were worsening carcinoid syndrome (n = 60), radiographic progression (n = 33), and rising urine 5-HIAA (n = 6). Of the patients whose doses were increased for refractory carcinoid syndrome, 62% (n = 34) experienced improvement in diarrhea, and 56% (n = 28) experienced improvement in flushing. CONCLUSIONS: In conclusion, octreotide LAR is commonly prescribed in doses or schedules above the recommended dose and frequency. Patients with refractory carcinoid syndrome appear to experience a clinical benefit from this change. Prospective data may be used to further evaluate this strategy.

Cytoplasmic Clusterin expression correlates with pancreatic neuroendocrine tumor size and pathological stage.

OBJECTIVES: Cytoplasmic clusterin (Clusterin), a ubiquitous multifunctional secretory sulfated glycoprotein, plays a role in apoptosis and is reportedly overexpressed in a variety of tumors. The role of Clusterin in pancreatic neuroendocrine tumors (PNETs) has not been investigated. In this study, Clusterin expression was evaluated in a subset of PNETs, and the results were correlated with the clinical-pathological features of the tumors. METHODS: Fifty-nine surgical cases were used to evaluate the immunohistochemical expression of Clusterin in PNETs. Using the avidin-biotin complex method, tissue sections from each case were stained with a rabbit anticlusterin antibody (Abcam, Cambridge, Mass). The immunohistochemical reactions were qualitatively and semiquantitatively evaluated by 2 pathologists. RESULTS: Strong Clusterin reactivity was identified in 36 (61%) of 59 PNETs. In 23 (39%) of 59 cases, the Clusterin score was 3 or less. Clusterin expression scores significantly associated with tumor size (P = 0.03) and with tumor stage (P = 0.02). The immunohistochemical score index did not correlate with tumor grade (P = 0.15). CONCLUSIONS: We report the expression of Clusterin in PNETs. The correlation of Clusterin with tumor size and stage suggests involvement of this molecule in pancreatic neuroendocrine tumor progression. Clusterin may represent a new target of therapy for PNETs.

Treatment of metastatic neuroendocrine tumors of the thymus with capecitabine and temozolomide: a case series.

BACKGROUND: Metastatic neuroendocrine tumors of the thymus are exceedingly rare with an annual incidence of approximately 0.2 per 1,000,000. They are highly resistant to therapy and there have been no reports of an objective radiographic response to treatment. MATERIALS AND METHODS: The authors retrospectively evaluated 3 patients with progressive, metastatic neuroendocrine tumors of the thymus who were treated with a combination of capecitabine and temozolomide. Radiographic scans were evaluated and response assessed using RECIST criteria. RESULTS: One patient experienced a partial radiographic response, another patient experienced a minor response and the third patient experienced stable disease as the best response to treatment. CONCLUSION: The combination of capecitabine and temozolomide appears to be active in a rare neuroendocrine malignancy that is generally refractory to systemic therapy. Prospective multicenter trials are needed to validate this strategy.

Prognostic validity of the American Joint Committee on Cancer staging classification for midgut neuroendocrine tumors.

PURPOSE: The American Joint Committee on Cancer (AJCC) staging manual has introduced a TNM staging classification for jejunal-ileal (midgut) neuroendocrine tumors (NETs). This classification has not been validated in a population consisting solely of midgut NETs. The purpose of this study was to test the prognostic validity of the classification in such a population. METHODS: Patients with jejunal and ileocecal NETs who were treated at the Moffitt Cancer Center between 2000 and 2010 were assigned stages (I through IV). Kaplan-Meier analyses for overall survival (OS) were performed on the basis of TNM stage and pathologic grade. Multivariate modeling was performed using Cox proportional hazards regression. RESULTS: We identified 691 patients with jejunal-ileocecal NETs. The AJCC classification in aggregate was highly prognostic for OS (P < .001). Five-year OS rates for stages I through IV were 100%, 100%, 91%, and 72%, respectively. The survival difference between stages III and IV was significant (P < .001); the difference between stages I/II versus III was not statistically significant (P = .1). Among patients with stage IIIB tumors, 5-year survival rates were 95% for resectable tumors versus 78% for unresectable mesenteric tumors (P = .02). A proliferative threshold of five mitoses per 10 high-power fields (HPF) was of greater prognostic value than a threshold of two mitoses per 10 HPF for discriminating between low- and intermediate-grade tumors. CONCLUSION: Stage I and II midgut NETs are associated with identical survival rates. Stage IIIB tumors are heterogeneous, with significant differences in survival observed between resectable mesenteric lymph nodes versus unresectable masses in the root of the mesentery. A higher mitotic cutoff of five per 10 HPF may lead to improved prognostic differentiation between low- and intermediate-grade tumors. Revisions to the current AJCC staging and grading classification may be warranted.

Pasireotide (SOM230) shows efficacy and tolerability in the treatment of patients with advanced neuroendocrine tumors refractory or resistant to octreotide LAR: results from a phase II study.

Pasireotide (SOM230) is a novel multireceptor-targeted somatostatin (sst) analog with high binding affinity for sst receptor subtype 1, 2, 3 (sst(1,2,3)) and sst(5). Because of this binding profile, pasireotide may offer symptom control in patients with neuroendocrine tumors (NETs) and carcinoid syndrome no longer responsive to octreotide LAR. This was a phase II, open-label, multicenter study of pasireotide in patients with advanced NET whose symptoms of carcinoid syndrome (diarrhea/flushing) were inadequately controlled by octreotide LAR. Patients received s.c. pasireotide 150 µg twice daily (bid), escalated to a maximum dose of 1200 µg bid until a clinical response was achieved. Forty-four patients were evaluated for efficacy and 45 for tolerability. Pasireotide 600-900 µg s.c. bid effectively controlled the symptoms of diarrhea and flushing in 27% of patients. Evaluation of tumor response in 23 patients showed 13 with stable disease and ten with progressive disease at study end. The most common drug-related adverse events were nausea (27%), abdominal pain (20%), weight loss (20%), and hyperglycemia (16%) and most were of mild or moderate severity. Pasireotide 600-900 µg s.c. bid was effective and generally well tolerated in controlling the symptoms of carcinoid syndrome in 27% of patients with advanced NET refractory or resistant to octreotide LAR therapy.

Relapse-free survival in patients with nonmetastatic, surgically resected pancreatic neuroendocrine tumors: an analysis of the AJCC and ENETS staging classifications.

BACKGROUND: The risk of metastatic spread among patients with early-stage pancreatic neuroendocrine tumors has not been well established. The authors sought to evaluate whether the new TNM staging systems proposed by the American Joint Committee on Cancer (AJCC) and European Neuroendocrine Tumor Society (ENETS) are prognostic for relapse-free survival (RFS) after surgical resection. METHODS: Patients with surgically resected localized or locally advanced pancreatic NETs treated at the H. Lee Moffitt Cancer Center between 1999 and 2010 were assigned a stage (I-III) based on the AJCC and ENETS classifications. RFS and overall survival were measured using Kaplan-Meier methodology, with log-rank testing for evaluation of the 2 tumor staging systems. Multivariate analysis was performed controlling for tumor grade, location, surgery type, functional hormonal status, and incidental diagnosis. RESULTS: The authors identified 123 patients with nonmetastatic, surgically resected pancreatic NETs. When using the AJCC classification, 5-year RFS rates for stages I through III were 78%, 53%, and 33%, respectively (P < 0.01). Using the ENETS classification, 5-year RFS rates for stages I to III were 100%, 70%, and 53% (P < 0.18). When excluding patients who were referred after their metastatic recurrence, the 5-year RFS rates for stages I to III were 90%, 73%, and 66% according to the AJCC classification, and 100%, 84%, and 75% according to the ENETS classification. Recurrence rates peaked at approximately 2 years after surgery. CONCLUSIONS: The AJCC and ENETS TNM classifications for pancreatic NETs are prognostic for recurrence-free survival and can be adopted in clinical practice.

Palladin is a marker of liver metastasis in primary pancreatic endocrine carcinomas.

BACKGROUND: Palladin is a metastasis-associated gene regulating cell motility. The expression of palladin protein in pancreatic neuroendocrine tumors (PET) and carcinomas (PECA) is not known. MATERIALS AND METHODS: A tissue microarray (TMA) of well-differentiated (WD) PETs/PECAs (AJCC 2010) and non-neoplastic, histologically normal pancreatic tissue/islets (HNPIs) was immunostained with palladin antibody and quantified using the Allred score. The results were correlated with the presence or absence of liver metastases. RESULTS: The retrospective study included 19 males and 19 females of age 27-79 years (mean 54). Tumor size was 0.9-11.5 cm (mean 3.8). Palladin expression was cytoplasmic and/or membranous. The tumors with high palladin expression were associated with liver metastasis (p<0.0001). All 14 primary PECA with hepatic metastases (MP-PECAs) exhibited palladin expression whereas 14 out of 24 (58%) clinically-localized primary PET (CLP-PETs) expressed palladin (p<0.01) with median Allred scores of 5 (range 3-7) and 2 (range 0-6) respectively (p<0.0001). The mean Allred score for the HNPIs in the MP-PECAs (N=6) was higher (4.2) as compared to that in the CLP-PETs (2.5,N=11) (p=0.23). CONCLUSION: Palladin may identify primary pancreatic endocrine neoplasms with a propensity to metastasize to the liver.

Evolving diagnostic and treatment strategies for pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors (NET) have diverse clinical presentations. Patients with symptoms of hormone secretion may require specific medical interventions to control those symptoms prior to antitumor intervention. In some patients, tumors in the pancreas may be occult and specialized diagnostic imaging or surgery may be required for diagnosis. Other patients may present with more advanced disease, presenting with symptoms of tumor bulk rather than hormone secretion. Treatment options for patients with advanced pancreatic neuroendocrine tumors include surgical resection and hepatic directed therapies, including partial hepatectomy, hepatic artery embolization, or other ablative techniques. Streptozocin or temozolomide-based chemotherapy regimens are active against pancreatic NET, and can also play an important role in the palliation of patients with advanced disease. A number of biologically targeted agents targeting the VEGF and mTOR signaling pathways have recently shown promise, with recent trials showing treatment with the VEGFR tyrosine kinase inhibitor sunitinib or the mTOR inhibitor everolimus improves progression-free survival in patients with advanced NET.

Prognostic validity of a novel American Joint Committee on Cancer Staging Classification for pancreatic neuroendocrine tumors.

PURPOSE: The American Joint Committee on Cancer (AJCC) staging manual (seventh edition) has introduced its first TNM staging classification for pancreatic neuroendocrine tumors (NETs) derived from the staging algorithm for exocrine pancreatic adenocarcinomas. This classification has not yet been validated. METHODS: Patients with pancreatic NETs treated at the H. Lee Moffitt Cancer Center between 1999 and 2010 were assigned a stage (I to IV) based on the new AJCC classification. Kaplan-Meier analyses for overall survival (OS) were performed based on age, race, histologic grade, incidental diagnosis, and TNM staging (European Neuroendocrine Tumors Society [ENETS] v AJCC) using log-rank tests. Survival time was measured from time of initial diagnosis to date of last contact or date of death. Multivariate modeling was performed using Cox proportional hazards regression. Weighted Cohen's κ coefficient was computed to evaluate the agreement of ENETS and AJCC classifications. RESULTS: We identified 425 patients with pancreatic NETs. On the basis of histopathologic grade, 5-year survival rates for low-, intermediate-, and high-grade tumors were 75%, 62%, and 7%, respectively (P < .001). When using the ENETS classification, 5-year OS rates for stages I, II, III, and IV were 100%, 88%, 85%, and 57%, respectively (P < .001). Subsequently, using the AJCC classification, 5-year OS rates for stages I, II, III, and IV were 92%, 84%, 81%, and 57%, respectively (P < .001). Both the novel AJCC classification and the ENETS classification were highly prognostic for survival. CONCLUSION: The AJCC TNM classification for pancreatic NETs is prognostic for OS and can be adopted in clinical practice.

RUNX1T1: a novel predictor of liver metastasis in primary pancreatic endocrine neoplasms.

OBJECTIVES: Using gene expression profiling on frozen primary pancreatic endocrine tumors (PETs), we discovered RUNX1T1 as a leading candidate progression gene. This study was designed (1) to validate the differential expression of RUNX1T1 protein on independent test sets of metastatic and nonmetastatic PETs and (2) to determine if RUNX1T1 underexpression in primary tumors was predictive of liver metastases. METHODS: Immunohistochemical expression of RUNX1T1 protein was quantified using Allred scores on archival metastatic (n = 13) and nonmetastatic (n = 24) primary adult PET tissues using custom-designed tissue microarrays. Wilcoxon rank sum/Fisher exact tests and receiver operating characteristic curves were used in the data analysis. RESULTS: Median RUNX1T1 scores were 2 (2-7) and 6 (3-8) in metastatic versus nonmetastatic primaries (P < 0.0001). Eleven of 13 metastatic and 1 of 24 nonmetastatic primaries exhibited RUNX1T1-scores of 4 or less (P < 0.0001). Low RUNX1T1 expression was highly associated with hepatic metastases (P < 0.0001), whereas conventional histological criteria (Ki-67 index, mitotic rate, necrosis) were weakly associated with metastases (P = 0.08-0.15). Considering RUNX1T1 expression (Allred) score of 4 or less to be predictive, the sensitivity to predict hepatic metastases was 85%, with a specificity of 96%. CONCLUSIONS: RUNX1T1 protein is underexpressed in well-differentiated metastatic primary PETs relative to nonmetastatic primaries and emerges as a promising novel biomarker for prediction of liver metastases.

A review of systemic and liver-directed therapies for metastatic neuroendocrine tumors of the gastroenteropancreatic tract.

BACKGROUND: Treatment options for metastatic gastroenteropancreatic neuroendocrine tumors (NETs) have evolved in recent years. The somatostatin analogs octreotide and lanreotide have long been used for management of symptoms such as flushing and diarrhea associated with hormonally active NETs. New evidence demonstrates that these agents can also inhibit tumor growth. Other novel agents targeting the VEGF and mTOR pathways have recently been investigated in multicenter phase III studies. METHODS: The authors review the recent literature on treatments for metastatic gastroenteropancreatic NETs and summarize new therapeutic developments. RESULTS: Novel agents targeting somatostatin receptors and the VEGF and mTOR pathways are capable of significantly prolonging progression-free survival in certain NET subtypes. New temozolomide-based chemotherapy regimens have demonstrated considerable activity in pancreatic NETs. Liver-targeted therapies, including surgical resection, radiofrequency ablation, and hepatic artery embolization, are effective options for patients whose metastases are predominantly confined to the liver. Embolization of (90)Y-embedded spheres (radioembolization) represents a novel approach to managing liver metastases. CONCLUSIONS: Treatment options are expanding rapidly for patients with metastatic gastroenteropancreatic NETs, driven largely by randomized, collaborative clinical trials. Future clinical trials should compare the efficacy of emerging therapies and evaluate combination vs sequential approaches.

Recent progress in the understanding, diagnosis, and treatment of gastroenteropancreatic neuroendocrine tumors.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are relatively rare tumors that arise from the diffuse neuroendocrine system. This heterogeneous group of tumors was often considered a single entity. This belied their biological diversity, and the biggest advance in understanding these tumors over the past decades has been in understanding this diversity. Diagnosis of these tumors has been aided by advances in pathological diagnosis and classification and tumor imaging with endoscopic ultrasound and somatostatin receptor fusion imaging. Genetic and molecular advances have identified molecular targets in the treatment of these tumors. Surgery remains the mainstay of treatment, amply supported by interventional radiological techniques, including embolization. Treatment of metastatic disease has improved significantly with the addition of several new agents, including tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and yttrium-90-DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and lutetium-177-DOTA octreotate. Despite significant advances in the understanding and management of GEP-NETs, the survival of patients remains largely unchanged and there remains a need for the development of national and international research collaborations to spearhead future efforts.

First-line chemotherapy with capecitabine and temozolomide in patients with metastatic pancreatic endocrine carcinomas.

BACKGROUND: Temozolomide is an active agent in metastatic pancreatic endocrine carcinomas. In vitro data indicate that the combination of capecitabine and temozolomide is synergistic for induction of apoptosis in neuroendocrine tumor cell lines. The authors retrospectively evaluated the efficacy of capecitabine and temozolomide in 30 patients with metastatic pancreatic endocrine carcinomas to assess response rate, progression free survival (PFS), and overall survival (OS). METHODS: Patients with metastatic, well, or moderately differentiated pancreatic endocrine carcinomas who had not received prior systemic chemotherapy were treated with capecitabine (750 mg/m² twice daily, days 1-14) and temozolomide (200 mg/m² once daily, days 10-14) every 28 days. RESULTS: Among 30 patients treated, 21 (70%) patients achieved an objective radiographic response. Median progression-free survival was 18 months. The rate of survival at two years was 92%. Only 4 patients (12%) experienced grade 3 or 4 adverse events. CONCLUSIONS: The combination of capecitabine and temozolomide is associated with an exceptionally high and durable response rate in metastatic endocrine carcinomas of the pancreas. Clinical endpoints, including response rate, survival, and toxicity, are superior to those observed with streptozocin-based regimens.