Pharmacotherapy of neuroendocrine cancers

Clinicopathological characteristics of extrahepatic biliary neuroendocrine neoplasms in the gallbladder, extrahepatic biliary tract, and ampulla of Vater: A single-center cross-sectional study

Backgrounds/Aims

In 2019, the grading and staging system for neuroendocrine neoplasms (NENs) was significantly changed. In this study, we report the clinicopathological characteristics and surgical outcomes of patients with extrahepatic biliary NENs who underwent curative resection with or without adjuvant treatment.

Methods

We retrospectively reviewed a database of 16 patients who developed NENs, neuroendocrine carcinoma (NEC), and mixed endocrine non-endocrine neoplasms (MiNENs) after curative resection. Among them, eight patients had ampulla of Vater (AoV) tumors, and eight patients had non-AoV tumors.

Results

G1 and G2 were more frequently observed in the AoV group than in the non-AoV group (12.5% and 62.5%, respectively). In contrast, NEC and MiNEN were more common in the non-AoV group (50.0%). High Ki-67 index (> 20%) and perineural invasion (PNI) were more frequently observed in the non-AoV group. Advanced age (> 65 years), mitotic count > 20 per 2 mm2, and Ki-67 index > 20% were strongly correlated with patient survival (p = 0.018, 0.009, and 0.044, respectively). Advanced age (> 65 years) and mitotic count > 20 per 2 mm2 were significantly correlated with disease recurrence (p = 0.033 and 0.010, respectively).

Conclusions

AoV and non-AoV tumors had significant differences in the histologic grade, Ki67, and PNI. Patients with non-AoV tumors had an increased risk for survival and recurrence than those in the AoV group. For extrahepatic biliary NENs, early detection of tumors, adequate surgery, and aggressive adjuvant treatment for high-risk patients are important to achieve long-term survival and prevent disease recurrence.

A rare occurrence of a poorly differentiated large cell neuroendocrine carcinoma of the gallbladder: A case report and review of the literature

INTRODUCTION

Neuroendocrine carcinoma (NEC) of the gallbladder is a rare entity with much of the surgical strategy and management mirroring that of adenocarcinoma of the gallbladder. In contrast to gallbladder adenocarcinoma, however, it tends to be a more aggressive and lethal malignancy associated with a short survival after the time of diagnosis. Furthermore, due to its rarity, there are no consensus guidelines for its management.

PRESENTATION OF CASE

We present the case of a 73-year-old female who presented with acute cholecystitis and was found to have a poorly differentiated large cell NEC of the gallbladder after laparoscopic cholecystectomy. She was treated with adjuvant chemotherapy and has shown no evidence of cancer recurrence on three-year follow up.

DISCUSSION

Surgical resection is the cornerstone of curative treatment for gallbladder NEC. Management may include simple cholecystectomy, extended cholecystectomy, radical cholecystectomy, or palliative cholecystectomy. It is unclear whether lymphadenectomy confers a survival benefit. Adjuvant chemotherapy with platinum-based regimens, on the other hand, has been associated with increased survival rates. Radiation, immunotherapy, somatostatin analogs and targeted therapy have also been used for treatment.

CONCLUSION

NEC of the gallbladder is extremely rare, aggressive, and carries a dismal prognosis. Further studies are needed to develop the optimal treatment approach to increase survival rates and establish best practices to manage these patients.

A Rare Case of Pure Primary Large Cell Neuroendocrine Carcinoma of the Gallbladder

Primary large cell neuroendocrine carcinoma (LCNEC) of the gallbladder is a rare malignancy which is often associated with non-LCNEC histologic components. Histologically “pure” LCNECs of the gallbladder are exceedingly rare with only 15 cases reported in the medical literature. Clinically, LCNECs present with abdominal pain and jaundice and follow an aggressive course with patients surviving a median of 15 months following initial diagnosis. To our knowledge, we present the 16th case of a histologically pure LCNEC in a 62-year-old African American male who was successfully treated surgically. After discharge, he was subsequently lost to follow-up. Due to the extreme rarity of such disease entity, accurate diagnosis and proper management are essential for the best clinical outcome.

Clinicopathological characteristics and prognostic factors of patients with primary gallbladder neuroendocrine carcinomas

OBJECTIVES

Primary gallbladder neuroendocrine carcinomas (GB-NEC) are malignant neoplasms that remained to be studied. In this study we aimed to summarize their clinicopathological characteristics, effective treatment and prognostic factors for patients with GB-NEC.

METHODS

Patients with GB-NEC admitted to Shanghai Jiao Tong University Affiliated Sixth People's Hospital and Renji Hospital, School of Medicine, Shanghai Jiao Tong University from October 2012 to August 2020 were enrolled. Clinicopathological characteristics of our patients and those reported in previous studies were recorded. The Kaplan-Meier method and univariate and multivariate Cox regression analyses were used for survival analysis.

RESULTS

Altogether 15 patients from our hospitals and 47 patients from previous studies were included. A total of 55 patients who underwent surgical resection, including R₀ and non-R₀ resection, had significantly longer overall survival compared with the other seven patients. A univariate analysis indicated that patients aged 60 years or older, with jaundice, carcinoid syndrome, non-R₀ resection, and advanced stage were associated with worse survival. A multivariate analysis showed that patients aged 60 years or older, carcinoid syndrome and non-R₀ resection, but not lymphadenectomy and adjuvant chemotherapy, were independently related to reduced survival.

CONCLUSIONS

R₀ resection should be the first-line treatment for GB-NEC. Older age, carcinoid syndrome and non-R₀ resection are independently associated with reduced survival after surgical resection.

Whole-exome mutational landscape of neuroendocrine carcinomas of the gallbladder

Neuroendocrine carcinoma (NEC) of the gallbladder (GB-NEC) is a rare but extremely malignant subtype of gallbladder cancer (GBC). The genetic and molecular signatures of GB-NEC are poorly understood; thus, molecular targeting is currently unavailable. In the present study, we applied whole-exome sequencing (WES) technology to detect gene mutations and predicted somatic single-nucleotide variants (SNVs) in 15 cases of GB-NEC and 22 cases of general GBC. In 15 GB-NECs, the C > T mutation was predominant among the 6 types of SNVs. TP53 showed the highest mutation frequency (73%, 11/15). Compared with neuroendocrine carcinomas of other organs, significantly mutated genes (SMGs) in GB-NECs were more similar to those in pulmonary large-cell neuroendocrine carcinomas (LCNECs), with driver roles for TP53 and RB1. In the COSMIC database of cancer-related genes, 211 genes were mutated. Strikingly, RB1 (4/15, 27%) and NAB2 (3/15, 20%) mutations were found specifically in GB-NECs; in contrast, mutations in 29 genes, including ERBB2 and ERBB3, were identified exclusively in GBC. Mutations in RB1 and NAB2 were significantly related to downregulation of the RB1 and NAB2 proteins, respectively, according to immunohistochemical (IHC) data (p values = 0.0453 and 0.0303). Clinically actionable genes indicated 23 mutated genes, including ALK, BRCA1, and BRCA2. In addition, potential somatic SNVs predicted by ISOWN and SomVarIUS constituted 6 primary COSMIC mutation signatures (1, 3, 30, 6, 7, and 13) in GB-NEC. Genes carrying somatic SNVs were enriched mainly in oncogenic signaling pathways involving the Notch, WNT, Hippo, and RTK-RAS pathways. In summary, we have systematically identified the mutation landscape of GB-NEC, and these findings may provide mechanistic insights into the specific pathogenesis of this deadly disease.

Synthetic Makaluvamine Analogs Decrease c-Kit Expression and Are Cytotoxic to Neuroendocrine Tumor Cells

In an effort to discover viable systemic chemotherapeutic agents for neuroendocrine tumors (NETs), we screened a small library of 18 drug-like compounds obtained from the Velu lab against pulmonary (H727) and thyroid (MZ-CRC-1 and TT) neuroendocrine tumor-derived cell lines. Two potent lead compounds (DHN-II-84 and DHN-III-14) identified from this screening were found to be analogs of the natural product makaluvamine. We further characterized the antitumor activities of these two compounds using pulmonary (H727), thyroid (MZ-CRC-1) and pancreatic (BON) neuroendocrine tumor cell lines. Flow cytometry showed a dose-dependent increase in apoptosis in all cell lines. Induction of apoptosis with these compounds was also supported by the decrease in myeloid cell leukemia-1 (MCL-1) and X-chromosome linked inhibitor of apoptosis (XIAP) detected by Western blot. Compound treatment decreased NET markers chromogranin A (CgA) and achaete-scute homolog 1 (ASCL1) in a dose-dependent manner. Moreover, the gene expression analysis showed that the compound treatment reduced c-Kit proto-oncogene expression in the NET cell lines. Induction of apoptosis could also have been caused by the inhibition of c-Kit expression, in addition to the known mechanisms such as damage of DNA by topoisomerase II inhibition for this class of compounds. In summary, makaluvamine analogs DHN-II-84 and DHN-III-14 induced apoptosis, decreased neuroendocrine tumor markers, and showed promising antitumor activity in pulmonary, thyroid, and pancreatic NET cell lines, and hold potential to be developed as an effective treatment to combat neuroendocrine tumors.

Flushing as atypical initial presentation of functional gallbladder neuroendocrine carcinoma: A case report

BACKGROUND

Neuroendocrine neoplasms are rarely located in the gallbladder (GB), and carcinoid syndrome is exceedingly rare in patients with GB neuroendocrine neoplasms.

CASE SUMMARY

We report a case of GB neuroendocrine carcinoma (GB-NEC) in a 65-year-old man, who presented with flushing for 2 mo. Pathological specimens of the flushed skin revealed that mucin was deposited between the collagen bundles in the dermis. Computed tomography and magnetic resonance imaging indicated neoplasm in the GB with liver invasion and enlarged lymph nodes in the portacaval space. High fluorodeoxyglucose uptake was detected in lymph nodes in the portacaval space, but distant metastasis was not seen by positron emission tomography. Ultrasound-guided needle biopsy of the GB neoplasm was suggestive of high-grade NEC. Because of the functional characteristics of poorly differentiated NEC, en bloc cholecystectomy, resection of hepatic segments IVb and V, pancreaticoduodenectomy, and regional lymphadenectomy were performed. A diagnosis of poorly differentiated NEC was made by pathological findings and immunohistochemical staining data. Ki-67 index was > 80%. The patient refused adjuvant therapy and passed away in the 7^th month.

CONCLUSION

Distinctive manifestation combined with imaging helps make correct preoperative diagnosis. Radical surgery and adjuvant chemotherapy might improve prognosis.

Paraganglion, a pitfall in diagnosis after regular cholecystectomy

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Neuroendocrine neoplasms are a rarity after cholecystectomy and current literature is scarce.

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Paraganglion of the gallbladder is an incidental benign finding.

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A paraganglion can mimic the histopathologic appearance of neuroendocrine tumours.

Introduction

Neuroendocrine neoplasm of the gallbladder is an extremely uncommon diagnosis. We present a case of a benign gallbladder paraganglion that was initially incorrectly diagnosed as a neuroendocrine tumour (NET).

Presentation of case

A 27-year-old female with symptomatic gallstone disease underwent an uncomplicated laparoscopic cholecystectomy. Routine histopathologic examination suggested the presence of a small adventitial NET. However, histopathological revision was performed by our pathologist because of regional gallbladder carcinoma (GBC) treatment evaluation. The revision demonstrated the presence of a normal paraganglion, a preexistent structure that is only rarely encountered during routine histopathologic examination of the gallbladder.

Discussion

Neuroendocrine neoplasms of the gallbladder are extremely rare. Treatment varies from a simple cholecystectomy to extensive surgical resections. Chemotherapy is usually reserved for metastatic disease. In contrast, a gallbladder paraganglion is a benign entity not requiring additional treatment.

Conclusion

A neuroendocrine neoplasm of the gallbladder may closely resemble a benign paraganglion. If a NET is suspected, the clinician should be aware of the histopathologic mimicry of a paraganglion prior to initiating additional treatments.

Can surgical treatment be justified for neuroendocrine carcinoma of the gallbladder?

Clinical features and treatment of GB neuroendocrine carcinoma (GB-NEC) are not well understood. This study aimed to analyze clinical outcomes of GB-NEC and verify the oncologic benefit of surgical treatment.From October 1994 to December 2014, the medical records of 31 patients with GB-NEC at a single center were retrospectively reviewed. There were 18 inoperable cases due to distant metastasis, including 7 of best supportive care (Tx.1) and 11 of non-operative palliative treatment (Tx.2). 4 patients received non-curative, palliative resection (Tx.3). Only 9 patients were able to undergo curative-intent resection (Tx.4).Among the 31 patients with GB-NEC, preoperative mean value of carbohydrate antigen 19-9 (CA 19-9) was 74.8 ± 156.1 U/mL and the median overall survival time was 10 months (range 7.0-12.0 months). Of these, 21 (67.7%) patients received systemic treatment. Among 9 patients who underwent curative-intent resection (Tx.4), 9 patients had poorly differentiated cancer cells and 7 patients received radical cholecystectomy. 6 patients had adjuvant treatment including concurrent chemoradiation therapy (CCRT) or chemotherapy alone. The recurrence rate was 88.9%. The median overall survival between 4 groups was as follows: 4.0 (3.0-18.0) months in Tx.1 (n = 7) versus 9.0 (3.0-21.0) months in Tx.2 (n = 11) versus 11.0 (3.0-15.0) months in Tx.3 (n = 4) versus 23.0 (8.0-34.0) months in Tx.4 (n = 9), respectively. Significant differences in median overall survival time existed between Tx.2 and Tx.4; 9 (3.0-21.0) months versus 23.0 (8.0-34.0) months (P = .017).Most GB-NECs show poor biologic behavior. Nonetheless, curative-intent resection could possibly promote longer survival than other treatment modalities for GB-NEC. Efforts to undergo curative resection through early detection and development of adjuvant treatment are needed.

Systematic Review and Meta-Analysis on the Role of Chemotherapy in Advanced and Metastatic Neuroendocrine Tumor (NET)

BACKGROUND/OBJECTIVES

In the era of somatostatin analogues and targeted therapies, the role of chemotherapy in NET remains largely undefined. This systematic review aimed to assess the effect of chemotherapy on response rates (RR), progression-free survival (PFS), overall survival (OS) and toxicity compared to other chemotherapies/systemic therapies or best supportive care in patients with advanced or metastatic NET.

METHODS

Randomised controlled trials (RCTs) from 1946 to 2015 were identified from MEDLINE, EMBASE, other databases and conference proceedings. Review of abstracts, quality assessment and data abstraction were performed independently by two investigators. Meta-analyses were conducted using Mantel-Haenszel analysis with random-effects modelling.

RESULTS

Six RCTs comparing standard streptozotocin plus 5-fluorouacil (STZ/5FU) chemotherapy to other chemotherapy regimens, and 2 comparing this to interferon (IFN) were included. Only 1 study was considered at low risk of bias. STZ/5-FU was no different to other chemotherapies in response rate [RR 0.96; 95% confidence interval (CI) 0.72-1.27], PFS (RR 0.95; CI 0.81-1.13), or OS (RR 1.03; CI 0.77-1.39). IFN may produce higher response than STZ/5FU (RR 0.20; CI 0.04-1.13), but event rates were small and survival was no different. Interferon was associated with higher overall haematological (RR 0.47; CI 0.27-0.82) and lower overall renal toxicity (RR 3.61; CI 1.24-10.51).

CONCLUSION

Strong evidence is lacking in the area of chemotherapy in neuroendocrine tumors. There is currently no evidence that one chemotherapeutic regimen is significantly better than the other, nor is interferon better than chemotherapy. There is an urgent need to design RCTs comparing modern chemotherapy to other agents in NET.

"Pure" large cell neuroendocrine carcinoma of the gallbladder. Report of a case and review of the literature

Primary Neuroendocrine Tumours (NETs) of the gallbladder are rare. Among all NETs of the gallbladder, large cell neuroendocrine carcinoma (LCNEC) is exceedingly rare. In most of the cases LCNECs are combined with other histological components. We reviewed clinical presentation and management of all patients with "pure" LCNEC from published literature since the first case was published in 2000, as well as one patient from our experience. Only 7 cases of "pure" LCNEC has been described in the last 15 years, our case is the eighth. The diagnosis of gallbladder NETs is rarely made preoperatively since the presentation generally consists of non-specific symptoms including upper abdominal pain, discomfort, jaundice, weight loss. The majority of patients are identified incidentally at the time of cholecystectomy for cholelithiasis. It is not possible to differentiate preoperatively between gallbladder adenocarcinoma and gallbladder neuroendocrine carcinoma (NEC) with imaging techniques. The only curative therapeutic modality for LCNECs is a complete en bloc surgical resection, including regional lymph node clearances and hepatic lobectomy, but only in patients without multiple metastasis. LCNECs benefit from an aggressive surgical resection in combination with chemotherapy, if resectability is possible. If the tumour is non-resectable, the primary management is therefore medical and not surgical. All patients with LCNEC presented a poor prognosis with a median survival of 10 months after the initial diagnosis. Only in five patients (62.5%) a wide surgical excision was performed, while in the other cases the tumour was non-resectable or multiple liver metastases were present at diagnosis.

Mixed large cell neuroendocrine carcinoma and adenocarcinoma of the gallbladder: a case report and brief review of the literature

Large-cell neuroendocrine carcinoma (LCNEC) of the gallbladder is extremely rare. We present a 63-year-old Chinese female who was admitted with right upper quadrant pain and a quasi-circular tumor measuring 2.0 cm on the body of the gallbladder, as indicated by computed tomography. LCNEC combined with adenocarcinoma was immunohistochemically confirmed after open radical cholecystectomy. Postoperative recovery of this patient was uneventful, and no evidence of recurrence or metastasis was observed after 12 months of follow-up. LCNEC of the gallbladder is thought to be extremely rare and is usually found in combination with other histological carcinoma types, such as adenocarcinoma, as determined histologically. The prognosis is poor overall, but early detection with complete resection may result in a relatively good prognosis.

Clinical outcomes of small cell neuroendocrine carcinoma and adenocarcinoma of the gallbladder

AIM: To compare the demographics and survival rates between gallbladder adenocarcinoma (GB-adenocarcinoma) and small cell neuroendocrine carcinoma of the gallbladder (GB-NEC-SCC).

METHODS: From March 2007 to September 2012, patients who underwent resection of tumor stage T2/T3 GB cancer were enrolled for this study. Forty-two patients were included in this study, including 38 diagnosed with GB-adenocarcinoma and four diagnosed with GB-NEC-SCC. In the GB-adenocarcinoma group, a radical operation was performed in 28 patients, and ten patients underwent simple cholecystectomy. In the GB-NEC-SCC group, a radical operation was performed in three patients, and one patient underwent simple cholecystectomy. Comparative analysis of the two groups was performed, including clinicopathologic features and survival rates.

RESULTS: The median age of the patients was 68 y (range: 35-83 years) and females comprised 26/42 of the patients. GB-adenocarcinoma patients were significantly older than GB-NEC-SCC patients (67.89 ± 11.15 vs 55.75 ± 10.31 years; P = 0.029). The median tumor size in GB-adenocarcinoma patients was 2.56 ± 1.75 cm and 3.98 ± 3.74 cm in GB-NEC-SCC patients; however, there was no significant difference between the two groups. For tumors > 2 cm, T stage (T2 vs T3), lymphovascular invasion, perineural invasion, lymph node metastasis and lymph node ratio showed no significant differences between the two groups. The overall survival rate of the 42 patients at five years was 77.0%. In the GB-adenocarcinoma group, the overall five-year survival rate was 74.8%, and survival in the GB-NEC-SCC group was 100%, which was not significantly different between the two groups.

CONCLUSION: The strategy for treating patients with GB-NEC-SCC should be similar to that used for treating GB-adenocarcinoma, including radical cholecystectomy and liver resection.

Neuroendocrine tumor of the gallbladder

Background

The primary neuroendocrine tumors of the gallbladder are very rare, representing 0.2% of all neuroendocrine tumors. The definite diagnosis is incidental in most cases.

Case Report

A 60-year-old male patient presented with a one-month history of epigastric pain and jaundice, itching, flushing, cough and wheezing. Ultrasound demonstrated the gallbladder containing multiple stones, with wall thickening and an adjacent liver lesion. Additionally, those structures showed noticeable contrast enhancement in CT and MRI. Histopathological examination revealed a primary gallbladder neuroendocrine tumor.

Conclusions

Though a rare entity, primary neuroendocrine tumor should be considered in the differential diagnosis of gallbladder cancers.

Neuroendocrine phenotype alteration and growth suppression through apoptosis by MK-2206, an allosteric inhibitor of AKT, in carcinoid cell lines in vitro

Carcinoids are neuroendocrine malignancies characterized by their overproduction of various bioactive hormones that lead to the carcinoid syndrome. We have shown previously that AKT serves as a key regulator of growth and phenotypic expression of tumor markers in carcinoids by the genetic depletion of AKT expression. However, no small-molecule inhibitor of AKT kinase activity has been developed until recently. MK-2206, a novel allosteric inhibitor of AKT, is currently undergoing clinical trials for the treatment of solid tumors. In this study, we explored the effect of MK-2206 on carcinoid cell proliferation and bioactive hormone production in vitro in two carcinoid cell lines - pancreatic carcinoid BON and bronchopulmonary H727. Treatment with MK-2206 effectively suppressed AKT phosphorylation at serine 473 and significantly reduced cell proliferation in a dose-dependent manner. Most importantly, MK-2206 treatment resulted in a significant reduction in ASCL1, CgA, and NSE expression, collectively recognized as markers of neuroendocrine tumor malignancy. Furthermore, MK-2206-treated cells showed an increase in levels of cleaved PARP and cleaved caspase-3, with a concomitant reduction in levels of Mcl-1 and XIAP, indicating that the antiproliferative effect of MK-2206 occurs through the induction of apoptosis. In conclusion, MK-2206 suppresses carcinoid tumor growth, and alters its neuroendocrine phenotype, indicating that this drug may be beneficial for patients with carcinoid syndrome. These studies merit further clinical investigation.

Pathology reporting of neuroendocrine tumors: essential elements for accurate diagnosis, classification, and staging

Much recent debate has focused on the optimal classification of epithelial neuroendocrine tumors (NETs). Multiple different systems of terminology, grading, and staging have been proposed, and some systems combine elements of grade and stage into a single prognostic classification. Recently, national and international consensus groups have attempted to standardize the classification of NETs, especially for those arising in the gastrointestinal tract and pancreas. Furthermore, the recognition that common classification criteria (such as proliferative rate) span multiple different systems allows the basic data necessary to predict outcome and tailor therapy to be included in pathology reports, even though a single uniform system of terminology may remain elusive. Formal tumor-node-metastasis (TNM)-based staging systems also have been developed recently, and advances in the treatment of some NETs (pancreatic in particular) are pointing towards the need to assess therapeutic biomarkers in routine practice. This review will present the most widely used systems for classifying, grading, and staging NETs and will summarize the recommendations for the data to be included in standard pathology reports of these uncommon tumors.

Robust labeling and comparative preclinical characterization of DOTA-TOC and DOTA-TATE

OBJECTIVES

Various radionuclide-labeled somatostatin analogues are used currently for diagnosis and therapy of neuroendocrine tumors. In particular, [68Ga]Ga-DOTA-TOC is commonly used for diagnosis, while [177Lu]Lu-DOTA-TATE is used for therapy. With the development of theranostics and personalized medicine where the imaging diagnosis is tailored to the subsequent radiotherapy, it is of paramount importance to investigate the relevance of the ligand exchange. The aim of this study was to compare binding capacity of [67/68Ga]Ga-DOTA-TOC ([67/68Ga]Ga-N-(4,7,10-(tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)acetyl-D-Phe-c[Cys-D-Tyr-Trp-Lys-Thr-Cys]-Thr(ol)) and [67/68Ga]Ga-DOTA-TATE ([67/68Ga]Ga-N-(4,7,10-(tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)acetyl-D-Phe-c[Cys-D-Tyr-Trp-Lys-Thr-Cys]-Thr) in vitro in monkey brain cryosections and in vivo in the rat, where, in contrast to transfected cell lines, there is a heterogeneous distribution of somatostatin receptor (SSTR) subtypes. The influence of various production methods of [68Ga]Ga-DOTA-TOC and [68Ga]Ga-DOTA-TATE on the biological performance of the tracers was also studied.

MATERIAL AND METHODS

[67Ga]Ga-DOTA-TOC, [68Ga]Ga-DOTA-TOC, [67Ga]Ga-DOTA-TATE and [68Ga]Ga-DOTA-TATE were synthesized including preconcentration and purification of the generator eluate. The binding of the radioligands was assessed in vitro using autoradiography on cryosections of Rhesus monkey brains and in vivo/ex vivo using organ distribution studies in rats.

RESULTS AND DISCUSSION

The tracer production method was improved in terms of higher robustness, simplification and good manufacturing practice (GMP) relevance. The synthesis variation did not influence the biological performance of the tracers. There was no statistically significant difference observed in the binding of [67/68Ga]Ga-DOTA-TOC and [67/68Ga]Ga-DOTA-TATE either in brain cortex in vitro or in rat biodistribution and uptake in SSTR-positive tissues such as pancreas, adrenals and pituitary. The uptake in these organs was precluded by the excess of octreotide (Sandostatin). The 10-fold higher affinity to SSTR2 of DOTA-TATE as compared to DOTA-TOC known from studies in transfected cells was reflected in a slightly more intense binding of [67/68Ga]Ga-DOTA-TATE than of [67/68Ga]Ga-DOTA-TOC in the monkey brain sections in vitro, but not in vivo in the rat.

CONCLUSION

A robust 68Ga-labeling method was introduced. The difference in the uptake of [67/68Ga]Ga-DOTA-TOC and [67/68Ga]Ga-DOTA-TATE in SSTR2-positive organs was not statistically significant either in vitro in tissue studies or in vivo/ex vivo in rat experiments. The results indicate that the more complex environment in vitro and in vivo diminishes the difference observed in transfected cell line binding.

Novel medical therapies of recurrent and metastatic gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors (NETs) of the gastrointestinal tract and pancreas are slow-growing but commonly advanced malignancies with increasing incidence and prevalence. While locoregional disease can be effectively managed with resection, treatment of recurrent, progressive or metastatic disease has until recently been limited to palliative embolization and cytoreducitve surgery, with cytotoxic chemotherapeutic agents being the last resort. However, novel molecular targeted therapies inhibiting malignant cell proliferation and neoangiogenesis, as well as new cytotoxic chemotherapy drugs and somatostatin analogues, are all being investigated for their potential use in advanced neuroendocrine tumors. Long-acting release forms of octreotide have been shown to not only improve symptoms in carcinoid syndrome but to also delay progression of gastrointestinal NETs. On the other hand, phase III trials have demonstrated everolimus (with octreotide) and sunitinib to increase progression-free survival in pancreatic NETs. Use of bevacizumab has also shown promise in a phase II study, and results of an ongoing phase III trial comparing it to interferon are eagerly expected. Use of radiolabeled somatostatin analogues is still under investigation, though several phase II studies are encouraging. New cytotoxic agents, most notably temozolomide and capecitabine, are already in use, but their relative effectiveness compared to streptozocin in pancreatic NETs is yet to be determined.

Survival and prognostic factors in patients with small bowel carcinoid tumour

BACKGROUND

Previous studies of small bowel carcinoid tumours usually presented overall or relative survival. This study, in addition, evaluated disease-specific survival in a cohort of patients in a geographically defined population.

METHODS

Patients diagnosed with carcinoid of the jejunum or ileum in Jönköping County between 1960 and 2005 were eligible for inclusion. Available tumour specimens were re-examined to confirm the diagnosis. Medical records and pathology reports were reviewed in detail.

RESULTS

A total of 145 patients were included in the study. One hundred and thirty-five patients underwent surgery in connection with the diagnosis. Resection was considered complete (R0) in 74 patients (54·8 per cent). Only two localized tumours recurred, whereas no patient with distant metastases was cured. Patients with regional metastases who underwent R0 resection had a better survival than patients with incomplete resection (P = 0·005), and a majority of patients remained recurrence-free. Median overall survival was 7·2 years and median disease-specific survival 12·3 years. In multivariable analysis, age 61-74 years (hazard ratio (HR) 3·78, 95 per cent confidence interval 1·86 to 7·68), age 75 years or more (HR 3·96, 1·79 to 8·74), distant metastases (HR 14·44, 1·59 to 131·36) and incomplete tumour resection (HR 2·71, 1·11 to 6·61) were associated with worse disease-specific survival. Later time period of diagnosis (HR 0·45, 0·24 to 0·84) was associated with better disease-specific survival.

CONCLUSION

Age, disease stage and complete resection were identified as independent prognostic factors for survival in patients with small bowel carcinoid tumours. The importance of achieving R0 resection is therefore emphasized.

The archaic distinction between functioning and nonfunctioning neuroendocrine neoplasms is no longer clinically relevant

BACKGROUND

Neuroendocrine neoplasms (NENs) are increasing in incidence and prevalence. This reflects greater clinical awareness, effective imaging, and increasing pathological diagnostic recognition. Although the identification and treatment of clinical neuroendocrine syndromes are established, there is confusion when a NEN has no discernible clinical symptoms.

DISCUSSION

Nonfunctional tumors are usually diagnosed incidentally and at a later stage largely because either they do not secrete a bioactive product or do so, but in a form that is either inactive or in quantities that have no discernible effect. Nevertheless, the histopathology is indistinguishable from functional NENs, and tumors exhibit somatostatin receptor expression, and positive immunohistochemistry for neuroendocrine cell markers (CgA, NSE/synaptophysin). Similarly, their rates of growth and metastatic behavior are, like other NENs, predictably based on staging and grading (mitotic rate and Ki67 expression). Both types are diagnosed biochemically (CgA) and by imaging in an identical fashion with computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, and endoscopic ultrasound. NENs, irrespective of function or bioactive secretory profile, respond with equal efficacy to the same regimen of surgery or antitumor drugs (e.g., somatostatin analogs with or without tyrosine kinase inhibitors/antiangiogenics or cytotoxics) depending on grade. Given the efficacy of somatostatin analogs in increasing progression free survival, nonfunctional NENs should be managed identically to symptomatic NENs. The consideration of NENs as functional or nonfunctional is an archaic clinical concept that should be discarded since the tumors are indistinguishable at a cellular, biological, and morphological level. All current evidences indicate that their diagnosis and treatment should follow the same common principles.

VEGFR-2 expression in carcinoid cancer cells and its role in tumor growth and metastasis

Carcinoid tumors are slow growing and highly vascular neuroendocrine neoplasms that are increasing in incidence. Previously, we showed that carcinoid tumors express vascular endothelial growth factor receptor 2 (VEGFR-2) in the epithelial compartment of carcinoid tumor sections; yet, its role is not completely understood. The purpose of our study was to: (i) assess the expression of VEGFR-2 in the novel human carcinoid cell line BON, (ii) to determine the role of PI3K/Akt signaling on VEGFR-2 expression and (iii) to assess the effect of VEGFR-2 on BON cell invasion, migration and proliferation. We found that, although VEGFR-2 is expressed in BON cells, reduction in VEGFR-2 expression actually enhanced proliferation, invasion, and migration of the BON cell line. Also, expression of VEGFR-2 was inversely related to PI3K signaling. Carcinoid liver metastases in mice demonstrated decreased VEGFR-2 expression. Furthermore, the expression of a truncated, soluble form of VEGFR-2 (sVEGFR-2), a protein demonstrated to inhibit cell growth, was detected in BON cells. The presence of VEGFR-2 in the epithelial component of carcinoid tumors and in the BON cell line suggests an alternate role for VEGFR-2, in addition to its well-defined role in angiogenesis. The expression of sVEGFR-2 may explain the inverse relationship between VEGFR-2 expression and PI3K/Akt signaling and the inhibitory effect VEGFR-2 has on BON cell proliferation, migration and invasion.

Rare and unusual endocrine cancer syndromes with mutated genes

The study of a number of rare familial syndromes associated with endocrine tumor development has led to the identification of genes involved in the development of these tumors. Major advances have expanded our understanding of the pathophysiology of these rare endocrine tumors, resulting in the elucidation of causative genes in rare familial diseases and a better understanding of the signaling pathways implicated in endocrine cancers. Recognition of the familial syndrome associated with a particular patient's endocrine tumor has important implications in terms of prognosis, screening of family members, and screening for associated conditions.

Neuroendocrine tumors of the gallbladder: an evaluation and reassessment of management strategy

BACKGROUND

Gallbladder neuroendocrine tumors (GB-NETs) represent only 0.5% of all NETs, and little is known about their biological behavior. We sought to provide an overview of the current state of knowledge about GB-NETs and provide a recommendation for management.

STUDY

A PubMed search was undertaken using the following criteria: primary gallbladder and carcinoid or NET. We also interrogated the SEER 9, 13 and 17 registries (1973 to 2005) and the Niigata registry (2003) to assess the epidemiology and clinicopathological characteristics. Finally, we compared the clinical presentation, management and prognosis of GB-NETs to that of gallbladder adenocarcinoma.

RESULTS

GB-NETs probably derive from either a multipotent stem cell or neuroendocrine cells in intestinal or gastric metaplasia of the gallbladder epithelium, which occurs consequent upon cholelithiasis/chronic inflammation. Clinically and at surgery, GB-NETs are indistinguishable from gallbladder cancer (GBC) and "carcinoid syndrome" is evident in only ∼1%.The median survival was only 9.8 months among 278 cases of GB-NETs reported in SEER. The 5 year survival rate for tumors classified as carcinoids/neuroendocrine carcinoma or small cell cancer (SCC) was 36.9 and 0%, respectively. Soga divided GB-NETs into typical and variant carcinoids with 5 year survival rates of 60.4% and 21.3% respectively.

CONCLUSIONS

GB-NETs have an aggressive behavior, and once diagnosed, extensive surgical management and careful NET follow up with CT scan is mandatory to facilitate early detection of recurrence. Since more aggressive surgical management for GBC has shown increased survival rates for these tumors, a similar strategy seems reasonable for GB-NETs. However, in high grade metastatic tumors, the primary management is mainly medical.

Pathology reporting of neuroendocrine tumors: application of the Delphic consensus process to the development of a minimum pathology data set

Epithelial neuroendocrine tumors (NETs) have been the subject of much debate regarding their optimal classification. Although multiple systems of nomenclature, grading, and staging have been proposed, none has achieved universal acceptance. To help define the underlying common features of these classification systems and to identify the minimal pathology data that should be reported to ensure consistent clinical management and reproducibility of data from therapeutic trials, a multidisciplinary team of physicians interested in NETs was assembled. At a group meeting, the participants discussed a series of "yes" or "no" questions related to the pathology of NETs and the minimal data to be included in the reports. After discussion, anonymous votes were taken, using the Delphic principle that 80% agreement on a vote of either yes or no would define a consensus. Questions that failed to achieve a consensus were rephrased once or twice and discussed, and additional votes were taken. Of 108 questions, 91 were answerable either yes or no by more than 80% of the participants. There was agreement about the importance of proliferation rate for tumor grading, the landmarks to use for staging, the prognostic factors assessable by routine histology that should be reported, the potential for tumors to progress biologically with metastasis, and the current status of advanced immunohistochemical and molecular testing for treatment-related biomarkers. The lack of utility of a variety of immunohistochemical stains and pathologic findings was also agreed upon. A consensus could not be reached for the remaining 17 questions, which included both minor points related to extent of disease assessment and some major areas such as terminology, routine immunohistochemical staining for general neuroendocrine markers, use of Ki67 staining to assess proliferation, and the relationship of tumor grade to degree of differentiation. On the basis of the results of the Delphic voting, a minimum pathology data set was developed. Although there remains disagreement among experts about the specific classification system that should be used, there is agreement about the fundamental pathology data that should be reported. Examination of the areas of disagreement reveals significant opportunities for collaborative study to resolve unanswered questions.

MicroRNA expression in ileal carcinoid tumors: downregulation of microRNA-133a with tumor progression

MicroRNAs (miRNAs) are involved in cell proliferation, differentiation, and apoptosis and can function as tumor suppressor genes or oncogenes. The role of miRNAs in neuroendocrine tumors such as ileal carcinoids is largely unknown. We examined the differential expression of 95 miRNAs by RT-PCR using the QuantiMir System in eight matching primary and metastatic carcinoid tumors from the ileum. All miRNAs chosen for the QuantiMir System array were based on their potential functions related to cancer biology, cell development, and apoptosis. The expression of miRNAs for the samples was normalized to miRNA-197, and the matching primary and metastatic tumors were compared. There was downregulation of miRNA-133a, -145, -146, -222, and -10b in all samples between the primary and matching metastatic tumors and upregulation of miRNA-183, -488, and -19a+b in six of eight metastatic carcinoids compared to the primary tumors. miRNA-133a was further analyzed by TaqMan real-time RT-PCR and northern hybridization using six additional matching primary and metastatic samples, which supported the PCR array findings. There were significant differences in miRNA-133a expression with downregulation in the metastasis compared to the primary in the eight original cases (P<0.009) and in the six additional cases used for validation (P<0.014). Laser capture microdissection and real-time RT-PCR analysis using normal ileum found miRNA-133a expression in normal enterochromaffin cells. In situ hybridization in normal ileum showed that some of the mucosal endocrine cells expressed miRNA-133a. Both primary and metastatic ileal carcinoid tumors expressed miRNA-133a by in situ hybridization. These results provide information about novel marker miRNAs that may be used as biomarkers and/or therapeutic targets in intestinal carcinoid tumors.

Primary carcinoid tumor of the gallbladder: a case report and brief review of the literature

Background

Primary carcinoid tumor of the gallbladder is rare and comprises less than 1% of all carcinoid tumors. Preoperative diagnosis of carcinoid tumor of the gallbladder is difficult. The imageology findings are similar to those in other gallbladder cancers.

Case presentation

A 46-year-old woman was hospitalized with a preoperative diagnosis of gallbladder carcinoma, The patient was referred for surgical opinion and laparotomy was subsequently performed. A 4 × 5 cm mass was found within the gallbladder, located on the free surface of the body and fundus of the gallbladder. Neither metastases nor direct invasion to the liver was found. The entire mass and gallbladder were excised and intact. Histologically, the tumor consisted of small oval cells with round-to-oval neclei and tumor cells formed small nodular, trabeculare and acinar structures. The tumor showed moderate pleomorphism with scattered mitotic figures, but no definite evidence of vascular permeation, perineural invasion or lymphatic permeation was seen. The tumor cells invaded the mucosa extensively, and some penetrated the muscular layer but not through the serosa of the gallbladder into the liver. Immunohistochemical studies revealed strong positive reaction for chromogranin A and NSE. This lesion was proved to be a primary carcinoid tumor of the gallbladder. A brief review of literature, clinical feature, pathology and treatment of this rare disease was discussed.

Conclusion

Primary carcinoid tumor of the gallbladder is uncommon. The definite diagnosis is often made on histopathological results after surgery.

Angiopoietin-2 promotes disease progression of neuroendocrine tumors

PURPOSE

Inhibition of angiogenesis represents a promising therapeutic strategy in neuroendocrine tumors. Angiopoietin-2 (Ang-2), a ligand of the endothelial tyrosine kinase Tie-2, is emerging as a key regulator of vascular remodeling during tumor angiogenesis. We therefore addressed the expression and biological significance of Ang-2 in human neuroendocrine tumors.

EXPERIMENTAL DESIGN

Surgical specimens and serum from neuroendocrine tumor patients were used to determine Ang-2 expression by in situ hybridization or ELISA (circulating Ang-2). Ang-2 biological effects were evaluated following stable transfection into BON human pancreatic neuroendocrine tumor cells. BON clones were grown as orthotopic xenografts in nude mice to determine tumor growth and abdominal metastatic spread. Further analyses included microvessel density, lymphatic vessel density, and nodal invasion.

RESULTS

Specimens from pancreatic neuroendocrine tumors and nontransformed pancreatic tissue revealed uniform expression of Ang-2 mRNA in endothelial cells. In contrast, epithelial expression of Ang-2 mRNA occurred exclusively in neuroendocrine tumors. Overexpression of Ang-2 in BON orthotopic xenografts did not affect primary tumor growth, although successful Ang-2 induction was confirmed from elevated serum levels. However, increased microvessel density and enhanced lymphatic metastasis were evident in Ang-2-expressing tumors, indicating a functional role of Ang-2 in experimental neuroendocrine tumors. Consistent with this notion, circulating Ang-2 was significantly elevated in neuroendocrine tumor patients compared with healthy controls. Circulating Ang-2 furthermore correlated with metastatic versus localized disease. The highest Ang-2 concentrations occurred in patients with liver metastasis, and concentrations >or=75th percentile predicted shorter survival (P = 0.0003).

CONCLUSION

Induction of Ang-2 in neuroendocrine tumors represents a clinically relevant pathomechanism of disease progression and constitutes an adverse prognostic marker.

Carcinoid tumors of the gastrointestinal tract

The gastrointestinal tract is the largest neuroendocrine system in the body. Carcinoid tumors are amine precursor uptake decarboxylase (APUD) omas that arise from enterochromaffin cells throughout the gut. These tumors secrete discrete bioactive substances producing characteristic immunohistochemical patterns. Most tumors are asymptomatic and detected at late stages. Hepatic metastases are commonly responsible for carcinoid syndrome. The small bowel is the most common location of carcinoids. Computed tomography scan and magnetic resonance imaging are useful in the detection of these tumors. The measurement of bioactive amines is the initial diagnostic test. Various treatment options, including somatostatin analogs, interferon, chemotherapy, surgery, hepatic artery chemoembolization, and surgery have emerged in the past two decades. However, the incidence and prevalence of carcinoid tumors has increased, while mean survival time has not changed significantly. The lack of standardized classification, federal support, and an incomplete understanding of the complications of this disease are some of the impediments to progress in treatment.

Differential efficacy of SSTR1, -2, and -5 agonists in the inhibition of C6 glioma growth in nude mice

Somatostatin receptors (SSTR1-5) mediate antiproliferative effects. In C6 rat glioma cells, somatostatin is cytostatic in vitro via phosphotyrosine phosphatase-dependent inhibition of ERK1/2 activity mediated by SSTR1, -2, and -5. Here we analyzed the effects of SSTR activation on C6 glioma growth in vivo and the intracellular mechanisms involved, comparing somatostatin effects with selective agonists for SSTR1, -2, and -5 (BIM-23745, BIM-23120, BIM-23206) or receptor biselective compounds (SSTR1 and -2, BIM-23704; and SSTR2 and -5, BIM-23190). Nude mice subcutaneously xenografted with C6 cells were treated with somatostatin, SSTR agonists (50 μg, twice/day), or vehicle. Tumor growth was evaluated every 3 days for 19 days. The intracellular pathways responsible of SSTR effects in vivo were evaluated measuring Ki-67, phospho-ERK1/2, and p27(kip1) expression by immunohistochemistry in sections from explanted tumors. Somatostatin and SSTR1, -2, and -5 agonists strongly inhibited in vivo C6 tumor growth, intratumoral neovessel formation, Ki-67 expression, and ERK1/2 phosphorylation and induced upregulation of p27(Kip1), whereas only a modest activation of caspase-3 was observed. Somatostatin (acting on SSTR1, -2, and -5) displayed the highest efficacy; SSTR5 selective agonist showed a stronger effect than SSTR1 agonist, and SSTR2 agonist was less effective. On the other hand, SSTR1 and -2 agonists maximally reduced tumor neovascularization. The combined activation of SSTR1 and -2 showed a synergistic activity, reaching a higher efficacy than BIM-23206, whereas the simultaneous activation of SSTR2 and -5 resulted in a response resembling SSTR5 effects. Thus the simultaneous activation of different SSTRs inhibits glioma cell proliferation in vivo through both direct cytotostatic and antiangiogenic effects.

[Indications and operative procedures for neuroendocrine liver metastases]

Neuroendocrine malignancies encompass a variety of tumors that differ considerably in origin, hormonal activity, and biological behavior. Because of their rarity most therapeutic recommendations have been based on limited evidence from small retrospective series observing miscellaneous patient cohorts. Only in recent years proposals for TNM and histological grading systems have been elaborated that allow further stratification of patients suffering from these tumors. Especially patients with well and moderately differentiated neuroendocrine malignancies benefit from resection of liver metastases, improving the 5-year survival rate from <50% to 80%. Orthotopic liver transplantation can likewise improve survival in carefully selected patients. New developments in imaging modalities, intensive care treatment, and in liver surgery itself have broadened the selection of potentially resectable tumors.

A simplified prognostic system for resected pancreatic neuroendocrine neoplasms

BACKGROUND

A number of prognostically relevant clinicopathological variables have been proposed for pancreatic neuroendocrine neoplasms. However, a standardized prognostication system has yet to be established for patients undergoing potentially curative tumour resection.

METHODS

We examined a prospectively maintained, single-institution database to identify patients who underwent potentially curative resection of non-metastatic primary pancreatic neuroendocrine neoplasms. Patient, operative and pathological characteristics were analysed to identify variables associated with disease-specific and disease-free survival.

RESULTS

Between 1991 and 2007, 43 patients met inclusion criteria. After a median follow-up of 68 months, 5-year disease-specific survival was 94% and 5-year disease-free survival was 72%. Tumours sized > or = 5 cm and vascular invasion were associated with worse disease-specific survival. Tumours sized > or = 5 cm, nodal metastases, positive resection margins and perineural invasion were associated with worse disease-free survival. A scoring system consisting of tumour size > or = 5 cm, histological grade, nodal metastases and resection margin positivity (SGNM) permitted stratification of disease-specific (P= 0.006) and disease-free (P= 0.0004) survival. This proposed scoring system demonstrated excellent discrimination of individual disease-specific and disease-free survival outcomes as reflected by concordance indices of 0.814 and 0.794, respectively.

CONCLUSIONS

A simple scoring system utilizing tumour size, histological grade, nodal metastases and resection margin status can be used to stratify outcomes in patients undergoing resection of primary pancreatic neuroendocrine neoplasms.

Treatment of liver metastases from neuroendocrine tumours in relation to the extent of hepatic disease (Br J Surg 2009; 96: 175-184)

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Review article: future therapies for management of metastatic gastroenteropancreatic neuroendocrine tumours

BACKGROUND

Gastroenteropancreatic neuroendocrine tumours (GEP NETs) are relatively uncommon tumours that occur anywhere within the gastrointestinal tract. The prevalence of GEP NETs is estimated to be 35 per 100 000 population. Patients often present with metastatic disease and consequently, palliative treatments form the mainstay of therapy.

AIM

To review the current and novel therapeutic options for management of GEP NETs.

METHODS

Searches for all studies related to GEP NETs, NETs and carcinoid tumours in Medline and abstracts from international meetings.

RESULTS

Somatostatin analogues remain the first line therapy for management of symptoms of GEP NETs and may have anti-proliferative action. New somatostatin analogues with different somatostatin receptor affinity have been developed. Radionuclide peptide receptor therapy is established in patients with positive somatostatin scintigraphy. A number of new agents and targeted therapies are currently being evaluated in a phase I and II studies and these include angiogenic inhibitors, mammalian target of rapamycin inhibitors and immune therapies.

CONCLUSIONS

A number of nonsurgical therapies are available for management of gastroenteropancreatic neuroendocrine tumours. It is hoped, the development of some of these promising novel therapies will expand the therapeutic armamentarium.