Nuclear medicine in the detection, staging and treatment of gastrointestinal carcinoid tumours

Multicenter, Observational Study of Lanreotide Autogel for the Treatment of Patients with Neuroendocrine Tumors in Routine Clinical Practice in Germany and Austria

Background The long-acting somatostatin analog lanreotide autogel is effective in the treatment of patients with neuroendocrine tumors.

Objective To evaluate the long-term treatment response in patients with neuroendocrine tumors receiving lanreotide autogel in routine clinical practice.

Methods Non-interventional, 24-month study in patients with neuroendocrine tumors treated with lanreotide autogel (NCT01840449).

Results Patients (n=80) from 26 centers in Germany and Austria were enrolled. Neuroendocrine tumors were mainly grade 1/2, metastasized, intestinal, and associated with carcinoid syndrome; 88.9% had received previous neuroendocrine tumor treatment. Of those, 84.4% had previous surgery, 18.7% had received octreotide. The primary endpoint, defined by a <50% chromogranin A increase at month 12 compared with the lowest value between baseline and month 3 was achieved by 89.5% patients. Stable disease according to Response Evaluation Criteria in Solid Tumors 1.1 was observed in 76.9 and 75.0% patients at months 12 and 24 of lanreotide treatment, respectively. Mean change of chromogranin A levels from baseline to month 24 was −0.12 × upper limit of normal (95% CI, −0.22; −0.45). In a post hoc analysis, 38.5% of the subgroup of patients with carcinoid syndrome had daily diarrhea at baseline vs. 21.4% at month 24. At baseline, 27.8% of patients received lanreotide 120 mg every 4 weeks vs. 56.7% at month 24. Quality of life data were heterogeneous. No new safety issues arose and/or required further investigation.

Conclusions Our study reflects routine lanreotide autogel use in patients with advanced/metastatic neuroendocrine tumors. This analysis shows effectiveness with stabilization of disease-related symptoms and good tolerability of lanreotide autogel in clinical practice.

Development of a nomogram model to predict survival outcomes in patients with primary hepatic neuroendocrine tumors based on SEER database

Background

Primary hepatic neuroendocrine tumors (PH-NETs) are extremely rare and unknown. Because of its rarity, its prognosis features and influencing factors are not well established.

Methods

Data of 140 patients with PH-NETs diagnosed in the SEER database from 1975 to 2016 were collected. The demographics and clinic-pathological features were described. By using propensity-score matching (PSM) analysis, three associated cohorts were selected to describe the malignancy of PH-NETs and univariate analysis was conducted. Then, multivariate Cox analyses were performed and a predicting nomograph was constructed. C-index, receiver operating characteristic (ROC) curve and calibration curves were used to evaluate the predictive value of nomogram.

Results

The overall survival outcomes of PH-NETs were superior to hepatocellular carcinoma (HCC) with a mean survival time 30.64 vs 25.11 months (p = 0.052), but inferior to gastrointestinal tract neuroendocrine tumors in situ (GI-NETs in situ) with a mean survival time 30.64 vs 41.62 months (p = 0.017). With reference to gastrointestinal neuroendocrine tumors with liver metastasis (GI-NETs-LM), GI-NETs-LM had better outcomes in short time (1-year survival rate: 64.75% vs 56.43%) but was worse in long time (5-year survival rate: 8. 63% vs 18.57%). Multivariate Cox analyses showed that tumor grade and surgery were two independent factors for prognosis of the patients (p < 0.00). Tumor grade and surgery were used to construct the predicting nomogram. The C-index was 0.79 (95%CI = 0.75–0.83). The area under curve (AUC) values in ROC were 0.868 in 1-year and 0.917 in 3-year survival and the calibration curves showed good consistency.

Conclusions

The overall prognosis PH-NETs is generally favorable, better than HCC and GI-NETs-LM in long term. Preoperative biopsy and complete pathological diagnosis were recommended. Radical surgical intervention including transplantation was the first choice in PH-NETs therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08337-y.

A Case of Primary Hepatic Neuroendocrine Tumor and Literature Review

We report an unusual presentation of primary hepatic neuroendocrine tumor which was initially misdiagnosed as intrahepatic cholangiocarcinoma. The diagnosis was only revealed after a major liver resection by histopathology. With adjuvant lanreotide injection, the patient survived for more than 16 months after the operation without tumor recurrence. Diagnosis of this rare tumor has been a major challenge and we emphasize the importance of a preoperative diagnosis. Surgical resection remains the mainstay for curative treatment, while peptide receptor radionuclide therapy is an emerging treatment option which has provided promising results.

Long-term postresection prognosis of primary neuroendocrine tumors of the liver

Purpose

Primary hepatic neuroendocrine tumor (PHNET) is a very rare neoplasm, requiring strict exclusion of metastasis from possible extrahepatic primary sites for its diagnosis.

Methods

We reviewed our clinical experience of 13 patients with primary hepatic NET who underwent liver resection from January 1997 to December 2015.

Results

The mean age of the 13 patients (8 males and 5 females) was 51.1 ± 12.8 years; the most common clinical manifestation was vague, nonspecific abdominal pain (n = 9). Of them, 11 patients underwent preoperative liver biopsy, 7 of which correctly diagnosed as neuroendocrine tumor (NET). Ten patients underwent R0 resection, and 3 underwent R1 resection. Diagnosis of PHNET was confirmed both immunohistochemically and by absence of extrahepatic primary sites. All tumors were single lesions, with a mean size of 9.6 ± 7.6 cm and a median size of 4.3 cm; all showed positive staining for synaptophysin and chromogranin. During a mean follow-up period of 95.1 ± 86.6 months, 7 patients died from tumor recurrence, whereas the other 6 remain alive to date, making the 5-year tumor recurrence rate 56.0% and the 5-year patient survival rate 61.5%. When confined to R0 resection, 5-year recurrence and survival rates were 42.9% and 70.0%, respectively. Univariate analysis showed that Ki-67 proliferative index was the only risk factor for tumor recurrence.

Conclusion

PHNET is a very rare tumor with no specific clinical features, and its final diagnosis depends primarily on pathology, immunohistochemistry, and exclusion of metastasis from other sites. Aggressive surgical treatment is highly recommended for PHNET because of acceptably favorable postresection outcomes.

Primary hepatic neuroendocrine tumours-Case series of a rare malignancy

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Primary hepatic neuroendocrine tumours are rare.

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Liver enzymes and tumour markers are often normal.

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Radiological imaging may mimic other hypervascular liver tumours.

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Surgical resection is the only curative treatment for localised disease.

Introduction

Primary hepatic neuroendocrine tumours (PHNET) were first described by Edmondson et al. in 1958 and are rare, accounting for only 0.3% of all neuroendocrine tumours. Only several hundred cases have been reported.

Presentation of case

We present two cases. The first is a 65-year-old asymptomatic male referred with a liver lesion on ultrasound performed to investigate a mildly elevated Alanine Aminotransferase (ALT). Hepatitis serology and tumour markers were normal. He had an unremarkable colonoscopy and gastroscopy. CT and MRI revealed a single liver lesion adjacent to the gallbladder suspicious for malignancy. He underwent a segment IVb/V liver resection. Histology was consistent with a 65 mm grade 2 PHNET. Subsequent Dotatate PET/CT scans have been normal at 5 years. The second is an asymptomatic 73-year-old male referred with fluctuating hepatic enzymes and a history of alcohol overuse. Imaging revealed a suspicious lesion in segment III of the liver. He underwent a left lateral liver resection. Histology revealed an 18 mm grade 1 PHNET. A subsequent Dotatate PET/CT was normal with no new disease at six months.

Discussion

PHNET, albeit rare are in the differential diagnosis for primary hepatic malignancies. Tumour markers are usually normal and radiological imaging can mimic other hypervascular hepatic tumours. Surgery is the only curative treatment for localised disease to date.

Conclusion

PHNET needs to be considered in asymptomatic patients with hypervascular hepatic lesions. More research is required before other adjunct treatment options can be suggested.

Neuroendocrine Testicular Tumors: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study is to study the main epidemiological, clinical, para clinical, pathological, therapeutic, and evolutionary features of patients with testicular neuroendocrine tumors (TNET).

MATERIALS AND METHODS

Nine case series and sixteen case reports were identified by searching PubMed database and qualified for inclusion in this study. We added the data of one case treated in the department of urology in Habib Bourguiba Hospital in Sfax, to the published cases.

RESULTS

A total of 132 cases were collected. Median age at diagnosis was 39 years old (range 10- 83 years). The most common presenting symptom was either a testicular mass or a swelling in 38.46% of cases. Carcinoid syndrome was documented in 10.60% of patients. The clinical examination revealed a palpable mass in 44.70% of patients. This mass was painless and firm in most cases. Serum tumor markers (β-gonadotrophine chorionique humaine, α-feto protein, and lactate dehydrogenase) were within normal limits in all patients except in one case. Most testicular neuroendocrine tumors (76.52%) were primary and pure. The tumors were positive for chromogranin (100%), synaptophysin (100%) and cytokeratin (93.10%). Metastases were detected at time of diagnosis in eight cases (6.06%). The main treatment was radical orchiectomy performed in 127 patients (96.21%). The 5-year overall survival rate was 78.70% and the 5-year specific survival rate was 84.30%.

CONCLUSION

The diagnosis of testicular carcinoids is based on the immunohistochemistry study. The treatment of choice for these tumors is radical orchiectomy. Somatostatin analogues were reported to be effective in patients with carcinoid syndrome.

On the potential for RF heating in MRI to affect metabolic rates and 18 FDG signal in PET/MR: simulations of long-duration, maximum normal mode heating

PURPOSE

To examine the possibility that MR-induced RF power deposition (SAR) and the resulting effects on temperature-dependent metabolic rates or perfusion rates might affect observed 18FDG signal in PET/MR.

METHODS

Using numerical simulations of the SAR, consequent temperature increase, effect on rates of metabolism or perfusion, and [18FDG] throughout the body, we simulated the potential effect of maximum-allowable whole-body SAR for the entire duration of an hour-long PET/MR scan on observed PET signal for two different 18FDG injection times: one hour before onset of imaging and concurrent with the beginning of imaging. This was all repeated three times with the head, the heart, and the abdomen (kidneys) at the center of the RF coil.

RESULTS

Qualitatively, little effect of MR-induced heating is observed on simulated PET images. Maximum relative increases in PET signal (26% and 31% increase, respectively, for the uptake models based on metabolism and the perfusion) occur in regions of low baseline metabolic rate (also associated with low perfusion and, thus, greater potential temperature increase due to high local SAR), such that PET signal in these areas remains comparatively low. Maximum relative increases in regions of high metabolic rate (and also high perfusion: heart, thyroid, brain, etc.) are affected mostly by the relatively small increase in core body temperature and thus are not affected greatly (10% maximum increase).

CONCLUSIONS

Even for worst-case heating, little effect of MR-induced heating is expected on 18FDG PET images during PET/MR for many clinically relevant applications. For quantitative, dynamic MR/PET studies requiring high SAR for extended periods, it is hoped that methods like those introduced here can help account for such potential effects in design of a given study, including selection of reference locations that should not experience notable increase in temperature.

Metastatic Gastrointestinal Carcinoid Tumor with Unknown Primary Site

Carcinoid tumors are rare and slow growing malignancies derived from enterochromaffin cells. Two-thirds of carcinoid tumors arise in the gastrointestinal tract, and in 3% of these cases the primary site cannot be determined. Presenting symptoms depend on the location of the primary tumor but may be nonspecific, and in 13% of patients distant metastases are discovered on diagnosis. The classic carcinoid syndrome occurs in less than 10% of cases and only after metastasis to the liver. We present a case of a young woman with a gastrointestinal carcinoid tumor of unknown site that had metastasized to the liver. We also provide a review of the current diagnostic modalities. Familiarity with the signs and symptoms of carcinoid tumors and the diagnostic techniques thereof may facilitate early detection and improved outcome.

Eastern Canadian Gastrointestinal Cancer Consensus Conference 2014

The annual Eastern Canadian Colorectal Cancer Consensus Conference was held in Montreal, Quebec, 23-25 October 2014. Expert radiation, medical, and surgical oncologists and pathologists involved in the management of patients with gastrointestinal malignancies participated in presentations and discussions resulting in consensus statements on such hot topics as management of neuroendocrine tumours, advanced and metastatic pancreatic cancer, and metastatic colorectal cancer.

Octreoscan Versus FDG-PET for Neuroendocrine Tumor Staging: A Biological Approach

BACKGROUND

Clinicians may order Octreoscan or positron emission tomography (PET) scan for staging patients with neuroendocrine tumors (NETs). (111)In-Octreoscan (Octreoscan) identifies tumors by radiolabeled targeting of somatostatin receptors, while 18F-fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) measures differential tissue glucose transport. We assessed the sensitivity of both nuclear imaging modalities with pathologic correlation to define the best initial choice for NET staging after standard cross-sectional imaging.

METHODS

We identified all patients diagnosed with NETs of gastrointestinal or pancreatic origin who underwent nuclear imaging staging by Octreoscan and/or PET from 2000 to 2013. Imaging results were correlated with tumor differentiation and grade of pathology specimens.

RESULTS

Imaging and pathology results were identified for 153 patients. Of these, 131 underwent Octreoscan, 43 underwent PET, and 21 patients had both performed. Overall sensitivity of Octreoscan and PET for NET detection was similar (77 vs. 72 %; p = not significant). For well-differentiated NETs, Octreoscan (n = 124) demonstrated sensitivity of 80 vs. 60 % (p = 0.28) for PET (n = 30). For poorly-differentiated NETs, Octreoscan (n = 7) proved significantly less sensitive than PET (n = 13) (57 vs. 100 %; p = 0.02). The sensitivity of Octreoscan versus PET varied similarly when analyzed by WHO tumor grade: Grade 1 (79 vs. 52 %; p = 0.16), Grade 2 (85 vs. 86 %; p = not significant), and Grade 3 (57 vs. 100 %; p = 0.02).

CONCLUSIONS

Tumor differentiation can be used to guide selection of nuclear imaging modalities for staging gastrointestinal and pancreatic NETs. Octreoscan appears more sensitive than (18)FDG-PET for well-differentiated NETs, whereas (18)FDG-PET demonstrates superior sensitivity for poorly-differentiated NETs.

Diagnosis and therapy of primary hepatic neuroendocrine carcinoma: clinical analysis of 10 cases

BACKGROUND

Primary hepatic neuroendocrine carcinoma (PHNEC) is rarer than extrahepatic gastrointestinal neuroendocrine carcinoma (NEC). It is difficult to make a correct diagnosis and poses a challenge for management.

MATERIALS AND METHODS

Ten PHNEC patients were admitted to our hospital from June 2006 to June 2011. Laboratory tests and imaging scans were performed for diagnosis and exclusion of extrahepatic NEC. All patients were AFP - and CA199- . Seven patients had solid tumors with cystic changes on ultrasonography, CT and/or MRI. For the initial treatment, four patients received combined-therapy and six monotherapy. Considering overall treatment, six patients received combined-therapy and four patients monotherapy. Staging criteria of primary hepatocellular carcinoma (PHC, AJCC 7th edition) were used to differentiate the stage of all patients: 3 patients were stage I, 2 stage II, 4 patients stage III and 1 stage IV. All patients were followed up and clinical data were gathered.

RESULTS

The median follow-up duration was 38.5 months. The 1-year, 2-year, 3-year and 6-year disease-free survival was 80.0%, 46.2% and 46.2% and 0% respectively. The overall survival rates were 100%, 67.1%, 67.1% and 33.6% respectively. Patients in early-stages (I/II) had similar disease-free and overall survival as those in advanced-stages (III/IV). Patients with monotherapy had significant shorter disease-free and overall survival than the patients with combination-therapy.

CONCLUSIONS

PHNEC has a unique specificity during its occurrence and development. The staging criteria of PHC might not be suitable for the PHENT. More convenient and effective features need to be found in imaging and laboratory detection. Surgical resection, TACE, chemotherapy and radiofrequency ablation should be performed in combination and actively for patients with PHNEC or recurrence to get the best effectiveness; they might extend the disease-free and overall survival.

Primary hepatic carcinoid tumor: case report and literature review

Primary hepatic carcinoid tumors are extremely rare neoplasms derived from hormone-producing neuroendocrine cells. It is difficult to make their diagnosis before biopsy, surgical resection or necropsy. A recent publication described only 94 cases of these tumors. There is no sex predilection and apparently it has no association with cirrhosis or preexisting hepatic disease. The most effective treatment is hepatectomy, and resection is determined by size and location of the lesions.

[Endocrine tumors: clinical overview]

The term endocrine tumor incorporates all neoplasms which originate from the various endocrine organs. Endocrine tumors can be characterized by different criteria: localization, endocrine function, dignity (i.e. tumorigenesis, sporadic or hereditary). These characteristics also determine the clinical outcome. The clinical history, symptoms and physical examination findings (e.g. amenorrhea, skin alterations, striae, virilization, increased blood pressure and flush) direct the diagnostic process of functioning endocrine tumors. Laboratory findings (endocrine parameters) are needed to establish a diagnosis supplemented by imaging for localization and special investigations (ophthalmological examination). In hereditary tumor syndromes, the familial history and molecular genetic testing and screening of family members are essential for establishing the diagnosis and achieve optimal and early treatment. Ideally, affected family members can be treated before clinical symptoms or metastatic disease occurs, improving outcome and prognosis. Incidentalomas are increasingly found due to widespread use of imaging techniques, especially in the thyroid, adrenal glands, pancreas and pituitary gland. In incidentalomas the functional status and risk of malignancy has to be evaluated as both parameters determine therapy decisions. The aim of this introductory article is to give an overview about particular features of endocrine tumors, clinical and related aspects for the diagnostic and therapeutic approach. The clinical features of tumors of the pituitary, parathyroid and adrenal glands and the gastroenteropancreatic system are summarized according to localization.

Diagnostic imaging of primary hepatic neuroendocrine tumors: a case and discussion of the literature

Neuroendocrine tumors (NETs) are derived from neuroendocrine cells that are capable of producing functional peptide hormones. These tumors occur most frequently in the GI tract and lungs. GI NETs frequently metastasize into the liver, though NETs of primary hepatic origin are extremely rare. Ultrasound, CT, and MRI are typically all employed for characterization of these lesions but their appearance on diagnostic imaging can be highly variable. Reported here is an interesting case of a primary hepatic neuroendocrine tumor (PHNET), along with a discussion of the imaging characteristics of these tumors. Additionally, the current standards for definitive diagnosis and treatment of PHNETs are discussed.

Somatostatin analogs therapy in gastroenteropancreatic neuroendocrine tumors: current aspects and new perspectives

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare tumors that present many clinical features secreting peptides and neuroamines that cause distinct clinical syndromes such as carcinoid syndrome. However most of them are clinically silent until late presentation with mass effects. Surgical resection is the first line treatment for a patient with a GEP-NET while in metastatic disease multiple therapeutic approaches are possible. GEP-NETs are able to express somatostatin receptors (SSTRs) bounded by somatostatin (SST) or its synthetic analogs, although the subtypes and number of SSTRs expressed are very variable. In particular, SST analogs are used frequently to control hormone-related symptoms while their anti-neoplastic activity seems to result prevalently in tumor stabilization. Patients who fail to respond or cease to respond to standard SST analogs treatment seem to have a response to higher doses of these drugs. For this reason, the use of higher doses of SST analogs will probably improve the clinical management of these patients.

The Diagnostic Efficiency of 99mTc-EDDA/HYNIC-Octreotate SPECT-CT in Comparison with 111In-Pentetrotide in the Detection of Neuroendocrine Tumours

Objective: The aim of this study was to assess the diagnostic efficiency of ^99mTc-EDDA/HYNIC-Octreotate in comparison with ¹¹¹Inpentetrotide scintigraphy in the detection of neuroendocrine tumors. This study also evaluates the impact of SPECT-CT hybrid imaging on somatostatin receptor scintigraphy (SRS) interpretation and clinical management of these tumors.

Methods: Fourteen patients were included in the study. All patients underwent a whole body and SPECT-CT imaging with both ^99mTc- EDDA/HYNIC-octreotate and ¹¹¹In-pentetrotide. Images were evaluated both visually and semiquantitatively.

Results: On patient basis, the diagnostic results of both studies were similar. The number of lesions detected by ^99mTc- EDDA/HYNICOctreotate were higher than the number of lesions detected by ¹¹¹In-pentetrotide however the difference was not significant (40/43( 93%), 36/43 (83%) p=0.109). Semiquantitative analysis showed higher tumor/organ count ratios for both whole-body and SPECT ^99mTc- EDDA/HYNIC-Octreotate scans.

Conclusion: The results of this study suggested that, ^99mTc- EDDA/HYNIC-Octreotate may be a better alternative to ¹¹¹In- pentetrotide due to high image quality and lower radiation dose. SPECT/CT is a valuable tool for the assessment of neuroendocrine tumors by providing the precise anatomic localization of scintigraphic findings thus improving lesion detectability and characterization.

Conflict of interest:None declared.

Guidelines for biomarker testing in gastroenteropancreatic neuroendocrine neoplasms: a national consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

The annual incidence of neuroendocrine tumours in the Caucasian population ranges from 2.5 to 5 new cases per 100,000 inhabitants. Gastroenteropancreatic neuroendocrine tumours is a family of neoplasms widely variable in terms of anatomical location, hormone composition, clinical syndromes they cause and in their biological behaviour. This high complexity and clinical heterogeneity, together with the known difficulty of predicting their behaviour from their pathological features, are reflected in the many classifications that have been developed over the years in this field. This article reviews the main tissue and clinical biomarkers and makes recommendations for their use in medical practice. This document represents a consensus reached jointly by the Spanish Society of Medical Oncology (SEOM) and the Spanish Society of Pathology (SEAP).

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.

Monoclonal antibodies against the human somatostatin receptor subtypes 1-5: development and immunohistochemical application in neuroendocrine tumors

BACKGROUND

Activation of somatostatin receptors (sstr1-5) by somatostatin and its analogues exerts an inhibitory effect on hormone secretion and provides the basis for the treatment of a range of endocrine diseases such as acromegaly, Cushing's disease and neuroendocrine tumors (NET). The lack of well-characterized commercially available sstr subtype-specific antibodies prevents routine identification of the sstr expression profile in patients.

METHODS

We generated and characterized new mouse monoclonal antibodies (mAbs) targeting the five human sstr subtypes using ELISA and immunohistochemistry, and tested their suitability in formalin-fixed and paraffin-embedded (FFPE) human tissues and archival samples of normal pancreatic tissue and NET.

RESULTS

All mAbs were highly specific with no cross-reactivity. The sstr1-5 immunoreactivity in gastrointestinal NET (n=67) was correlated with clinicopathologic data. With the exception of sstr3, NET were highly positive for all receptor subtypes (42, 63, 6, 32 and 65% of tumors were positive for sstr1, sstr2a, sstr3, sstr4 and sstr5, respectively). sstr1, sstr2a and sstr5 were present at the plasma membrane and in the cytoplasm of tumor cells, whereas sstr3 and sstr4 were almost exclusively cytoplasmic. Immunoreactivity of sstr1, sstr2a and sstr4 tended to decrease as tumor aggressiveness increased. sstr5 showed an opposite pattern, with higher staining in well-differentiated carcinomas compared with well-differentiated tumors. sstr5 immunoreactivity was correlated with the presence of metastases and angioinvasion, suggesting a possible association with more aggressive behavior.

CONCLUSION

Determination of the sstr1-5 by immunohistochemistry using subtype-specific mAbs is feasible in FFPE tissue and may provide a tool for routine clinical practice.

Consensus recommendations for the diagnosis and management of well-differentiated gastroenterohepatic neuroendocrine tumours: a revised statement from a Canadian National Expert Group

Well-differentiated neuroendocrine tumours (nets-previously called "carcinoid tumours") are relatively rare tumours originating from the diffuse neuroendocrine system; they are found most often in the bronchial or gastrointestinal systems. In Canada, gastroenterohepatic NETS represent less than 0.25% of oncology cases. Because of the relative rarity of these tumours, diagnostic and therapeutic approaches vary and are often based on individual physician experience. A number of European and North American groups have developed consensus guidelines for the diagnosis and management of well-differentiated gastroenterohepatic NETS, and in 2006, Canadian consensus guidelines were published by a Canadian expert group. The updated and expanded current Canadian guidelines are based on a consensus meeting held in Paris, France, in 2008 and are based on the most current literature.

Primary Hepatic Neuroendocrine Tumor: What Do We Know Now?

Primary hepatic neuroendocrine tumors (PHNETs) are rear neoplasm. Diagnosis is an evolution, and requires a systematic clinical exclusion with histological confirmation. Treatment is surgical with excellent prognosis, and a long-term follow-up is required due to high tumor recurring rate. Knowledge from this species of tumor remains limited due to paucity of cases. This article elaborates the key features, diagnosis algorithm, current management, other treatment options and extensive review of literature on this rear tumor.

68Ga-DOTA-NOC PET/CT imaging of neuroendocrine tumors: comparison with ¹¹¹In-DTPA-octreotide (OctreoScan®)

PURPOSE

Recent data have indicated that ⁶⁸Ga-DOTA-NOC positron emission tomography/X-ray computed tomography (PET/CT) may yield improved images in a shorter acquisition protocol than ¹¹¹In-DTPA-octreotide (OctreoScan®, OCT). Therefore, we performed a prospective comparison of ⁶⁸Ga-DOTA-NOC and OCT for the detection of neuroendocrine tumors (NETs).

METHODS

Nineteen patients (eight carcinoid, nine pancreatic NETs, and two NE carcinoma of unknown origin) with previous positive OCT scans underwent ⁶⁸Ga-DOTA-NOC PET/CT and OCT single-photon emission computed tomography imaging for staging or follow-up. Findings were compared by region and verified with conventional imaging.

RESULTS

All images of both modalities demonstrated focal uptake, often at multiple sites. ⁶⁸Ga-DOTA-NOC images were clearer than OCT images, facilitating interpretation. Similar foci were identified with both modalities in 41 regions, with additional foci on ⁶⁸Ga-DOTA-NOC in 21 and on OCT in 15 regions. CT, magnetic resonance imaging, or ultrasound confirmed the concordant findings in 31 of 41 regions and findings seen with ⁶⁸Ga-DOTA-NOC only in 15 of 21 regions. Findings seen with OCT only were less clear and were only confirmed in 4 of 15 regions. ⁶⁸Ga-DOTA-NOC had impact on staging in four patients and on management in three patients.

CONCLUSIONS

Although ⁶⁸Ga-DOTA-NOC and OCT images were similar, in this study, ⁶⁸Ga-DOTA-NOC demonstrated more true positive tumor foci and was better tolerated by patients. This direct comparison supports replacement of OCT with ⁶⁸Ga-DOTA-NOC-PET/CT in the evaluation of NETs.

In vitro cytotoxicity of novel platinum-based drugs and dichloroacetate against lung carcinoid cell lines

INTRODUCTION

Chemotherapy for advanced well-differentiated carcinoids is characterised by low response rates and short duration of responses. The present study aimed to assess the in vitro activity of novel platinum-based chemotherapeutic drugs in combination with dichloroacetate (DCA), a sensitiser to apoptosis, against lung carcinoid cell lines.

METHODS

Three permanent cell lines (UMC-11, H727 and H835) were exposed to 14 different established cytotoxic drugs and the novel platinum-based compounds as satraplatin, JM118 and picoplatin in combination with DCA, and viability of the cells was measured using a tetrazoliumbased dye assay.

RESULTS

With exception of the highly chemoresistant UMC- 11 line, the carcinoid cell lines (H727, H835) were sensitive to the majority of chemotherapeutics in vitro. Among the platinum-based drugs, carboplatin and oxaliplatin showed highest efficacy. H835 cells growing as multicellular spheroids were 2.7-8.7-fold more resistant to picoplatin, satraplatin and its metabolite compared to single cell suspensions. DCA (10 mM) inhibited the growth of UMC- 11 cells by 22% and sensitised these highly resistant cells to carboplatin, satraplatin and JM118 1.4-2.4-fold.

CONCLUSION

The highly resistant UMC-11 lung carcinoid cells are sensitive to carboplatin, oxaliplatin and the satraplatin metabolite JM118, but multicellular spheroidal growth, as observed in the H835 cell line and pulmonary tumourlets, seems to increase chemoresistance markedly. The activity of carboplatin and JM118 is significantly and specifically increased in combination with the apoptosis sensitiser DCA that promotes mitochondrial respiration over aerobic glycolysis. In summary, among the novel platinum drugs satraplatin has the potential for treatment of lung carcinoids and DCA potentiates the cytotoxicity of selected platinum drugs.

Clinical value of right hemicolectomy for appendiceal carcinoids using pathologic criteria

BACKGROUND

Appendiceal carcinoids (AC) are usually adequately treated by appendectomy. The European Neuroendocrine Tumours Society (ENETS) has recently reconsidered the previous pathologic criteria to identify patients at high risk of extra-appendiceal disease, who are thought to require right hemicolectomy (RHC).

AIM

The aim of this retrospective, observational study was to evaluate previous and currently introduced criteria, in identifying patients with AC in whom RHC is justified.

SUBJECTS AND METHODS

Twelve patients who underwent RHC for AC were retrospectively identified. Demographic and follow-up data were collected and appendectomy specimens were reviewed for the presence of indications leading to RHC defined as: tumor diameter ≥2 cm, tumor location at the base, mesoappendiceal extension, mitotic index Ki-67≥2%. RHC specimens were examined to identify evidence of extra-appendiceal disease, remaining and/or metastatic disease.

RESULTS

Four patients fulfilled two criteria and 8 one criterion for RHC. Two patients had tumors ≥2.0 cm, 5 located at the base, 8 invading the mesoappendix and periappendiceal fat; Ki-67 PI was 1% in all cases measured except one, in which it was 3%. Post-RHC, 3 patients (25%) had extra-appendiceal disease (no residual disease was identified in surgical margins); 1 had tumor at the colon specimen and 2 had lymph node metastasis. All 3 patients fulfilled only one pathologic criterion; 1 had tumor mesoappendiceal extension and 2 tumor location at the base of the appendix.

CONCLUSIONS

Applying previous and currently introduced pathologic criteria, 25% of high-risk patients with AC had identifiable extra-appendiceal disease following RHC that might be not detected following the recently introduced ENETS criteria.

Standard imaging techniques for neuroendocrine tumors

Several diagnostic imaging techniques have been used successfully for evaluating patients with neuroendocrine tumors (NETs). These techniques include computed tomography (CT), magnetic resonance imaging, positron emission tomography/CT, single-photon emission CT (SPECT), and SPECT/CT. This article reviews the various imaging methods and their respective advantages and limitations for use in different types of NETs, in particular carcinoid tumors.

[Contributions of nuclear medicine to the diagnosis and follow-up of gastroenteropancreatic neuroendocrine tumors]

The optimal treatment of patients with gastroenteropancreatic neuroendocrine tumors requires accurate staging. Nuclear medicine is an imaging technique that provides functional information. In gastroenteropancreatic neuroendocrine tumors this information is obtained from radiotracers providing data on amine synthesis (MIBG) and/or somatostatin receptor expression (111-In-octreotide, 68Galio-DOTATOC) by the tumoral cell, both in primary and metastatic tumors. The accumulated experience shows that nuclear medicine techniques are essential in the management of these patients. The indications in the diagnosis, extension study and follow-up of these tumors, as well as the distinct radiotracers available, are reviewed.

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.

Somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine tumours, current aspects and new perspectives

Gastroenteropancreatic neuroendocrine tumours (GEP NETs) are rare tumours that present many clinical features.They secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome. However, many are clinically silent until late presentation with mass effects.In 2000 the WHO developed a new classification which gives a better description of the characteristics and biological behaviour of the tumour.Surgical resection is the treatment of first choice for a patient with a GEP NET. In metastatic disease multiple therapeutic approaches are possible. In these cases the goal is to improve quality of life and to extent survival.GEP NETs express somatostatin receptors (SSTRs), which are bound by somatostatin (SST) or its synthetic analogues, although the subtypes and number of SSTRs expressed is very variable.Somatostatin analogues are used frequently to control hormone-related symptoms while their anti-neoplastic activity, even if it has not been widely studied and the regarding data are discordant, seems to result prevalently in tumour stabilisation.A few patients who fail to respond or cease to respond to standard SST analogues treatment seem to have a response to higher doses of these drugs.The use of higher doses of somatostatin analogues or the development of new subtype selective agonists and chimaeric somatostatin analogues, or pan-somatostatin will probably improve the clinical management of these patients.This review provides an update on the use of somatostatin analogues in the management of GEP NETs and discusses novel clinical strategies based on SSTR 2 gene transfer therapy.

Primary hepatic carcinoid: A case report and literature review

Carcinoids are tumors derived from neuroendocrine cells and often produce functional peptide hormones. Approximately 54.5% arise in the gastrointestinal tract and frequently metastasize to the liver. Primary hepatic carcinoid tumors (PHCT) are extremely rare; only 95 cases have been reported. A 65-year-old man came to our attention due to occasional ultrasound findings in absence of clinical manifestations. His previous medical history, since 2003, included an echotomography of the dishomogeneous parenchymal area but no focal lesions. A computed tomography scan performed in 2005 showed an enhanced pseudonodular-like lesion of about 2 cm. Cholangio-magnetic resonance imaging identified the lesion as a possible cholangiocarcinoma. No positive findings were obtained with positron emission tomography. Histology suggested a secondary localization in the liver caused by a low-grade malignant neuroendocrine tumor. Immunohistochemistry was positive for anti chromogranin antibodies, Ki67 antibodies and synaptophysin. Octreoscan scintigraphy indicated intense activity in the lesion. Endoscopic investigations were performed to exclude the presence of extrahepatic neoplasms. Diagnosis of PHCT was established. The patient underwent left hepatectomy, followed by hormone therapy with sandostatine LAR. Two months after surgery he had a lymph nodal relapse along the celiac trunk and caudate lobe, which was histologically confirmed. The postoperative clinical course was uneventful, with a negative follow-up for hematochemical, clinical and radiological investigations at 18 mo post-surgery. Diagnosis of PHCT is based principally on the histopathological confirmation of a carcinoid tumor and the exclusion of a non-hepatic primary tumor. Surgical resection is the recommended primary treatment for PHCT. Recurrence rate and survival rate in patients treated with resection were 18% and 74%, respectively.

Chromogranin a levels in diagnosis, treatment and follow-up of 42 patients with non-functioning pancreatic endocrine tumours

BACKGROUND/AIMS

Non-functioning pancreatic endocrine tumours (NFPET) constitute the largest component (35-50%) of pancreatic endocrine tumours. They are characterized by the absence of symptoms of hormone hypersecretion and frequently have clinical manifestations similar to the more common exocrine pancreatic adenocarcinoma. The present studyaims toevaluate the clinical features, diagnostic approach and, in particular, the significance of serum chromogranin A levels (CgA) in the management and outcome of 42 patients with NFPET (from a series of 121 patients with pancreatic endocrine tumours).

METHODS

Twenty-five males and 17 females were included, and the mean age at diagnosis was 52.3 years (range: 26-68 years). The diagnosis for each patient was established by histopathological examination and immunohistochemistry. After the histopathological confirmation of diagnosis and during the follow-up period, patients were evaluated clinically and radiologically (including OctreoScan), whilst fasting gut hormones (including CgA) were also estimated. At diagnosis, all patients were checked for the presence of multiple endocrine neoplasia type I syndrome. The follow-up was complete and ranged from 12 to 86 months (mean: 49 months).

RESULTS

Dyspepsia (66.5%) and weight loss (47.6%) were the most common symptoms at diagnosis, while in 21.4% of patients tumour lesions were revealed incidentally. Plasma CgA levels were significantly or moderately elevated in all patients with liver metastases at diagnosis (64.3%). The levels also reflected tumour progression or response to treatment during the follow-up period. OctreoScan showed avid uptake in 77.8% of patients with hepatic metastases. Moreover, in 2 patients OctreoScan revealed unexpected metastatic mesenteric deposits, which had not been found by the other studies. However, it was negative in 6 patients with liver metastases, in whom tumours were proved to be poorly differentiated (high-grade).

CONCLUSIONS

(1) NFPET may present with clinical manifestations similar to those of an exocrine pancreatic tumour; (2) plasma CgA levels reflect tumour load, and also seem to correlate with tumour progression or response to treatment; (3) surgeryin patients with localized disease at presentation can be curative, while it can also reduce tumour burden in patients with metastases; (4) long-acting somatostatin analogues provide good quality of life and temporary disease stabilization in patients with low-grade tumours; (5) systemic chemotherapy or chemoembolization seem to be beneficial in high-grade and progressive tumours.

Prediction and diagnosis of bone metastases in well-differentiated gastro-entero-pancreatic endocrine cancer: a prospective comparison of whole body magnetic resonance imaging and somatostatin receptor scintigraphy

PURPOSE

Our purpose was to compare the sensitivity of whole body (WB) magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS) for the diagnosis of bone metastases (BMs) in patients with well-differentiated gastro-entero-pancreatic endocrine cancer (WD-GEP-EC) and to determine predictive factors of BM.

PATIENTS AND METHODS

WB-MRI and SRS were prospectively performed in 79 patients with bronchial (11), thymic (five), gastric (two), duodeno-pancreatic (24), ileal (26), colic (one), or unknown primary (10) WD-GEP-EC.

RESULTS

A total of 36 patients (46%) had 333 BMs involving 119 skeletal segments. WB-MRI and SRS were equally sensitive for detecting patients with BM (86 vs. 81%; P = 0.56), with 33% of the patients diagnosed with only one procedure. WB-MRI detected more BMs than SRS (80 vs. 57%; P = 0.017). Compared with SRS, WB-MRI detected more spine BMs (96 vs. 45%; P < 0.001) and tended to detect more pelvic and lower limb BMs (P = 0.054 and P = 0.06, respectively). Compared with WB-MRI, SRS detected more skull BMs (100 vs. 0%; P < 0.001) and tended to detect more rib BMs (P = 0.08). Sternal and upper-limb BMs were equally detected with WB-MRI and SRS (P = 0.32 and P = 0.46, respectively). Bone staging with SRS and spine MRI rather than WB-MRI would have detected 92% of the patients with BMs and 83% of all BMs. The extent of liver involvement and bronchial-thymic primary tumors were independent predictive factors for BM.

CONCLUSIONS

We recommend bone staging with SRS and spine MRI in all patients with bronchial-thymic or unknown primary WD-GEP-EC. In case of duodeno-pancreatic or ileal primary, bone imaging may be restricted to patients with liver metastases.

90Y Radioembolization for metastatic neuroendocrine liver tumors: preliminary results from a multi-institutional experience

PURPOSE

Minimally invasive therapies such as transarterial chemoembolization and radiofrequency ablation are used for hepatic metastatic neuroendocrine tumor (NET) therapy. Results from another minimally invasive therapy, radioembolization, remain unknown. The purpose of this multicenter open label phase II study was to assess the efficacy and safety of yttrium-90 (Y) radioembolization for treating hepatic metastatic NET using a primary outcome of tumor response and secondary outcomes of serologic toxicities and survival.

MATERIAL/METHODS

In this multicenter study, all patients underwent lobar radioembolization using glass or resin Y radioembolic agents. Patients were assessed serologically and radiographically at 2 to 4 weeks and then at 1 to 3 month intervals after treatment. We 1) compared liver volumes, radiation doses, and serologic liver function tests (unpaired t test, P = 0.05) and 2) assessed tumor response, serologic toxicity, and median survival from first Y therapy. The clinicaltrials.gov identifier was NCT00532740.

RESULTS

Forty-two patients underwent radioembolization using glass (mean age 58 +/- 12 years) or resin (mean age 61 +/- 11 years) microspheres. A statistically significant greater median radiation dose was delivered to each lobe using glass (right lobe 117 Gy; left lobe 108 Gy) than using resin (right 50.8 Gy; left 44.5 Gy) (P < 0.01). Using Response Criteria in Solid Tumors, 92% of glass and 94% of resin patients were classified as partial response or stable disease at 6 months after treatment. Six patients experienced grade 3/4 toxicities during the follow-up period. Median survival was 22 months (glass) and 28 months (resin) (P = 0.82).

CONCLUSION

Y radioembolization of metastatic NET is a viable therapy with acceptable toxicity. Further investigation is warranted.

The role of somatostatin analogues in the treatment of neuroendocrine tumours

Neuroendocrine tumours belong to a heterogeneous family of neoplasms, originating in endocrine glands (such as the pituitary, parathyroid or the neuroendocrine adrenal glands), in endocrine islets (within the thyroid or pancreas) as well as in endocrine cells dispersed between exocrine cells throughout the digestive or respiratory tracts. The clinical behaviour of neuroendocrine tumours is variable; they may be functioning or not functioning, ranging from well-differentiated slow growing neuroendocrine tumours to poorly differentiated neuroendocrine tumours, which are highly aggressive malignant tumours. The development of somatostatin analogues as important diagnostic and treatment tools have revolutionised the clinical management of patients with neuroendocrine tumours. However, although symptomatic relief and stabilisation of tumour growth for various periods of time are observed in many patients treated with somatostatin analogues, tumour regression is rare. Development of new somatostatin analogues and new drug combination therapies should further improve the clinical management of these patients.

Surgical treatment of primary neuroendocrine tumors of the liver

Primary neuroendocrine tumor (NET) of the liver is a very rare neoplasm, requiring strict exclusion of possible extrahepatic primary sites for its diagnosis. We have analyzed our clinical experience of eight patients with hepatic primary NET. From January 1997 to December 2006, eight patients with a mean age of 50.4 +/- 9.5 years underwent liver resection for primary hepatic NET. Seven patients underwent preoperative liver biopsies, which correctly diagnosed NET in four. Of the eight patients, six underwent R0 and two underwent R1 resection. Diagnosis of hepatic primary NET was confirmed immunohistochemically and by the absence of extrahepatic primary sites. All tumors were single lesions, of mean size 8.6 +/- 5.7 cm, and all showed positive staining for synaptophysin and chromogranin. During a mean follow-up of 34.0 +/- 39.7 months, three patients died of multiple liver metastases after tumor recurrence, whereas the other five remain alive to date, making the 5-year recurrence rate 40% and the 5-year survival rate 56.3%. Univariate analysis showed that Ki67 proliferative index was a risk factor for tumor recurrence. In conclusion, although primary hepatic NET is very rare, it should be distinguished from other liver neoplasms. The mainstay of treatment is curative liver resection.

Appendectomy or right hemicolectomy in the treatment of appendiceal carcinoid tumors?

AIMS AND BACKGROUND

Carcinoids of the appendix continue to be of interest, despite their low incidence. There is still considerable controversy surrounding these tumors, especially with regard to the role of right hemicolectomy in the surgical management. The aim of this work was to explicate the current therapeutic knowledge and to review the criteria for the indications of appendectomy or hemicolectomy.

METHODS

The records of patients who underwent appendectomies from 1990 to 2000 were analyzed. Seven patients were included in the study. The clinical data were reviewed for demographic details, tumor size, localization in the appendix, histological patterns and surgical procedures. All patients underwent appendectomy including removal of the mesenteriolum, and in one of them a right hemicolectomy was performed 3 weeks later. The mean follow-up was 7 years (range, 4-14). Follow-up data included symptoms, urinary 5-hydroxyindoleacetic acid, ultrasound examination, computerized tomography, and octreotide scanning.

RESULTS

Seven patients (0.9% of all appendectomies) were reported to have carcinoid tumors of the appendix. They were 3 men and 4 women with a mean age of 29 years. All patients were admitted for appendicitis. None suffered from the carcinoid syndrome. The site of the tumor was the apex of the appendix in 4 cases, the body in 2 cases and the base in 1 case. Mean tumor diameter was 8 mm (range, 5-29 mm); in 6 patients it was <2 cm. Treatment was appendectomy in all cases; additional right hemicolectomy was necessary in one case because of a tumor of more than 2 cm with invasion of the mesoappendix and lymph nodes. The 7-year survival rate is 100%. Six patients are without disease, while 1 patient (the one who underwent a right hemicolectomy) developed metastases in the liver 6 years after the operation. This patient, who was treated with a liver resection, is still alive.

CONCLUSIONS

According to current guidelines, an appendectomy may be performed for small carcinoid tumors (<1 cm). Reasons for more extensive surgery than appendectomy are tumor size >2 cm, lymphatic invasion, lymph node involvement, spread to the mesoappendix, tumor-positive resection margins, and cellular pleomorphism with a high mitotic index. The criteria that direct us towards major (hemicolectomy) or minor surgery (appendectomy) are controversial. Tumor size is still considered the most important prognostic factor, with a presumed increase in the risk of metastasis for tumors greater than 2.0 cm. The accepted treatment of such tumors is a right hemicolectomy. However, there is no evidence demonstrating a survival benefit for right hemicolectomy over simple appendectomy in patients with carcinoids greater than 2.0 cm in diameter.

Radio-guided surgery in neuroendocrine tumors

The majority of Neuroendocrine tumors (NET) express somatostatin (SS) receptors, and thus can be successfully targeted with radiolabeled SS analogs in vivo. Somatostatin receptor scintigraphy (SRS) with (111)In-DTPA Octreotide is the main imaging technique for evaluation of NETs. Radio-guided surgery for NETs, therefore, primarily utilizes (111)In-DTPA Octreotide tumor localization mechanism and kinetics. Somatostatin analog radiopharmacy continues to evolve to include the development of more selective and higher affinity analogs and PET tracers. These changes are expected to open new venues for radio-guided surgery technology.

Anatomic and functional imaging of metastatic carcinoid tumors

Carcinoid tumors are a fascinating group of neuroendocrine neoplasms that develop either sporadically or as part of an inheritable syndrome. Many tumors arise in the bronchopulmonary or gastrointestinal tract, but a neuroendocrine tumor can arise in almost any organ. The tumors have varied malignant potential depending on the site of their origin, and the clinical manifestations often are nonspecific. Metastases may be present at the time of diagnosis, which often occurs at a late stage of the disease. Imaging plays a pivotal role in the localization and staging of neuroendocrine tumors and in monitoring the treatment response. Imaging is often challenging, and a combination of anatomic and functional techniques is usually required, depending on the tumor type and location. Techniques include ultrasonography, barium studies, endoscopy, computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, iobenguane scintigraphy, and, in select cases, positron emission tomography. Coregistration of structural and functional images is often of incremental value for accurate localization of the primary tumor and any meta-static disease. Radiologists must understand the contribution of each imaging modality in the assessment of different neuroendocrine tumors. In addition, knowledge of the optimal technique for each radiologic and radionuclide imaging examination is essential. Familiarity with the protean imaging appearances of both primary and metastatic disease is essential for accurate staging, treatment monitoring, and surveillance. Finally, an understanding of the wide variety of treatment options for patients with carcinoid tumors is vital for optimal management.

Gastroenteropancreatic endocrine tumors: clinical characterization before therapy

Gastroenteropancreatic endocrine tumors (GEP ETs) constitute a spectrum of tumors that arise throughout the entire body but are drawn together under a common definition based on the expression of proteins derived from granules, vesicles, or both. GEP ET characterization is dependent on the primary tumor, and encompasses various factors: the WHO classification; hormone-related symptom recognition; hormone marker measurements; screening for inherited syndromes; staging; and somatostatin receptor characterization. Hypervascularization and somatostatin expression constitute major features of endocrine tumors that affect diagnosis, imaging, and therapy. GEP ET prognosis is characterized by its diversity, including a subgroup of patients with slowly progressive disease even at the metastatic stage. Prognosis assessment is mainly based on WHO classification and staging. A second cancer and cardiovascular comorbidity might also play a major prognostic part when present. Mastery of several key points analyzed in this Review, to be applied during the diagnostic and prognostic processes, is essential for defining a tailored therapeutic management.

Imaging of neuroendocrine tumors

Neuroendocrine tumors (NETs) are rare neoplasms, which are characterized by the presence of neuroamine uptake mechanisms and/or peptide receptors at the cell membrane and these features constitute the basis of the clinical use of specific radiolabeled ligands, both for imaging and therapy. Radiolabeled metaiodobenzylguanidine (MIBG) was the first radiopharmaceutical used to specifically depict and localize catecholamine-secreting tumors (pheochromocytomas, paragangliomas, and neuroblastomas) and is still regarded as a first-choice imaging technique for diagnosis and follow-up; in patients with malignant disease, MIBG scintigraphy is an essential step to select patients for (131)I-MIBG therapy. Scintigraphy with (111)In- or (99m)Tc-labeled somatostatin analogs has become the main imaging technique for NETs, particularly those expressing a high density of somatostatin receptors, such as gastroenteropancreatic tumors; this procedure is used routinely for localizing the primary tumor, evaluating disease extension, monitoring the effect of treatment and for selecting patients for radioreceptor therapy. Since the recent development of hybrid machines, it has been possible to obtain images that simultaneously hold both anatomic (computed tomography [CT]) and functional (single-photon emission computed tomography [SPECT] or positron emission tomography [PET]) information, with great impact on diagnostic accuracy. Significant improvements have been made during the past few years with the development of highly specific radiopharmaceuticals for PET studies that reflect the different metabolic pathways of NETs, such as glucose metabolism ((18)F-fluorodeoxyglucose), the uptake of hormone precursors ((11)C-5-hydroxytryptophan, (11)C- or (18)F-dihydroxyphenylalanine, (18)F-fluorodopamine), the expression of receptors ((68)Ga-labeled somatostatin analogs), as well as the synthesis, storage, and release of hormones ((11)C-hydroxyephedrine and others). Among these radiopharmaceuticals, (68)Ga-labeled somatostatin analogs are increasingly used in specialized centers in Europe for PET and PET/CT imaging and show very promising results with high diagnostic sensitivity. New somatostatin analogs with different receptor affinity as well as other peptides are currently under investigation and will further improve our diagnostic and therapeutic capabilities in the future.

Large bowel carcinoid tumors

PURPOSE OF REVIEW

Gastrointestinal carcinoids comprise 90% of all carcinoid tumors and all carcinoids have malignant potential. This review focuses on the morphology, prognosis, detection and treatment for appendiceal, colonic and rectal carcinoids.

RECENT FINDINGS

Computed tomography exists as an initial examination for the primary carcinoid tumor as well as for metastases. There have, however, been recent developments of newer and more accurate modalities. Octreotide scanning has a sensitivity of primary tumor detection of 90%; additionally, I- or I-meta-iodobenzylguanidine scanning and tracer-specific positron emission tomographic scans have demonstrated encouraging results. Further advancements in treatment with tumor-targeted therapy and biochemical evaluation of carcinoids have shown promise.

SUMMARY

The recent progress with scintigraphic and radiologic modalities has provided better means for diagnosis of primary and metastatic carcinoid tumors. These newly discovered diagnostic modalities have been more encouraging than the recent treatment approaches that have been studied with regard to metastatic carcinoids. While surgery remains the mainstay of treatment of nonmetastatic carcinoid, there have been studies for various medical treatments of metastatic disease. Unfortunately, there have been disappointing results with regard to improvement of tumor response and patient survival, but a foundation has been established for future trials employing alternative agents and exploration of combination therapies.

Gastrointestinal Carcinoids: Imaging Features with Clinicopathologic Comparison

Gastrointestinal carcinoids are well-differentiated endocrine neoplasms that belong to a diverse group of tumors that arise from cells of the diffuse endocrine system. A wide variety of specialized endocrine cells that populate the gastrointestinal mucosa and submucosa give rise to carcinoids. Consequently, carcinoids may occur throughout the gastrointestinal tract and produce a variety of hormones and protein products that are associated with specific clinical symptoms. Biologic behavior of carcinoids varies by site and cell type, but all gastrointestinal carcinoids are considered to have malignant potential. They may produce specific syndromes such as Zollinger-Ellison syndrome, or they may occur in association with inherited syndromes such as multiple endocrine neoplasia type 1 or neurofibromatosis type 1. Metastatic carcinoids may produce carcinoid syndrome. The small intestine is the most common location for gastrointestinal carcinoids. Most small intestinal carcinoids arise from enterochromaffin cells of the distal ileum that produce serotonin. Small intestinal carcinoids often have an aggressive biologic behavior and, as such, patients frequently have metastases to regional lymph nodes and the liver at initial presentation. Pathologic and radiologic manifestations of serotonin-producing small intestinal carcinoids are related to local and regional effects of serotonin and its metabolites. In contrast, carcinoids of the appendix and rectum are commonly discovered incidentally as small lesions that are unassociated with clinical evidence of hormone production and have a more indolent clinical course. Carcinoids of the stomach, duodenum, and colon are uncommon but have distinctive clinical, pathologic, and radiologic appearances. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of gastrointestinal carcinoids is important in the imaging and management of patients with suspected carcinoids or focal gastrointestinal masses.