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 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There are six major steps in the management of patients with neuroendocrine tumors (NETs) (carcinoids and pancreatic endocrine tumors). One of the steps that is increasing in its importance is the need to assess primary tumor location and tumor extent in these patients. Without such information, it is not possible to adequately manage these patients. Conventional imaging studies (CT scan, MRI, ultrasound, angiography), functional localization studies measuring hormonal gradients, endoscopic ultrasound, and most recently, somatostatin receptor scintigraphy (SRS) with [125I-DTPA-DPhe1]-octreotide have all been advocated to localize NETs in different studies. Whereas it is now established that for all NETs, except insulinomas, SRS has the greatest sensitivity, it remains unclear whether this increased sensitivity translates into increased clinical usefulness. It, therefore, remains unclear based on fiscal and clinical considerations what should be the recommended algorithm for the use of the different localization methods. To address this issue, we have recently performed two prospective studies on patients with gastrinomas. In this paper, the methods and results of each are summarized and based on these results, an algorithm for localization studies in NETs is proposed. One study assessed the role of SRS in management in 122 patients and shows that the use of SRS changed management in 47 percent of patients according to six different criteria when the patients were stratified according to their principal management problem. Determining whether liver metastases were present is one of the major goals of tumor localization studies and is frequently a source of confusion because of the difficulty in distinguishing small NETs liver metastases from hemangiomas. In the second study, the ability of SRS and other tumor localization methods to distinguish these two possibilities was assessed in 15 patients with small hemangiomas and 15 patients with small hepatic metastases (mean size 1.3 cm). SRS correctly identified 93 percent of the patients with liver metastases and was not positive in any patient with a hemangioma, suggesting it was not a liver metastases. SRS had greater negative and positive predictive value than conventional studies. Based on these two studies, and SRS's greater sensitivity and fiscal considerations, it is proposed that SRS should be the initial tumor imaging study in all NETs except insulinomas, and algorithms for the use of other localization studies in both NETs and insulinomas are proposed.
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PMID:Definition of the role of somatostatin receptor scintigraphy in gastrointestinal neuroendocrine tumor localization. 982 76

In vitro studies have shown that gastroenteropancreatic tumors, with the exception of insulinomas, have a high density of somatostatin receptors and can be imaged in vivo using somatostatin receptor scintigraphy (SRS) with either [123I-Tyr3]octreotide or [111In DTPA,DPhe1]octreotide. However, the sensitivity in relation to conventional imaging studies (ultrasound, CT, MRI, angiography) remains unclear. To address this question, we performed a prospective study of 80 patients with gastrinomas where SRS was compared with other conventional imaging techniques for detecting extrahepatic gastrinomas or liver metastases. Extrahepatic gastrinomas were identified by SRS in 58 percent of patients, whereas conventional imaging studies detected gastrinomas in 9 percent to 48 percent of patients. In detecting hepatic metastases in 24 patients with histologically-proven metastases, SRS was positive in 92 percent; ultrasound, CT or angiography in 42 percent to 62 percent; and MRI in 71 percent of patients. These results are compared with other studies in detecting gastrinomas as well as series including other PETs, excluding insulinomas, with insulinomas alone, and with carcinoid tumors. An analysis of the ability of SRS to identify gastrinomas found in different sites at surgery was performed. The role of endoscopic ultrasound (EUS) in detecting various PETs, in comparison to that of SRS, is yet to be established, particularly for extrapancreatic PETs. Therefore, the results of EUS in various studies containing patients with PETs are compared to those with SRS and conventional imaging studies. These data suggest that EUS is the first choice of localization methods for detecting insulinoma, which is an intrapancreatic tumor in almost all cases. In other PETs there still is not sufficient data to establish the relative roles of EUS and SRS.
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PMID:Comparative analysis of diagnostic techniques for localization of gastrointestinal neuroendocrine tumors. 982 78

[111In-DTPA-D-Phe1]-pentetreotide has been shown to localize well-differentiated and slowly growing neuroendocrine tumours, whereas increased FDG uptake is associated with malignancy. This prospective study explores the role of metabolic (PET) and receptor (SPET) imaging in well- and less well-differentiated tumours--gastroenteropancreatic (GEP) tumours, medullary thyroid carcinomas (MTC) and thymic carcinomas--in comparison with the expression of the Ki-67 antigen. Ten patients with GEP tumours, five with MTC and five with thymic carcinomas were studied. Prior to PET, somatostatin receptor scintigraphy (SRS) was performed in all patients. Sixty minutes after the intravenous administration of 18F-FDG (370 MBq), whole-body PET was performed. In addition, the resected tissues were prepared for immunocytochemistry examination (cell cycle-associated Ki-67 antigen). Preoperative SRS detected multiple primary tumours and metastatic lesions in four patients with well-differentiated carcinoids (low Ki-67 expression). Whole-body PET demonstrated normal distribution of FDG in all of these patients. In patients with recurrent MTC and rapidly increasing CEA levels, SRS showed no in vivo somatostatin receptor expression, whereas whole-body PET localized 24 locoregional lymph node metastases with increased FDG uptake. Immunocytochemistry of the resected lymph nodes demonstrated high Ki-67 expression associated with a high proliferative activity. Similar results in receptor scintigraphic and metabolic behaviour were obtained from patients with metastasizing thymic carcinomas (high Ki-67 expression). In conclusion, SRS has been shown to localize well-differentiated GEP tumours. In contrast, FDG PET is only valuable for predicting malignancy in less well-differentiated GEP tumours and malignant MTC associated with rapidly increasing CEA levels. Therefore, an additional 18F-FDG PET procedure should only be performed if SRS is negative. Furthermore, our preliminary results suggest that increased FDG metabolism reflects the invasiveness of thymic carcinomas.
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PMID:Metabolic (PET) and receptor (SPET) imaging of well- and less well-differentiated tumours: comparison with the expression of the Ki-67 antigen. 985 44

Several authors proposed the stage at diagnosis and some histopathological features as prognostic factors of bronchial carcinoids. However, since large tumour diameters or nodal metastases are frequently associated to aggressive histology, their prognostic role is unclear. To investigate the relationships between the clinicopathological parameters at diagnosis and outcome, 21 patients were analysed. Overall 26% of the radically resected patients recurred. Recurrences and disease-specific mortality were related to atypical histology and, only in cases with typical histology, to the presence of hilar or mediastinal lymph node metastases. These prognostic factors were valuable independently of the size of the primary tumour, that was remarkably homogeneous, always less than 3 cm, thus not predictive of recurrence. Moreover we evaluated the role of somatostatin receptor scintigraphy, a diagnostic tool only preliminary studied in this field. Scintigraphy with 111In-octreotide revealed the primary tumours at diagnosis (8/8), the increase in tumour size in two unresected patients, and all the cases of recurrent or metastatic disease (5/11), sometimes before the appearance of symptoms. These results suggest the usefulness of histology and nodal status as prognostic factors in clinical practice. Somatostatin receptor scintigraphy turns out to be a powerful diagnostic tool, for an accurate staging and an early diagnosis of recurrence in bronchial carcinoids.
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PMID:Bronchial carcinoid tumours: a study on clinicopathological features and role of octreotide scintigraphy. 1002 17

Neuroendocrine tumors are not seen frequently. They are most commonly located in the small bowel including the vermiform appendix. Neuroendocrine tumors of pancreatic origin are extremely rare. Symptoms caused by excessive hormone production by large liver metastases often lead to their diagnosis. Preoperative diagnostics include analysis of specific hormones in serum and urine, ultrasound, CT and somatostatin receptor scintigraphy. Liver metastases of neuroendocrine tumors of the pancreas are common at the time of diagnosis. Curative resection should be performed whenever possible, although patients often benefit from debulking procedures, too. Liver metastases can be subjected to surgical resection, embolization, regional chemotherapy or local procedures such as alcohol injection or cryoablation. As an exception, liver transplantation can be considered in selected cases where radical surgery for the primary tumor could be performed and extrahepatic metastases are not present. Supplementary or alternative options include octreotide and/or interferon-alpha administration. In this article, we report on 6 patients suffering from primary neuroendocrine tumors of the pancreas or the ampulla of Vater who were treated at our department over the past 5 years. In addition, we discuss our own experience with this rare condition in the light of the recent literature.
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PMID:Multimodal treatment of neuroendocrine tumors of the pancreas and the ampulla of Vater. 1020 42

The guidelines for publishing economic evaluations require a statement of the economic importance of the analysis and the viewpoint from which it has been carried out, as well as specification of at least two alternative programmes or interventions, the form of economic evaluation, the outcome measure, the method of costing, the time horizon and adjustment for timing of costs and benefits (e.g. by a discount factor), and the allowance for uncertainties (e.g. by implementation of a sensitivity analysis). The decision analysis can be based on clinical trial data, on retrospective or administrative databases, or on modelling. The choice of outcome measures is the key issue in an economic evaluation. In cost-effectiveness analysis, benefits are usually measured in natural units. This is the form of economic evaluation most frequently used in nuclear medicine. Endpoints of effectiveness applied in studies in this field have been procedures avoided, procedures initiated, cardiac events, survival probability, morbidity, quality of life and protracted or failed surgical procedures. In other instances, surrogate endpoints have been used such as metastases detected, staging, viability or tumour response. This, however, limits comparability of cost-effectiveness considerably, as proof of a change in the health outcome cannot be obtained. Measures of utility such as QALYs (quality-adjusted life years) have so far only been applied for decision tree analysis. Useful examples of economic evaluation studies in nuclear medicine are presented here for fluorodeoxyglucose positron emission tomography (FDG-PET) in the preoperative staging of non-small cell lung cancer, for FDG-PET in differentiating indeterminate solitary pulmonary nodules, for somatostatin receptor scintigraphy in detecting metastases of carcinoid tumours, for routine preoperative scintigraphy with sestamibi in patients with parathyroid adenoma, for periodic measurement of thyroid-stimulating hormone in detecting mild thyroid failure, for diagnostic algorithms including a lung scan in patients with suspected pulmonary embolism, for myocardial perfusion imaging as an incremental prognostic factor in patients with coronary artery disease, and for the use of radioiodine as first-line therapy of Graves' hyperthyroidism and of toxic nodular goitres. Further evaluations of effectiveness or utility should be carried out within a multidisciplinary framework to ensure that nuclear medical procedures are included in the general management guidelines.
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PMID:Economic evaluation studies in nuclear medicine: the need for standardization. 1036 54

Three patients are described who had regional and distant metastases of medullary thyroid cancer detected by somatostatin receptor scintigraphy but not by CT; two had minimal disease that was amenable to surgery. The first patient had been followed for 2 years before having a repeated scan and positive CT, with subsequent surgical removal of metastatic paratracheal nodes. The plasma calcitonin level, however, did not approach normal values after surgery, and a third scan showed persistence of focal uptake in the left paratracheal area of the lower neck, whereas CT was negative. At repeated exploration, a tumor mass of medullary carcinoma, embedded in lymphatic tissue, was removed. Nine months after the last surgical procedure, calcitonin and carcinoembryonic antigen levels were normal. The second patient underwent microdissection of the mediastinum and removal of two metastatic nodes that were demonstrable only by the scintigraphic technique. The plasma calcitonin level subsequently became normal. The third patient, with multiple endocrine neoplasia IIB and associated pheochromocytoma, had bony metastatic involvement of the left shoulder, demonstrable initially on somatostatin receptor scintigraphy and subsequently with radioiodinated metaiodobenzylguanidine but not on CT.
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PMID:Somatostatin receptor scintigraphy for early detection of regional and distant metastases of medullary carcinoma of the thyroid. 1046 22

Staging of any tumor, i.e. determination of the extent of the disease, serves to select the patients who might profit from curative surgical intervention or to define those patients with inoperable carcinomas who should be referred for other therapies, such as chemotherapy or irradiation. Furthermore, accurate staging is necessary for assessment of prognosis, for radiation therapy planning, and for differentiation of those with small-cell lung cancer or for follow-up examinations of small-cell lung cancer patients after during and after chemotherapy. The primary radiological staging and diagnostic modalities for assessment of bronchial carcinomas are computed tomography (CT) of the thorax including liver and adrenal glands, abdominal sonography, and bone scintigraphy. Magnetic resonance imaging (MRI) should be reserved for specific indications, e.g. infiltration of the chest wall or staging of patients with intolerance/allergy to intravenous contrast medium. The clinical value of nuclear medicine techniques, such as [18F]2-fluoride-2-desoxy-D-glucose positron emission tomography (FDG-PET) for evaluation of lymph nodes and distant metastases, In-111 octreotide/somatostatin receptor scans for staging of small-cell lung cancer, and thallium-201 SPECT are currently being assessed in numerous studies, although these techniques are already in routine use. In future these or nuclear medicine techniques, as well as techniques using molecular-based contrast material, especially for MR imaging, currently in experimental status, may yield serious potential for staging purposes.
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PMID:[Staging of bronchial carcinoma]. 1047 80

Recent studies report that the radiolabelled synthetic somatostatin analogue, [111In-DTPA-DPhe1]octreotide, is useful for imaging carcinoid tumours and pancreatic endocrine tumours. At present, it is unclear whether this method is superior to conventional imaging studies (computed tomography, magnetic resonance imaging, ultrasound, angiography) and what its role should be, if any, in the management of these patients. The aim of this paper is to review five recent studies performed at the National Institutes of Health in patients with Zollinger-Ellison syndrome to define the role of somatostatin receptor scintigraphy. Patients were from a tertiary referral centre, all had Zollinger-Ellison syndrome. In Study n. 1: the sensitivity of somatostatin receptor scintigraphy was assessed compared to conventional studies in 80 patients. Study n. 2: the effect of somatostatin receptor scintigraphy on management was determined in 122 patients. Study n. 3: ability of somatostatin receptor scintigraphy and other conventional methods to distinguish small hepatic metastases (< 2 cm) from hepatic haemangiomas was assessed in 29 patients. Study n. 4: somatostatin receptor scintigraphy, magnetic resonance imaging and bone scanning were compared in 115 consecutive patients to detect bone metastases. Study n. 5: ability of somatostatin receptor scintigraphy to detect gastrinomas found at surgery in 35 patients and its effect on cure rate and determinants of detection of gastrinomas by somatostatin receptor scintigraphy were analysed. Briefly, results showed: Study n. 1: somatostatin receptor scintigraphy is the most sensitive modality for detection of primary or metastatic gastrinomas; Study n. 2: somatostatin receptor scintigraphy changes management in 47% of cases; Study n. 3: somatostatin receptor scintigraphy is the only method to distinguish small liver metastases from small haemangiomas; Study n. 4: somatostatin receptor scintigraphy and magnetic resonance imaging have higher sensitivity and predictive values for bone metastases than bone scanning; Study n. 5: somatostatin receptor scintigraphy misses 33% of gastrinomas found at surgery, primarily small duodenal tumours. Size is the important factor. The use of somatostatin receptor scintigraphy does not increase cure rate. In conclusion, Somatostatin receptor scintigraphy is now the imaging method of choice in patients with Zollinger-Ellison syndrome for preoperative primary tumour localization, detection of bone or liver metastases, and to distinguish small liver metastases from small hepatic haemangiomas. Its specificity appears to be high but has been poorly studied as has the use of it in combination with endoscopic ultrasound. Studies by others suggest these recommendations will apply to carcinoid tumours and other pancreatic endocrine tumours except insulinomas.
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PMID:Somatostatin receptor scintigraphy in gastrinomas. 1060 26

In patients with gastro-enteropancreatic neuroendocrine tumours the localization of all the neoplastic lesions and an accurate staging of the diseases have important therapeutic implications. Somatostatin receptor scintigraphy with In-111 pentatreotide has proved to be useful in detecting gastro-enteropancreatic tumours; however, the role of abdominal single photon emission computed tomography has not yet been definitively established. In a series of 52 patients with gastro-enteropancreatic tumours (9 non-functioning islet cell carcinomas, 4 insulinomas, 3 somatostatinomas, 2 VIPomas, 1 glucagonoma and 33 carcinoids) we compared somatostatin receptor scintigraphy with the results of computed tomography and magnetic resonance imaging performed within one month. Four and 24-hour total body planar images and 4-hour abdominal single photon emission computed tomography were acquired after the i.v. injection of approximately 250 MBq of In-111 pentatreotide. Only abdominal localizations were considered: planar scans detected 16 extrahepatic lesions in 13 patients and 54 liver sites in 21 patients; single photon emission computed tomography visualized 31 extrahepatic lesions and 89 liver metastases in 27 and 28 patients, respectively; computed tomography and magnetic resonance imaging detected 11 extrahepatic lesions in 10 patients and 73 liver sites in 21 patients. In-111 pentatreotide single photon emission computed tomography was the only imaging method able to localize tumoural lesions in 13 patients; all these localizations were then histologically verified. The scintigraphic positivity did not depend on the site or on the presence of hormonal hypersecretions. In conclusion, our results indicate that single photon emission computed tomography is more sensitive than planar images and computed tomography/magnetic resonance imaging in detecting abdominal gastro-enteropancreatic tumours and their metastases; it is able to increase both the number of visualized lesions and that of patients with positive findings. Single photon emission computed tomography is particularly useful in patients in whom tumoural lesions have not been already localized; it should be the first imaging modality in patients with gastro-enteropancreatic tumours: its initial use will result in more information and proper management.
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PMID:Single photon emission computed tomography procedure improves accuracy of somatostatin receptor scintigraphy in gastro-entero pancreatic tumours. 1060 27


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