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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Positron emission tomography (PET) performed with various radiolabelled compounds facilitates the study of tumor biochemistry. If the tumor uptake of an administered tracer is greater than that of surrounding normal tissue, it is also possible to localize the tumor. In initial studies, 18F-labeled deoxyglucose (FDG) was attempted to visualize the tumors, since this tracer had been successfully used in oncology, reflecting increased glucose metabolism in cancerous tissue. However, this tracer was not to any significant degree taken up by the neuroendocrine tumors. Instead, the serotonin precursor 5-hydroxytryptophan (5-HTP) labeled with 11C was used and showed an increased uptake and irreversible trapping of this tracer in carcinoid tumors. The uptake was selective and the resolution so high that we could detect more liver and lymph node metastases with PET than with CT or octreotide scintigraphy. One problem was, however, the high renal excretion of the tracer producing streaky artifacts in the area of interest. Using the decarboxylase inhibitor carbidopa, given as peroral premedication, the renal excretion decreased 6-fold and at the same time the tumor uptake increased 3-fold, hence improving the visualization of the tumors. When patients were followed during treatment with PET using 5-HTP as a tracer, a > 95% correlation between changes in urinary 5-hydroxyindoleacetic acid (U-5-HIAA) and changes in the transport rate constant for 5-HTP was observed. Thus, PET can be used to monitor treatment effects. Elevation of U-5-HIAA is considered to be uncommon in endocrine pancreatic tumors (EPTs). Initially, 11C-labeled L-DOPA was attempted as another amine important in the APUD system. With L-DOPA about half of the EPTs, mainly functioning tumors, could be detected. Recently, 5-HTP was explored as a universal tracer also for EPT and foregut carcinoids, extending the PET-examination to both thorax and abdomen (whole-body PET-examination). With this method we were able to visualize small lesions in the pancreas and thorax (e.g. ACTH-producing bronchial carcinoids) not detectable by any other method including octreotide scintigraphy, MRI and CT. Several other tracers have been investigated, e.g. the monoamineoxidase (MAO-A) inhibitor harmine with promising results in non-functioning EPTs. We are currently exploring a wide range of biochemical systems, including enzymes and receptors, both for neurotransmitters and for peptides and proteins in in vitro assays with the potential to use some of the developed tracers for in vivo visualization and tumor biological studies. In conclusion, PET is a valuable tool in the diagnosis of neuroendocrine tumors. It can detect small lesions in the thorax and abdomen not detected by other methods, which has been of great value preoperatively in several cases. It detects more lesions in the liver and lymph nodes than other methods and furthermore, it can be used to monitor treatment effects.
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PMID:Use of PET in neuroendocrine tumors. In vivo applications and in vitro studies. 1093 3

Positron emission tomography with fluoro-18-deoxyglucose as tracer molecule (FDG-PET) is a relatively new imaging technique used in oncology to study tumour metabolism in vivo. Both qualitative and quantitative data obtained by PET provide unique information to the clinician and may guide the therapeutic approach in selected patients, where conventional diagnostic tests like CT or MRI yield equivocal results. According to the experience obtained in the Vrije Universiteit Medical Centre in Amsterdam, the additional value of FDG-PET can be explained by the sensitivity and the specificity of the technique, combined with the visualization of the whole body. FDG-PET may reveal metastases and tumour tissue may be differentiated from scar tissue and necrosis. PET is expensive and its effects on patient outcome has yet to be established.
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PMID:[Added value of positron emission tomography with fluoro-18-deoxyglucose as the tracer (FDG-PET) in clinical problem cases in oncology]. 1094 34

This study was performed to evaluate the ability of a dual-head gamma camera with 18fluoro-2-deoxy-glucose coincidence detection emission tomography (FDG-CDET) to detect primary tumors in patients with cervical lymph node metastases of head and neck squamous cell carcinoma from an unknown origin. From 60 patients with untreated head and neck squamous cell carcinoma, we selected 4 in whom no evidence of the primary's origin was found by the conventional methods used for the evaluation of head and neck tumors. In addition to the panendoscopy, chest radiography, a computed tomography (CT) scan, and FDG-CDET were performed. Both FDG-CDET and the CT scan located cervical lymph node metastases. In addition, FDG-CDET located the primary tumor in 3 of the 4 patients, and the tumors were confirmed with histopathologic findings. In contrast, the CT scan detected the primary tumor in none of them. FDG tomography performed on a coincidence gamma camera appears to be a successful new tool in detecting occult primary tumors in head and neck carcinoma, and is useful in guiding endoscopic biopsies. It has, further, the important potential ability to detect distant metastases on whole body images.
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PMID:Use of a coincidence gamma camera to detect primary tumor with 18fluoro-2-deoxy-glucose in cervical lymph node metastases from an unknown origin. 1096 9

CT is readily available to all patients. It is relatively inexpensive and fees are usually reimbursed. It provides exquisite anatomic detail of the chest and abdomen in patients with esophageal cancer. The only reliable use of CT in the determination of T is the exclusion of T4 tumors, which is suggested by the preservation of fat planes. Enlarged lymph nodes are suspicious for metastatic disease but require further study or tissue sampling if nodal metastases will determine treatment. Its major use is in the detection of distant metastatic disease; however, 30% to 60% of distant metastases may be radiographically occult. There is a significant learning curve for EUS staging of esophageal cancer. It is suggested that this study be performed at institutions where there is a dedicated, experienced endoscopic ultrasonographer with adequate instrumentation that allows specialty imaging and EUS-FNA. EUS is the best means of clinically determining T. The addition of EUS-FNA to routine EUS evaluation of lymph nodes allows an accuracy similar to the EUS determination of T. EUS has no purpose in assessment of non-nodal distant metastatic disease; however, the serendipitous finding of distant metastases in adjacent structures visualized during the evaluation of the primary tumor and lymph nodes has, on occasion, detected M1b disease. FDG-PET represents an advance over CT scanning in the screening for distant metastases. The major problems with FDG-PET staging of esophageal cancer is failure to detect metastatic deposits less than 1 cm in diameter and lack of anatomic definition. It is unable to determine T and has been inaccurate in the detection of lymph node metastases. Because this test is not readily available, is expensive, and is not routinely reimbursed, its use in staging esophageal cancer continues to be limited. Today, CT and EUS are the mainstays in the clinical staging of esophageal carcinoma. When possible, FDG-PET should be added to CT to improve the evaluation of non-nodal M1b disease. Results of these studies should determine the necessity for invasive staging techniques and direct their use.
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PMID:Clinical staging of esophageal carcinoma. CT, EUS, and PET. 1096 51

The purpose of this study was to compare positron emission tomography using fluorine-18 fluorodeoxyglucose (FDG-PET) and technetium-99m methylene diphosphonate (MDP) bone scintigraphy in the detection of osseous metastases from malignant primary osseous tumours. In 70 patients with histologically proven malignant primary bone tumours (32 osteosarcomas, 38 Ewing's sarcomas), 118 FDG-PET examinations were evaluated. FDG-PET scans were analysed with regard to osseous metastases in comparison with bone scintigraphy. The reference methods for both imaging modalities were histopathological analysis, morphological imaging [additional conventional radiography, computed tomography (CT) or magnetic resonance imaging (MRI)] and/or clinical follow-up over 6-64 months (median 20 months). In 21 examinations (18%) reference methods revealed 54 osseous metastases (49 from Ewing's sarcomas, five from osteosarcomas). FDG-PET had a sensitivity of 0.90, a specificity of 0.96 and an accuracy of 0.95 on an examination-based analysis. Comparable values for bone scintigraphy were 0.71, 0.92 and 0.88. On a lesion-based analysis the sensitivity of FDG-PET and bone scintigraphy was 0.80 and 0.72, respectively. Analysing only Ewing's sarcoma patients, the sensitivity, specificity and accuracy of FDG-PET and bone scan were 1.00, 0.96 and 0.97 and 0.68, 0.87 and 0.82, respectively (examination-based analysis). None of the five osseous metastases from osteosarcoma were detected by FDG-PET, but all of them were true-positive using bone scintigraphy. In conclusion, the sensitivity, specificity and accuracy of FDG-PET in the detection of osseous metastases from Ewing's sarcomas are superior to those of bone scintigraphy. However, in the detection of osseous metastases from osteosarcoma, FDG-PET seems to be less sensitive than bone scintigraphy.
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PMID:FDG-PET for detection of osseous metastases from malignant primary bone tumours: comparison with bone scintigraphy. 1100 11

Liver metastasis is a common consequence of colorectal carcinoma. Early and accurate detection of liver metastasis is crucial for a decision about partial hepatectomy, which is considered a standard and potentially curative therapy in such a setting. The presence of extrahepatic metastases will exclude surgical resection as a therapeutic option. Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) has been successful in detecting and staging a variety of malignancies. The purpose of this study was to assess the utility of FDG-PET in the accurate detection of liver and distal metastases from colorectal cancer. The results of 80 PET and computed tomography (CT) scans were compared with surgical pathology and clinical outcome. FDG-PET detected liver metastases in 28 patients, with a sensitivity of 100%. CT detected metastasis in 20 patients, giving a sensitivity of 71.4%. In addition, in one patient with negative CT findings, PET detected a focus of hypermetabolism in the region adjacent to liver, which was proven to be a second focus of primary colon carcinoma. In six patients with liver metastases, PET correctly detected extrahepatic lesions, while CT only detected hepatic lesions. In conclusion, FDG-PET is an excellent imaging modality for the detection and staging of liver metastases in patients with colorectal carcinomas.
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PMID:The role of positron emission tomography with fluorine-18-deoxyglucose in identifying colorectal cancer metastases to liver. 1106 50

After a brief reminder concerning the PET technique and use of FDG, the author sets out to summarize the results of numerous PET centers in the world and in more detail, results of European units he visited. Leaving neurology and cardiology out, the most important works are dealing with tumoral pathology. The sensitivity of the technique is high for localizing tumoral tissue, evaluating lymphatic spread and detecting metastases. On the contrary, specificity is low as non tumoral lesions, especially inflammatory lesions, tuberculosis may pick up FDG though with less intensity. PET contributes to precise staging TNM of cancer, especially in case of pulmonary neoplasms. Results of clinical evaluation of bronchial carcinoma are presented. Other research programs show similar positive results for the staging of digestive tract neoplasm, primary or metastatic lymph node diseases, metastases from a quiescent, unknown primary tumor. The fact that the number of PET units is small explains the relatively poor dissemination of the method. It is rather obvious that the limitation of the number of PET units is due to economic reasons. Since 1990, many scientific evaluations of this technique conclude positively on PET's future. As it essentially is a functional method, the future developments of PET will largely depend on the discovery of new tracers.
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PMID:[Positron emission tomography in tumor pathology]. 1107 22

Neck lymph nodes (LNs) from 18 patients with nasopharyngeal carcinoma (NPC) were evaluated with 18-fluoro-2-deoxyglucose positron emission tomography (FDG-PET). Eighteen NPC patients underwent head and neck FDG-PET and computed tomography (CT) for detection of suspected neck LN metastases. For final diagnosis, biopsies were taken from neck LNs with discordant findings between FDG-PET and CT. Meanwhile, standard uptake values (SUVs) of the FDG-PET images were calculated to differentiate metastatic LNs from benign LNs. A total of 90 neck LNs found on either FDG-PET or CT were evaluated. In addition to 27 concordant positive results and 42 concordant negative LN results, biopsy findings revealed 11 metastatic LNs that were detected by FDG-PET but not by CT. However, the SUVs of the 11 metastatic LNs and 7 benign LNs were not significantly different. The CT scanning showed positive findings for I metastatic LN with negative FDG-PET findings. In addition, the tumor stage was upgraded in 5 patients on the basis of FDG-PET findings. In comparison with CT, FDG-PET has a higher potential for detecting neck LN metastases of NPC and assessing NPC tumor stage.
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PMID:Comparison of 18-fluoro-2-deoxyglucose positron emission tomography and computed tomography in detection of cervical lymph node metastases of nasopharyngeal carcinoma. 1113 Aug 25

A 77-year-old man with stage IIB squamous cell carcinoma of the lung underwent right upper lobectomy. One month later he was examined for right chest pain, dyspnea, cough, and weakness. A roentgenogram showed nondiagnostic diffuse opacification of his right lung cavity. An F-18 FDG positron emission tomographic (PET) study revealed extensive uptake in the right pleural area, left adrenal gland, right axilla, and soft tissues consistent with extensive local recurrence and metastatic disease. Biopsy of a right chest soft tissue lesion showed spindle cell carcinoma, a rare variant of squamous cell carcinoma.
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PMID:Extensive F-18 FDG uptake in metastatic spindle cell carcinoma of the lung. 1113 69

Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumors seen at the KFSH&RC between 1975 to 1998 only 3 patients had primary pituitary cancer. We have previously reported a case of pituitary fibrosarcoma arising as a rare complication of external radiotherapy (ERT) for GH-secreting pituitary adenoma (PA) [1]. We report now 2 cases of ACTH-producing primary pituitary carcinoma (ACTH-PPC); their follow-up data provide information on the natural history of this cancer. Patient #1; a 46 year old lady with Cushing's disease (CD) presented with an enlarged right cervical lymph node (LN) 2 years after having undergone a partial hypophysectomy through transsphenoidal surgery (PHYPX/TSS) and ERT for an invasive pituitary tumor. Patient #2; a 26 year old man presented with CD and underwent bilateral adrenalectomy (ADx) and pituitary ERT. Thirty-nine months later he developed Nelson's syndrome and a PHYPX/TSS was performed. Incidentally discovered hepatic metastases in this patient and an excisional biopsy of the LN in patient #1 showed histological features very similar to the pituitary tumor, and they stained strongly positive for ACTH. Perinuclear spherical hyalinized cytoplasmic inclusions were seen in the LN biopsy that corresponded to bundles of type 1 microfilaments (specific for pituitary ACTH-producing cells) seen by electron microscopy. A whole body 18-Fluoro-2-Deoxy-D-Glucose positron emission (FDG-PET) scanning, showed an intense uptake in the neck mass. A trial of octreotide did not change the exceedingly high levels of ACTH in patient #2, further supporting the diagnosis of ACTH-PPC. The clinical course of 102 months prior to his demise showed continued progression of the primary and the metastatic tumor. Patient #1, is alive at 15 months follow-up; hypercortisolemia is controlled using ketoconazole. ACTH-PPC should be entertained in a patient with CD presenting with persistent cervical lymphadenopathy. The clinical course in our patients suggests that the emergence of PC may involve a proliferative continuum from a pre-existing PA to an invasive tumor, culminating in a carcinoma. Adjunctive events such as ERT/ADx may predispose to the evolution of PC in genetically susceptible individuals. Because ERT is an effective treatment for PA its use will continue; it is important to be aware of the possible complication of primary pituitary carcinoma.
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PMID:ACTH-producing pituitary cancer: experience at the King Faisal Specialist Hospital & Research Centre. 1114 93


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