Iodine-123 metaiodobenzylguanidine scintigraphy in localising phaeochromocytomas - Experience and meta-analysis

BACKGROUND: Recommendations on the use of I-123 metaiodobenzylguanidine (MIBG) scintigraphy in localising phaeochromocytomas vary. The accuracy of I-123 MIBG scintigraphy was determined by evaluating our own I-123 MIBG scans and performing a meta-analysis. MATERIALS AND METHODS: Between January 1992 and May 2002, the I-123 MIBG scans of consecutive patients suspected of a phaeochromocytoma were re-evaluated. For the meta-analysis, studies with more than 5 I-123 MIBG scans were selected. RESULTS: Thirty patients were evaluated. The sensitivity in our own population was 92% and the specificity was 100%. Twelve articles were selected for our meta-analysis. The overall sensitivity and specificity were 96% and 100%, respectively. The sensitivity and specificity for tumours in the adrenal gland was 98% for both. For tumours located outside the adrenal gland, the sensitivity was 98% and the sensitivity for malignancies was 79%. CONCLUSION: 1-123 MIBG scintigraphy has an excellent sensitivity and specificity in localising phaeochromocytomas, except for malignant tumours. 1-123 MIBG scintigraphy is superior in localising tumours outside the adrenal gland

Clinical Relevance of F-18-FDG PET and F-18-DOPA PET in Recurrent Medullary Thyroid Carcinoma

The transition from stable to progressive disease is unpredictable in patients with biochemical evidence of medullary thyroid carcinoma (MTC). Calcitonin and carcinoembryonic antigen (CEA) doubling times are currently the most reliable markers for progression, but for accurate determination, serial measurements, which need time, are required. We compared F-18-FDG PET and F-18-dihydroxyphenylanaline (F-18-DOPA) PET with biochemical parameters and survival to assess whether these imaging modalities could be of value in detecting progressive disease. Methods: We evaluated the outcome of F-18-FDG PET or F-18-DOPA PET with calcitonin and CEA doubling times in 47 MTC patients. A subgroup of patients was included in the whole metabolic burden (WBMTB) analysis, with determination of standardized uptake values and number of lesions. WBMTB of F-18-DOPA PET and F-18-FDG PET was compared with biochemical parameters. Furthermore, survival was compared with F-18-DOPA PET or F-18-FDG PET positivity. Results: Doubling times were available for 38 of 40 patients undergoing F-18-FDG PET. There was a significant correlation with F-18-FDG PET positivity. Doubling times were less than 24 mo in 77% (n = 10/13) of F-18-FDG PET-positive patients, whereas 88% (n = 22/25) of F-18-FDG PET-negative patients had doubling times greater than 24 mo (P < 0.001). Between doubling times and F-18-DOPA PET positivity, no significant correlation existed. F-18-DOPA PET detected significantly more lesions (75%, 56/75) than did F-18-FDG PET (47%, 35/75) in the 21 patients included in WBMTB analysis (P = 0.009). Calcitonin and CEA levels correlated significantly with WBMTB on F-18-DOPA PET, but doubling times did not. F-18-FDG PET positivity was a more important indicator for poor survival in patients for whom both scans were obtained. Conclusion: F-18-FDG PET is superior in detecting patients with biochemical progressive disease and identifying patients with poor survival. Although F-18-DOPA PET has less prognostic value, it can more accurately assess the extent of the disease in patients with residual MTC. Hence, both scans are informative about tumor localization and behavior. On the basis of these results, we designed a clinical flow diagram for general practice in detecting recurrent MTC

Catecholamine-Synthesizing Enzymes Are Expressed in Parasympathetic Head and Neck Paraganglioma Tissue

Background/Aim: Increased dopamine production may be a feature of head and neck paraganglioma (HNPGL). F-18-fluorodihydroxyphenylalanine positron emission tomography scintigraphy has a high sensitivity for detecting HNPGLs. These observations strongly suggest that HNPGLs have the capacity for L-3,4-dihydroxyphenylalanine uptake and conversion towards dopamine. Therefore, our aim was to demonstrate the presence of catecholamine-synthesizing enzymes, i.e. tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC) and dopamine beta-hydroxylase (DBH) in HNPGL tissue. Methods: A single-center study was performed among patients who underwent surgery for HNPGL at a single university referral center between 1994 and 2012. HNPGL tissue was immunohistochemically stained for TH, AADC and DBH. Data on paraganglioma-associated germline mutations, preoperative biochemical phenotype and imaging studies were retrieved. Catecholamine excess was defined as preoperative plasma and/or urinary levels of metanephrine, normetanephrine or 3-methoxytyramine above the upper reference limit. Results: Nineteen HNPGLs from 18 patients were evaluated. All tumor tissues (100%) stained positive for AADC, 6 (32%) for TH and 2 (11%) for DBH. Of 3 HNPGLs staining positive for DBH, 2 were also positive for AADC and TH. Catecholamine excess was only present in 1 patient (5%). The HNPGLs of this single patient only showed positive staining for AADC. Conclusions: Catecholamine-synthesizing enzymes, in particular AADC, are expressed in the majority of HNPGL tissues. (C) 2015 S. Karger AG, Base

Sexual Function in Patients with Metastatic Midgut Carcinoid Tumours

Background: Sexual dysfunction is a poorly studied aspect of quality of life in patients with midgut carcinoid tumours. We investigated whether carcinoid patients experience sexual problems. Methods: Patients with metastatic midgut carcinoid tumours filled in a validated questionnaire for sexual dysfunction. The prevalence of dysfunction on the subscales arousal, erection, lubrication, orgasm and dyspareunia was compared to a Dutch reference population. Plasma concentration of gonadal hormones, tryptophan and urinary 5-hydroxyindolacetic acid concentrations were measured. Results: 43 patients were studied, 27 men and 16 women. Sexual dysfunction was present in 29.6% of men and 6.3% of women. The prevalence of sexual dysfunction on the different subscales did not differ from the reference population. Patients with a sexual dysfunction had, compared to those without a sexual dysfunction, a longer duration of disease, 95.3 months (range 5.4-314.5) versus 18.6 months (range 0.6-167.9) (p = 0.024), lower plasma tryptophan concentration (+/- SD) of 31.5 +/- 16.1 and 48.9 +/- 14.5 mu mol/l (p = 0.031), and more often used interferon-alpha, 50% of patients versus 10.5% of patients (p = 0.044). Conclusion: Patients with metastatic midgut carcinoid tumours do not experience sexual problems more often than a reference population. Male patients with sexual dysfunction are characterised by more long-standing disease and lower tryptophan concentration. Copyright (c) 2008 S. Karger AG, Base