Plasmatic and Urinary 5-Hydroxyindolacetic Acid Measurements in Patients With Midgut Neuroendocrine Tumors: A GTE Study.

CONTEXT: Although 24-hour urinary 5-hydroxyindolacetic acid (24u5HIAA) is a key biomarker in midgut neuroendocrine tumors (NETs), it may be inaccurate and inconvenient. OBJECTIVE: We compared the diagnostic performances of 24u5HIAA, overnight urinary 5HIAA (Ou5HIAA), and plasmatic 5HIAA (p5HIAA) in midgut NETs. METHODS: This prospective, multicenter study included 80 patients with metastatic midgut NETs and 17 control patients with irritable bowel syndrome. 24u5HIAA, Ou5HIAA, and p5HIAA were measured in urine and plasma collected on 2 consecutive days following a specific recommended diet. Reproducibility of the biomarkers was evaluated by the Spearman test. Diagnostic performance was assessed by the area under the receiver operating characteristic curve (AUROC). Correlations with the main clinical features and declared observance to the specific diet were assessed using AUROC and logistic regression models. RESULTS: The reproducibility of 24u5HIAA, Ou5HIAA, and p5HIAA were excellent (ρ = 0.916; 0.897; 0.978, respectively, P < .001) with significant discrimination between patients and controls (AUROC = 0.795, P < .001; 0.757, P = .001; 0.717, P = .005, respectively). All 3 markers were correlated with the presence of carcinoid syndrome (AUROC = 0.702, P = .006; 0.701, P = .006; 0.697, P = .007, respectively), carcinoid heart disease (AUROC = 0.896; 0.887; 0.923, P < .001, respectively, P < .001), and liver metastatic involvement greater than 30% (AUROC = 0.827; 0.807; 0.849, P < .001, respectively, P < .001), independent from other traditional prognostic factors. Biomarker levels were similar between patients with optimal or suboptimal diet observance. CONCLUSION: Ou5HIAA and p5HIAA could be used as more convenient alternatives to 24u5HIAA in patients with metastatic midgut NETs. Prospective long-term studies with repeated dosages are needed.

[Determination of thresholds values for platelet serotonin and urinary 5-HIAA concentrations for the biological diagnosis of digestive neuroendocrine tumors]. / Quelles valeurs de référence pour la concentration de la sérotonine plaquettaire et du 5-HIAA urinaire pour le diagnostic des tumeurs neuroendocrines digestives ?

OBJECTIVES: Platelet serotonin and its urinary metabolite 5-HIAA (5-hydroxyindolacetic acid) are the main biomarkers measured for the detection of neuroendocrine tumors (NET). We observe in our laboratory many false positives or false negatives for the 2 assays using threshold values given by the manufacturer. We aim to determine our own local threshold values for a better detection of gastrointestinal NETs. METHODS: We studied patients with measurement of platelet serotonin and/or urinary 5-HIAA in University Hospital of Tours between January 2005 and June 2016. We established an « index ¼ cohort with 75% of patients to determine local threshold value for the 2 parameters. A "validation" cohort constituted with 25% of remaining patients allowed us to compare the performances of manufacturer's values with local threshold values. RESULTS: Two hundred ninety patients were included, with 19 suffering from NETs. Local threshold value for platelet serotonin was determined at 5.13 amol/platelet, the one for urinary 5-HIAA at 3.60 µmol/mmol urinary creatinine. Platelet serotonin specificity was better with local threshold value for identical sensibility (0.75). Urinary 5-HIAA sensibility was improved with local threshold value (1 vs 0.667) for identical specificity (0.902). CONCLUSION: Using our local threshold value for platelet serotonin and urinary 5-HIAA improved diagnostic performances of these biochemical markers to detect NETs.

Evaluation of 5-hydroxyindoloacetic acid excretion in urine in patients with small intestine neuroendocrine neoplasm and carcinoid syndrome treated with somatostatin analogues.

BACKGROUND: The assessment of hormonal function of neuroendocrine neoplasm (NEN) is an important stage in the diagnosis and monitoring of these diseases treatment. Objective of this study was to analyze the results of urinary excretion of 5-hydroxyindoloacetic acid (5-HIAA) in patients with carcinoid syndrome treated with somatostatin analogues, depending on the histologic maturity, degree of liver involvement and stage of the disease. METHODS: The final group comprised of 41 patients. All patients were subject to surgical removal of the primary site. Presence of hepatic metastases was determined in all patients. All patients were treated with somatostatin analogues. The 5-HIAA urine excretion was determined using the ELISA immunoenzymatic method. RESULTS: The mean excretion of 5-HIAA in patients with histological maturity grade G1 was 45.64 mg/24h, while in the group G2 the mean excretion was 108.41 mg/24h and was higher than in the group G1 (p=0.003). In the analysis of 5-HIAA value depending on the degree of liver involvement, the mean value of 5-HIAA excretion in patients with 10% liver involvement was 38.99 mg/24h, whereas in patients with 25% liver involvement this value was considerably higher and amounted 131.00 mg/24h (p< 0.001). In patients with disease progression the mean excretion was 117.37 mg/24h compared to the group of patients with stabilization of the disease, where the mean value was lower and amounted to 39.39 mg/24h (p<0.001). CONCLUSION: Assessment of 5-HIAA excretion in patients with carcinoid syndrome is of considerable significance in the diagnostics and monitoring of the treatment.

Effect of Lanreotide Depot/Autogel on Urinary 5-Hydroxyindoleacetic Acid and Plasma Chromogranin A Biomarkers in Nonfunctional Metastatic Enteropancreatic Neuroendocrine Tumors.

BACKGROUND: Urinary 5-hydroxyindoleacetic acid (5-HIAA) is an established biomarker in neuroendocrine tumors and carcinoid syndrome; however, its role in nonfunctional neuroendocrine tumors is not defined. We present post hoc data on urinary 5-HIAA and plasma chromogranin A (CgA) from the CLARINET study. METHODS: Patients with well- or moderately differentiated, nonfunctioning, locally advanced or metastatic enteropancreatic neuroendocrine tumors were randomized to deep subcutaneous lanreotide depot/autogel 120 mg or placebo once every 28 days for 96 weeks. Tumor response, evaluated centrally (RECIST 1.0), and progression-free survival (PFS) were assessed by treatment and biochemical response, defined as (a) baseline >upper limit of normal (ULN, 41.6 µmol per day 5-HIAA; 98.1 µg/L CgA) and (b) ≥50% decrease from baseline and to ≤ULN value on study. RESULTS: Forty-eight percent (82 of 171; lanreotide, n = 45; placebo, n = 37) and 66% (129 of 195; lanreotide, n = 65; placebo, n = 64) of randomized patients had 5-HIAA and CgA > ULN at baseline. Among patients with >ULN baseline values who did not progress after 96 weeks of treatment, significantly greater reductions in 5-HIAA and CgA were observed in lanreotide-treated versus placebo-treated patients throughout the study (all p < .05). PFS was significantly prolonged among 5-HIAA responders versus nonresponders (median not reached vs. 16.2 months, p < .0001; hazard ratio [HR] = 0.21, 95% confidence interval [CI], 0.09-0.48) and CgA responders versus nonresponders (median not reached vs. 16.2 months, p = .0070; HR = 0.30, 95% CI, 0.12-0.76), regardless of treatment arm. PFS was also significantly prolonged among lanreotide-treated 5-HIAA responders versus nonresponders (p = .0071) but was not significantly different among placebo-treated 5-HIAA responders versus nonresponders. There were no significant differences in PFS between lanreotide-treated CgA responders versus nonresponders or between placebo-treated CgA responders versus nonresponders. CONCLUSIONS: The 5-HIAA findings are noteworthy because they occurred in patients with nonfunctioning enteropancreatic neuroendocrine tumors. Monitoring 5-HIAA and CgA may be useful when treating patients with nonfunctional neuroendocrine tumors. IMPLICATIONS FOR PRACTICE: Current guidelines focus only on the monitoring of 5-hydroxyindoleacetic acid (5-HIAA) in the diagnosis and management of functional neuroendocrine tumors with carcinoid syndrome. The current post hoc analysis of patients with nonfunctional enteropancreatic neuroendocrine tumors in the CLARINET study demonstrated that measuring and following both 5-HIAA and chromogranin A as biomarkers of disease progression may be useful in the management of patients with nonfunctional neuroendocrine tumors.

Prognostic Utility of 24-Hour Urinary 5-HIAA Doubling Time in Patients With Neuroendocrine Tumors.

OBJECTIVE: New clinical prognostic tools are needed to select the population of patients with neuroendocrine tumors (NETs) that have a high risk of disease progression and disease-specific mortality (DSM). Biochemical biomarker doubling time (DT) is used clinically for prognosis prediction in several solid malignancies. The aim of the current study was to determine whether 24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA) level DT has any prognostic utility in patients with NETs. METHODS: Patients with NETs were enrolled in a prospective study with comprehensive biochemical analysis. The current analysis included 90 subjects with increasing 5-HIAA levels in two consecutive measurements. DT was calculated using the Schwartz equation. The primary outcome measures were DSM and disease progression. RESULTS: 5-HIAA DT of <434 days was associated with a higher rate of DSM ( P = .02), with positive and negative predictive values for DSM of 75 and 77%, respectively. The difference in DSM was accounted for mainly by patients with small intestine or unknown primary NET ( P = .01). In addition, a shorter 5-HIAA DT in patients with small intestine or unknown primary NET was associated with a higher risk of disease progression both in univariate ( P = .001) and multivariable analyses (hazard ratio, 15.8; 95% confidence interval, 1.3 to 198.0; P = .03). CONCLUSION: 5-HIAA DT may be used as a risk stratification tool in patients with small intestine NET or NET of unknown primary after it is validated in an independent cohort and can assist in identifying patients with a high risk for disease progression and DSM. ABBREVIATIONS: CT = computed tomography; DSM = disease-specific mortality; DT = doubling time; 5-HIAA = 5-hydroxyindoleacetic acid; MRI = magnetic resonance imaging; NET = neuroendocrine tumor; NETUP = neuroendocrine tumor of unknown primary; PET = positron emission tomography; PFS = progression-free survival; PNET = pancreatic neuroendocrine tumor; ROC = receiver operating characteristic; SINET = small-intestine neuroendocrine tumor.

Limited value for urinary 5-HIAA excretion as prognostic marker in gastrointestinal neuroendocrine tumours.

OBJECTIVE: To determine if urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion is of prognostic value for overall survival (OS) in patients with a gastrointestinal neuroendocrine tumour (NET) and to compare the prognostic value with patient characteristics, ENETS/WHO grading, ENETS TNM staging and biomarkers. DESIGN AND METHODS: Data was collected from patients with a gastrointestinal NET or a NET with gastrointestinal metastases and available 5-HIAA excretion in 24-h urine samples. Laboratory results were stratified for urinary 5-HIAA and chromogranin A (CgA): <2× upper limit of normal (ULN), 2-10× ULN, or >10× ULN. For neuron-specific enolase (NSE), this was the reference range or >1× ULN. OS was compared using Kaplan-Meier and log-rank tests, and hazard ratios were calculated using Cox regression for univariate and multivariate analyses. RESULTS: A total of 371 patients were included, 46.6% female with a mean age of 59.9 years. OS was shortest in patients with urinary 5-HIAA excretion >10× ULN vs reference range (median 83 months vs 141 months, P = 0.002). In univariate analysis, urinary 5-HIAA excretion >10× ULN was a negative predictor (HR 1.62, 95% CI: 1.09-2.39). However, in multivariate analysis, only age (HR 1.04, 95% CI: 1.01-1.08), grade 3 disease (HR 5.09, 95% CI: 2.20-11.79), NSE >1× ULN (HR 2.36, 95% CI: 1.34-4.14) and CgA >10× ULN (HR 3.61, 95% CI: 1.56-8.34) remained as the predictors. CONCLUSION: Urinary 5-HIAA excretion >10× ULN is a negative predictor for OS. However, when added to other biomarkers and grading, it is no longer a predictor for OS. Therefore, it should only be determined to assess carcinoid syndrome and not for prognostic value.

Urology pertinent neuroendocrine tumors: focusing on renal pelvis, bladder, prostate located sympathetic functional paragangliomas.

Urology pertinent neuroendocrine neoplasias are more and more driving to research attractive contributions mainly as regards the urinary tract paragangliomas, besides the prostate cancer neuroendocrine differentiation. About such visceral sympathetic paragangliomas, a considerable attention is aroused by those concerning the renal pelvis, urinary bladder and, particularly, the prostate gland. Essential catecholamine/adrenergic signal-mediated pathophysiological implications and outlined diagnostic approaches are here taken into consideration. Particularly, to reach an accurate functional diagnostic assessment, both plasma and urine catecholamine level tests are required together with ¹²³I or ¹³¹I-meta-iodobenzylguanidine (MIBG) scan while ¹³¹I-, instead of ¹²³I-, labeled MIBG, proving to be also useful to targeted radionuclide therapy of sympathetic paragangliomas. Nevertheless, a thorough diagnostic confirmation should be obtained by a proper histologic/ immunohistochemical study, so that it respectively highlighting the typical "zellballen" cell setting and neuroendocrine tumor cell specific biomarkers such as chromogranin-A, synaptophysin, neuron-specific enolase. Open/laparoscopic/robot-assisted surgical procedures are performed under α1 (doxazosin, prazosin) - and ß(propranolol)-adrenergic blockade to avoid the risk of an intraoperative adrenergic signal-triggered hypertensive crisis, what moreover may occur also during cystoscopy and biopsy in case of bladder or prostate paraganglioma. Given a conceivable likeness, about some adrenergic-mediated pathophysiological implications, between prostate paraganglioma and prostate cancer neuroendocrine transdifferentiation - although as regards two obviously different diseases - a reliable pathogenetic matter concerning prostate paraganglioma is requiring novel research approaches.

Metastatic small bowel neuroendocrine tumour with bilateral carcinoid heart disease.

A 63-year-old woman was admitted with a year's history of exertional breathlessness, anxiety attacks, syncopal episodes, diarrhoea, fatigue, reduced appetite, 2 stones weight loss, and flushing affecting her face and trunk. Investigations revealed raised urine 5-hydroxy indole acetic acid (5-HIAA) and chromogranin A. CT scan demonstrated extensive soft tissue encasing the major vessels intra-abdominally, and a retroperitoneal mass. (111)In-octreotide single-photon emission CT (SPECT CT) showed increased focal activity in the mediastinum, retroperitoneum and mesenteric lymph nodes. Para aortic lymph node biopsy confirmed the diagnosis of metastatic well-differentiated grade 1 gastrointestinal neuroendocrine tumour (NET). Extensive cardiac investigations confirmed severe mitral regurgitation, moderate aortic and tricuspid regurgitation, and mild pulmonary regurgitation. The patient's symptoms of flushing and diarrhoea were controlled with octreotide LAR, and she underwent mechanical aortic and mitral valve replacement. Following discharge from surgery, she went on to develop hydronephrosis and urosepsis, followed by infective endocarditis, resulting in recurrent admissions, and eventually passed away in her sleep nearly 14 months after her initial diagnosis.

Niacin (Vitamin B3) Supplementation in Patients with Serotonin-Producing Neuroendocrine Tumor.

BACKGROUND/AIMS: Tryptophan is the precursor of serotonin and niacin (vitamin B3). The latter is critical for normal cellular metabolism. Tryptophan and niacin can be deficient in patients with serotonin-producing neuroendocrine tumors (NETs). Niacin deficiency may lead to severe symptoms including pellagra. In patients with serotonin-producing NET, data on niacin status are scarce and niacin supplementation hardly receives attention. We aimed to assess the niacin status before and after supplementation in these patients. METHODS: We identified serotonin-producing NET patients who had received oral niacin supplementation (mean dose 144 mg daily) for tryptophan deficiency and/or pellagra-associated symptoms. Presupplementation plasma tryptophan levels and niacin status based on the urinary niacin metabolite N1-methylnicotinamide (N1-MN) before (n = 42) and after the start of the supplementation (in 34 paired samples) were assessed. Reference values for urinary N1-MN levels were established in 133 healthy individuals. RESULTS: The mean presupplementation plasma tryptophan level was 31.8 ± 9.7 µmol/l (reference value 40.0-70.0). Presupplementation urinary N1-MN levels were lower in patients (median 17.9 µmol/24 h, range 2.6-70.3) compared to healthy controls (median 43.7 µmol/24 h, range 9.5-169.3, p < 0.0001) and below normal in 45% of the patients. Niacin supplementation increased urinary N1-MN levels to high normal levels (median 55.5 µmol/24 h, range 7.4-489.0) in 86% of the niacin-deficient patients. CONCLUSION: In serotonin-producing NET patients, niacin deficiency is prevalent. Therefore, urinary N1-MN deserves to be included in their standard biochemical evaluation. Niacin supplementation normalizes the niacin status in most niacin-deficient serotonin-producing NET patients. A prospective study is warranted.

Histidine decarboxylase and urinary methylimidazoleacetic acid in gastric neuroendocrine cells and tumours.

AIM: To study histidine decarboxylase (HDC) expression in normal and neoplastic gastric neuroendocrine cells in relationship to the main histamine metabolite. METHODS: Control tissues from fundus (n = 3) and corpus (n = 3) mucosa of six patients undergoing operations for gastric adenocarcinoma, biopsy and/or gastric surgical specimens from 64 patients with primary gastric neuroendocrine tumours (GNETs), as well as metastases from 22 of these patients, were investigated using conventional immunohistochemistry and double immunofluorescence with commercial antibodies vs vesicular monoamine transporter 2 (VMAT-2), HDC and ghrelin. The urinary excretion of the main histamine metabolite methylimidazoleacetic acid (U-MeImAA) was determined using high-performance liquid chromatography in 27 of the 64 patients. RESULTS: In the gastric mucosa of the control tissues, co-localization studies identified neuroendocrine cells that showed immunoreactivity only to VMAT-2 and others with reactivity only to HDC. A third cell population co-expressed both antigens. There was no co-expression of HDC and ghrelin. Similar results were obtained in the foci of neuroendocrine cell hyperplasia associated with chronic atrophic gastritis type A and also in the tumours. The relative incidence of the three aforementioned markers varied in the tumours that were examined using conventional immunohistochemistry. All of these GNETs revealed both VMAT-2 and HDC immunoreactivity, and their metastases showed an immunohistochemical pattern and frequency similar to that of their primary tumours. In four patients, increased U-MeImAA excretion was detected, but only two of the patients exhibited related endocrine symptoms. CONCLUSION: Human enterochromaffin-like cells appear to partially co-express VMAT-2 and HDC. Co-expression of VMAT-2 and HDC might be required for increased histamine production in patients with GNETs.

Biochemical Testing in Patients with Neuroendocrine Tumors.

Neuroendocrine tumors are usually slow-growing tumors. Many of these are capable of secreting peptide hormones or biogenic amines that may lead to endocrine syndromes. Nonfunctioning tumors can either secrete no hormones at all, or secrete hormones not giving rise to endocrine symptoms, such as chromogranin A, chromogranin B or pancreatic polypeptide. Chromogranin A is produced by the majority of endocrine tumors, both functioning and nonfunctioning, and is the best available marker for diagnosis, follow-up and treatment monitoring of patients with differentiated neuroendocrine tumors. Examples of endocrine syndromes are classical carcinoid syndrome caused by serotonin (measured in the urine as its metabolite 5-HIAA), insulinoma syndrome caused by insulin or proinsulin, Zollinger-Ellison syndrome resulting from gastrin secretion, glucagonoma syndrome caused by glucagon, WDHA syndrome caused by vasoactive intestinal peptide, or Cushing's syndrome resulting from ectopic production of adrenocorticotropic hormone or corticotropin-releasing hormone. In case there is uncertainty about the diagnosis, specific tests can be applied, such as the secretin test for diagnosis of gastrinomas and the 72-hour fast for diagnosis of an insulinoma. In patients with suspicion of an inherited syndrome, such as multiple endocrine neoplasia (MEN) 1 and MEN2 syndromes, genetic testing is indicated.

Association of dose escalation of octreotide long-acting release on clinical symptoms and tumor markers and response among patients with neuroendocrine tumors.

Patients with nonresectable metastatic neuroendocrine tumors (NETs) experience symptoms of hormone hypersecretion including diarrhea, flushing, and bronchoconstriction, which can interfere with quality of life [Anthony and Vinik (2011) Pancreas, 40:987]. Treatment with a long-acting release formulation of octreotide, a somatostatin analog, can help to alleviate these symptoms. Although high doses of octreotide are often required for adequate symptom control, the relationship between octreotide dose escalation and symptom control in the NET context is not well quantified in the literature. A retrospective chart review was conducted of nonresectable metastatic NET patients who received a dose greater than 30 mg intramuscular octreotide long-acting formulation (O-LAR) at any time between January 2005 and December 2011 at the British Columbia Cancer Agency (BCCA). The association between dose escalation of O-LAR, chromogranin A (CGA), 24-h urine 5-hydoxyindoacetate (5-HIAA), symptom control, and radiological progression was explored. Dose escalation of O-LAR was associated with improved symptom control in NET patients who were refractory to the standard dose levels. Reduction of serum CGA & 5-HIAA levels by at least 10% was observed in 31% and 23% respectively. Retrospective review of imaging did not document any reductions in tumor volume. Higher doses of O-LAR are associated with improved symptom control in NET patients. The variability in tumor marker levels in response to O-LAR dose escalation may indicate that tumor marker levels may not be an accurate assessment of therapeutic efficacy.

Urinary Biomarkers of Brain Diseases.

Biomarkers are the measurable changes associated with a physiological or pathophysiological process. Unlike blood, urine is not subject to homeostatic mechanisms. Therefore, greater fluctuations could occur in urine than in blood, better reflecting the changes in human body. The roadmap of urine biomarker era was proposed. Although urine analysis has been attempted for clinical diagnosis, and urine has been monitored during the progression of many diseases, particularly urinary system diseases, whether urine can reflect brain disease status remains uncertain. As some biomarkers of brain diseases can be detected in the body fluids such as cerebrospinal fluid and blood, there is a possibility that urine also contain biomarkers of brain diseases. This review summarizes the clues of brain diseases reflected in the urine proteome and metabolome.

Urinary TIMP-1 and MMP-2 levels detect the presence of pancreatic malignancies.

BACKGROUND: A majority of patients with pancreatic malignancies, including both pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine tumours (pNETs), present with advanced disease due to a lack of specific symptoms and current diagnostic limitations, making this disease extremely difficult to detect. Our goal was to determine whether urinary matrix metalloproteases (uMMPs) and/or their endogenous inhibitors, urinary tissue inhibitor of metalloproteases (uTIMPs), could be detected in the urine of patients with pancreatic malignancies and whether they may serve as independent predictors of disease status. METHODS: Retrospective analyses of urine samples (n=139) from PDAC and pNET patients as well as age- and sex-matched controls were conducted. Urinary MMP-2 and uTIMP-1 levels were determined using ELISA and zymography. Biomarker expression in tumour and normal pancreatic tissues was analysed via immunohistochemistry (IHC). RESULTS: Multivariable logistic regression analyses indicated that, when controlling for age and sex, uMMP-2 (P<0.0001) and uTIMP-1 (P<0.0001) but not uMMP-9, were significant independent predictors for distinguishing between PDAC patients and healthy controls. Our data also indicated that uMMP-2 was an independent predictor of the presence of pNET. In addition, uTIMP-1 levels could differentiate the two cancer groups, PDAC and pNET, respectively. Immunohistochemistry analysis confirmed that MMP-2 and TIMP-1 protein expression is significantly upregulated in PDAC tissue compared with the normal pancreas. CONCLUSIONS: Taken together, our results suggest that the detection of uMMP-2 and uTIMP-1 may have diagnostic value in the detection of pancreatic malignancies and that uTIMP-1 may be useful in distinguishing between pancreatic adenocarcinoma and neuroendocrine tumours.

Radiation safety of outpatient 177Lu-octreotate radiopeptide therapy of neuroendocrine tumors.

PURPOSE: To demonstrate the safety of outpatient 7.8 GBq (177)Lu-DOTA-tyr(3)-octreotate radiopeptide therapy of neuroendocrine tumors by measurement of radiation exposures of hospital personnel, carers and members of the public. METHODS: Seventy-six patients with progressive, metastatic neuroendocrine tumors each received four cycles of prescribed activity of 7.8 GBq (177)Lu-octreotate at 8-week intervals, as an outpatient procedure. Cohorts comprising four patients were treated in one room, each patient remaining in hospital until radiation exposure from them was below the release limit of 25 µSv h(-1) at 1 m. On occasion, a single patient was treated in a single room. Radiation exposures of hospital staff and patient carers were monitored by personal dosimeter, and nearby areas monitored with a survey meter. RESULTS: Mean whole-body radiation exposures per therapy day ranged from 8 µSv (physicist) to 33 µSv (nurse), with exposures to personnel, carers and members of the public well within the limits recommended by the International Commission on Radiological Protection. Patients excreted a mean of 46 % of the total administered activity of (177)Lu-octreotate within 4 h of therapy. CONCLUSION: Lutetium-177-octreotate radiopeptide therapy of neuroendocrine tumors can be safely performed as an outpatient treatment.

Are serotonin metabolite levels related to bone mineral density in patients with neuroendocrine tumours?

BACKGROUND: Bone mineral density (BMD) is influenced by multiple factors. Recent studies have highlighted a possible relationship between serotonin and BMD. Patients with neuroendocrine tumours (NETs) frequently have elevated urinary 5-hydroxy-indoleacetic acid (5-HIAA) levels, a serotonin metabolite. Evaluation of the relationship between 5-HIAA and BMD in patients with NETs may provide insights into the relationship between serotonin and BMD. METHODS: One-year audit of consecutive patients with NETs within two institutions. Relationships between urinary 5-HIAA and dual X-ray absorptiometry (DEXA)-scan-measured BMD were investigated by group comparisons, correlation and regression. RESULTS: Of 65 patients with NETs, 19 did not participate or were excluded. Of 46 subjects evaluated (48·9% males, 63·8 ± 10·5 years, BMI 26·6 ± 4·4 kg/m(2) ) with 32 gastrointestinal, 9 pancreatic, 3 pulmonary and 2 ovarian NETs, 72·3% had the carcinoid syndrome. Median interval from diagnosis was 4·0 years (IQR 2·0-6·0); 41·3% had osteoporosis and 32·6% osteopaenia (WHO definition). The group with a higher urinary 5-HIAA had a lower hip BMD (total T-score and Z-score), confirmed on individual analysis (Spearman's rank correlation -0·41, P = 0·004; -0·44, P = 0·002, respectively); urinary 5-HIAA was not found to be an independent predictor for BMD on multiple linear regression analysis. CONCLUSION: These data of patients with NETs with higher serotonin metabolites having a lower BMD at the hip in group and individual comparisons, warrants further evaluation. Urinary 5-HIAA measurement alone cannot be used to predict future BMD. A larger cohort with prospective design including fractures as a clinical outcome will aid these data in determining whether patients with NETs should be subject to targeted osteoporosis prevention.

Chemometric evaluation of urinary steroid hormone levels as potential biomarkers of neuroendocrine tumors.

Neuroendocrine tumors (NETs) are uncommon tumors which can secrete specific hormone products such as peptides, biogenic amines and hormones. So far, the diagnosis of NETs has been difficult because most NET markers are not specific for a given tumor and none of the NET markers can be used to fulfil the criteria of high specificity and high sensitivity for the screening procedure. However, by combining the measurements of different NET markers, they become highly sensitive and specific diagnostic tests. The aim of the work was to identify whether urinary steroid hormones can be identified as potential new biomarkers of NETs, which could be used as prognostic and clinical course monitoring factors. Thus, a rapid and sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) with UV detection has been developed for the determination of cortisol, cortisone, corticosterone, testosterone, epitestosterone and progesterone in human urine. The method has been validated for accuracy, precision, selectivity, linearity, recovery and stability. The limits of detection and quantification were 0.5 and 1 ng mL-1 for each steroid hormone, respectively. Linearity was confirmed within a range of 1-300 ng mL-1 with a correlation coefficient greater than 0.9995 for all analytes. The described method was successfully applied for the quantification of six endogenous steroid levels in human urine. Studies were performed on 20 healthy volunteers and 19 patients with NETs. Next, for better understanding of tumor biology in NETs and for checking whether steroid hormones can be used as potential biomarkers of NETs, a chemometric analysis of urinary steroid hormone levels in both data sets was performed.

Circulating serotonin and bone density, structure, and turnover in carcinoid syndrome.

CONTEXT: Gut-derived serotonin has been proposed as a regulator of bone formation, and inhibition of gut serotonin synthesis increases bone formation in rodents. Carcinoid neuroendocrine tumors can produce very high levels of circulating serotonin and so offer a model of serotonin excess in humans. OBJECTIVES: The objective of the study was to determine whether patients with carcinoid syndrome have lower bone formation markers, lower bone density, or poor bone structure compared with healthy controls. DESIGN: We conducted a cross-sectional study of 25 patients with carcinoid syndrome and 25 healthy controls, individually matched to carcinoid patients by gender, age, height, and body mass index. OUTCOME MEASURES: We measured circulating serotonin in blood and plasma and 5-hydroxyindoleacetic acid (5HIAA) in plasma and urine. We measured lumbar spine and hip bone mineral density by dual-energy x-ray absorptiometry, the distal radius and tibia with high-resolution peripheral quantitative computed tomography, and bone turnover with serum osteocalcin, amino-terminal propeptide of type I procollagen (PINP) and C-terminal telopeptide of type I collagen (CTX). RESULTS: All measures of serotonin and 5HIAA were higher in carcinoid patients than in controls. No measures of bone density or bone structure differed significantly between cases and controls. Osteocalcin was higher in the cases than controls (26.0 vs 21.1 ng/mL, P = .02). PINP and CTX did not differ between cases and controls. In patients with carcinoid syndrome, plasma 5HIAA was positively correlated with osteocalcin. In controls, whole-blood serotonin was positively correlated with osteocalcin, PINP, and CTX (R values = 0.40-0.47, all P < .05.). CONCLUSIONS: High circulating serotonin in carcinoid syndrome is not associated with clinically significant lower bone density, poorer bone structure, or lower bone formation markers.

A reliable and simple method for the assay of neuroendocrine tumor markers in human urine by solid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry.

Homovanillic acid (HVA), vanylmandelic acid (VMA), and 5-hydroxyindoleacetic acid (5-HIAA) are the metabolites of some catecholamines such as epinephrine, nor-epinephrine, dopamine and serotonin and their quantification is used in the diagnosis and management of patients with neurocrine tumors. A novel approach in the assay of these biomarkers in human urine samples by solid phase microextraction (SPME) combined with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) is presented. A preliminary derivatization with ethyl chloroformate/ethanol was used and the corresponding derivatives were then extracted by SPME in immersion mode. The performance of five SPME fibers and three chloroformates were evaluated in univariate mode and the best results were obtained using the polyacrylate fiber and ethyl chloroformate. The variables affecting the efficiency of SPME analysis were optimized by the multivariate approach of "Experimental design" and, in particular, a central composite design (CCD) was applied. The optimum working conditions in terms of response values were achieved by performing analysis at room temperature with addition of NaCl (9.5%) and with an extraction time of 25.8 min. Identification and quantification of analytes were carried out by using a gas chromatography-triple quadrupole mass spectrometry (GC-QqQ MS) system in multiple reaction monitoring (MRM) acquisition. An evaluation of all analytical parameters shows that the proposed method provides satisfactory results. Very good linearities were, in fact, achieved in the tested calibration ranges with correlation coefficient values >0.99 for all the analytes and accuracies and RSDs calculated for between-run and tested at concentrations of 1, 10, and 80 mg L(-1) were ranging from 91.3% to 106.6%, and from 0.5 to 8.9%, respectively. Moreover, the LOD values obtained can be considered very satisfactory (1.3, 0.046 and 24.3 µg L(-1) for HVA, VMA and 5-HIAA, respectively). The developed protocol represents, therefore, a simple, rapid and selective tool for assaying these acidic biomarkers in urine samples for neuroendocrine cancer diagnosis.

A single fasting plasma 5-HIAA value correlates with 24-hour urinary 5-HIAA values and other biomarkers in midgut neuroendocrine tumors (NETs).

OBJECTIVES: 5-Hydroxyindoleacetic acid (5-HIAA) is used for the evaluation of neuroendocrine tumors (NETs) but currently requires a 24-hour urine collection. METHODS: We developed a gas chromatography mass spectroscopy-based plasma 5-HIAA assay. We compared 24-hour urine 5-HIAA values against plasma 5-HIAA values in 115 mixed-variety patients with NETs and in a subset of 72 patients with only small bowel NETs. We also compared the information gained from urinary and plasma 5-HIAA values with other biomarkers of midgut NET activity to determine the plasma assay's clinical implications. RESULTS: In a group of 115 patients with all types of NETS, in a subset of patients with midgut NET and in a subgroup of midgut NETS with liver metastasis, the correlation between the urine and fasting plasma 5-HIAA values were statistically significant (P ≤ 0.0001). Comparison of the proportion of normal or abnormal urinary and plasma 5-HIAA values to the proportion of chromogranin, serotonin, neurokinin, or pancreastatin values that were in the normal or abnormal range yielded essentially identical information. CONCLUSIONS: Plasma fasting 5-HIAA values are proportional to urinary 5-HIAA values and yielded identical clinical correlation with other biomarkers.