Discriminating capacity of indole markers in the diagnosis of carcinoid tumors

Citation
Wg. Meijer et al., Discriminating capacity of indole markers in the diagnosis of carcinoid tumors, CLIN CHEM, 46(10), 2000, pp. 1588-1596
Citations number
41
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
CLINICAL CHEMISTRY
ISSN journal
00099147 → ACNP
Volume
46
Issue
10
Year of publication
2000
Pages
1588 - 1596
Database
ISI
SICI code
0009-9147(200010)46:10<1588:DCOIMI>2.0.ZU;2-K
Abstract
Background: We evaluated the discriminating capacity of the indole markers urinary 5-hydroxyindoleacetic acid (5-HIAA), urinary serotonin, and platele t serotonin in the diagnosis of carcinoid tumors. Methods: Indole markers were measured in 688 patients with suspect-ed carci noid disease. The initial values of indole markers from patients in whom. a carcinoid tumor was confirmed during follow-up (n = 98) were used for ROC analysis. Two groups served as reference populations. The first consisted o f 45 healthy individuals ("healthy controls"). The second was a random samp le of 40 patients, drawn from the 590 (688 minus 98) patients with carcinoi d-like symptoms but without a carcinoid tumor ("clinically suspected patien ts"). Results: ROC curve analysis showed platelet-serotonin to have the highest d iscriminating capacity, especially in foregut carcinoids. Cutoff values for platelet serotonin obtained from ROC analysis. with healthy controls as re ference group (5.4 nmol/10(9) platelets) gave a sensitivity of 74%, specifi city of 91%, positive predictive value of 63%, and negative predictive valu e of 95% when applied to the initial 688 patients. Using the cutoff value w ith the clinically suspected patients as the reference group (9.3 nmol/10(9 ) platelets) gave a sensitivity of 63%, specificity of 99%, positive predic tive value of 89%, and negative predictive value of 93%. Indole markers wer e increased in 169 (25%) of 688 patients. In 76 (45%) of these 169 patients , a carcinoid tumor was present. Slight increases of markers were associate d with non-carcinoid neuroendocrine tumors, non-neuroendocrine tumors, and disturbed bowel motility. Conclusions: ROC curve analysis shows that platelet serotonin is the most d iscriminating indole marker for the diagnosis of carcinoid tumors. Platelet serotonin especially improves the diagnosis of carcinoids producing small amounts of serotonin. (C) 2000 American Association for Clinical Chemistry.