Total ^sup 18^F-dopa PET tumor uptake reflects metabolic endocrine tumor activity in patients with a carcinoid tumor

• Published in: European journal of nuclear medicine and molecular imaging Vol. 38; no. 10; p. 1854
• Main Authors: Fiebrich, Helle-brit, de Jong, Johan R, Kema, Ido P, Koopmans, Klaas Pieter, Sluiter, Wim, Dierckx, Rudi Ajo, Walenkamp, Annemiek M, Links, Thera P, Brouwers, Adrienne H, de Vries, Elisabeth Ge
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01.10.2011
• Subjects: Biomarkers; Endocrine system; Nervous system; Tomography; Tumors
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-011-1862-5

Positron emission tomography (PET) using 6-[^sup 18^F]fluoro-L-dihydroxyphenylalanine (^sup 18^F-dopa) has an excellent sensitivity to detect carcinoid tumor lesions. ^sup 18^F-dopa tumor uptake and the levels of biochemical tumor markers are mediated by tumor endocrine metabolic activity. We evaluated whether total ^sup 18^F-dopa tumor uptake on PET, defined as whole-body metabolic tumor burden (WBMTB), reflects tumor load per patient, as measured with tumor markers. Seventy-seven consecutive carcinoid patients who underwent an ^sup 18^F-dopa PET scan in two previously published studies were analyzed. For all tumor lesions mean standardized uptake values (SUVs) at 40% of the maximal SUV and tumor volume on ^sup 18^F-dopa PET were determined and multiplied to calculate a metabolic burden per lesion. WBMTB was the sum of the metabolic burden of all individual lesions per patient. The 24-h urinary serotonin, urine and plasma 5-hydroxindoleacetic acid (5-HIAA), catecholamines (nor)epinephrine, dopamine and their metabolites, measured in urine and plasma, and serum chromogranin A served as tumor markers. All but 1 were evaluable for WBMTB; 74 patients had metastatic disease. ^sup 18^F-dopa PET detected 979 lesions. SUV^sub max^ on ^sup 18^F-dopa PET varied up to 29-fold between individual lesions within the same patients. WBMTB correlated with urinary serotonin (r=0.51) and urinary and plasma 5-HIAA (r=0.78 and 0.66). WBMTB also correlated with urinary norepinephrine, epinephrine, dopamine and plasma dopamine, but not with serum chromogranin A. tumor load per patient measured with ^sup 18^F-dopa PET correlates with tumor markers of the serotonin and catecholamine pathway in urine and plasma in carcinoid patients, reflecting metabolic tumor activity.[PUBLICATION ABSTRACT]