Total F-dopa PET tumour uptake reflects metabolic endocrine tumour activity in patients with a carcinoid tumour.

Fiebrich, Helle-Brit; de Jong, Johan R.; Kema, Ido P.; Koopmans, Klaas Pieter; Sluiter, Wim; Dierckx, Rudi A. J. O.; Walenkamp, Annemiek M.; Links, Thera P.; Brouwers, Adrienne H.; de Vries, Elisabeth G. E.

Purpose: Positron emission tomography (PET) using 6-[F]fluoro- L-dihydroxyphenylalanine (F-dopa) has an excellent sensitivity to detect carcinoid tumour lesions. F-dopa tumour uptake and the levels of biochemical tumour markers are mediated by tumour endocrine metabolic activity. We evaluated whether total F-dopa tumour uptake on PET, defined as whole-body metabolic tumour burden (WBMTB), reflects tumour load per patient, as measured with tumour markers. Methods: Seventy-seven consecutive carcinoid patients who underwent an F-dopa PET scan in two previously published studies were analysed. For all tumour lesions mean standardised uptake values (SUVs) at 40% of the maximal SUV and tumour volume on 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 tumour markers. Results: All but 1 were evaluable for WBMTB; 74 patients had metastatic disease. F-dopa PET detected 979 lesions. SUV on 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. Conclusion: Tumour load per patient measured with F-dopa PET correlates with tumour markers of the serotonin and catecholamine pathway in urine and plasma in carcinoid patients, reflecting metabolic tumour activity.

POSITRON emission tomography; ENDOCRINE gland tumors; CARCINOID; DOPA; SEROTONIN

European Journal of Nuclear Medicine & Molecular Imaging, 2011, Vol 38, Issue 10, p1854

1619-7070

Academic Journal

10.1007/s00259-011-1862-5