title: Staging of carcinoid tumours with 18F-DOPA PET: a prospective, diagnostic accuracy study.
abstract: BACKGROUND
  To assess individual treatment options for patients with carcinoid tumours, accurate knowledge of tumour localisation is essential. We aimed to test the diagnostic sensitivity of 6-[fluoride-18]fluoro-levodopa ((18)F-DOPA PET), compared with conventional imaging methods, in patients with carcinoid tumours.
  
  
  METHODS
  In a prospective, single-centre, diagnostic accuracy study, (18)F-DOPA PET with carbidopa pretreatment was compared with somatostatin-receptor scintigraphy (SRS), CT, and combined SRS and CT in 53 patients with a metastatic carcinoid tumour. The performance of all imaging methods was analysed for individual patients, for eight body regions, and for the detection of individual lesions. PET and CT images were fused to improve localisation. To produce a composite reference standard, we used cytological and histological findings; all imaging tests, including secondary assessments for newly found lesions; follow-up; and biochemical data. Sensitivities were calculated and compared.
  
  
  RESULTS
  In patient-based analysis, we recorded sensitivities of 100% (95% CI 93-100) for (18)F-DOPA-PET, 92% (82-98) for SRS, 87% (75-95) for CT, and 96% (87-100) for combined SRS and CT (p=0.45 for (18)F-DOPA PET vs combined SRS and CT). However, (18)F-DOPA PET detected more lesions, more positive regions, and more lesions per region than combined SRS and CT. In region-based analysis, sensitivity of (18)F-DOPA PET was 95% (90-98) versus 66% (57-74) for SRS, 57% (48-66) for CT, and 79% (70-86) for combined SRS and CT (p=0.0001, PET vs combined SRS and CT). In individual-lesion analysis, corresponding sensitivities were 96% (95-98), 46% (43-50), 54% (51-58), and 65% (62-69; p<0.0001 for PET vs combined SRS and CT).
  
  
  CONCLUSIONS
  If the improved tumour localisation seen with (18)F-DOPA-PET compared with conventional imaging is confirmed in future studies, this imaging method could replace use of SRS, help improve prediction of prognosis, and be used to assess patients' response to treatment for carcinoid tumours.
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, Groningen, Netherlands.
authors.forename: Klaas P
authors.initials: KP
authors.lastname: Koopmans
authors.forename: Elisabeth G E
authors.initials: EG
authors.lastname: de Vries
authors.forename: Ido P
authors.initials: IP
authors.lastname: Kema
authors.forename: Philip H
authors.initials: PH
authors.lastname: Elsinga
authors.forename: Oliver C
authors.initials: OC
authors.lastname: Neels
authors.forename: Wim J
authors.initials: WJ
authors.lastname: Sluiter
authors.forename: Anouk N A
authors.initials: AN
authors.lastname: van der Horst-Schrivers
authors.forename: Pieter L
authors.initials: PL
authors.lastname: Jager
mesh_terms: D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin / Q000378:metabolism; D015203:Reproducibility of Results; D013004:Somatostatin / Q000031:analogs & derivatives; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; D019788:Fluorodeoxyglucose F18; C043437:fluorodopa F 18; D013004:Somatostatin; D004295:Dihydroxyphenylalanine