Impact of Fluorodihydroxyphenylalanine-(18F) Positron Emission Tomography on Management of Adult Patients with Documented or Occult Digestive Endocrine Tumors

Context and Objectives: Fluorodihydroxyphenylalanine-(18F)(FDOPA) positron emission tomography (PET) is a recent imaging modality used to localize endocrine tumors. This study was conducted to evaluate the impact of FDOPA-PET on the management of patients referred for carcinoid or noncarcinoid digestive tumors and the clinical relevance of the treatment decisions based on this examination. Methods and Patients: Between March 2002 and December 2006, 101 FDOPA-PET examinations were performed in 78 adult patients for follow-up of histologically documented carcinoid tumor of the ileum (23 patients) or noncarcinoid digestive tumor (26 patients) or to screen for occult digestive endocrine tumors (29 patients). More than one FDOPA-PET examination was performed in 12 patients. The impact of FDOPA PET was evaluated on a per-patient basis by means of a questionnaire completed by the referring physician, and the relevance of the treatment decision was assessed on the basis of follow-up data. Results: The survey response rate was 91% (71 of 78). The overall impact rate of FDOPA-PET on patient management was 25% (18 of 71). The greatest impact was observed for carcinoid tumors (50%: 11 of 22) and was clinically relevant in every case, followed by occult endocrine tumors (16%: four of 25), and was clinically relevant in three of the four cases, and noncarcinoid tumors (13%: 3 of 22), clinically relevant in only one case. Conclusion: FDOPA-PET appears to be a major tool for the management of carcinoid tumors with excellent diagnostic performances and induced relevant changes in patient management. FDOPA-PET was less sensitive and less useful for the management of noncarcinoid tumors. (J Clin Endocrinol Metab 94: 1295-1301, 2009)