Can fluorodihydroxyphenylalanine PET replace somatostatin receptor scintigraphy in patients with digestive endocrine tumors?
The aim of this study was to evaluate whether (18)F-fluorodihydroxyphenylalanine ((18)F-FDOPA) PET is accurate for the diagnosis and follow-up of any type of well-differentiated digestive endocrine tumor and to assess its performance compared with standard somatostatin receptor scintigraphy (SRS) using (111)In-pentetreotide.


METHODS
We reviewed the results of 33 evaluable (18)F-FDOPA PET and (111)In-pentetreotide SRS examinations performed between March 2002 and September 2005 in 30 patients referred for documented well-differentiated digestive endocrine tumor.


RESULTS
The sensitivity and accuracy of (18)F-FDOPA PET were significantly better for carcinoid tumors (defined according to the World Health Organization 2000 classification) (n = 19) than for noncarcinoid tumors (n = 14)-that is, 93% versus 25% for sensitivity (P < 0.01) and 89% versus 36% for accuracy (P < 0.01), respectively. In contrast, the performances of (111)In-pentetreotide SRS did not differ according to the carcinoid or noncarcinoid type of the primary endocrine tumor-that is, 81% versus 75% for sensitivity and 79% versus 71% for accuracy, respectively. In carcinoid tumors, comparison between (18)F-FDOPA PET and (111)In-pentetreotide SRS showed that (18)F-FDOPA PET more accurately evaluated the extent of disease than (111)In-pentetreotide SRS. (111)In-Pentetreotide SRS did not reveal any additional lesions in any case. Conversely, in noncarcinoid tumors, the extent of the disease was more accurately evaluated in all cases by (111)In-pentetreotide SRS than by (18)F-FDOPA PET.


CONCLUSIONS
This preliminary study emphasizes the importance of a precise histologic characterization of well-differentiated digestive endocrine tumor to select the best radiopharmaceutical. (18)F-FDOPA PET appears to be useful in carcinoid tumors and could become the first-line scintigraphic imaging modality for these tumors, but (111)In-pentetreotide SRS appeared to be a better first-line scintigraphic imaging modality for noncarcinoid digestive tumors.
Montravers
Françoise
F
Médecine Nucléaire, Hôpital Tenon AP-HP and Université Pierre et Marie Curie, Paris6, Paris, France. francoise.montravers@tnn.aphp.fr
Grahek
Dany
D
Kerrou
Khaldoun
K
Ruszniewski
Philippe
P
de Beco
Virginie
V
Aide
Nicolas
N
Gutman
Fabrice
F
Grangé
Jean-Didier
JD
Lotz
Jean-Pierre
JP
Talbot
Jean-Noël
JN
D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging* / Q000378:metabolism; D004067:Digestive System Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004701:Endocrine Gland Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017481:Receptors, Somatostatin / Q000378:metabolism; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; C043437:fluorodopa F 18; D013004:Somatostatin; D004295:Dihydroxyphenylalanine; C081788:pentetreotide