Somatostatin receptor scintigraphy in the follow-up of patients with differentiated thyroid cancer.
The aim of this study was to compare the results of somatostatin receptor scintigraphy (SRS) and of radioiodine scintigraphy in patients with metastatic differentiated thyroid carcinoma during L-thyroxine suppression therapy and after withdrawal. Twenty-five patients were studied: 16 patients had papillary cancer and 12 of them had metastatic disease; 9 patients had follicular cancer and 7 of these had known metastases. In 7 patients SRS was performed during thyroxine withdrawal, in 12 during thyroxine therapy within 9 months from radioiodine scintigraphy, in 6 others both during suppression therapy and after withdrawal. SRS was positive in 18 of 25 (72%) patients. It demonstrated lesions in 11 of 13 (85%) patients after thyroxine withdrawal and in 12 of 18 (67%) patients during thyroxine suppression. In 6 patients in whom a direct comparison was made before and after withdrawal, essentially the same information was obtained. Six of 8 (75%) patients with lesions that did not concentrate radioiodine showed uptake of labeled octreotide in these lesions. In 5 of 17 (29%) patients whose tumors concentrated radioiodine, no uptake was found during SRS.


CONCLUSIONS
1) in patients with metastatic differentiated thyroid carcinoma, tumor sites can be visualized using SRS; 2) there is no need to withdraw patients from suppression therapy in order to perform SRS; 3) in some patients whose lesions do concentrate labeled octreotide but not radioiodine, the use of somatostatin analogues labeled with (111)In or [90Y] can provide new therapeutic options.
Haslinghuis
L M
LM
Department of Nuclear Medicine, University Hospital Rotterdam, The Netherlands.
Krenning
E P
EP
De Herder
W W
WW
Reijs
A E
AE
Kwekkeboom
D J
DJ
D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000032:analysis*; D013954:Thyroglobulin / Q000097:blood; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage / Q000627:therapeutic use
D007457:Iodine Radioisotopes; D017481:Receptors, Somatostatin; D013972:Thyrotropin; D013954:Thyroglobulin; D013974:Thyroxine