Somatostatin receptor imaging (SRI) with [(111)In-
DTPA(0)]
octreotide has proven its role in the diagnosis and staging of gastroenteropancreatic
neuroendocrine tumors (GEPNETs). Newer radiolabeled
somatostatin analogs which can be used in positron emission tomography (PET) imaging, and which have a higher affinity for the
somatostatin receptor, especially receptor subtype-2, have been developed. It would be desirable, however, if one radiolabeled analog became the new standard for PET imaging, because the current application of a multitude of analogs implies a fragmented knowledge on the interpretation of the images that are obtained in clinical practice. In our view, the most likely candidates for such a universal PET tracer for SRI are [(68)Ga-
DOTA(0),
Tyr(3)]octreotate or [(68)Ga-
DOTA(0),
Tyr(3)]octreotide. Treatment with radiolabeled
somatostatin analogs is a promising new tool in the management of patients with inoperable or metastasized
neuroendocrine tumors. Symptomatic improvement may occur with all (111)In-, (90)Y-, or (177)Lu-labeled
somatostatin analogs that have been used for
peptide receptor radionuclide therapy (PRRT). The results that were obtained with [(90)
Y-DOTA(0),
Tyr(3)]octreotide and [(177)Lu-
DOTA(0),
Tyr(3)]octreotate are very encouraging in terms of
tumor regression. Also, if kidney
protective agents are used, the side effects of this
therapy are few and mild, and the median duration of the
therapy response for these
radiopharmaceuticals is 30 and 40 months respectively. The patients' self-assessed quality of life increases significantly
after treatment with [(177)Lu-
DOTA(0),
Tyr(3)]octreotate. Lastly, compared to historical controls, there is a benefit in overall survival of several years from the time of diagnosis in patients treated with [(177)Lu-
DOTA(0),
Tyr(3)]octreotate. These data compare favorably with the limited number of alternative treatment approaches. If more widespread use of PRRT can be guaranteed, such
therapy may well become the
therapy of first choice in patients with metastasized or inoperable GEPNETs.